add spack.util.url.git_url_parse() method and tests

Add a method to parse git URLs (but not arbitrary file paths). This method parses git URLs into scheme, username, hostname, port, and path. It will raise an error if its argument is not proper git URL. - [x] add `spack.util.url.git_url_parse` method - [x] add 31 tests for `git_url_parse`
2021-09-13 21:46:52 -07:00
8256 changed files with 188064 additions and 320245 deletions
--- a/.flake8
+++ b/.flake8
@@ -1,25 +1,43 @@
 # -*- conf -*-
-# flake8 settings for Spack.
+# flake8 settings for Spack core files.
 #
 # These exceptions are for Spack core files. We're slightly more lenient
 # with packages.  See .flake8_packages for that.
 #
-# This is the only flake8 rule Spack violates somewhat flagrantly
+# E1: Indentation
+# - E129: visually indented line with same indent as next logical line
+#
+# E2: Whitespace
+# - E221: multiple spaces before operator
+# - E241: multiple spaces after ','
+# - E272: multiple spaces before keyword
+#
+# E7: Statement
 # - E731: do not assign a lambda expression, use a def
 #
-# This is the only flake8 exception needed when using Black.
-# - E203: white space around slice operators can be required, ignore : warn
+# W5: Line break warning
+# - W503: line break before binary operator
+# - W504: line break after binary operator
 #
-# We still allow these in packages (Would like to get rid of them or rely on mypy
-# in the future)
-# - F403: from/import * used; unable to detect undefined names
+# These are required to get the package.py files to test clean:
+# - F999: syntax error in doctest
+#
+# N8: PEP8-naming
+# - N801: class names should use CapWords convention
+# - N813: camelcase imported as lowercase
+# - N814: camelcase imported as constant
+#
+# F4: pyflakes import checks, these are now checked by mypy more precisely
+# - F403: from module import *
 # - F405: undefined name or from *
-# - F821: undefined name (needed with from/import *)
+#
+# Black ignores, these are incompatible with black style and do not follow PEP-8
+# - E203: white space around slice operators can be required, ignore : warn
+# - W503: see above, already ignored for line-breaks
 #
 [flake8]
-#ignore = E129,,W503,W504,F999,N801,N813,N814,F403,F405,E203
-extend-ignore = E731,E203
-max-line-length = 99
+ignore = E129,E221,E241,E272,E731,W503,W504,F999,N801,N813,N814,F403,F405
+max-line-length = 88

 # F4: Import
 # - F405: `name` may be undefined, or undefined from star imports: `module`
@@ -28,7 +46,7 @@ max-line-length = 99
 # - F821: undefined name `name`
 #
 per-file-ignores =
-  var/spack/repos/*/package.py:F403,F405,F821
+  var/spack/repos/*/package.py:F405,F821

 # exclude things we usually do not want linting for.
 # These still get linted when passed explicitly, as when spack flake8 passes
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -1,3 +0,0 @@
-# .git-blame-ignore-revs
-# Formatted entire codebase with black
-f52f6e99dbf1131886a80112b8c79dfc414afb7c
--- a/.github/ISSUE_TEMPLATE/build_error.yml
+++ b/.github/ISSUE_TEMPLATE/build_error.yml
@@ -16,29 +16,19 @@ body:
    attributes:
      label: Steps to reproduce the issue
      description: |
-        Fill in the console output from the exact spec you are trying to build.
-      value: |
+        Fill in the exact spec you are trying to build and the relevant part of the error message
+      placeholder: |
        ```console
-        $ spack spec -I <spec>
+        $ spack install <spec>
        ...
        ```
-  - type: textarea
-    id: error
-    attributes:
-      label: Error message
-      description: |
-        Please post the error message from spack inside the `<details>` tag below:
-      value: |
-        <details><summary>Error message</summary><pre>
-        ...
-        </pre></details>
    validations:
      required: true
  - type: textarea
    id: information
    attributes:
      label: Information on your system
-      description: Please include the output of `spack debug report`.
+      description: Please include the output of `spack debug report`
    validations:
      required: true
  - type: markdown
--- a/.github/workflows/bootstrap.yml
+++ b/.github/workflows/bootstrap.yml
@@ -1,8 +1,6 @@
 name: Bootstrapping

 on:
-  # This Workflow can be triggered manually
-  workflow_dispatch:
  pull_request:
    branches:
      - develop
@@ -12,7 +10,6 @@ on:
      # built-in repository or documentation
      - 'var/spack/repos/builtin/**'
      - '!var/spack/repos/builtin/packages/clingo-bootstrap/**'
-      - '!var/spack/repos/builtin/packages/clingo/**'
      - '!var/spack/repos/builtin/packages/python/**'
      - '!var/spack/repos/builtin/packages/re2c/**'
      - 'lib/spack/docs/**'
@@ -20,16 +17,11 @@ on:
    # nightly at 2:16 AM
    - cron: '16 2 * * *'

-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
-  cancel-in-progress: true
-
 jobs:

-  fedora-clingo-sources:
+  fedora-sources:
    runs-on: ubuntu-latest
    container: "fedora:latest"
-    if: github.repository == 'spack/spack'
    steps:
      - name: Install dependencies
        run: |
@@ -37,33 +29,26 @@ jobs:
              bzip2 curl file gcc-c++ gcc gcc-gfortran git gnupg2 gzip \
              make patch unzip which xz python3 python3-devel tree \
              cmake bison bison-devel libstdc++-static
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Setup non-root user
-        run: |
-          # See [1] below
-          git config --global --add safe.directory /__w/spack/spack
-          useradd spack-test && mkdir -p ~spack-test
-          chown -R spack-test . ~spack-test
-      - name: Setup repo
-        shell: runuser -u spack-test -- bash {0}
+      - uses: actions/checkout@v2
+      - name: Setup repo and non-root user
        run: |
          git --version
          git fetch --unshallow
          . .github/workflows/setup_git.sh
+          useradd spack-test
+          chown -R spack-test .
      - name: Bootstrap clingo
        shell: runuser -u spack-test -- bash {0}
        run: |
          source share/spack/setup-env.sh
-          spack bootstrap untrust github-actions-v0.2
+          spack bootstrap untrust github-actions
          spack external find cmake bison
          spack -d solve zlib
          tree ~/.spack/bootstrap/store/

-  ubuntu-clingo-sources:
+  ubuntu-sources:
    runs-on: ubuntu-latest
    container: "ubuntu:latest"
-    if: github.repository == 'spack/spack'
    steps:
      - name: Install dependencies
        env:
@@ -74,125 +59,75 @@ jobs:
              bzip2 curl file g++ gcc gfortran git gnupg2 gzip \
              make patch unzip xz-utils python3 python3-dev tree \
              cmake bison
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Setup non-root user
-        run: |
-          # See [1] below
-          git config --global --add safe.directory /__w/spack/spack
-          useradd spack-test && mkdir -p ~spack-test
-          chown -R spack-test . ~spack-test
-      - name: Setup repo
-        shell: runuser -u spack-test -- bash {0}
+      - uses: actions/checkout@v2
+      - name: Setup repo and non-root user
        run: |
          git --version
          git fetch --unshallow
          . .github/workflows/setup_git.sh
+          useradd -m spack-test
+          chown -R spack-test .
      - name: Bootstrap clingo
        shell: runuser -u spack-test -- bash {0}
        run: |
          source share/spack/setup-env.sh
-          spack bootstrap untrust github-actions-v0.2
+          spack bootstrap untrust github-actions
          spack external find cmake bison
          spack -d solve zlib
          tree ~/.spack/bootstrap/store/

-  ubuntu-clingo-binaries-and-patchelf:
+  opensuse-sources:
    runs-on: ubuntu-latest
-    container: "ubuntu:latest"
-    if: github.repository == 'spack/spack'
-    steps:
-      - name: Install dependencies
-        env:
-          DEBIAN_FRONTEND: noninteractive
-        run: |
-          apt-get update -y && apt-get upgrade -y
-          apt-get install -y \
-              bzip2 curl file g++ gcc gfortran git gnupg2 gzip \
-              make patch unzip xz-utils python3 python3-dev tree
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Setup non-root user
-        run: |
-          # See [1] below
-          git config --global --add safe.directory /__w/spack/spack
-          useradd spack-test && mkdir -p ~spack-test
-          chown -R spack-test . ~spack-test
-      - name: Setup repo
-        shell: runuser -u spack-test -- bash {0}
-        run: |
-          git --version
-          git fetch --unshallow
-          . .github/workflows/setup_git.sh
-      - name: Bootstrap clingo
-        shell: runuser -u spack-test -- bash {0}
-        run: |
-          source share/spack/setup-env.sh
-          spack -d solve zlib
-          tree ~/.spack/bootstrap/store/
-
-  opensuse-clingo-sources:
-    runs-on: ubuntu-latest
-    container: "opensuse/leap:latest"
-    if: github.repository == 'spack/spack'
+    container: "opensuse/tumbleweed:latest"
    steps:
      - name: Install dependencies
        run: |
-          # Harden CI by applying the workaround described here: https://www.suse.com/support/kb/doc/?id=000019505
-          zypper update -y || zypper update -y
+          zypper update -y
          zypper install -y \
              bzip2 curl file gcc-c++ gcc gcc-fortran tar git gpg2 gzip \
              make patch unzip which xz python3 python3-devel tree \
              cmake bison
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Setup repo
+      - uses: actions/checkout@v2
+      - name: Setup repo and non-root user
        run: |
-          # See [1] below
-          git config --global --add safe.directory /__w/spack/spack
          git --version
          git fetch --unshallow
          . .github/workflows/setup_git.sh
      - name: Bootstrap clingo
        run: |
          source share/spack/setup-env.sh
-          spack bootstrap untrust github-actions-v0.2
+          spack bootstrap untrust github-actions
          spack external find cmake bison
          spack -d solve zlib
          tree ~/.spack/bootstrap/store/

-  macos-clingo-sources:
+  macos-sources:
    runs-on: macos-latest
-    if: github.repository == 'spack/spack'
    steps:
      - name: Install dependencies
        run: |
          brew install cmake bison@2.7 tree
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
+      - uses: actions/checkout@v2
      - name: Bootstrap clingo
        run: |
          source share/spack/setup-env.sh
          export PATH=/usr/local/opt/bison@2.7/bin:$PATH
-          spack bootstrap untrust github-actions-v0.2
+          spack bootstrap untrust github-actions
          spack external find --not-buildable cmake bison
          spack -d solve zlib
          tree ~/.spack/bootstrap/store/

  macos-clingo-binaries:
-    runs-on: ${{ matrix.macos-version }}
+    runs-on: macos-latest
    strategy:
      matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10']
-        macos-version: ['macos-11', 'macos-12']
-    if: github.repository == 'spack/spack'
+        python-version: ['3.5', '3.6', '3.7', '3.8', '3.9']
    steps:
      - name: Install dependencies
        run: |
          brew install tree
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
        with:
          python-version: ${{ matrix.python-version }}
      - name: Bootstrap clingo
@@ -202,19 +137,18 @@ jobs:
          spack -d solve zlib
          tree ~/.spack/bootstrap/store/

+
  ubuntu-clingo-binaries:
    runs-on: ubuntu-latest
    strategy:
      matrix:
-        python-version: ['2.7', '3.6', '3.7', '3.8', '3.9', '3.10']
-    if: github.repository == 'spack/spack'
+        python-version: ['2.7', '3.5', '3.6', '3.7', '3.8', '3.9']
    steps:
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
        with:
          python-version: ${{ matrix.python-version }}
-      - name: Setup repo
+      - name: Setup repo and non-root user
        run: |
          git --version
          git fetch --unshallow
@@ -225,120 +159,3 @@ jobs:
          spack bootstrap untrust spack-install
          spack -d solve zlib
          tree ~/.spack/bootstrap/store/
-
-  ubuntu-gnupg-binaries:
-    runs-on: ubuntu-latest
-    container: "ubuntu:latest"
-    if: github.repository == 'spack/spack'
-    steps:
-      - name: Install dependencies
-        env:
-          DEBIAN_FRONTEND: noninteractive
-        run: |
-          apt-get update -y && apt-get upgrade -y
-          apt-get install -y \
-              bzip2 curl file g++ gcc patchelf gfortran git gzip \
-              make patch unzip xz-utils python3 python3-dev tree
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Setup non-root user
-        run: |
-          # See [1] below
-          git config --global --add safe.directory /__w/spack/spack
-          useradd spack-test && mkdir -p ~spack-test
-          chown -R spack-test . ~spack-test
-      - name: Setup repo
-        shell: runuser -u spack-test -- bash {0}
-        run: |
-          git --version
-          git fetch --unshallow
-          . .github/workflows/setup_git.sh
-      - name: Bootstrap GnuPG
-        shell: runuser -u spack-test -- bash {0}
-        run: |
-          source share/spack/setup-env.sh
-          spack bootstrap untrust spack-install
-          spack -d gpg list
-          tree ~/.spack/bootstrap/store/
-
-  ubuntu-gnupg-sources:
-    runs-on: ubuntu-latest
-    container: "ubuntu:latest"
-    if: github.repository == 'spack/spack'
-    steps:
-      - name: Install dependencies
-        env:
-          DEBIAN_FRONTEND: noninteractive
-        run: |
-          apt-get update -y && apt-get upgrade -y
-          apt-get install -y \
-              bzip2 curl file g++ gcc patchelf gfortran git gzip \
-              make patch unzip xz-utils python3 python3-dev tree \
-              gawk
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Setup non-root user
-        run: |
-          # See [1] below
-          git config --global --add safe.directory /__w/spack/spack
-          useradd spack-test && mkdir -p ~spack-test
-          chown -R spack-test . ~spack-test
-      - name: Setup repo
-        shell: runuser -u spack-test -- bash {0}
-        run: |
-          git --version
-          git fetch --unshallow
-          . .github/workflows/setup_git.sh
-      - name: Bootstrap GnuPG
-        shell: runuser -u spack-test -- bash {0}
-        run: |
-          source share/spack/setup-env.sh
-          spack solve zlib
-          spack bootstrap untrust github-actions-v0.2
-          spack -d gpg list
-          tree ~/.spack/bootstrap/store/
-
-  macos-gnupg-binaries:
-    runs-on: macos-latest
-    if: github.repository == 'spack/spack'
-    steps:
-      - name: Install dependencies
-        run: |
-          brew install tree
-          # Remove GnuPG since we want to bootstrap it
-          sudo rm -rf /usr/local/bin/gpg
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Bootstrap GnuPG
-        run: |
-          source share/spack/setup-env.sh
-          spack bootstrap untrust spack-install
-          spack -d gpg list
-          tree ~/.spack/bootstrap/store/
-
-  macos-gnupg-sources:
-    runs-on: macos-latest
-    if: github.repository == 'spack/spack'
-    steps:
-      - name: Install dependencies
-        run: |
-          brew install gawk tree
-          # Remove GnuPG since we want to bootstrap it
-          sudo rm -rf /usr/local/bin/gpg
-      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      - name: Bootstrap GnuPG
-        run: |
-          source share/spack/setup-env.sh
-          spack solve zlib
-          spack bootstrap untrust github-actions-v0.2
-          spack -d gpg list
-          tree ~/.spack/bootstrap/store/
-
-
-# [1] Distros that have patched git to resolve CVE-2022-24765 (e.g. Ubuntu patching v2.25.1)
-#     introduce breaking behaviorso we have to set `safe.directory` in gitconfig ourselves.
-#     See:
-#     - https://github.blog/2022-04-12-git-security-vulnerability-announced/
-#     - https://github.com/actions/checkout/issues/760
-#     - http://changelogs.ubuntu.com/changelogs/pool/main/g/git/git_2.25.1-1ubuntu3.3/changelog
--- a/.github/workflows/build-containers.yml
+++ b/.github/workflows/build-containers.yml
@@ -1,33 +1,15 @@
-name: Containers
-
+name: Build & Deploy Docker Containers
 on:
-  # This Workflow can be triggered manually
-  workflow_dispatch:
  # Build new Spack develop containers nightly.
  schedule:
    - cron: '34 0 * * *'
-  # Run on pull requests that modify this file
-  pull_request:
-    branches:
-      - develop
-    paths:
-      - '.github/workflows/build-containers.yml'
-      - 'share/spack/docker/*'
-      - 'share/templates/container/*'
-      - 'lib/spack/spack/container/*'
  # Let's also build & tag Spack containers on releases.
  release:
    types: [published]

-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
-  cancel-in-progress: true
-
 jobs:
  deploy-images:
-    runs-on: ubuntu-latest
-    permissions:
-      packages: write
+    runs-on: ubuntu-latest 
    strategy:
      # Even if one container fails to build we still want the others
      # to continue their builds.
@@ -35,26 +17,19 @@ jobs:
      # A matrix of Dockerfile paths, associated tags, and which architectures
      # they support.
      matrix:
-        # Meaning of the various items in the matrix list
-        # 0: Container name (e.g. ubuntu-bionic)
-        # 1: Platforms to build for
-        # 2: Base image (e.g. ubuntu:18.04)
-        dockerfile: [[amazon-linux, 'linux/amd64,linux/arm64', 'amazonlinux:2'],
-                     [centos7, 'linux/amd64,linux/arm64,linux/ppc64le', 'centos:7'],
-                     [centos-stream, 'linux/amd64,linux/arm64,linux/ppc64le', 'centos:stream'],
-                     [leap15, 'linux/amd64,linux/arm64,linux/ppc64le', 'opensuse/leap:15'],
-                     [ubuntu-bionic, 'linux/amd64,linux/arm64,linux/ppc64le', 'ubuntu:18.04'],
-                     [ubuntu-focal, 'linux/amd64,linux/arm64,linux/ppc64le', 'ubuntu:20.04'],
-                     [ubuntu-jammy, 'linux/amd64,linux/arm64,linux/ppc64le', 'ubuntu:22.04']]
+        dockerfile: [[amazon-linux, amazonlinux-2.dockerfile, 'linux/amd64,linux/arm64'], 
+                     [centos7, centos-7.dockerfile, 'linux/amd64,linux/arm64'],
+                     [leap15, leap-15.dockerfile, 'linux/amd64,linux/arm64'],
+                     [ubuntu-xenial, ubuntu-1604.dockerfile, 'linux/amd64,linux/arm64'],
+                     [ubuntu-bionic, ubuntu-1804.dockerfile, 'linux/amd64,linux/arm64']]
    name: Build ${{ matrix.dockerfile[0] }}
-    if: github.repository == 'spack/spack'
    steps:
      - name: Checkout
-        uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+        uses: actions/checkout@v2

      - name: Set Container Tag Normal (Nightly)
        run: |
-          container="${{ matrix.dockerfile[0] }}:latest"
+          container="ghcr.io/spack/${{ matrix.dockerfile[0]}}:latest"
          echo "container=${container}" >> $GITHUB_ENV
          echo "versioned=${container}" >> $GITHUB_ENV

@@ -62,59 +37,36 @@ jobs:
      - name: Set Container Tag on Release
        if: github.event_name == 'release'
        run: |
-          versioned="${{matrix.dockerfile[0]}}:${GITHUB_REF##*/}"
+          versioned="ghcr.io/spack/${{matrix.dockerfile[0]}}:${GITHUB_REF##*/}"
          echo "versioned=${versioned}" >> $GITHUB_ENV

-      - name: Generate the Dockerfile
-        env:
-          SPACK_YAML_OS: "${{ matrix.dockerfile[2] }}"
+      - name: Check ${{ matrix.dockerfile[1] }} Exists
        run: |
-          .github/workflows/generate_spack_yaml_containerize.sh
-          . share/spack/setup-env.sh
-          mkdir -p dockerfiles/${{ matrix.dockerfile[0] }}
-          spack containerize --last-stage=bootstrap | tee dockerfiles/${{ matrix.dockerfile[0] }}/Dockerfile
-          printf "Preparing to build ${{ env.container }} from dockerfiles/${{ matrix.dockerfile[0] }}/Dockerfile"
-          if [ ! -f "dockerfiles/${{ matrix.dockerfile[0] }}/Dockerfile" ]; then
-              printf "dockerfiles/${{ matrix.dockerfile[0] }}/Dockerfile does not exist"
+          printf "Preparing to build ${{ env.container }} from ${{ matrix.dockerfile[1] }}"
+          if [ ! -f "share/spack/docker/${{ matrix.dockerfile[1]}}" ]; then
+              printf "Dockerfile ${{ matrix.dockerfile[0]}} does not exist"
              exit 1;
          fi

-      - name: Upload Dockerfile
-        uses: actions/upload-artifact@3cea5372237819ed00197afe530f5a7ea3e805c8
-        with:
-          name: dockerfiles
-          path: dockerfiles
-
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@8b122486cedac8393e77aa9734c3528886e4a1a8 # @v1
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@dc7b9719a96d48369863986a06765841d7ea23f6 # @v1
-
      - name: Log in to GitHub Container Registry
-        uses: docker/login-action@49ed152c8eca782a232dede0303416e8f356c37b # @v1
+        uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

-      - name: Log in to DockerHub
-        if: github.event_name != 'pull_request'
-        uses: docker/login-action@49ed152c8eca782a232dede0303416e8f356c37b # @v1
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1

-      - name: Build & Deploy ${{ matrix.dockerfile[0] }}
-        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94 # @v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
+      - name: Build & Deploy ${{ matrix.dockerfile[1] }}
+        uses: docker/build-push-action@v2
        with:
-          context: dockerfiles/${{ matrix.dockerfile[0] }}
-          platforms: ${{ matrix.dockerfile[1] }}
-          push: ${{ github.event_name != 'pull_request' }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          file: share/spack/docker/${{matrix.dockerfile[1]}}
+          platforms: ${{ matrix.dockerfile[2] }}
+          push: true
          tags: |
-            spack/${{ env.container }}
-            spack/${{ env.versioned }}
-            ghcr.io/spack/${{ env.container }}
-            ghcr.io/spack/${{ env.versioned }}
+            ${{ env.container }}
+            ${{ env.versioned }}
--- a/.github/workflows/execute_installer.ps1
+++ b/.github/workflows/execute_installer.ps1
@@ -1,7 +0,0 @@
-$ proc = Start-Process  ${{ env.spack_installer }}\spack.exe "/install /quiet" -Passthru
-$handle = $proc.Handle # cache proc.Handle
-$proc.WaitForExit();
-
-if ($proc.ExitCode -ne 0) {
-    Write-Warning "$_ exited with status code $($proc.ExitCode)"
-}
--- a/.github/workflows/generate_spack_yaml_containerize.sh
+++ b/.github/workflows/generate_spack_yaml_containerize.sh
@@ -1,9 +0,0 @@
-#!/bin/bash
-    (echo "spack:" \
-&&   echo "  specs: []" \
-&&   echo "  container:" \
-&&   echo "    format: docker" \
-&&   echo "    images:" \
-&&   echo "      os: \"${SPACK_YAML_OS}\"" \
-&&   echo "      spack:" \
-&&   echo "        ref: ${GITHUB_REF}") > spack.yaml
--- a/.github/workflows/install_spack.sh
+++ b/.github/workflows/install_spack.sh
@@ -2,7 +2,19 @@
 . share/spack/setup-env.sh
 echo -e "config:\n  build_jobs: 2" > etc/spack/config.yaml
 spack config add "packages:all:target:[x86_64]"
-spack compiler find
+# TODO: remove this explicit setting once apple-clang detection is fixed
+cat <<EOF > etc/spack/compilers.yaml
+compilers:
+- compiler:
+    spec: apple-clang@11.0.3
+    paths:
+      cc: /usr/bin/clang
+      cxx: /usr/bin/clang++
+      f77: /usr/local/bin/gfortran-9
+      fc: /usr/local/bin/gfortran-9
+    modules: []
+    operating_system: catalina
+    target: x86_64
+EOF
 spack compiler info apple-clang
 spack debug report
-spack solve zlib
--- a/.github/workflows/macos_python.yml
+++ b/.github/workflows/macos_python.yml
@@ -0,0 +1,78 @@
+# These are nightly package tests for macOS
+# focus areas:
+# - initial user experience
+# - scientific python stack
+name: macOS builds nightly
+
+on:
+  schedule:
+    # nightly at 1 AM
+    - cron: '0 1 * * *'
+  pull_request:
+    branches:
+    - develop
+    paths:
+      # Run if we modify this yaml file
+      - '.github/workflows/macos_python.yml'
+      # TODO: run if we touch any of the recipes involved in this
+
+# GitHub Action Limits
+# https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
+
+jobs:
+  install_gcc:
+    name: gcc with clang
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: spack install
+      run: |
+        . .github/workflows/install_spack.sh
+        # 9.2.0 is the latest version on which we apply homebrew patch
+        spack install -v --fail-fast gcc@9.2.0 %apple-clang
+
+  install_jupyter_clang:
+    name: jupyter
+    runs-on: macos-latest
+    timeout-minutes: 700
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: spack install
+      run: |
+        . .github/workflows/install_spack.sh
+        spack install -v --fail-fast py-jupyterlab %apple-clang
+
+  install_scipy_clang:
+    name: scipy, mpl, pd
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: spack install
+      run: |
+        . .github/workflows/install_spack.sh
+        spack install -v --fail-fast py-scipy %apple-clang
+        spack install -v --fail-fast py-matplotlib %apple-clang
+        spack install -v --fail-fast py-pandas %apple-clang
+
+  install_mpi4py_clang:
+    name: mpi4py, petsc4py
+    runs-on: macos-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: spack install
+      run: |
+        . .github/workflows/install_spack.sh
+        spack install -v --fail-fast py-mpi4py %apple-clang
+        spack install -v --fail-fast py-petsc4py %apple-clang
--- a/.github/workflows/setup_git.ps1
+++ b/.github/workflows/setup_git.ps1
@@ -1,12 +0,0 @@
-# (c) 2021 Lawrence Livermore National Laboratory
-
-Set-Location spack
-
-git config --global user.email "spack@example.com"
-git config --global user.name "Test User"
-git config --global core.longpaths true
-
-if ($(git branch --show-current) -ne "develop")
-{
-    git branch develop origin/develop
-}
--- a/.github/workflows/setup_git.sh
+++ b/.github/workflows/setup_git.sh
@@ -1,8 +1,9 @@
-#!/bin/bash -e
+#!/usr/bin/env sh
 git config --global user.email "spack@example.com"
 git config --global user.name "Test User"
-
-# create a local pr base branch
-if [[ -n $GITHUB_BASE_REF ]]; then
-    git fetch origin "${GITHUB_BASE_REF}:${GITHUB_BASE_REF}"
+# With fetch-depth: 0 we have a remote develop
+# but not a local branch. Don't do this on develop
+if [ "$(git branch --show-current)" != "develop" ]
+then
+  git branch develop origin/develop
 fi
--- a/.github/workflows/system_shortcut_check.ps1
+++ b/.github/workflows/system_shortcut_check.ps1
@@ -1,4 +0,0 @@
-param ($systemFolder, $shortcut)
-
-$start = [System.Environment]::GetFolderPath("$systemFolder")
-Invoke-Item "$start\Programs\Spack\$shortcut"
--- a/.github/workflows/unit_tests.yaml
+++ b/.github/workflows/unit_tests.yaml
@@ -9,39 +9,34 @@ on:
    branches:
      - develop
      - releases/**
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
-  cancel-in-progress: true
-
 jobs:
  # Validate that the code can be run on all the Python versions
  # supported by Spack
  validate:
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
      with:
-        python-version: '3.10'
+        python-version: 3.9
    - name: Install Python Packages
      run: |
        pip install --upgrade pip
        pip install --upgrade vermin
    - name: vermin (Spack's Core)
-      run: vermin --backport argparse --violations --backport typing -t=2.7- -t=3.6- -vvv lib/spack/spack/ lib/spack/llnl/ bin/
+      run: vermin --backport argparse --violations --backport typing -t=2.6- -t=3.5- -vvv lib/spack/spack/ lib/spack/llnl/ bin/
    - name: vermin (Repositories)
-      run: vermin --backport argparse --violations --backport typing -t=2.7- -t=3.6- -vvv var/spack/repos
+      run: vermin --backport argparse --violations --backport typing -t=2.6- -t=3.5- -vvv var/spack/repos
  # Run style checks on the files that have been changed
  style:
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
+    - uses: actions/setup-python@v2
      with:
-        python-version: '3.10'
+        python-version: 3.9
    - name: Install Python packages
      run: |
        pip install --upgrade pip six setuptools types-six
@@ -53,6 +48,26 @@ jobs:
    - name: Run style tests
      run: |
          share/spack/qa/run-style-tests
+  # Build the documentation
+  documentation:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: Install System packages
+      run: |
+        sudo apt-get -y update
+        sudo apt-get install -y coreutils ninja-build graphviz
+    - name: Install Python packages
+      run: |
+        pip install --upgrade pip six setuptools
+        pip install --upgrade -r lib/spack/docs/requirements.txt
+    - name: Build documentation
+      run: |
+          share/spack/qa/run-doc-tests
+
  # Check which files have been updated by the PR
  changes:
    runs-on: ubuntu-latest
@@ -62,12 +77,12 @@ jobs:
      packages: ${{ steps.filter.outputs.packages }}
      with_coverage: ${{ steps.coverage.outputs.with_coverage }}
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
      if: ${{ github.event_name == 'push' }}
      with:
        fetch-depth: 0
    # For pull requests it's not necessary to checkout the code
-    - uses: dorny/paths-filter@b2feaf19c27470162a626bd6fa8438ae5b263721
+    - uses: dorny/paths-filter@v2
      id: filter
      with:
        # See https://github.com/dorny/paths-filter/issues/56 for the syntax used below
@@ -97,22 +112,17 @@ jobs:

  # Run unit tests with different configurations on linux
  unittests:
-    needs: [ validate, style, changes ]
+    needs: [ validate, style, documentation, changes ]
    runs-on: ubuntu-latest
    strategy:
      matrix:
-        python-version: ['2.7', '3.6', '3.7', '3.8', '3.9', '3.10']
-        concretizer: ['clingo']
-        include:
-        - python-version: 2.7
-          concretizer: original
-        - python-version: 3.9
-          concretizer: original
+        python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]
+        concretizer: ['original', 'clingo']
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
+    - uses: actions/setup-python@v2
      with:
        python-version: ${{ matrix.python-version }}
    - name: Install System packages
@@ -124,16 +134,12 @@ jobs:
              patchelf cmake bison libbison-dev kcov
    - name: Install Python packages
      run: |
-          pip install --upgrade pip six setuptools pytest codecov "coverage[toml]<=6.2"
+          pip install --upgrade pip six setuptools codecov coverage[toml]
          # ensure style checks are not skipped in unit tests for python >= 3.6
          # note that true/false (i.e., 1/0) are opposite in conditions in python and bash
          if python -c 'import sys; sys.exit(not sys.version_info >= (3, 6))'; then
-              pip install --upgrade flake8 "isort>=4.3.5" "mypy>=0.900" "click==8.0.4" "black<=21.12b0"
+              pip install --upgrade flake8 isort>=4.3.5 mypy>=0.900 black
          fi
-    - name: Pin pathlib for Python 2.7
-      if: ${{ matrix.python-version == 2.7 }}
-      run: |
-          pip install -U pathlib2==2.3.6
    - name: Setup git configuration
      run: |
          # Need this for the git tests to succeed.
@@ -165,21 +171,21 @@ jobs:
          SPACK_TEST_SOLVER: ${{ matrix.concretizer }}
      run: |
          share/spack/qa/run-unit-tests
-    - uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # @v2.1.0
+    - uses: codecov/codecov-action@v2.0.3
      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
      with:
        flags: unittests,linux,${{ matrix.concretizer }}
  # Test shell integration
  shell:
-    needs: [ validate, style, changes ]
+    needs: [ validate, style, documentation, changes ]
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
+    - uses: actions/setup-python@v2
      with:
-        python-version: '3.10'
+        python-version: 3.9
    - name: Install System packages
      run: |
          sudo apt-get -y update
@@ -187,7 +193,7 @@ jobs:
          sudo apt-get install -y coreutils kcov csh zsh tcsh fish dash bash
    - name: Install Python packages
      run: |
-          pip install --upgrade pip six setuptools pytest codecov coverage[toml]==6.2
+          pip install --upgrade pip six setuptools codecov coverage[toml]
    - name: Setup git configuration
      run: |
          # Need this for the git tests to succeed.
@@ -203,15 +209,44 @@ jobs:
          COVERAGE: true
      run: |
          share/spack/qa/run-shell-tests
-    - uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # @v2.1.0
+    - uses: codecov/codecov-action@v2.0.3
      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
      with:
        flags: shelltests,linux
+  # Test for Python2.6 run on Centos 6
+  centos6:
+    needs: [ validate, style, documentation, changes ]
+    runs-on: ubuntu-latest
+    container: spack/github-actions:centos6
+    steps:
+    - name: Run unit tests (full test-suite)
+      # The CentOS 6 container doesn't run with coverage, but
+      # under the same conditions it runs the full test suite
+      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
+      env:
+          HOME: /home/spack-test
+      run: |
+          whoami && echo $HOME && cd $HOME
+          git clone https://github.com/spack/spack.git && cd spack
+          git fetch origin ${{ github.ref }}:test-branch
+          git checkout test-branch
+          share/spack/qa/run-unit-tests
+    - name: Run unit tests (only package tests)
+      if: ${{ needs.changes.outputs.with_coverage == 'false' }}
+      env:
+          HOME: /home/spack-test
+          ONLY_PACKAGES: true
+      run: |
+          whoami && echo $HOME && cd $HOME
+          git clone https://github.com/spack/spack.git && cd spack
+          git fetch origin ${{ github.ref }}:test-branch
+          git checkout test-branch
+          share/spack/qa/run-unit-tests

  # Test RHEL8 UBI with platform Python. This job is run
  # only on PRs modifying core Spack
  rhel8-platform-python:
-    needs: [ validate, style, changes ]
+    needs: [ validate, style, documentation, changes ]
    runs-on: ubuntu-latest
    if: ${{ needs.changes.outputs.with_coverage == 'true' }}
    container: registry.access.redhat.com/ubi8/ubi
@@ -221,7 +256,7 @@ jobs:
          dnf install -y \
              bzip2 curl file gcc-c++ gcc gcc-gfortran git gnupg2 gzip \
              make patch tcl unzip which xz
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
    - name: Setup repo and non-root user
      run: |
          git --version
@@ -233,19 +268,18 @@ jobs:
      shell: runuser -u spack-test -- bash {0}
      run: |
          source share/spack/setup-env.sh
-          spack -d solve zlib
          spack unit-test -k 'not cvs and not svn and not hg' -x --verbose
  # Test for the clingo based solver (using clingo-cffi)
  clingo-cffi:
-    needs: [ validate, style, changes ]
+    needs: [ validate, style, documentation, changes ]
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
+    - uses: actions/setup-python@v2
      with:
-        python-version: '3.10'
+        python-version: 3.9
    - name: Install System packages
      run: |
          sudo apt-get -y update
@@ -255,7 +289,7 @@ jobs:
              patchelf kcov
    - name: Install Python packages
      run: |
-          pip install --upgrade pip six setuptools pytest codecov coverage[toml]==6.2 clingo
+          pip install --upgrade pip six setuptools codecov coverage[toml] clingo
    - name: Setup git configuration
      run: |
          # Need this for the git tests to succeed.
@@ -277,28 +311,28 @@ jobs:
          SPACK_TEST_SOLVER: clingo
      run: |
          share/spack/qa/run-unit-tests
-    - uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # @v2.1.0
+    - uses: codecov/codecov-action@v2.0.3
      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
      with:
        flags: unittests,linux,clingo
  # Run unit tests on MacOS
  build:
-    needs: [ validate, style, changes ]
+    needs: [ validate, style, documentation, changes ]
    runs-on: macos-latest
    strategy:
      matrix:
        python-version: [3.8]
    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
+    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
+    - uses: actions/setup-python@v2
      with:
        python-version: ${{ matrix.python-version }}
    - name: Install Python packages
      run: |
          pip install --upgrade pip six setuptools
-          pip install --upgrade pytest codecov coverage[toml]==6.2
+          pip install --upgrade codecov coverage[toml]
    - name: Setup Homebrew packages
      run: |
        brew install dash fish gcc gnupg2 kcov
@@ -323,37 +357,8 @@ jobs:
          echo "ONLY PACKAGE RECIPES CHANGED [skipping coverage]"
          $(which spack) unit-test -x -m "not maybeslow" -k "package_sanity"
        fi
-    - uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # @v2.1.0
+    - uses: codecov/codecov-action@v2.0.3
      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
      with:
        files: ./coverage.xml
        flags: unittests,macos
-
-  # Run audits on all the packages in the built-in repository
-  package-audits:
-    needs: [ validate, style, changes ]
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b # @v2
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5 # @v2
-      with:
-        python-version: '3.10'
-    - name: Install Python packages
-      run: |
-        pip install --upgrade pip six setuptools pytest codecov coverage[toml]==6.2
-    - name: Package audits (with coverage)
-      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
-      run: |
-          . share/spack/setup-env.sh
-          coverage run $(which spack) audit packages
-          coverage combine
-          coverage xml
-    - name: Package audits (without coverage)
-      if: ${{ needs.changes.outputs.with_coverage == 'false' }}
-      run: |
-          . share/spack/setup-env.sh
-          $(which spack) audit packages
-    - uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # @v2.1.0
-      if: ${{ needs.changes.outputs.with_coverage == 'true' }}
-      with:
-        flags: unittests,linux,audits
--- a/.github/workflows/windows_python.yml
+++ b/.github/workflows/windows_python.yml
@@ -1,193 +0,0 @@
-name: windows tests
-
-on:
-  push:
-    branches:
-      - develop
-      - releases/**
-  pull_request:
-    branches:
-      - develop
-      - releases/**
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_number }}
-  cancel-in-progress: true
-
-defaults:
-  run:
-    shell:
-     powershell Invoke-Expression -Command ".\share\spack\qa\windows_test_setup.ps1"; {0}
-jobs:
-  validate:
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python Packages
-      run: |
-        python -m pip install --upgrade pip
-        python -m pip install --upgrade vermin
-    - name: vermin (Spack's Core)
-      run: vermin --backport argparse --backport typing -t='2.7-' -t='3.6-' -v spack/lib/spack/spack/ spack/lib/spack/llnl/ spack/bin/
-    - name: vermin (Repositories)
-      run: vermin --backport argparse --backport typing -t='2.7-' -t='3.6-' -v spack/var/spack/repos
-  # Run style checks on the files that have been changed
-  style:
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-        python -m pip install --upgrade pip six setuptools flake8 "isort>=4.3.5" "mypy>=0.800" "click==8.0.4" "black<=21.12b0" pywin32 types-python-dateutil
-    - name: Create local develop
-      run: |
-        .\spack\.github\workflows\setup_git.ps1
-    - name: Run style tests
-      run: |
-        spack style
-    - name: Verify license headers
-      run: |
-        python spack\bin\spack license verify
-  unittest:
-    needs: [ validate, style ]
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip six pywin32 setuptools codecov coverage
-    - name: Create local develop
-      run: |
-        .\spack\.github\workflows\setup_git.ps1
-    - name: Unit Test
-      run: |
-        echo F|xcopy .\spack\share\spack\qa\configuration\windows_config.yaml $env:USERPROFILE\.spack\windows\config.yaml
-        spack unit-test --verbose --ignore=lib/spack/spack/test/cmd
-  unittest-cmd:
-    needs: [ validate, style ]
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip six pywin32 setuptools codecov coverage
-    - name: Create local develop
-      run: |
-        .\spack\.github\workflows\setup_git.ps1
-    - name: Command Unit Test
-      run: |
-        echo F|xcopy .\spack\share\spack\qa\configuration\windows_config.yaml $env:USERPROFILE\.spack\windows\config.yaml
-        spack unit-test lib/spack/spack/test/cmd --verbose
-  buildtest:
-    needs: [ validate, style ]
-    runs-on: windows-latest
-    steps:
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip six pywin32 setuptools codecov coverage
-    - name: Build Test
-      run: |
-        spack compiler find
-        echo F|xcopy .\spack\share\spack\qa\configuration\windows_config.yaml $env:USERPROFILE\.spack\windows\config.yaml
-        spack external find cmake
-        spack external find ninja
-        spack install abseil-cpp
-  generate-installer-test:
-    needs: [ validate, style ]
-    runs-on: windows-latest
-    steps:
-    - name: Disable Windows Symlinks
-      run: |
-        git config --global core.symlinks false
-      shell:
-        powershell
-    - uses: actions/checkout@2541b1294d2704b0964813337f33b291d3f8596b
-      with:
-        fetch-depth: 0
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip six pywin32 setuptools codecov coverage
-    - name: Add Light and Candle to Path
-      run: |
-        $env:WIX >> $GITHUB_PATH
-    - name: Run Installer
-      run: |
-        .\spack\share\spack\qa\setup_spack.ps1
-        spack make-installer -s spack -g SILENT pkg
-        echo "installer_root=$((pwd).Path)" | Out-File -FilePath $Env:GITHUB_ENV -Encoding utf8 -Append
-      env:
-        ProgressPreference: SilentlyContinue
-    - uses: actions/upload-artifact@3cea5372237819ed00197afe530f5a7ea3e805c8
-      with:
-        name: Windows Spack Installer Bundle
-        path: ${{ env.installer_root }}\pkg\Spack.exe
-    - uses: actions/upload-artifact@3cea5372237819ed00197afe530f5a7ea3e805c8
-      with:
-        name: Windows Spack Installer
-        path: ${{ env.installer_root}}\pkg\Spack.msi
-  execute-installer:
-    needs: generate-installer-test
-    runs-on: windows-latest
-    defaults:
-      run:
-        shell: pwsh
-    steps:
-    - uses: actions/setup-python@b55428b1882923874294fa556849718a1d7f2ca5
-      with:
-        python-version: 3.9
-    - name: Install Python packages
-      run: |
-          python -m pip install --upgrade pip six pywin32 setuptools codecov coverage
-    - name: Setup installer directory
-      run: |
-        mkdir -p spack_installer
-        echo "spack_installer=$((pwd).Path)\spack_installer" | Out-File -FilePath $Env:GITHUB_ENV -Encoding utf8 -Append
-    - uses: actions/download-artifact@v3
-      with:
-        name: Windows Spack Installer Bundle
-        path: ${{ env.spack_installer }}
-    - name: Execute Bundled Installer
-      run: |
-        $proc = Start-Process  ${{ env.spack_installer }}\spack.exe "/install /quiet" -Passthru
-        $handle = $proc.Handle # cache proc.Handle
-        $proc.WaitForExit();
-        $LASTEXITCODE
-      env:
-        ProgressPreference: SilentlyContinue
-    - uses: actions/download-artifact@v3
-      with:
-        name: Windows Spack Installer
-        path: ${{ env.spack_installer }}
-    - name: Execute MSI
-      run: |
-        $proc = Start-Process  ${{ env.spack_installer }}\spack.msi "/quiet" -Passthru
-        $handle = $proc.Handle # cache proc.Handle
-        $proc.WaitForExit();
-        $LASTEXITCODE
--- a/.gitignore
+++ b/.gitignore
@@ -132,11 +132,11 @@ celerybeat.pid
 .env
 .venv
 env/
+!/lib/spack/env
 venv/
 ENV/
 env.bak/
 venv.bak/
-!/lib/spack/env

 # Spyder project settings
 .spyderproject
@@ -210,9 +210,6 @@ tramp
 /eshell/history
 /eshell/lastdir

-# zsh byte-compiled files
-*.zwc
-
 # elpa packages
 /elpa/

--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -2,7 +2,6 @@ version: 2

 sphinx:
  configuration: lib/spack/docs/conf.py
-  fail_on_warning: true

 python:
  version: 3.7
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,457 +1,3 @@
-# v0.18.1 (2022-07-19)
-
-### Spack Bugfixes
-* Fix several bugs related to bootstrapping (#30834,#31042,#31180)
-* Fix a regression that was causing spec hashes to differ between 
-  Python 2 and Python 3 (#31092)
-* Fixed compiler flags for oneAPI and DPC++ (#30856)
-* Fixed several issues related to concretization (#31142,#31153,#31170,#31226)
-* Improved support for Cray manifest file and `spack external find` (#31144,#31201,#31173,#31186)
-* Assign a version to openSUSE Tumbleweed according to the GLIBC version
-  in the system (#19895) 
-* Improved Dockerfile generation for `spack containerize` (#29741,#31321)
-* Fixed a few bugs related to concurrent execution of commands (#31509,#31493,#31477)  
-
-### Package updates
-* WarpX: add v22.06, fixed libs property (#30866,#31102)
-* openPMD: add v0.14.5, update recipe for @develop (#29484,#31023)
-
-# v0.18.0 (2022-05-28)
-
-`v0.18.0` is a major feature release.
-
-## Major features in this release
-
-1. **Concretizer now reuses by default**
-
-   `spack install --reuse` was introduced in `v0.17.0`, and `--reuse`
-   is now the default concretization mode. Spack will try hard to
-   resolve dependencies using installed packages or binaries (#30396).
-
-   To avoid reuse and to use the latest package configurations, (the
-   old default), you can use `spack install --fresh`, or add
-   configuration like this to your environment or `concretizer.yaml`:
-
-   ```yaml
-   concretizer:
-       reuse: false
-   ```
-
-2. **Finer-grained hashes**
-
-   Spack hashes now include `link`, `run`, *and* `build` dependencies,
-   as well as a canonical hash of package recipes. Previously, hashes
-   only included `link` and `run` dependencies (though `build`
-   dependencies were stored by environments). We coarsened the hash to
-   reduce churn in user installations, but the new default concretizer
-   behavior mitigates this concern and gets us reuse *and* provenance.
-   You will be able to see the build dependencies of new installations
-   with `spack find`. Old installations will not change and their
-   hashes will not be affected. (#28156, #28504, #30717, #30861)
-
-3. **Improved error messages**
-
-   Error handling with the new concretizer is now done with
-   optimization criteria rather than with unsatisfiable cores, and
-   Spack reports many more details about conflicting constraints.
-   (#30669)
-
-4. **Unify environments when possible**
-
-   Environments have thus far supported `concretization: together` or
-   `concretization: separately`. These have been replaced by a new
-   preference in `concretizer.yaml`:
-
-   ```yaml
-   concretizer:
-       unify: [true|false|when_possible]
-   ```
-
-   `concretizer:unify:when_possible` will *try* to resolve a fully
-   unified environment, but if it cannot, it will create multiple
-   configurations of some packages where it has to. For large
-   environments that previously had to be concretized separately, this
-   can result in a huge speedup (40-50x). (#28941)
-
-5. **Automatically find externals on Cray machines**
-
-   Spack can now automatically discover installed packages in the Cray
-   Programming Environment by running `spack external find` (or `spack
-   external read-cray-manifest` to *only* query the PE). Packages from
-   the PE (e.g., `cray-mpich` are added to the database with full
-   dependency information, and compilers from the PE are added to
-   `compilers.yaml`. Available with the June 2022 release of the Cray
-   Programming Environment. (#24894, #30428)
-
-6. **New binary format and hardened signing**
-
-   Spack now has an updated binary format, with improvements for
-   security. The new format has a detached signature file, and Spack
-   verifies the signature before untarring or decompressing the binary
-   package. The previous format embedded the signature in a `tar`
-   file, which required the client to run `tar` *before* verifying
-   (#30750). Spack can still install from build caches using the old
-   format, but we encourage users to switch to the new format going
-   forward.
-
-   Production GitLab pipelines have been hardened to securely sign
-   binaries. There is now a separate signing stage so that signing
-   keys are never exposed to build system code, and signing keys are
-   ephemeral and only live as long as the signing pipeline stage.
-   (#30753)
-
-7. **Bootstrap mirror generation**
-
-   The `spack bootstrap mirror` command can automatically create a
-   mirror for bootstrapping the concretizer and other needed
-   dependencies in an air-gapped environment. (#28556)
-
-8. **Nascent Windows support**
-
-   Spack now has initial support for Windows. Spack core has been
-   refactored to run in the Windows environment, and a small number of
-   packages can now build for Windows. More details are
-   [in the documentation](https://spack.rtfd.io/en/latest/getting_started.html#spack-on-windows)
-   (#27021, #28385, many more)
-
-9. **Makefile generation**
-
-   `spack env depfile` can be used to generate a `Makefile` from an
-   environment, which can be used to build packages the environment
-   in parallel on a single node. e.g.:
-
-   ```console
-   spack -e myenv env depfile > Makefile
-   make
-   ```
-
-   Spack propagates `gmake` jobserver information to builds so that
-   their jobs can share cores. (#30039, #30254, #30302, #30526)
-
-10. **New variant features**
-
-    In addition to being conditional themselves, variants can now have
-    [conditional *values*](https://spack.readthedocs.io/en/latest/packaging_guide.html#conditional-possible-values)
-    that are only possible for certain configurations of a package. (#29530)
-
-    Variants can be
-    [declared "sticky"](https://spack.readthedocs.io/en/latest/packaging_guide.html#sticky-variants),
-    which prevents them from being enabled or disabled by the
-    concretizer. Sticky variants must be set explicitly by users
-    on the command line or in `packages.yaml`. (#28630)
-
-* Allow conditional possible values in variants
-* Add a "sticky" property to variants
-
-
-## Other new features of note
-
-* Environment views can optionally link only `run` dependencies
-  with `link:run` (#29336)
-* `spack external find --all` finds library-only packages in
-  addition to build dependencies (#28005)
-* Customizable `config:license_dir` option (#30135)
-* `spack external find --path PATH` takes a custom search path (#30479)
-* `spack spec` has a new `--format` argument like `spack find` (#27908)
-* `spack concretize --quiet` skips printing concretized specs (#30272)
-* `spack info` now has cleaner output and displays test info (#22097)
-* Package-level submodule option for git commit versions (#30085, #30037)
-* Using `/hash` syntax to refer to concrete specs in an environment
-  now works even if `/hash` is not installed. (#30276)
-
-## Major internal refactors
-
-* full hash (see above)
-* new develop versioning scheme `0.19.0-dev0`
-* Allow for multiple dependencies/dependents from the same package (#28673)
-* Splice differing virtual packages (#27919)
-
-## Performance Improvements
-
-* Concretization of large environments with `unify: when_possible` is
-  much faster than concretizing separately (#28941, see above)
-* Single-pass view generation algorithm is 2.6x faster (#29443)
-
-## Archspec improvements
-
-* `oneapi` and `dpcpp` flag support (#30783)
-* better support for `M1` and `a64fx` (#30683)
-
-## Removals and Deprecations
-
-* Spack no longer supports Python `2.6` (#27256)
-* Removed deprecated `--run-tests` option of `spack install`;
-  use `spack test` (#30461)
-* Removed deprecated `spack flake8`; use `spack style` (#27290)
-
-* Deprecate `spack:concretization` config option; use
-  `concretizer:unify` (#30038)
-* Deprecate top-level module configuration; use module sets (#28659)
-* `spack activate` and `spack deactivate` are deprecated in favor of
-  environments; will be removed in `0.19.0` (#29430; see also `link:run`
-  in #29336 above)
-
-## Notable Bugfixes
-
-* Fix bug that broke locks with many parallel builds (#27846)
-* Many bugfixes and consistency improvements for the new concretizer
-  and `--reuse` (#30357, #30092, #29835, #29933, #28605, #29694, #28848)
-
-## Packages
-
-* `CMakePackage` uses `CMAKE_INSTALL_RPATH_USE_LINK_PATH` (#29703)
-* Refactored `lua` support: `lua-lang` virtual supports both
-  `lua` and `luajit` via new `LuaPackage` build system(#28854)
-* PythonPackage: now installs packages with `pip` (#27798)
-* Python: improve site_packages_dir handling (#28346)
-* Extends: support spec, not just package name (#27754)
-* `find_libraries`: search for both .so and .dylib on macOS (#28924)
-* Use stable URLs and `?full_index=1` for all github patches (#29239)
-
-## Spack community stats
-
-* 6,416 total packages, 458 new since `v0.17.0`
-    * 219 new Python packages
-    * 60 new R packages
-* 377 people contributed to this release
-    * 337 committers to packages
-    * 85 committers to core
-
-# v0.17.3 (2022-07-14)
-
-### Spack bugfixes
-
-* Fix missing chgrp on symlinks in package installations (#30743)
-* Allow having non-existing upstreams (#30744, #30746)
-* Fix `spack stage` with custom paths (#30448)
-* Fix failing call for `spack buildcache save-specfile` (#30637)
-* Fix globbing in compiler wrapper (#30699)
-
-# v0.17.2 (2022-04-13)
-
-### Spack bugfixes
-* Fix --reuse with upstreams set in an environment (#29680)
-* config add: fix parsing of validator error to infer type from oneOf (#29475)
-* Fix spack -C command_line_scope used in conjunction with other flags (#28418)
-* Use Spec.constrain to construct spec lists for stacks (#28783)
-* Fix bug occurring when searching for inherited patches in packages (#29574)
-* Fixed a few bugs when manipulating symlinks (#28318, #29515, #29636)
-* Fixed a few minor bugs affecting command prompt, terminal title and argument completion (#28279, #28278, #28939, #29405, #29070, #29402)
-* Fixed a few bugs affecting the spack ci command (#29518, #29419)
-* Fix handling of Intel compiler environment (#29439)
-* Fix a few edge cases when reindexing the DB (#28764)
-* Remove "Known issues" from documentation (#29664)
-* Other miscellaneous bugfixes (0b72e070583fc5bcd016f5adc8a84c99f2b7805f, #28403, #29261)
-
-# v0.17.1 (2021-12-23)
-
-### Spack Bugfixes
-* Allow locks to work under high contention (#27846)
-* Improve errors messages from clingo (#27707 #27970)
-* Respect package permissions for sbang (#25764)
-* Fix --enable-locks behavior (#24675)
-* Fix log-format reporter ignoring install errors (#25961)
-* Fix overloaded argparse keys (#27379)
-* Allow style commands to run with targets other than "develop" (#27472)
-* Log lock messages to debug level, instead of verbose level (#27408)
-* Handle invalid unicode while logging (#21447)
-* spack audit: fix API calls to variants (#27713)
-* Provide meaningful message for empty environment installs (#28031)
-* Added opensuse leap containers to spack containerize (#27837)
-* Revert "patches: make re-applied patches idempotent" (#27625)
-* MANPATH can use system defaults (#21682)
-* Add "setdefault" subcommand to `spack module tcl` (#14686)
-* Regenerate views when specs already installed (#28113)
-
-### Package bugfixes
-* Fix external package detection for OpenMPI (#27255)
-* Update the UPC++ package to 2021.9.0 (#26996)
-* Added py-vermin v1.3.2 (#28072)
-
-# v0.17.0 (2021-11-05)
-
-`v0.17.0` is a major feature release.
-
-## Major features in this release
-
-1. **New concretizer is now default**
-   The new concretizer introduced as an experimental feature in `v0.16.0`
-   is now the default (#25502). The new concretizer is based on the
-   [clingo](https://github.com/potassco/clingo) logic programming system,
-   and it enables us to do much higher quality and faster dependency solving
-   The old concretizer is still available via the `concretizer: original`
-   setting, but it is deprecated and will be removed in `v0.18.0`.
-
-2. **Binary Bootstrapping**
-   To make it easier to use the new concretizer and binary packages,
-   Spack now bootstraps `clingo` and `GnuPG` from public binaries. If it
-   is not able to bootstrap them from binaries, it installs them from
-   source code. With these changes, you should still be able to clone Spack
-   and start using it almost immediately. (#21446, #22354, #22489, #22606,
-   #22720, #22720, #23677, #23946, #24003, #25138, #25607, #25964, #26029,
-   #26399, #26599).
-
-3. **Reuse existing packages (experimental)**
-   The most wanted feature from our
-   [2020 user survey](https://spack.io/spack-user-survey-2020/) and
-   the most wanted Spack feature of all time (#25310). `spack install`,
-   `spack spec`, and `spack concretize` now have a `--reuse` option, which
-   causes Spack to minimize the number of rebuilds it does. The `--reuse`
-   option will try to find existing installations and binary packages locally
-   and in registered mirrors, and will prefer to use them over building new
-   versions. This will allow users to build from source *far* less than in
-   prior versions of Spack. This feature will continue to be improved, with
-   configuration options and better CLI expected in `v0.17.1`. It will become
-   the *default* concretization mode in `v0.18.0`.
-
-4. **Better error messages**
-   We have improved the error messages generated by the new concretizer by
-   using *unsatisfiable cores*. Spack will now print a summary of the types
-   of constraints that were violated to make a spec unsatisfiable (#26719).
-
-5. **Conditional variants**
-   Variants can now have a `when="<spec>"` clause, allowing them to be
-   conditional based on the version or other attributes of a package (#24858).
-
-6. **Git commit versions**
-   In an environment and on the command-line, you can now provide a full,
-   40-character git commit as a version for any package with a top-level
-   `git` URL.  e.g., `spack install hdf5@45bb27f58240a8da7ebb4efc821a1a964d7712a8`.
-   Spack will compare the commit to tags in the git repository to understand
-   what versions it is ahead of or behind.
-
-7. **Override local config and cache directories**
-   You can now set `SPACK_DISABLE_LOCAL_CONFIG` to disable the `~/.spack` and
-   `/etc/spack` configuration scopes. `SPACK_USER_CACHE_PATH` allows you to
-   move caches out of `~/.spack`, as well (#27022, #26735). This addresses
-   common problems where users could not isolate CI environments from local
-   configuration.
-
-8. **Improvements to Spack Containerize**
-   For added reproducibility, you can now pin the Spack version used by
-   `spack containerize` (#21910). The container build will only build
-   with the Spack version pinned at build recipe creation instead of the
-   latest Spack version.
-
-9. **New commands for dealing with tags**
-   The `spack tags` command allows you to list tags on packages (#26136), and you
-   can list tests and filter tags with `spack test list` (#26842).
-
-## Other new features of note
-
-* Copy and relocate environment views as stand-alone installations (#24832)
-* `spack diff` command can diff two installed specs (#22283, #25169)
-* `spack -c <config>` can set one-off config parameters on CLI (#22251)
-* `spack load --list` is an alias for `spack find --loaded` (#27184)
-* `spack gpg` can export private key with `--secret` (#22557)
-* `spack style` automatically bootstraps dependencies (#24819)
-* `spack style --fix` automatically invokes `isort` (#24071)
-* build dependencies can be installed from build caches with `--include-build-deps` (#19955)
-* `spack audit` command for checking package constraints (#23053)
-* Spack can now fetch from `CVS` repositories (yep, really) (#23212)
-* `spack monitor` lets you upload analysis about installations to a
-  [spack monitor server](https://github.com/spack/spack-monitor) (#23804, #24321,
-  #23777, #25928))
-* `spack python --path` shows which `python` Spack is using (#22006)
-* `spack env activate --temp` can create temporary environments (#25388)
-* `--preferred` and `--latest` options for `spack checksum` (#25830)
-* `cc` is now pure posix and runs on Alpine (#26259)
-* `SPACK_PYTHON` environment variable sets which `python` spack uses (#21222)
-* `SPACK_SKIP_MODULES` lets you source `setup-env.sh` faster if you don't need modules (#24545)
-
-## Major internal refactors
-
-* `spec.yaml` files are now `spec.json`, yielding a large speed improvement (#22845)
-* Splicing allows Spack specs to store mixed build provenance (#20262)
-* More extensive hooks API for installations (#21930)
-* New internal API for getting the active environment (#25439)
-
-## Performance Improvements
-
-* Parallelize separate concretization in environments; Previously 55 min E4S solve
-    now takes 2.5 min (#26264)
-* Drastically improve YamlFilesystemView file removal performance via batching (#24355)
-* Speed up spec comparison (#21618)
-* Speed up environment activation (#25633)
-
-## Archspec improvements
-* support for new generic `x86_64_v2`, `x86_64_v3`, `x86_64_v4` targets
-    (see [archspec#31](https://github.com/archspec/archspec-json/pull/31))
-* `spack arch --generic` lets you get the best generic architecture for
-    your node (#27061)
-* added support for aocc (#20124), `arm` compiler on `graviton2` (#24904)
-    and on `a64fx` (#24524),
-
-## Infrastructure, buildcaches, and services
-
-* Add support for GCS Bucket Mirrors (#26382)
-* Add `spackbot` to help package maintainers with notifications. See
-  [spack.github.io/spackbot](https://spack.github.io/spackbot/)
-* Reproducible pipeline builds with `spack ci rebuild` (#22887)
-* Removed redundant concretizations from GitLab pipeline generation (#26622)
-* Spack CI no longer generates jobs for unbuilt specs (#20435)
-* Every pull request pipeline has its own buildcache (#25529)
-* `--no-add` installs only specified specs and only if already present in… (#22657)
-* Add environment-aware `spack buildcache sync` command (#25470)
-* Binary cache installation speedups and improvements (#19690, #20768)
-
-## Deprecations and Removals
-
-* `spack setup` was deprecated in v0.16.0, and has now been removed.
-  Use `spack develop` and `spack dev-build`.
-* Remove unused `--dependencies` flag from `spack load` (#25731)
-* Remove stubs for `spack module [refresh|find|rm|loads]`, all of which
-  were deprecated in 2018.
-
-## Notable Bugfixes
-
-* Deactivate previous env before activating new one (#25409)
-* Many fixes to error codes from `spack install` (#21319, #27012, #25314)
-* config add: infer type based on JSON schema validation errors (#27035)
-* `spack config edit` now works even if `spack.yaml` is broken (#24689)
-
-## Packages
-
-* Allow non-empty version ranges like `1.1.0:1.1` (#26402)
-* Remove `.99`'s from many version ranges (#26422)
-* Python: use platform-specific site packages dir (#25998)
-* `CachedCMakePackage` for using *.cmake initial config files (#19316)
-* `lua-lang` allows swapping `lua` and `luajit` (#22492)
-* Better support for `ld.gold` and `ld.lld` (#25626)
-* build times are now stored as metadata in `$prefix/.spack` (#21179)
-* post-install tests can be reused in smoke tests (#20298)
-* Packages can use `pypi` attribute to infer `homepage`/`url`/`list_url` (#17587)
-* Use gnuconfig package for `config.guess` file replacement (#26035)
-* patches: make re-applied patches idempotent (#26784)
-
-## Spack community stats
-
-* 5969 total packages, 920 new since `v0.16.0`
-    * 358 new Python packages, 175 new R packages
-* 513 people contributed to this release
-    * 490 committers to packages
-    * 105 committers to core
-* Lots of GPU updates:
-    * ~77 CUDA-related commits
-    * ~66 AMD-related updates
-    * ~27 OneAPI-related commits
-    * 30 commits from AMD toolchain support
-* `spack test` usage in packages is increasing
-    * 1669 packages with tests (mostly generic python tests)
-    * 93 packages with their own tests
-
-
-# v0.16.3 (2021-09-21)
-
-* clang/llvm: fix version detection (#19978)
-* Fix use of quotes in Python build system (#22279)
-* Cray: fix extracting paths from module files (#23472)
-* Use AWS CloudFront for source mirror (#23978)
-* Ensure all roots of an installed environment are marked explicit in db (#24277)
-* Fix fetching for Python 3.8 and 3.9 (#24686)
-* locks: only open lockfiles once instead of for every lock held (#24794)
-* Remove the EOL centos:6 docker image
-
 # v0.16.2 (2021-05-22)

 * Major performance improvement for `spack load` and other commands. (#23661)
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -1,58 +0,0 @@
-# If you are referencing Spack in a publication, please cite the SC'15 paper
-# described here.
-#
-# Here's the raw citation:
-#
-#   Todd Gamblin, Matthew P. LeGendre, Michael R. Collette, Gregory L. Lee,
-#   Adam Moody, Bronis R. de Supinski, and W. Scott Futral.
-#   The Spack Package Manager: Bringing Order to HPC Software Chaos.
-#   In Supercomputing 2015 (SC’15), Austin, Texas, November 15-20 2015. LLNL-CONF-669890.
-#
-# Or, in BibTeX:
-#
-# @inproceedings{Gamblin_The_Spack_Package_2015,
-#     address = {Austin, Texas, USA},
-#     author = {Gamblin, Todd and LeGendre, Matthew and
-#               Collette, Michael R. and Lee, Gregory L. and
-#               Moody, Adam and de Supinski, Bronis R. and Futral, Scott},
-#     doi = {10.1145/2807591.2807623},
-#     month = {November 15-20},
-#     note = {LLNL-CONF-669890},
-#     series = {Supercomputing 2015 (SC’15)},
-#     title = {{The Spack Package Manager: Bringing Order to HPC Software Chaos}},
-#     url = {https://github.com/spack/spack},
-#     year = {2015}
-# }
-#
-# And here's the CITATION.cff format:
-#
-cff-version: 1.2.0
-message: "If you are referencing Spack in a publication, please cite the paper below."
-preferred-citation:
-  type: conference-paper
-  doi: "10.1145/2807591.2807623"
-  url: "https://github.com/spack/spack"
-  authors:
-  - family-names: "Gamblin"
-    given-names: "Todd"
-  - family-names: "LeGendre"
-    given-names: "Matthew"
-  - family-names: "Collette"
-    given-names: "Michael R."
-  - family-names: "Lee"
-    given-names: "Gregory L."
-  - family-names: "Moody"
-    given-names: "Adam"
-  - family-names: "de Supinski"
-    given-names: "Bronis R."
-  - family-names: "Futral"
-    given-names: "Scott"
-  title: "The Spack Package Manager: Bringing Order to HPC Software Chaos"
-  conference:
-    name: "Supercomputing 2015 (SC’15)"
-    city: "Austin"
-    region: "Texas"
-    country: "USA"
-  month: November 15-20
-  year: 2015
-  notes: LLNL-CONF-669890
--- a/32
+++ b/32
@@ -34,22 +34,10 @@ includes the sbang tool directly in bin/sbang. These packages are covered
 by various permissive licenses. A summary listing follows. See the
 license included with each package for full details.

-PackageName: altgraph
-PackageHomePage: https://altgraph.readthedocs.io/en/latest/index.html
-PackageLicenseDeclared: MIT
-
 PackageName: argparse
 PackageHomePage: https://pypi.python.org/pypi/argparse
 PackageLicenseDeclared: Python-2.0

-PackageName: astunparse
-PackageHomePage: https://github.com/simonpercivall/astunparse
-PackageLicenseDeclared: Python-2.0
-
-PackageName: attrs
-PackageHomePage: https://github.com/python-attrs/attrs
-PackageLicenseDeclared: MIT
-
 PackageName: ctest_log_parser
 PackageHomePage: https://github.com/Kitware/CMake
 PackageLicenseDeclared: BSD-3-Clause
@@ -58,8 +46,8 @@ PackageName: distro
 PackageHomePage: https://pypi.python.org/pypi/distro
 PackageLicenseDeclared: Apache-2.0

-PackageName: functools32
-PackageHomePage: https://github.com/MiCHiLU/python-functools32
+PackageName: functools
+PackageHomePage: https://github.com/python/cpython/blob/2.7/Lib/functools.py
 PackageLicenseDeclared: Python-2.0

 PackageName: jinja2
@@ -70,10 +58,6 @@ PackageName: jsonschema
 PackageHomePage: https://pypi.python.org/pypi/jsonschema
 PackageLicenseDeclared: MIT

-PackageName: macholib
-PackageHomePage: https://macholib.readthedocs.io/en/latest/index.html
-PackageLicenseDeclared: MIT
-
 PackageName: markupsafe
 PackageHomePage: https://pypi.python.org/pypi/MarkupSafe
 PackageLicenseDeclared: BSD-3-Clause
@@ -86,10 +70,6 @@ PackageName: py
 PackageHomePage: https://pypi.python.org/pypi/py
 PackageLicenseDeclared: MIT

-PackageName: pyrsistent
-PackageHomePage: http://github.com/tobgu/pyrsistent
-PackageLicenseDeclared: MIT
-
 PackageName: pytest
 PackageHomePage: https://pypi.python.org/pypi/pytest
 PackageLicenseDeclared: MIT
@@ -105,3 +85,11 @@ PackageLicenseDeclared: Apache-2.0 OR MIT
 PackageName: six
 PackageHomePage: https://pypi.python.org/pypi/six
 PackageLicenseDeclared: MIT
+
+PackageName: macholib
+PackageHomePage: https://macholib.readthedocs.io/en/latest/index.html
+PackageLicenseDeclared: MIT
+
+PackageName: altgraph
+PackageHomePage: https://altgraph.readthedocs.io/en/latest/index.html
+PackageLicenseDeclared: MIT
--- a/2
+++ b/2
@@ -1,6 +1,6 @@
 MIT License

-Copyright (c) 2013-2022 LLNS, LLC and other Spack Project Developers.
+Copyright (c) 2013-2020 LLNS, LLC and other Spack Project Developers.

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
--- a/README.md
+++ b/README.md
@@ -2,10 +2,9 @@

 [![Unit Tests](https://github.com/spack/spack/workflows/linux%20tests/badge.svg)](https://github.com/spack/spack/actions)
 [![Bootstrapping](https://github.com/spack/spack/actions/workflows/bootstrap.yml/badge.svg)](https://github.com/spack/spack/actions/workflows/bootstrap.yml)
+[![macOS Builds (nightly)](https://github.com/spack/spack/workflows/macOS%20builds%20nightly/badge.svg?branch=develop)](https://github.com/spack/spack/actions?query=workflow%3A%22macOS+builds+nightly%22)
 [![codecov](https://codecov.io/gh/spack/spack/branch/develop/graph/badge.svg)](https://codecov.io/gh/spack/spack)
-[![Containers](https://github.com/spack/spack/actions/workflows/build-containers.yml/badge.svg)](https://github.com/spack/spack/actions/workflows/build-containers.yml)
 [![Read the Docs](https://readthedocs.org/projects/spack/badge/?version=latest)](https://spack.readthedocs.io)
-[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![Slack](https://slack.spack.io/badge.svg)](https://slack.spack.io)

 Spack is a multi-platform package manager that builds and installs
@@ -27,7 +26,7 @@ for examples and highlights.
 To install spack and your first package, make sure you have Python.
 Then:

-    $ git clone -c feature.manyFiles=true https://github.com/spack/spack.git
+    $ git clone https://github.com/spack/spack.git
    $ cd spack/bin
    $ ./spack install zlib

@@ -125,9 +124,6 @@ If you are referencing Spack in a publication, please cite the following paper:
   [**The Spack Package Manager: Bringing Order to HPC Software Chaos**](https://www.computer.org/csdl/proceedings/sc/2015/3723/00/2807623.pdf).
   In *Supercomputing 2015 (SC’15)*, Austin, Texas, November 15-20 2015. LLNL-CONF-669890.

-On GitHub, you can copy this citation in APA or BibTeX format via the "Cite this repository"
-button. Or, see the comments in `CITATION.cff` for the raw BibTeX.
-
 License
 ----------------

--- a/SECURITY.md
+++ b/SECURITY.md
@@ -1,25 +0,0 @@
-# Security Policy
-
-## Supported Versions
-
-We provide security updates for the following releases.
-For more on Spack's release structure, see
-[`README.md`](https://github.com/spack/spack#releases).
-
-
-| Version | Supported          |
-| ------- | ------------------ |
-| develop | :white_check_mark: |
-| 0.17.x  | :white_check_mark: |
-| 0.16.x  | :white_check_mark: |
-
-## Reporting a Vulnerability
-
-To report a vulnerability or other security
-issue, email maintainers@spack.io.
-
-You can expect to hear back within two days.
-If your security issue is accepted, we will do
-our best to release a fix within a week. If
-fixing the issue will take longer than this,
-we will discuss timeline options with you.
--- a/bin/haspywin.py
+++ b/bin/haspywin.py
@@ -1,18 +0,0 @@
-# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-import subprocess
-import sys
-
-
-def getpywin():
-    try:
-        import win32con  # noqa: F401
-    except ImportError:
-        subprocess.check_call([sys.executable, "-m", "pip", "-q", "install", "--upgrade", "pip"])
-        subprocess.check_call([sys.executable, "-m", "pip", "-q", "install", "pywin32"])
-
-
-if __name__ == "__main__":
-    getpywin()
--- a/bin/spack
+++ b/bin/spack
@@ -1,7 +1,7 @@
 #!/bin/sh
 # -*- python -*-
 #
-# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -33,11 +33,11 @@ import sys

 min_python3 = (3, 5)

-if sys.version_info[:2] < (2, 7) or (
+if sys.version_info[:2] < (2, 6) or (
    sys.version_info[:2] >= (3, 0) and sys.version_info[:2] < min_python3
 ):
    v_info = sys.version_info[:3]
-    msg = "Spack requires Python 2.7 or %d.%d or higher " % min_python3
+    msg = "Spack requires Python 2.6, 2.7 or %d.%d or higher " % min_python3
    msg += "You are running spack with Python %d.%d.%d." % v_info
    sys.exit(msg)

@@ -54,6 +54,8 @@ spack_external_libs = os.path.join(spack_lib_path, "external")

 if sys.version_info[:2] <= (2, 7):
    sys.path.insert(0, os.path.join(spack_external_libs, "py2"))
+if sys.version_info[:2] == (2, 6):
+    sys.path.insert(0, os.path.join(spack_external_libs, "py26"))

 sys.path.insert(0, spack_external_libs)

@@ -77,23 +79,21 @@ if "ruamel" in sys.modules:
 try:
    import argparse
 except ImportError:
-    argparse_pyc = os.path.join(spack_external_libs, "argparse.pyc")
+    argparse_pyc = os.path.join(spack_external_libs, 'argparse.pyc')
    if not os.path.exists(argparse_pyc):
        raise
    try:
        os.remove(argparse_pyc)
-        import argparse  # noqa: F401
+        import argparse  # noqa
    except Exception:
-        msg = (
-            "The file\n\n\t{0}\n\nis corrupted and cannot be deleted by Spack. "
-            "Either delete it manually or ask some administrator to "
-            "delete it for you."
-        )
+        msg = ('The file\n\n\t{0}\n\nis corrupted and cannot be deleted by Spack. '
+               'Either delete it manually or ask some administrator to '
+               'delete it for you.')
        print(msg.format(argparse_pyc))
        sys.exit(1)


-import spack.main  # noqa: E402
+import spack.main  # noqa

 # Once we've set up the system path, run the spack main method
 if __name__ == "__main__":
--- a/bin/spack-python
+++ b/bin/spack-python
@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/bin/spack.bat
+++ b/bin/spack.bat
@@ -1,223 +0,0 @@
-:: Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
-:: Spack Project Developers. See the top-level COPYRIGHT file for details.
-::
-:: SPDX-License-Identifier: (Apache-2.0 OR MIT)
-::#######################################################################
-::
-:: This file is part of Spack and sets up the spack environment for batch,
-:: This includes environment modules and lmod support,
-:: and it also puts spack in your path. The script also checks that at least
-:: module support exists, and provides suggestions if it doesn't. Source
-:: it like this:
-::
-::    . /path/to/spack/install/spack_cmd.bat
-::
-@echo off
-
-set spack=%SPACK_ROOT%\bin\spack
-
-::#######################################################################
-:: This is a wrapper around the spack command that forwards calls to
-:: 'spack load' and 'spack unload' to shell functions.  This in turn
-:: allows them to be used to invoke environment modules functions.
-::
-:: 'spack load' is smarter than just 'load' because it converts its
-:: arguments into a unique Spack spec that is then passed to module
-:: commands.  This allows the user to use packages without knowing all
-:: their installation details.
-::
-:: e.g., rather than requiring a full spec for libelf, the user can type:
-::
-::     spack load libelf
-::
-:: This will first find the available libelf module file and use a
-:: matching one.  If there are two versions of libelf, the user would
-:: need to be more specific, e.g.:
-::
-::     spack load libelf@0.8.13
-::
-:: This is very similar to how regular spack commands work and it
-:: avoids the need to come up with a user-friendly naming scheme for
-:: spack module files.
-::#######################################################################
-
-:_sp_shell_wrapper
-set "_sp_flags="
-set "_sp_args="
-set "_sp_subcommand="
-setlocal enabledelayedexpansion
-:: commands have the form '[flags] [subcommand] [args]'
-:: flags will always start with '-', e.g. --help or -V
-:: subcommands will never start with '-'
-:: everything after the subcommand is an arg
-for %%x in (%*) do (
-    set t="%%~x"
-    if "!t:~0,1!" == "-" (
-        if defined _sp_subcommand (
-            :: We already have a subcommand, processing args now
-            set "_sp_args=!_sp_args! !t!"
-        ) else (
-            set "_sp_flags=!_sp_flags! !t!"
-            shift
-        )
-    ) else if not defined _sp_subcommand (
-        set "_sp_subcommand=!t!"
-        shift
-    ) else (
-        set "_sp_args=!_sp_args! !t!"
-        shift
-    )
-)
-
-:: --help, -h and -V flags don't require further output parsing.
-:: If we encounter, execute and exit
-if defined _sp_flags (
-    if NOT "%_sp_flags%"=="%_sp_flags:-h=%" (
-        python "%spack%" %_sp_flags%
-        exit /B 0
-    ) else if NOT "%_sp_flags%"=="%_sp_flags:--help=%" (
-        python "%spack%" %_sp_flags%
-        exit /B 0
-    ) else if NOT "%_sp_flags%"=="%_sp_flags:-V=%" (
-        python "%spack%" %_sp_flags%
-        exit /B 0
-    )
-)
-:: pass parsed variables outside of local scope. Need to do
-:: this because delayedexpansion can only be set by setlocal
-echo %_sp_flags%>flags
-echo %_sp_args%>args
-echo %_sp_subcommand%>subcmd
-endlocal
-set /p _sp_subcommand=<subcmd
-set /p _sp_flags=<flags
-set /p _sp_args=<args
-set str_subcommand=%_sp_subcommand:"='%
-set str_flags=%_sp_flags:"='%
-set str_args=%_sp_args:"='%
-if "%str_subcommand%"=="ECHO is off." (set "_sp_subcommand=")
-if "%str_flags%"=="ECHO is off." (set "_sp_flags=")
-if "%str_args%"=="ECHO is off." (set "_sp_args=")
-del subcmd
-del flags
-del args
-
-:: Filter out some commands. For any others, just run the command.
-if "%_sp_subcommand%" == "cd" (
-    goto :case_cd
-) else if "%_sp_subcommand%" == "env" (
-    goto :case_env
-) else if "%_sp_subcommand%" == "load" (
-    goto :case_load
-) else if "%_sp_subcommand%" == "unload" (
-    goto :case_load
-) else (
-    goto :default_case
-)
-
-::#######################################################################
-
-:case_cd
-:: Check for --help or -h
-:: TODO: This is not exactly the same as setup-env.
-:: In setup-env, '--help' or '-h' must follow the cd
-:: Here, they may be anywhere in the args
-if defined _sp_args (
-    if NOT "%_sp_args%"=="%_sp_args:--help=%" (
-        python "%spack%" cd -h
-        goto :end_switch
-    ) else if NOT "%_sp_args%"=="%_sp_args:-h=%" (
-        python "%spack%" cd -h
-        goto :end_switch
-    )
-)
-
-for /F "tokens=* USEBACKQ" %%F in (
-  `python "%spack%" location %_sp_args%`) do (
-    set "LOC=%%F"
-)
-for %%Z in ("%LOC%") do if EXIST %%~sZ\NUL (cd /d "%LOC%")
-goto :end_switch
-
-:case_env
-:: If no args or args contain --bat or -h/--help: just execute.
-if NOT defined _sp_args (
-    goto :default_case
-)else if NOT "%_sp_args%"=="%_sp_args:--help=%" (
-    goto :default_case
-) else if NOT "%_sp_args%"=="%_sp_args: -h=%" (
-    goto :default_case
-) else if NOT "%_sp_args%"=="%_sp_args:--bat=%" (
-    goto :default_case
-) else if NOT "%_sp_args%"=="%_sp_args:deactivate=%" (
-    for /f "tokens=* USEBACKQ" %%I in (
-        `call python "%spack%" %_sp_flags% env deactivate --bat %_sp_args:deactivate=%`
-    ) do %%I
-) else if NOT "%_sp_args%"=="%_sp_args:activate=%" (
-    for /f "tokens=* USEBACKQ" %%I in (
-        `call python "%spack%" %_sp_flags% env activate --bat %_sp_args:activate=%`
-    ) do %%I
-) else (
-    goto :default_case
-)
-goto :end_switch
-
-:case_load
-:: If args contain --sh, --csh, or -h/--help: just execute.
-if defined _sp_args (
-    if NOT "%_sp_args%"=="%_sp_args:--help=%" (
-        goto :default_case
-    ) else if NOT "%_sp_args%"=="%_sp_args: -h=%" (
-        goto :default_case
-    ) else if NOT "%_sp_args%"=="%_sp_args:--bat=%" (
-        goto :default_case
-    )
-)
-
-for /f "tokens=* USEBACKQ" %%I in (
-    `python "%spack%" %_sp_flags% %_sp_subcommand% --bat %_sp_args%`) do %%I
-)
-goto :end_switch
-
-:case_unload
-goto :case_load
-
-:default_case
-python "%spack%" %_sp_flags% %_sp_subcommand% %_sp_args%
-goto :end_switch
-
-:end_switch
-exit /B %ERRORLEVEL%
-
-
-::########################################################################
-:: Prepends directories to path, if they exist.
-::      pathadd /path/to/dir            # add to PATH
-:: or   pathadd OTHERPATH /path/to/dir  # add to OTHERPATH
-::########################################################################
-
-:_spack_pathadd
-set "_pa_varname=PATH"
-set "_pa_new_path=%~1"
-if NOT "%~2" == "" (
-    set "_pa_varname=%~1"
-    set "_pa_new_path=%~2"
-    )
-set "_pa_oldvalue=%_pa_varname%"
-for %%Z in ("%_pa_new_path%") do if EXIST %%~sZ\NUL (
-    if defined %_pa_oldvalue% (
-        set "_pa_varname=%_pa_new_path%:%_pa_oldvalue%"
-    ) else (
-        set "_pa_varname=%_pa_new_path%"
-    )
-)
-exit /b 0
-
-:: set module system roots
-:_sp_multi_pathadd 
-for %%I in (%~2) do (
-    for %%Z in (%_sp_compatible_sys_types%) do (
-        :pathadd "%~1" "%%I\%%Z"
-    )
-)
-exit /B %ERRORLEVEL%
--- a/bin/spack_cmd.bat
+++ b/bin/spack_cmd.bat
@@ -1,72 +0,0 @@
-@ECHO OFF
-setlocal EnableDelayedExpansion
-:: (c) 2021 Lawrence Livermore National Laboratory
-:: To use this file independently of Spack's installer, execute this script in its directory, or add the
-:: associated bin directory to your PATH. Invoke to launch Spack Shell.
-::
-:: source_dir/spack/bin/spack_cmd.bat
-::
-pushd %~dp0..
-set SPACK_ROOT=%CD%
-pushd %CD%\..
-set spackinstdir=%CD%
-popd
-
-
-:: Check if Python is on the PATH
-if not defined python_pf_ver (
-(for /f "delims=" %%F in ('where python.exe') do (
-                                                    set "python_pf_ver=%%F"
-                                                    goto :found_python
-                                                  ) ) 2> NUL
-)
-:found_python
-if not defined python_pf_ver (
-    :: If not, look for Python from the Spack installer
-    :get_builtin
-    (for /f "tokens=*" %%g in ('dir /b /a:d "!spackinstdir!\Python*"') do (
-        set "python_ver=%%g")) 2> NUL
-
-    if not defined python_ver (
-        echo Python was not found on your system.
-        echo Please install Python or add Python to your PATH.
-    ) else (
-        set "py_path=!spackinstdir!\!python_ver!"
-        set "py_exe=!py_path!\python.exe"
-    )
-    goto :exitpoint
-) else (
-    :: Python is already on the path
-    set "py_exe=!python_pf_ver!"
-    (for /F "tokens=* USEBACKQ" %%F in (
-        `"!py_exe!" --version`) do (set "output=%%F")) 2>NUL
-    if not "!output:Microsoft Store=!"=="!output!" goto :get_builtin
-    goto :exitpoint
-)
-:exitpoint
-
-set "PATH=%SPACK_ROOT%\bin\;%PATH%"
-if defined py_path (
-    set "PATH=%py_path%;%PATH%"
-)
-
-if defined py_exe (
-    "%py_exe%" "%SPACK_ROOT%\bin\haspywin.py"
-    "%py_exe%" "%SPACK_ROOT%\bin\spack" external find python >NUL
-)
-
-set "EDITOR=notepad"
-
-DOSKEY spacktivate=spack env activate $*
-
-@echo **********************************************************************
-@echo ** Spack Package Manager
-@echo **********************************************************************
-
-IF "%1"=="" GOTO CONTINUE
-set
-GOTO:EOF
-
-:continue
-set PROMPT=[spack] %PROMPT%
-%comspec% /k
--- a/bin/spack_pwsh.ps1
+++ b/bin/spack_pwsh.ps1
@@ -1,10 +0,0 @@
-# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-$Env:SPACK_PS1_PATH="$PSScriptRoot\..\share\spack\setup-env.ps1"
-& (Get-Process -Id $pid).Path -NoExit {
-     . $Env:SPACK_PS1_PATH ; 
-    Push-Location $ENV:SPACK_ROOT
- }
--- a/etc/spack/defaults/bootstrap.yaml
+++ b/etc/spack/defaults/bootstrap.yaml
@@ -4,19 +4,29 @@ bootstrap:
  enable: true
  # Root directory for bootstrapping work. The software bootstrapped
  # by Spack is installed in a "store" subfolder of this root directory
-  root: $user_cache_path/bootstrap
+  root: ~/.spack/bootstrap
  # Methods that can be used to bootstrap software. Each method may or
-  # may not be able to bootstrap all the software that Spack needs,
+  # may not be able to bootstrap all of the software that Spack needs,
  # depending on its type.
  sources:
-  - name: 'github-actions-v0.2'
-    metadata: $spack/share/spack/bootstrap/github-actions-v0.2
-  - name: 'github-actions-v0.1'
-    metadata: $spack/share/spack/bootstrap/github-actions-v0.1
-  - name: 'spack-install'
-    metadata: $spack/share/spack/bootstrap/spack-install
+  - name: 'github-actions'
+    type: buildcache
+    description: |
+      Buildcache generated from a public workflow using Github Actions.
+      The sha256 checksum of binaries is checked before installation.
+    info:
+      url: https://mirror.spack.io/bootstrap/github-actions/v0.1
+      homepage: https://github.com/alalazo/spack-bootstrap-mirrors
+      releases: https://github.com/alalazo/spack-bootstrap-mirrors/releases
+  # This method is just Spack bootstrapping the software it needs from sources.
+  # It has been added here so that users can selectively disable bootstrapping
+  # from sources by "untrusting" it.
+  - name: spack-install
+    type: install
+    description: |
+      Specs built from sources by Spack. May take a long time.
  trusted:
    # By default we trust bootstrapping from sources and from binaries
    # produced on Github via the workflow
-    github-actions-v0.2: true
-    spack-install: true
+    github-actions: true
+    spack-install: true
--- a/etc/spack/defaults/concretizer.yaml
+++ b/etc/spack/defaults/concretizer.yaml
@@ -1,36 +0,0 @@
-# -------------------------------------------------------------------------
-# This is the default spack configuration file.
-#
-# Settings here are versioned with Spack and are intended to provide
-# sensible defaults out of the box. Spack maintainers should edit this
-# file to keep it current.
-#
-# Users can override these settings by editing
-# `$SPACK_ROOT/etc/spack/concretizer.yaml`, `~/.spack/concretizer.yaml`,
-# or by adding a `concretizer:` section to an environment.
-# -------------------------------------------------------------------------
-concretizer:
-  # Whether to consider installed packages or packages from buildcaches when
-  # concretizing specs. If `true`, we'll try to use as many installs/binaries
-  # as possible, rather than building. If `false`, we'll always give you a fresh
-  # concretization.
-  reuse: true
-  # Options that tune which targets are considered for concretization. The
-  # concretization process is very sensitive to the number targets, and the time
-  # needed to reach a solution increases noticeably with the number of targets
-  # considered.
-  targets:
-    # Determine whether we want to target specific or generic microarchitectures.
-    # An example of the first kind might be for instance "skylake" or "bulldozer",
-    # while generic microarchitectures are for instance "aarch64" or "x86_64_v4".
-    granularity: microarchitectures
-    # If "false" allow targets that are incompatible with the current host (for
-    # instance concretize with target "icelake" while running on "haswell").
-    # If "true" only allow targets that are compatible with the host.
-    host_compatible: true
-  # When "true" concretize root specs of environments together, so that each unique
-  # package in an environment corresponds to one concrete spec. This ensures
-  # environments can always be activated. When "false" perform concretization separately
-  # on each root spec, allowing different versions and variants of the same package in
-  # an environment.
-  unify: false
--- a/etc/spack/defaults/config.yaml
+++ b/etc/spack/defaults/config.yaml
@@ -33,9 +33,6 @@ config:
  template_dirs:
    - $spack/share/spack/templates

-  # Directory where licenses should be located
-  license_dir: $spack/etc/spack/licenses
-
  # Temporary locations Spack can try to use for builds.
  #
  # Recommended options are given below.
@@ -45,8 +42,8 @@ config:
  # (i.e., ``$TMP` or ``$TMPDIR``).
  #
  # Another option that prevents conflicts and potential permission issues is
-  # to specify `$user_cache_path/stage`, which ensures each user builds in their
-  # home directory.
+  # to specify `~/.spack/stage`, which ensures each user builds in their home
+  # directory.
  #
  # A more traditional path uses the value of `$spack/var/spack/stage`, which
  # builds directly inside Spack's instance without staging them in a
@@ -63,13 +60,13 @@ config:
  # identifies Spack staging to avoid accidentally wiping out non-Spack work.
  build_stage:
    - $tempdir/$user/spack-stage
-    - $user_cache_path/stage
+    - ~/.spack/stage
  # - $spack/var/spack/stage

  # Directory in which to run tests and store test results.
  # Tests will be stored in directories named by date/time and package
  # name/hash.
-  test_stage: $user_cache_path/test
+  test_stage: ~/.spack/test

  # Cache directory for already downloaded source tarballs and archived
  # repositories. This can be purged with `spack clean --downloads`.
@@ -78,7 +75,7 @@ config:

  # Cache directory for miscellaneous files, like the package index.
  # This can be purged with `spack clean --misc-cache`
-  misc_cache: $user_cache_path/cache
+  misc_cache: ~/.spack/cache


  # Timeout in seconds used for downloading sources etc. This only applies
@@ -137,7 +134,7 @@ config:
  # enabling locks.
  locks: true

-  # The default url fetch method to use.
+  # The default url fetch method to use. 
  # If set to 'curl', Spack will require curl on the user's system
  # If set to 'urllib', Spack will use python built-in libs to fetch
  url_fetch_method: urllib
@@ -158,18 +155,16 @@ config:

  # The concretization algorithm to use in Spack. Options are:
  #
-  #   'clingo': Uses a logic solver under the hood to solve DAGs with full
-  #       backtracking and optimization for user preferences. Spack will
-  #       try to bootstrap the logic solver, if not already available.
-  #
  #   'original': Spack's original greedy, fixed-point concretizer. This
  #       algorithm can make decisions too early and will not backtrack
-  #       sufficiently for many specs. This will soon be deprecated in
-  #       favor of clingo.
+  #       sufficiently for many specs.
  #
-  # See `concretizer.yaml` for more settings you can fine-tune when
-  # using clingo.
-  concretizer: clingo
+  #   'clingo': Uses a logic solver under the hood to solve DAGs with full
+  #       backtracking and optimization for user preferences.
+  #
+  # 'clingo' currently requires the clingo ASP solver to be installed and
+  # built with python bindings. 'original' is built in.
+  concretizer: original


  # How long to wait to lock the Spack installation database. This lock is used
@@ -196,8 +191,3 @@ config:
  # Set to 'false' to allow installation on filesystems that doesn't allow setgid bit
  # manipulation by unprivileged user (e.g. AFS)
  allow_sgid: true
-
-  # Whether to set the terminal title to display status information during
-  # building and installing packages. This gives information about Spack's
-  # current progress as well as the current and total number of packages.
-  terminal_title: false
--- a/etc/spack/defaults/cray/modules.yaml
+++ b/etc/spack/defaults/cray/modules.yaml
@@ -13,4 +13,9 @@
 # Per-user settings (overrides default and site settings):
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
-modules: {}
+modules:
+  prefix_inspections:
+    lib:
+      - LD_LIBRARY_PATH
+    lib64:
+      - LD_LIBRARY_PATH
--- a/etc/spack/defaults/darwin/modules.yaml
+++ b/etc/spack/defaults/darwin/modules.yaml
@@ -15,7 +15,7 @@
 # -------------------------------------------------------------------------
 modules:
  prefix_inspections:
-    ./lib:
+    lib:
      - DYLD_FALLBACK_LIBRARY_PATH
-    ./lib64:
+    lib64:
      - DYLD_FALLBACK_LIBRARY_PATH
--- a/etc/spack/defaults/linux/modules.yaml
+++ b/etc/spack/defaults/linux/modules.yaml
@@ -13,4 +13,9 @@
 # Per-user settings (overrides default and site settings):
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
-modules: {}
+modules:
+  prefix_inspections:
+    lib:
+      - LD_LIBRARY_PATH
+    lib64:
+      - LD_LIBRARY_PATH
--- a/etc/spack/defaults/modules.yaml
+++ b/etc/spack/defaults/modules.yaml
@@ -14,43 +14,39 @@
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
 modules:
-  # This maps paths in the package install prefix to environment variables
-  # they should be added to. For example, <prefix>/bin should be in PATH.
+  # Paths to check when creating modules for all module sets
  prefix_inspections:
-    ./bin:
+    bin:
      - PATH
-    ./man:
+    man:
      - MANPATH
-    ./share/man:
+    share/man:
      - MANPATH
-    ./share/aclocal:
+    share/aclocal:
      - ACLOCAL_PATH
-    ./lib/pkgconfig:
+    lib/pkgconfig:
      - PKG_CONFIG_PATH
-    ./lib64/pkgconfig:
+    lib64/pkgconfig:
      - PKG_CONFIG_PATH
-    ./share/pkgconfig:
+    share/pkgconfig:
      - PKG_CONFIG_PATH
-    ./:
+    '':
      - CMAKE_PREFIX_PATH

  # These are configurations for the module set named "default"
  default:
+    # These values are defaulted in the code. They are not defaulted here so
+    # that we can enable backwards compatibility with the old syntax more
+    # easily (old value is in the config yaml, config:module_roots)
    # Where to install modules
-    roots:
-     tcl:    $spack/share/spack/modules
-     lmod:   $spack/share/spack/lmod
+    # roots:
+    #  tcl:    $spack/share/spack/modules
+    #  lmod:   $spack/share/spack/lmod
    # What type of modules to use
    enable:
      - tcl

-    tcl:
-      all:
-        autoload: none
-
    # Default configurations if lmod is enabled
    lmod:
-      all:
-        autoload: direct
      hierarchy:
        - mpi
--- a/etc/spack/defaults/packages.yaml
+++ b/etc/spack/defaults/packages.yaml
@@ -25,19 +25,16 @@ packages:
      fftw-api: [fftw, amdfftw]
      flame: [libflame, amdlibflame]
      fuse: [libfuse]
-      gl: [glx, osmesa]
+      gl: [mesa+opengl, mesa18, opengl]
      glu: [mesa-glu, openglu]
+      glx: [mesa+glx, mesa18+glx, opengl]
      golang: [gcc]
      iconv: [libiconv]
      ipp: [intel-ipp]
      java: [openjdk, jdk, ibm-java]
      jpeg: [libjpeg-turbo, libjpeg]
      lapack: [openblas, amdlibflame]
-      libglx: [mesa+glx, mesa18+glx]
-      libllvm: [llvm]
-      libosmesa: [mesa+osmesa, mesa18+osmesa]
-      lua-lang: [lua, lua-luajit-openresty, lua-luajit]
-      luajit: [lua-luajit-openresty, lua-luajit]
+      lua-lang: [lua, lua-luajit]
      mariadb-client: [mariadb-c-client, mariadb]
      mkl: [intel-mkl]
      mpe: [mpe2]
@@ -45,6 +42,7 @@ packages:
      mysql-client: [mysql, mariadb-c-client]
      opencl: [pocl]
      onedal: [intel-oneapi-dal]
+      osmesa: [mesa+osmesa, mesa18+osmesa]
      pbs: [openpbs, torque]
      pil: [py-pillow]
      pkgconfig: [pkgconf, pkg-config]
--- a/etc/spack/defaults/windows/config.yaml
+++ b/etc/spack/defaults/windows/config.yaml
@@ -1,5 +0,0 @@
-config:
-  locks: false
-  concretizer: original
-  build_stage::
-    - '$spack/.staging'
--- a/lib/spack/docs/analyze.rst
+++ b/lib/spack/docs/analyze.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -59,7 +59,7 @@ are available:
    install_files            : install file listing read from install_manifest.json
    environment_variables    : environment variables parsed from spack-build-env.txt
    config_args              : config args loaded from spack-configure-args.txt
-    libabigail               : Application Binary Interface (ABI) features for objects
+    abigail                  : Application Binary Interface (ABI) features for objects


 In the above, the first three are fairly simple - parsing metadata files from
--- a/lib/spack/docs/basic_usage.rst
+++ b/lib/spack/docs/basic_usage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -31,13 +31,13 @@ colorized output with a flag

 .. code-block:: console

-    $ spack --color always find | less -R
+    $ spack --color always | less -R

 or an environment variable

 .. code-block:: console

-   $ SPACK_COLOR=always spack find | less -R
+   $ SPACK_COLOR=always spack | less -R

 --------------------------
 Listing available packages
@@ -188,37 +188,6 @@ configuration a **spec**.  In the commands above, ``mpileaks`` and
 ``mpileaks@3.0.4`` are both valid *specs*.  We'll talk more about how
 you can use them to customize an installation in :ref:`sec-specs`.

-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Reusing installed dependencies
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-By default, when you run ``spack install``, Spack tries hard to reuse existing installations
-as dependencies, either from a local store or from remote buildcaches if configured.
-This minimizes unwanted rebuilds of common dependencies, in particular if
-you update Spack frequently.
-
-In case you want the latest versions and configurations to be installed instead,
-you can add the ``--fresh`` option:
-
-.. code-block:: console
-
-   $ spack install --fresh mpich
-
-Reusing installations in this mode is "accidental", and happening only if
-there's a match between existing installations and what Spack would have installed
-anyhow.
-
-You can use the ``spack spec -I mpich`` command to see what
-will be reused and what will be built before you install.
-
-You can configure Spack to use the ``--fresh`` behavior by default in
-``concretizer.yaml``:
-
-.. code-block:: yaml
-
-   concretizer:
-     reuse: false
-
 .. _cmd-spack-uninstall:

 ^^^^^^^^^^^^^^^^^^^
@@ -896,12 +865,11 @@ your path:
   $ which mpicc
   ~/spack/opt/linux-debian7-x86_64/gcc@4.4.7/mpich@3.0.4/bin/mpicc

-These commands will add appropriate directories to your ``PATH``
-and ``MANPATH`` according to the
+These commands will add appropriate directories to your ``PATH``,
+``MANPATH``, ``CPATH``, and ``LD_LIBRARY_PATH`` according to the
 :ref:`prefix inspections <customize-env-modifications>` defined in your
-modules configuration.
-When you no longer want to use a package, you can type unload or
-unuse similarly:
+modules configuration.  When you no longer want to use a package, you
+can type unload or unuse similarly:

 .. code-block:: console

@@ -942,22 +910,6 @@ first ``libelf`` above, you would run:

   $ spack load /qmm4kso

-To see which packages that you have loaded to your enviornment you would
-use ``spack find --loaded``.
-
-.. code-block:: console
-
-    $ spack find --loaded
-    ==> 2 installed packages
-    -- linux-debian7 / gcc@4.4.7 ------------------------------------
-    libelf@0.8.13
-
-    -- linux-debian7 / intel@15.0.0 ---------------------------------
-    libelf@0.8.13
-
-You can also use ``spack load --list`` to get the same output, but it
-does not have the full set of query options that ``spack find`` offers.
-
 We'll learn more about Spack's spec syntax in the next section.


@@ -1093,8 +1045,6 @@ could depend on ``mpich@1.2:`` if it can only build with version

 Below are more details about the specifiers that you can add to specs.

-.. _version-specifier:
-
 ^^^^^^^^^^^^^^^^^
 Version specifier
 ^^^^^^^^^^^^^^^^^
@@ -1110,37 +1060,6 @@ set of arbitrary versions, such as ``@1.0,1.5,1.7`` (``1.0``, ``1.5``,
 or ``1.7``).  When you supply such a specifier to ``spack install``,
 it constrains the set of versions that Spack will install.

-For packages with a ``git`` attribute, ``git`` references 
-may be specified instead of a numerical version i.e. branches, tags 
-and commits. Spack will stage and build based off the ``git`` 
-reference provided.  Acceptable syntaxes for this are:
-
-.. code-block:: sh
-   
-    # branches and tags
-   foo@git.develop # use the develop branch
-   foo@git.0.19 # use the 0.19 tag
-   
-    # commit hashes
-   foo@abcdef1234abcdef1234abcdef1234abcdef1234    # 40 character hashes are automatically treated as git commits
-   foo@git.abcdef1234abcdef1234abcdef1234abcdef1234
-   
-Spack versions from git reference either have an associated version supplied by the user,
-or infer a relationship to known versions from the structure of the git repository. If an
-associated version is supplied by the user, Spack treats the git version as equivalent to that
-version for all version comparisons in the package logic (e.g. ``depends_on('foo', when='@1.5')``).
-
-The associated version can be assigned with ``[git ref]=[version]`` syntax, with the caveat that the specified version is known to Spack from either the package definition, or in the configuration preferences (i.e. ``packages.yaml``).
-
-.. code-block:: sh
-
-   foo@git.my_ref=3.2 # use the my_ref tag or branch, but treat it as version 3.2 for version comparisons
-   foo@git.abcdef1234abcdef1234abcdef1234abcdef1234=develop # use the given commit, but treat it as develop for version comparisons
-
-If an associated version is not supplied then the tags in the git repo are used to determine
-the most recent previous version known to Spack. Details about how versions are compared
-and how Spack determines if one version is less than another are discussed in the developer guide.
-
 If the version spec is not provided, then Spack will choose one
 according to policies set for the particular spack installation.  If
 the spec is ambiguous, i.e. it could match multiple versions, Spack
@@ -1316,7 +1235,7 @@ Normally users don't have to bother specifying the architecture if they
 are installing software for their current host, as in that case the
 values will be detected automatically.  If you need fine-grained control
 over which packages use which targets (or over *all* packages' default
-target), see :ref:`package-preferences`.
+target), see :ref:`concretization-preferences`.

 .. admonition:: Cray machines

@@ -1730,7 +1649,6 @@ and it will be added to the ``PYTHONPATH`` in your current shell:

 Now ``import numpy`` will succeed for as long as you keep your current
 session open.
-The loaded packages can be checked using ``spack find --loaded``

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Loading Extensions via Modules
@@ -1756,8 +1674,8 @@ Activating Extensions in a View

 Another way to use extensions is to create a view, which merges the
 python installation along with the extensions into a single prefix.
-See :ref:`configuring_environment_views` for a more in-depth description
-of views.
+See :ref:`filesystem-views` for a more in-depth description of views and
+:ref:`cmd-spack-view` for usage of the ``spack view`` command.

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Activating Extensions Globally
--- a/lib/spack/docs/binary_caches.rst
+++ b/lib/spack/docs/binary_caches.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -50,13 +50,6 @@ build cache files for the "ninja" spec:
 Note that the targeted spec must already be installed. Once you have a build cache,
 you can add it as a mirror, discussed next.

-.. warning::
-
-   Spack improved the format used for binary caches in v0.18. The entire v0.18 series
-   will be able to verify and install binary caches both in the new and in the old format.
-   Support for using the old format is expected to end in v0.19, so we advise users to
-   recreate relevant buildcaches using Spack v0.18 or higher.
-
 ---------------------------------------
 Finding or installing build cache files
 ---------------------------------------
--- a/lib/spack/docs/bootstrapping.rst
+++ b/lib/spack/docs/bootstrapping.rst
@@ -1,160 +0,0 @@
-.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
-   Spack Project Developers. See the top-level COPYRIGHT file for details.
-
-   SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-.. _bootstrapping:
-
-=============
-Bootstrapping
-=============
-
-In the :ref:`Getting started <getting_started>` Section we already mentioned that
-Spack can bootstrap some of its dependencies, including ``clingo``. In fact, there
-is an entire command dedicated to the management of every aspect of bootstrapping:
-
-.. command-output:: spack bootstrap --help
-
-The first thing to know to understand bootstrapping in Spack is that each of
-Spack's dependencies is bootstrapped lazily; i.e. the first time it is needed and
-can't be found. You can readily check if any prerequisite for using Spack
-is missing by running:
-
-.. code-block:: console
-
-   % spack bootstrap status
-   Spack v0.17.1 - python@3.8
-
-   [FAIL] Core Functionalities
-     [B] MISSING "clingo": required to concretize specs
-
-   [FAIL] Binary packages
-     [B] MISSING "gpg2": required to sign/verify buildcaches
-
-
-   Spack will take care of bootstrapping any missing dependency marked as [B]. Dependencies marked as [-] are instead required to be found on the system.
-
-In the case of the output shown above Spack detected that both ``clingo`` and ``gnupg``
-are missing and it's giving detailed information on why they are needed and whether
-they can be bootstrapped. Running a command that concretize a spec, like:
-
-.. code-block:: console
-
-   % spack solve zlib
-   ==> Bootstrapping clingo from pre-built binaries
-   ==> Fetching https://mirror.spack.io/bootstrap/github-actions/v0.1/build_cache/darwin-catalina-x86_64/apple-clang-12.0.0/clingo-bootstrap-spack/darwin-catalina-x86_64-apple-clang-12.0.0-clingo-bootstrap-spack-p5on7i4hejl775ezndzfdkhvwra3hatn.spack
-   ==> Installing "clingo-bootstrap@spack%apple-clang@12.0.0~docs~ipo+python build_type=Release arch=darwin-catalina-x86_64" from a buildcache
-   [ ... ]
-
-triggers the bootstrapping of clingo from pre-built binaries as expected.
-
-----------------------
-The Bootstrapping store
-----------------------
-
-The software installed for bootstrapping purposes is deployed in a separate store.
-Its location can be checked with the following command:
-
-.. code-block:: console
-
-   % spack bootstrap root
-
-It can also be changed with the same command by just specifying the newly desired path:
-
-.. code-block:: console
-
-   % spack bootstrap root /opt/spack/bootstrap
-
-You can check what is installed in the bootstrapping store at any time using:
-
-.. code-block:: console
-
-   % spack find -b
-   ==> Showing internal bootstrap store at "/Users/spack/.spack/bootstrap/store"
-   ==> 11 installed packages
-   -- darwin-catalina-x86_64 / apple-clang@12.0.0 ------------------
-   clingo-bootstrap@spack  libassuan@2.5.5  libgpg-error@1.42  libksba@1.5.1  pinentry@1.1.1  zlib@1.2.11
-   gnupg@2.3.1             libgcrypt@1.9.3  libiconv@1.16      npth@1.6       python@3.8
-
-In case it is needed you can remove all the software in the current bootstrapping store with:
-
-.. code-block:: console
-
-   % spack clean -b
-   ==> Removing bootstrapped software and configuration in "/Users/spack/.spack/bootstrap"
-
-   % spack find -b
-   ==> Showing internal bootstrap store at "/Users/spack/.spack/bootstrap/store"
-   ==> 0 installed packages
-
--------------------------------------------
-Enabling and disabling bootstrapping methods
--------------------------------------------
-
-Bootstrapping is always performed by trying the methods listed by:
-
-.. command-output:: spack bootstrap list
-
-in the order they appear, from top to bottom. By default Spack is
-configured to try first bootstrapping from pre-built binaries and to
-fall-back to bootstrapping from sources if that failed.
-
-If need be, you can disable bootstrapping altogether by running:
-
-.. code-block:: console
-
-   % spack bootstrap disable
-
-in which case it's your responsibility to ensure Spack runs in an
-environment where all its prerequisites are installed. You can
-also configure Spack to skip certain bootstrapping methods by *untrusting*
-them. For instance:
-
-.. code-block:: console
-
-   % spack bootstrap untrust github-actions
-   ==> "github-actions" is now untrusted and will not be used for bootstrapping
-
-tells Spack to skip trying to bootstrap from binaries. To add the "github-actions" method back you can:
-
-.. code-block:: console
-
-   % spack bootstrap trust github-actions
-
-There is also an option to reset the bootstrapping configuration to Spack's defaults:
-
-.. code-block:: console
-
-   % spack bootstrap reset
-   ==> Bootstrapping configuration is being reset to Spack's defaults. Current configuration will be lost.
-   Do you want to continue? [Y/n]
-   %
-
----------------------------------------
-Creating a mirror for air-gapped systems
----------------------------------------
-
-Spack's default configuration for bootstrapping relies on the user having
-access to the internet, either to fetch pre-compiled binaries or source tarballs.
-Sometimes though Spack is deployed on air-gapped systems where such access is denied.
-
-To help with similar situations Spack has a command that recreates, in a local folder
-of choice, a mirror containing the source tarballs and/or binary packages needed for
-bootstrapping.
-
-.. code-block:: console
-
-   % spack bootstrap mirror --binary-packages /opt/bootstrap
-   ==> Adding "clingo-bootstrap@spack+python %apple-clang target=x86_64" and dependencies to the mirror at /opt/bootstrap/local-mirror
-   ==> Adding "gnupg@2.3: %apple-clang target=x86_64" and dependencies to the mirror at /opt/bootstrap/local-mirror
-   ==> Adding "patchelf@0.13.1:0.13.99 %apple-clang target=x86_64" and dependencies to the mirror at /opt/bootstrap/local-mirror
-   ==> Adding binary packages from "https://github.com/alalazo/spack-bootstrap-mirrors/releases/download/v0.1-rc.2/bootstrap-buildcache.tar.gz" to the mirror at /opt/bootstrap/local-mirror
-
-   To register the mirror on the platform where it's supposed to be used run the following command(s):
-     % spack bootstrap add --trust local-sources /opt/bootstrap/metadata/sources
-     % spack bootstrap add --trust local-binaries /opt/bootstrap/metadata/binaries
-
-
-This command needs to be run on a machine with internet access and the resulting folder
-has to be moved over to the air-gapped system. Once the local sources are added using the
-commands suggested at the prompt, they can be used to bootstrap Spack.
--- a/lib/spack/docs/build_settings.rst
+++ b/lib/spack/docs/build_settings.rst
@@ -1,13 +1,13 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)

 .. _build-settings:

-================================
-Package Settings (packages.yaml)
-================================
+===================
+Build Customization
+===================

 Spack allows you to customize how your software is built through the
 ``packages.yaml`` file.  Using it, you can make Spack prefer particular
@@ -209,81 +209,11 @@ Specific limitations include:
  then Spack will not add a new external entry (``spack config blame packages``
  can help locate all external entries).

-.. _concretizer-options:
+.. _concretization-preferences:

----------------------
-Concretizer options
----------------------
-
-``packages.yaml`` gives the concretizer preferences for specific packages,
-but you can also use ``concretizer.yaml`` to customize aspects of the
-algorithm it uses to select the dependencies you install:
-
-.. literalinclude:: _spack_root/etc/spack/defaults/concretizer.yaml
-   :language: yaml
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Reuse already installed packages
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The ``reuse`` attribute controls whether Spack will prefer to use installed packages (``true``), or
-whether it will do a "fresh" installation and prefer the latest settings from
-``package.py`` files and ``packages.yaml`` (``false``).
-You can use:
-
-.. code-block:: console
-
-   % spack install --reuse <spec>
-
-to enable reuse for a single installation, and you can use:
-
-.. code-block:: console
-
-   spack install --fresh <spec>
-
-to do a fresh install if ``reuse`` is enabled by default.
-``reuse: true`` is the default.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Selection of the target microarchitectures
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The options under the ``targets`` attribute control which targets are considered during a solve.
-Currently the options in this section are only configurable from the ``concretization.yaml`` file
-and there are no corresponding command line arguments to enable them for a single solve.
-
-The ``granularity`` option can take two possible values: ``microarchitectures`` and ``generic``.
-If set to:
-
-.. code-block:: yaml
-
-   concretizer:
-     targets:
-       granularity: microarchitectures
-
-Spack will consider all the microarchitectures known to ``archspec`` to label nodes for
-compatibility. If instead the option is set to:
-
-.. code-block:: yaml
-
-   concretizer:
-     targets:
-       granularity: generic
-
-Spack will consider only generic microarchitectures. For instance, when running on an
-Haswell node, Spack will consider ``haswell`` as the best target in the former case and
-``x86_64_v3`` as the best target in the latter case.
-
-The ``host_compatible`` option is a Boolean option that determines whether or not the
-microarchitectures considered during the solve are constrained to be compatible with the
-host Spack is currently running on. For instance, if this option is set to ``true``, a
-user cannot concretize for ``target=icelake`` while running on an Haswell node.
-
-.. _package-preferences:
-
-------------------
-Package Preferences
-------------------
+--------------------------
+Concretization Preferences
+--------------------------

 Spack can be configured to prefer certain compilers, package
 versions, dependencies, and variants during concretization.
@@ -339,97 +269,6 @@ concretization rules.  A provider lists a value that packages may
 ``depend_on`` (e.g, MPI) and a list of rules for fulfilling that
 dependency.

-.. _package-requirements:
-
--------------------
-Package Requirements
--------------------
-
-You can use the configuration to force the concretizer to choose
-specific properties for packages when building them. Like preferences,
-these are only applied when the package is required by some other
-request (e.g. if the package is needed as a dependency of a
-request to ``spack install``).
-
-An example of where this is useful is if you have a package that
-is normally built as a dependency but only under certain circumstances
-(e.g. only when a variant on a dependent is active): you can make
-sure that it always builds the way you want it to; this distinguishes
-package configuration requirements from constraints that you add to
-``spack install`` or to environments (in those cases, the associated
-packages are always built).
-
-The following is an example of how to enforce package properties in
-``packages.yaml``:
-
-.. code-block:: yaml
-
-   packages:
-     libfabric:
-       require: "@1.13.2"
-     openmpi:
-       require:
-       - any_of: ["~cuda", "gcc"]
-     mpich:
-      require:
-      - one_of: ["+cuda", "+rocm"]
-
-Requirements are expressed using Spec syntax (the same as what is provided
-to ``spack install``). In the simplest case, you can specify attributes
-that you always want the package to have by providing a single spec to
-``require``; in the above example, ``libfabric`` will always build
-with version 1.13.2.
-
-You can provide a more-relaxed constraint and allow the concretizer to
-choose between a set of options using ``any_of`` or ``one_of``:
-
-* ``any_of`` is a list of specs. One of those specs must be satisfied
-  and it is also allowed for the concretized spec to match more than one.
-  In the above example, that means you could build ``openmpi+cuda%gcc``,
-  ``openmpi~cuda%clang`` or ``openmpi~cuda%gcc`` (in the last case,
-  note that both specs in the ``any_of`` for ``openmpi`` are
-  satisfied).
-* ``one_of`` is also a list of specs, and the final concretized spec
-  must match exactly one of them.  In the above example, that means
-  you could build ``mpich+cuda`` or ``mpich+rocm`` but not
-  ``mpich+cuda+rocm`` (note the current package definition for
-  ``mpich`` already includes a conflict, so this is redundant but
-  still demonstrates the concept).
-
-You can also set default requirements for all packages under ``all``
-like this:
-
-.. code-block:: yaml
-
-   packages:
-     all:
-       require: '%clang'
-
-which means every spec will be required to use ``clang`` as a compiler.
-
-Note that in this case ``all`` represents a *default set of requirements* -
-if there are specific package requirements, then the default requirements
-under ``all`` are disregarded. For example, with a configuration like this:
-
-.. code-block:: yaml
-
-   packages:
-     all:
-       require: '%clang'
-     cmake:
-       require: '%gcc'
-
-Spack requires ``cmake`` to use ``gcc`` and all other nodes (including cmake dependencies)
-to use ``clang``.
-
-Other notes about ``requires``:
-
-* You cannot specify requirements for virtual packages (e.g. you can
-  specify requirements for ``openmpi`` but not ``mpi``).
-* For ``any_of`` and ``one_of``, the order of specs indicates a
-  preference: items that appear earlier in the list are preferred
-  (note that these preferences can be ignored in favor of others).
-
 .. _package_permissions:

 -------------------
--- a/lib/spack/docs/build_systems.rst
+++ b/lib/spack/docs/build_systems.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -39,7 +39,6 @@ on these ideas for each distinct build system that Spack supports:

   build_systems/autotoolspackage
   build_systems/cmakepackage
-   build_systems/cachedcmakepackage
   build_systems/mesonpackage
   build_systems/qmakepackage
   build_systems/sippackage
@@ -48,12 +47,10 @@ on these ideas for each distinct build system that Spack supports:
   :maxdepth: 1
   :caption: Language-specific

-   build_systems/luapackage
   build_systems/octavepackage
   build_systems/perlpackage
   build_systems/pythonpackage
   build_systems/rpackage
-   build_systems/racketpackage
   build_systems/rubypackage

 .. toctree::
@@ -62,12 +59,11 @@ on these ideas for each distinct build system that Spack supports:

   build_systems/bundlepackage
   build_systems/cudapackage
-   build_systems/custompackage
   build_systems/inteloneapipackage
   build_systems/intelpackage
-   build_systems/multiplepackage
   build_systems/rocmpackage
-   build_systems/sourceforgepackage
+   build_systems/custompackage
+   build_systems/multiplepackage

 For reference, the :py:mod:`Build System API docs <spack.build_systems>`
 provide a list of build systems and methods/attributes that can be
--- a/lib/spack/docs/build_systems/autotoolspackage.rst
+++ b/lib/spack/docs/build_systems/autotoolspackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -112,44 +112,20 @@ phase runs:

 .. code-block:: console

-   $ autoreconf --install --verbose --force -I <aclocal-prefix>/share/aclocal
-
-In case you need to add more arguments, override ``autoreconf_extra_args``
-in your ``package.py`` on class scope like this:
-
-.. code-block:: python
-
-   autoreconf_extra_args = ["-Im4"]
+   $ libtoolize
+   $ aclocal
+   $ autoreconf --install --verbose --force

 All you need to do is add a few Autotools dependencies to the package.
 Most stable releases will come with a ``configure`` script, but if you
-check out a commit from the ``master`` branch, you would want to add:
+check out a commit from the ``develop`` branch, you would want to add:

 .. code-block:: python

-   depends_on('autoconf', type='build', when='@master')
-   depends_on('automake', type='build', when='@master')
-   depends_on('libtool',  type='build', when='@master')
-
-It is typically redundant to list the ``m4`` macro processor package as a
-dependency, since ``autoconf`` already depends on it.
-
-"""""""""""""""""""""""""""""""
-Using a custom autoreconf phase
-"""""""""""""""""""""""""""""""
-
-In some cases, it might be needed to replace the default implementation
-of the autoreconf phase with one running a script interpreter. In this
-example, the ``bash`` shell is used to run the ``autogen.sh`` script.
-
-.. code-block:: python
-
-   def autoreconf(self, spec, prefix):
-       which('bash')('autogen.sh')
-
-"""""""""""""""""""""""""""""""""""""""
-patching configure or Makefile.in files
-"""""""""""""""""""""""""""""""""""""""
+   depends_on('autoconf', type='build', when='@develop')
+   depends_on('automake', type='build', when='@develop')
+   depends_on('libtool',  type='build', when='@develop')
+   depends_on('m4',       type='build', when='@develop')

 In some cases, developers might need to distribute a patch that modifies
 one of the files used to generate ``configure`` or ``Makefile.in``.
@@ -159,57 +135,6 @@ create a new patch that directly modifies ``configure``. That way,
 Spack can use the secondary patch and additional build system
 dependencies aren't necessary.

-""""""""""""""""""""""""""""
-Old Autotools helper scripts
-""""""""""""""""""""""""""""
-
-Autotools based tarballs come with helper scripts such as ``config.sub`` and
-``config.guess``. It is the responsibility of the developers to keep these files
-up to date so that they run on every platform, but for very old software
-releases this is impossible. In these cases Spack can help to replace these
-files with newer ones, without having to add the heavy dependency on
-``automake``.
-
-Automatic helper script replacement is currently enabled by default on
-``ppc64le`` and ``aarch64``, as these are the known cases where old scripts fail.
-On these targets, ``AutotoolsPackage`` adds a build dependency on ``gnuconfig``,
-which is a very light-weight package with newer versions of the helper files.
-Spack then tries to run all the helper scripts it can find in the release, and
-replaces them on failure with the helper scripts from ``gnuconfig``.
-
-To opt out of this feature, use the following setting:
-
-.. code-block:: python
-
-   patch_config_files = False
-
-To enable it conditionally on different architectures, define a property and
-make the package depend on ``gnuconfig`` as a build dependency:
-
-.. code-block
-
-   depends_on('gnuconfig', when='@1.0:')
-
-   @property
-   def patch_config_files(self):
-      return self.spec.satisfies("@1.0:")
-
-.. note::
-
-    On some exotic architectures it is necessary to use system provided
-    ``config.sub`` and ``config.guess`` files. In this case, the most
-    transparent solution is to mark the ``gnuconfig`` package as external and
-    non-buildable, with a prefix set to the directory containing the files:
-
-   .. code-block:: yaml
-
-       gnuconfig:
-         buildable: false
-         externals:
-         - spec: gnuconfig@master
-           prefix: /usr/share/configure_files/
-
-
 """"""""""""""""
 force_autoreconf
 """"""""""""""""
@@ -399,47 +324,8 @@ options:

   --with-libfabric=</path/to/libfabric>

-"""""""""""""""""""""""
-The ``variant`` keyword
-"""""""""""""""""""""""
-
-When Spack variants and configure flags do not correspond one-to-one, the
-``variant`` keyword can be passed to ``with_or_without`` and
-``enable_or_disable``. For example:
-
-.. code-block:: python
-
-   variant('debug_tools', default=False)
-   config_args += self.enable_or_disable('debug-tools', variant='debug_tools')
-
-Or when one variant controls multiple flags:
-
-.. code-block:: python
-
-   variant('debug_tools', default=False)
-   config_args += self.with_or_without('memchecker', variant='debug_tools')
-   config_args += self.with_or_without('profiler', variant='debug_tools')
-
-
 """"""""""""""""""""
-Conditional variants
-""""""""""""""""""""
-
-When a variant is conditional and its condition is not met on the concrete spec, the
-``with_or_without`` and ``enable_or_disable`` methods will simply return an empty list.
-
-For example:
-
-.. code-block:: python
-
-   variant('profiler', when='@2.0:')
-   config_args += self.with_or_without('profiler')
-
-will neither add ``--with-profiler`` nor ``--without-profiler`` when the version is
-below ``2.0``.
-
-""""""""""""""""""""
-Activation overrides
+activation overrides
 """"""""""""""""""""

 Finally, the behavior of either ``with_or_without`` or
--- a/lib/spack/docs/build_systems/bundlepackage.rst
+++ b/lib/spack/docs/build_systems/bundlepackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/cachedcmakepackage.rst
+++ b/lib/spack/docs/build_systems/cachedcmakepackage.rst
@@ -1,123 +0,0 @@
-.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
-   Spack Project Developers. See the top-level COPYRIGHT file for details.
-
-   SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-.. _cachedcmakepackage:
-
------------------
-CachedCMakePackage
------------------
-
-The CachedCMakePackage base class is used for CMake-based workflows
-that create a CMake cache file prior to running ``cmake``. This is
-useful for packages with arguments longer than the system limit, and
-for reproducibility.
-
-The documentation for this class assumes that the user is familiar with
-the ``CMakePackage`` class from which it inherits. See the documentation
-for :ref:`CMakePackage <cmakepackage>`.
-
-^^^^^^
-Phases
-^^^^^^
-
-The ``CachedCMakePackage`` base class comes with the following phases:
-
-#. ``initconfig`` - generate the CMake cache file
-#. ``cmake`` - generate the Makefile
-#. ``build`` - build the package
-#. ``install`` - install the package
-
-By default, these phases run:
-
-.. code-block:: console
-
-   $ mkdir spack-build
-   $ cd spack-build
-   $ cat << EOF > name-arch-compiler@version.cmake
-   # Write information on compilers and dependencies
-   # includes information on mpi and cuda if applicable
-   $ cmake .. -DCMAKE_INSTALL_PREFIX=/path/to/installation/prefix -C name-arch-compiler@version.cmake
-   $ make
-   $ make test  # optional
-   $ make install
-
-The ``CachedCMakePackage`` class inherits from the ``CMakePackage``
-class, and accepts all of the same options and adds all of the same
-flags to the ``cmake`` command. Similar to the ``CMakePAckage`` class,
-you may need to add a few arguments yourself, and the
-``CachedCMakePackage`` provides the same interface to add those
-flags.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Adding entries to the CMake cache
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-In addition to adding flags to the ``cmake`` command, you may need to
-add entries to the CMake cache in the ``initconfig`` phase. This can
-be done by overriding one of four methods:
-
-#. ``CachedCMakePackage.initconfig_compiler_entries``
-#. ``CachedCMakePackage.initconfig_mpi_entries``
-#. ``CachedCMakePackage.initconfig_hardware_entries``
-#. ``CachedCMakePackage.initconfig_package_entries``
-
-Each of these methods returns a list of CMake cache strings. The
-distinction between these methods is merely to provide a
-well-structured and legible cmake cache file -- otherwise, entries
-from each of these methods are handled identically.
-
-Spack also provides convenience methods for generating CMake cache
-entries. These methods are available at module scope in every Spack
-package. Because CMake parses boolean options, strings, and paths
-differently, there are three such methods:
-
-#. ``cmake_cache_option``
-#. ``cmake_cache_string``
-#. ``cmake_cache_path``
-
-These methods each accept three parameters -- the name of the CMake
-variable associated with the entry, the value of the entry, and an
-optional comment -- and return strings in the appropriate format to be
-returned from any of the ``initconfig*`` methods. Additionally, these
-methods may return comments beginning with the ``#`` character.
-
-A typical usage of these methods may look something like this:
-
-.. code-block:: python
-
-   def initconfig_mpi_entries(self)
-       # Get existing MPI configurations
-       entries = super(self, Foo).initconfig_mpi_entries()
-
-       # The existing MPI configurations key on whether ``mpi`` is in the spec
-       # This spec has an MPI variant, and we need to enable MPI when it is on.
-       # This hypothetical package controls MPI with the ``FOO_MPI`` option to
-       # cmake.
-       if '+mpi' in self.spec:
-           entries.append(cmake_cache_option('FOO_MPI', True, "enable mpi"))
-       else:
-           entries.append(cmake_cache_option('FOO_MPI', False, "disable mpi"))
-
-   def initconfig_package_entries(self):
-       # Package specific options
-       entries = []
-
-       entries.append('#Entries for build options')
-
-       bar_on = '+bar' in self.spec
-       entries.append(cmake_cache_option('FOO_BAR', bar_on, 'toggle bar'))
-
-       entries.append('#Entries for dependencies')
-
-       if self.spec['blas'].name == 'baz':  # baz is our blas provider
-       entries.append(cmake_cache_string('FOO_BLAS', 'baz', 'Use baz'))
-       entries.append(cmake_cache_path('BAZ_PREFIX', self.spec['baz'].prefix))
-
-^^^^^^^^^^^^^^^^^^^^^^
-External documentation
-^^^^^^^^^^^^^^^^^^^^^^
-
-For more information on CMake cache files, see:
-https://cmake.org/cmake/help/latest/manual/cmake.1.html
--- a/lib/spack/docs/build_systems/cmakepackage.rst
+++ b/lib/spack/docs/build_systems/cmakepackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -145,99 +145,6 @@ and without the :meth:`~spack.build_systems.cmake.CMakePackage.define` and

       return args

-Spack supports CMake defines from conditional variants too. Whenever the condition on
-the variant is not met, ``define_from_variant()`` will simply return an empty string,
-and CMake simply ignores the empty command line argument. For example the following
-
-.. code-block:: python
-
-   variant('example', default=True, when='@2.0:')
-
-   def cmake_args(self):
-      return [self.define_from_variant('EXAMPLE', 'example')]
-
-will generate ``'cmake' '-DEXAMPLE=ON' ...`` when `@2.0: +example` is met, but will
-result in ``'cmake' '' ...`` when the spec version is below ``2.0``.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-CMake arguments provided by Spack
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The following default arguments are controlled by Spack:
-
-
-``CMAKE_INSTALL_PREFIX``
------------------------
-
-Is set to the the package's install directory.
-
-
-``CMAKE_PREFIX_PATH``
---------------------
-
-CMake finds dependencies through calls to ``find_package()``, ``find_program()``,
-``find_library()``, ``find_file()``, and ``find_path()``, which use a list of search
-paths from ``CMAKE_PREFIX_PATH``. Spack sets this variable to a list of prefixes of the
-spec's transitive dependencies.
-
-For troubleshooting cases where CMake fails to find a dependency, add the
-``--debug-find`` flag to ``cmake_args``.
-
-``CMAKE_BUILD_TYPE``
--------------------
-
-Every CMake-based package accepts a ``-DCMAKE_BUILD_TYPE`` flag to
-dictate which level of optimization to use. In order to ensure
-uniformity across packages, the ``CMakePackage`` base class adds
-a variant to control this:
-
-.. code-block:: python
-
-   variant('build_type', default='RelWithDebInfo',
-           description='CMake build type',
-           values=('Debug', 'Release', 'RelWithDebInfo', 'MinSizeRel'))
-
-However, not every CMake package accepts all four of these options.
-Grep the ``CMakeLists.txt`` file to see if the default values are
-missing or replaced. For example, the
-`dealii <https://github.com/spack/spack/blob/develop/var/spack/repos/builtin/packages/dealii/package.py>`_
-package overrides the default variant with:
-
-.. code-block:: python
-
-   variant('build_type', default='DebugRelease',
-           description='The build type to build',
-           values=('Debug', 'Release', 'DebugRelease'))
-
-For more information on ``CMAKE_BUILD_TYPE``, see:
-https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html
-
-
-``CMAKE_INSTALL_RPATH`` and ``CMAKE_INSTALL_RPATH_USE_LINK_PATH=ON``
--------------------------------------------------------------------
-
-CMake uses different RPATHs during the build and after installation, so that executables
-can locate the libraries they're linked to during the build, and installed executables
-do not have RPATHs to build directories. In Spack, we have to make sure that RPATHs are
-set properly after installation.
-
-Spack sets ``CMAKE_INSTALL_RPATH`` to a list of ``<prefix>/lib`` or ``<prefix>/lib64``
-directories of the spec's link-type dependencies. Apart from that, it sets
-``-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=ON``, which should add RPATHs for directories of
-linked libraries not in the directories covered by ``CMAKE_INSTALL_RPATH``.
-
-Usually it's enough to set only ``-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=ON``, but the
-reason to provide both options is that packages may dynamically open shared libraries,
-which CMake cannot detect. In those cases, the RPATHs from ``CMAKE_INSTALL_RPATH`` are
-used as search paths.
-
-.. note::
-
-   Some packages provide stub libraries, which contain an interface for linking without
-   an implementation. When using such libraries, it's best to override the option
-   ``-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=OFF`` in ``cmake_args``, so that stub libraries
-   are not used at runtime.
-

 ^^^^^^^^^^
 Generators
@@ -275,6 +182,36 @@ generators, but it should be simple to add support for alternative
 generators. For more information on CMake generators, see:
 https://cmake.org/cmake/help/latest/manual/cmake-generators.7.html

+^^^^^^^^^^^^^^^^
+CMAKE_BUILD_TYPE
+^^^^^^^^^^^^^^^^
+
+Every CMake-based package accepts a ``-DCMAKE_BUILD_TYPE`` flag to
+dictate which level of optimization to use. In order to ensure
+uniformity across packages, the ``CMakePackage`` base class adds
+a variant to control this:
+
+.. code-block:: python
+
+   variant('build_type', default='RelWithDebInfo',
+           description='CMake build type',
+           values=('Debug', 'Release', 'RelWithDebInfo', 'MinSizeRel'))
+
+However, not every CMake package accepts all four of these options.
+Grep the ``CMakeLists.txt`` file to see if the default values are
+missing or replaced. For example, the
+`dealii <https://github.com/spack/spack/blob/develop/var/spack/repos/builtin/packages/dealii/package.py>`_
+package overrides the default variant with:
+
+.. code-block:: python
+
+   variant('build_type', default='DebugRelease',
+           description='The build type to build',
+           values=('Debug', 'Release', 'DebugRelease'))
+
+For more information on ``CMAKE_BUILD_TYPE``, see:
+https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html
+
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 CMakeLists.txt in a sub-directory
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
--- a/lib/spack/docs/build_systems/cudapackage.rst
+++ b/lib/spack/docs/build_systems/cudapackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/custompackage.rst
+++ b/lib/spack/docs/build_systems/custompackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/inteloneapipackage.rst
+++ b/lib/spack/docs/build_systems/inteloneapipackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -84,8 +84,8 @@ build ``hdf5`` with Intel oneAPI MPI do::

  spack install hdf5 +mpi ^intel-oneapi-mpi

-Using Externally Installed oneAPI Tools
-=======================================
+Using an Externally Installed oneAPI
+====================================

 Spack can also use oneAPI tools that are manually installed with
 `Intel Installers`_.  The procedures for configuring Spack to use
@@ -110,7 +110,7 @@ Another option is to manually add the configuration to
 Libraries
 ---------

-If you want Spack to use oneMKL that you have installed without Spack in
+If you want Spack to use MKL that you have installed without Spack in
 the default location, then add the following to
 ``~/.spack/packages.yaml``, adjusting the version as appropriate::

@@ -139,7 +139,7 @@ You can also use Spack-installed libraries. For example::
  spack load intel-oneapi-mkl

 Will update your environment CPATH, LIBRARY_PATH, and other
-environment variables for building an application with oneMKL.
+environment variables for building an application with MKL.

 More information
 ================
--- a/lib/spack/docs/build_systems/intelpackage.rst
+++ b/lib/spack/docs/build_systems/intelpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -15,9 +15,6 @@ IntelPackage
 Intel packages in Spack
 ^^^^^^^^^^^^^^^^^^^^^^^^

-This is an earlier version of Intel software development tools and has
-now been replaced by Intel oneAPI Toolkits.
-
 Spack can install and use several software development products offered by Intel.
 Some of these are available under no-cost terms, others require a paid license.
 All share the same basic steps for configuration, installation, and, where
@@ -652,7 +649,7 @@ follow `the next section <intel-install-libs_>`_ instead.

   * If you specified a custom variant (for example ``+vtune``) you may want to add this as your
     preferred variant in the packages configuration for the ``intel-parallel-studio`` package
-     as described in :ref:`package-preferences`. Otherwise you will have to specify
+     as described in :ref:`concretization-preferences`. Otherwise you will have to specify
     the variant everytime ``intel-parallel-studio`` is being used as ``mkl``, ``fftw`` or ``mpi``
     implementation to avoid pulling in a different variant.

@@ -814,13 +811,13 @@ by one of the following means:
     $ spack install libxc@3.0.0%intel


-* Alternatively, request Intel compilers implicitly by package preferences.
+* Alternatively, request Intel compilers implicitly by concretization preferences.
  Configure the order of compilers in the appropriate ``packages.yaml`` file,
  under either an ``all:`` or client-package-specific entry, in a
  ``compiler:`` list. Consult the Spack documentation for
  `Configuring Package Preferences <https://spack-tutorial.readthedocs.io/en/latest/tutorial_configuration.html#configuring-package-preferences>`_
  and
-  :ref:`Package Preferences <package-preferences>`.
+  :ref:`Concretization Preferences <concretization-preferences>`.

 Example: ``etc/spack/packages.yaml`` might simply contain:

@@ -870,7 +867,7 @@ virtual package, in order of decreasing preference.  To learn more about the
 ``providers:`` settings, see the Spack tutorial for
 `Configuring Package Preferences <https://spack-tutorial.readthedocs.io/en/latest/tutorial_configuration.html#configuring-package-preferences>`_
 and the section
-:ref:`Package Preferences <package-preferences>`.
+:ref:`Concretization Preferences <concretization-preferences>`.

 Example: The following fairly minimal example for ``packages.yaml`` shows how
 to exclusively use the standalone ``intel-mkl`` package for all the linear
--- a/lib/spack/docs/build_systems/luapackage.rst
+++ b/lib/spack/docs/build_systems/luapackage.rst
@@ -1,105 +0,0 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
-   Spack Project Developers. See the top-level COPYRIGHT file for details.
-
-   SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-.. _luapackage:
-
------------
-LuaPackage
------------
-
-LuaPackage is a helper for the common case of Lua packages that provide
-a rockspec file.  This is not meant to take a rock archive, but to build
-a source archive or repository that provides a rockspec, which should cover
-most lua packages. In the case a Lua package builds by Make rather than
-luarocks, prefer MakefilePackage.
-
-^^^^^^
-Phases
-^^^^^^
-
-The ``LuaPackage`` base class comes with the following phases:
-
-#. ``unpack`` - if using a rock, unpacks the rock and moves into the source directory
-#. ``preprocess`` - adjust sources or rockspec to fix build
-#. ``install`` - install the project
-
-By default, these phases run:
-
-.. code-block:: console
-
-   # If the archive is a source rock
-   $ luarocks unpack <archive>.src.rock
-   $ # preprocess is a noop by default
-   $ luarocks make <name>.rockspec
-
-
-Any of these phases can be overridden in your package as necessary.
-
-^^^^^^^^^^^^^^^
-Important files
-^^^^^^^^^^^^^^^
-
-Packages that use the Lua/LuaRocks build system can be identified by the
-presence of a ``*.rockspec`` file in their sourcetree, or can be fetched as
-a source rock archive (``.src.rock``). This file declares things like build
-instructions and dependencies, the ``.src.rock`` also contains all code.
-
-It is common for the rockspec file to list the lua version required in
-a dependency. The LuaPackage class adds appropriate dependencies on a Lua
-implementation, but it is a good idea to specify the version required with
-a ``depends_on`` statement.  The block normally will be a table definition like
-this:
-
-.. code-block:: lua
-
-   dependencies = {
-      "lua >= 5.1",
-   }
-
-The LuaPackage class supports source repositories and archives containing
-a rockspec and directly downloading source rock files.  It *does not* support
-downloading dependencies listed inside a rockspec, and thus does not support
-directly downloading a rockspec as an archive.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^
-Build system dependencies
-^^^^^^^^^^^^^^^^^^^^^^^^^
-
-All base dependencies are added by the build system, but LuaRocks is run to
-avoid downloading extra Lua dependencies during build.  If the package needs
-Lua libraries outside the standard set, they should be added as dependencies.
-
-To specify a Lua version constraint but allow all lua implementations, prefer
-to use ``depends_on("lua-lang@5.1:5.1.99")`` to express any 5.1 compatible
-version. If the package requires LuaJit rather than Lua,
-a ``depends_on("luajit")`` should be used to ensure a LuaJit distribution is
-used instead of the Lua interpreter. Alternately, if only interpreted Lua will
-work ``depends_on("lua")`` will express that.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Passing arguments to luarocks make
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-If you need to pass any arguments to the ``luarocks make`` call, you can
-override the ``luarocks_args`` method like so:
-
-.. code-block:: python
-
-    def luarocks_args(self):
-        return ['flag1', 'flag2']
-
-One common use of this is to override warnings or flags for newer compilers, as in:
-
-.. code-block:: python
-
-    def luarocks_args(self):
-        return ["CFLAGS='-Wno-error=implicit-function-declaration'"]
-
-^^^^^^^^^^^^^^^^^^^^^^
-External documentation
-^^^^^^^^^^^^^^^^^^^^^^
-
-For more information on the LuaRocks build system, see:
-https://luarocks.org/
--- a/lib/spack/docs/build_systems/makefilepackage.rst
+++ b/lib/spack/docs/build_systems/makefilepackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/mavenpackage.rst
+++ b/lib/spack/docs/build_systems/mavenpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/mesonpackage.rst
+++ b/lib/spack/docs/build_systems/mesonpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/multiplepackage.rst
+++ b/lib/spack/docs/build_systems/multiplepackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/octavepackage.rst
+++ b/lib/spack/docs/build_systems/octavepackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/perlpackage.rst
+++ b/lib/spack/docs/build_systems/perlpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/pythonpackage.rst
+++ b/lib/spack/docs/build_systems/pythonpackage.rst
--- a/lib/spack/docs/build_systems/qmakepackage.rst
+++ b/lib/spack/docs/build_systems/qmakepackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/racketpackage.rst
+++ b/lib/spack/docs/build_systems/racketpackage.rst
@@ -1,46 +0,0 @@
-.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
-   Spack Project Developers. See the top-level COPYRIGHT file for details.
-
-   SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-.. _racketpackage:
-
-------------
-RacketPackage
-------------
-
-Much like Python, Racket packages and modules have their own special build system.
-To learn more about the specifics of Racket package system, please refer to the
-`Racket Docs <https://docs.racket-lang.org/pkg/cmdline.html>`_.
-
-^^^^^^
-Phases
-^^^^^^
-
-The ``RacketPackage`` base class provides an ``install`` phase that
-can be overridden, corresponding to the use of:
-
-.. code-block:: console
-
-   $ raco pkg install
-
-^^^^^^^
-Caveats
-^^^^^^^
-
-In principle, ``raco`` supports a second, ``setup`` phase; however, we have not
-implemented this separately, as in normal circumstances, ``install`` also handles
-running ``setup`` automatically.
-
-Unlike Python, Racket currently on supports two installation scopes for packages, user
-or system, and keeps a registry of installed packages at each scope in its configuration files.
-This means we can't simply compose a "``RACKET_PATH``" environment variable listing all of the
-places packages are installed, and update this at will.
-
-Unfortunately this means that all currently installed packages which extend Racket via ``raco pkg install``
-are accessible whenever Racket is accessible.
-
-Additionally, because Spack does not implement uninstall hooks, uninstalling a Spack  ``rkt-`` package
-will have no effect on the ``raco`` installed packages visible to your Racket installation.
-Instead, you must manually run ``raco pkg remove`` to keep the two package managers in a mutually
-consistent state.
--- a/lib/spack/docs/build_systems/rocmpackage.rst
+++ b/lib/spack/docs/build_systems/rocmpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -95,7 +95,7 @@ class of your package.  For example, you can add it to your
                # Set up the hip macros needed by the build
                args.extend([
                    '-DENABLE_HIP=ON',
-                    '-DHIP_ROOT_DIR={0}'.format(spec['hip'].prefix)])
+                    '-DHIP_ROOT_DIR={0}'.format(spec['hip'].prefix])
                rocm_archs = spec.variants['amdgpu_target'].value
                if 'none' not in rocm_archs:
                    args.append('-DHIP_HIPCC_FLAGS=--amdgpu-target={0}'
--- a/lib/spack/docs/build_systems/rpackage.rst
+++ b/lib/spack/docs/build_systems/rpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/rubypackage.rst
+++ b/lib/spack/docs/build_systems/rubypackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/sconspackage.rst
+++ b/lib/spack/docs/build_systems/sconspackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/sippackage.rst
+++ b/lib/spack/docs/build_systems/sippackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/build_systems/sourceforgepackage.rst
+++ b/lib/spack/docs/build_systems/sourceforgepackage.rst
@@ -1,55 +0,0 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
-   Spack Project Developers. See the top-level COPYRIGHT file for details.
-
-   SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-.. _sourceforgepackage:
-
------------------
-SourceforgePackage
------------------
-
-``SourceforgePackage`` is a 
-`mixin-class <https://en.wikipedia.org/wiki/Mixin>`_. It automatically
-sets the URL based on a list of Sourceforge mirrors listed in
-`sourceforge_mirror_path`, which defaults to a half dozen known mirrors.
-Refer to the package source 
-(`<https://github.com/spack/spack/blob/develop/lib/spack/spack/build_systems/sourceforge.py>`__) for the current list of mirrors used by Spack.
-
-
-^^^^^^^
-Methods
-^^^^^^^
-
-This package provides a method for populating mirror URLs.
-
-**urls**
-
-    This method returns a list of possible URLs for package source.
-    It is decorated with `property` so its results are treated as
-    a package attribute.
-
-    Refer to 
-    `<https://spack.readthedocs.io/en/latest/packaging_guide.html#mirrors-of-the-main-url>`__
-    for information on how Spack uses the `urls` attribute during
-    fetching.
-
-^^^^^
-Usage
-^^^^^
-
-This helper package can be added to your package by adding it as a base
-class of your package and defining the relative location of an archive
-file for one version of your software.
-
-.. code-block:: python
-   :emphasize-lines: 1,3
-
-    class MyPackage(AutotoolsPackage, SourceforgePackage):
-        ...
-        sourceforge_mirror_path = "my-package/mypackage.1.0.0.tar.gz"
-        ...
-
-Over 40 packages are using ``SourceforcePackage`` this mix-in as of
-July 2022 so there are multiple packages to choose from if you want
-to see a real example.
--- a/lib/spack/docs/build_systems/wafpackage.rst
+++ b/lib/spack/docs/build_systems/wafpackage.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/chain.rst
+++ b/lib/spack/docs/chain.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/conf.py
+++ b/lib/spack/docs/conf.py
@@ -1,4 +1,4 @@
-# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -23,48 +23,42 @@
 import sys
 from glob import glob

-from docutils.statemachine import StringList
-from sphinx.domains.python import PythonDomain
 from sphinx.ext.apidoc import main as sphinx_apidoc
-from sphinx.parsers import RSTParser

 # -- Spack customizations -----------------------------------------------------
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
-sys.path.insert(0, os.path.abspath("_spack_root/lib/spack/external"))
-sys.path.insert(0, os.path.abspath("_spack_root/lib/spack/external/pytest-fallback"))
+sys.path.insert(0, os.path.abspath('_spack_root/lib/spack/external'))

 if sys.version_info[0] < 3:
-    sys.path.insert(0, os.path.abspath("_spack_root/lib/spack/external/yaml/lib"))
+    sys.path.insert(
+        0, os.path.abspath('_spack_root/lib/spack/external/yaml/lib'))
 else:
-    sys.path.insert(0, os.path.abspath("_spack_root/lib/spack/external/yaml/lib3"))
+    sys.path.insert(
+        0, os.path.abspath('_spack_root/lib/spack/external/yaml/lib3'))

-sys.path.append(os.path.abspath("_spack_root/lib/spack/"))
+sys.path.append(os.path.abspath('_spack_root/lib/spack/'))

 # Add the Spack bin directory to the path so that we can use its output in docs.
-os.environ["SPACK_ROOT"] = os.path.abspath("_spack_root")
-os.environ["PATH"] += "%s%s" % (os.pathsep, os.path.abspath("_spack_root/bin"))
+os.environ['SPACK_ROOT'] = os.path.abspath('_spack_root')
+os.environ['PATH'] += "%s%s" % (os.pathsep, os.path.abspath('_spack_root/bin'))

 # Set an environment variable so that colify will print output like it would to
 # a terminal.
-os.environ["COLIFY_SIZE"] = "25x120"
-os.environ["COLUMNS"] = "120"
+os.environ['COLIFY_SIZE'] = '25x120'
+os.environ['COLUMNS'] = '120'

 # Generate full package list if needed
-subprocess.call(["spack", "list", "--format=html", "--update=package_list.html"])
+subprocess.call([
+    'spack', 'list', '--format=html', '--update=package_list.html'])

 # Generate a command index if an update is needed
-subprocess.call(
-    [
-        "spack",
-        "commands",
-        "--format=rst",
-        "--header=command_index.in",
-        "--update=command_index.rst",
-    ]
-    + glob("*rst")
-)
+subprocess.call([
+    'spack', 'commands',
+    '--format=rst',
+    '--header=command_index.in',
+    '--update=command_index.rst'] + glob('*rst'))

 #
 # Run sphinx-apidoc
@@ -74,12 +68,12 @@
 # Without this, the API Docs will never actually update
 #
 apidoc_args = [
-    "--force",  # Overwrite existing files
-    "--no-toc",  # Don't create a table of contents file
-    "--output-dir=.",  # Directory to place all output
+    '--force',         # Overwrite existing files
+    '--no-toc',        # Don't create a table of contents file
+    '--output-dir=.',  # Directory to place all output
 ]
-sphinx_apidoc(apidoc_args + ["_spack_root/lib/spack/spack"])
-sphinx_apidoc(apidoc_args + ["_spack_root/lib/spack/llnl"])
+sphinx_apidoc(apidoc_args + ['_spack_root/lib/spack/spack'])
+sphinx_apidoc(apidoc_args + ['_spack_root/lib/spack/llnl'])

 # Enable todo items
 todo_include_todos = True
@@ -87,77 +81,60 @@
 #
 # Disable duplicate cross-reference warnings.
 #
+from sphinx.domains.python import PythonDomain
+
+
 class PatchedPythonDomain(PythonDomain):
    def resolve_xref(self, env, fromdocname, builder, typ, target, node, contnode):
-        if "refspecific" in node:
-            del node["refspecific"]
+        if 'refspecific' in node:
+            del node['refspecific']
        return super(PatchedPythonDomain, self).resolve_xref(
-            env, fromdocname, builder, typ, target, node, contnode
-        )
-
-
-#
-# Disable tabs to space expansion in code blocks
-# since Makefiles require tabs.
-#
-class NoTabExpansionRSTParser(RSTParser):
-    def parse(self, inputstring, document):
-        if isinstance(inputstring, str):
-            lines = inputstring.splitlines()
-            inputstring = StringList(lines, document.current_source)
-        super().parse(inputstring, document)
-
+            env, fromdocname, builder, typ, target, node, contnode)

 def setup(sphinx):
    sphinx.add_domain(PatchedPythonDomain, override=True)
-    sphinx.add_source_parser(NoTabExpansionRSTParser, override=True)
-

 # -- General configuration -----------------------------------------------------

 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = "3.4"
+needs_sphinx = '3.4'

 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
-    "sphinx.ext.autodoc",
-    "sphinx.ext.graphviz",
-    "sphinx.ext.intersphinx",
-    "sphinx.ext.napoleon",
-    "sphinx.ext.todo",
-    "sphinx.ext.viewcode",
-    "sphinxcontrib.programoutput",
+    'sphinx.ext.autodoc',
+    'sphinx.ext.graphviz',
+    'sphinx.ext.intersphinx',
+    'sphinx.ext.napoleon',
+    'sphinx.ext.todo',
+    'sphinx.ext.viewcode',
+    'sphinxcontrib.programoutput',
 ]

 # Set default graphviz options
 graphviz_dot_args = [
-    "-Grankdir=LR",
-    "-Gbgcolor=transparent",
-    "-Nshape=box",
-    "-Nfontname=monaco",
-    "-Nfontsize=10",
-]
+    '-Grankdir=LR', '-Gbgcolor=transparent',
+    '-Nshape=box', '-Nfontname=monaco', '-Nfontsize=10']

 # Get nice vector graphics
 graphviz_output_format = "svg"


 # Add any paths that contain templates here, relative to this directory.
-templates_path = ["_templates"]
+templates_path = ['_templates']

 # The suffix of source filenames.
-source_suffix = ".rst"
+source_suffix = '.rst'

 # The encoding of source files.
-source_encoding = "utf-8-sig"
+source_encoding = 'utf-8-sig'

 # The master toctree document.
-master_doc = "index"
+master_doc = 'index'

 # General information about the project.
-project = u"Spack"
-copyright = u"2013-2021, Lawrence Livermore National Laboratory."
+project = u'Spack'
+copyright = u'2013-2021, Lawrence Livermore National Laboratory.'

 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -166,16 +143,16 @@ def setup(sphinx):
 # The short X.Y version.
 import spack

-version = ".".join(str(s) for s in spack.spack_version_info[:2])
+version = '.'.join(str(s) for s in spack.spack_version_info[:2])
 # The full version, including alpha/beta/rc tags.
 release = spack.spack_version

 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
-# language = None
+#language = None

 # Places to look for .po/.mo files for doc translations
-# locale_dirs = []
+#locale_dirs = []

 # Sphinx gettext settings
 gettext_compact = True
@@ -183,42 +160,40 @@ def setup(sphinx):

 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
-# today = ''
+#today = ''
 # Else, today_fmt is used as the format for a strftime call.
-# today_fmt = '%B %d, %Y'
+#today_fmt = '%B %d, %Y'

 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = ["_build", "_spack_root", ".spack-env"]
+exclude_patterns = ['_build', '_spack_root', '.spack-env']

 nitpicky = True
 nitpick_ignore = [
    # Python classes that intersphinx is unable to resolve
-    ("py:class", "argparse.HelpFormatter"),
-    ("py:class", "contextlib.contextmanager"),
-    ("py:class", "module"),
-    ("py:class", "_io.BufferedReader"),
-    ("py:class", "unittest.case.TestCase"),
-    ("py:class", "_frozen_importlib_external.SourceFileLoader"),
-    ("py:class", "clingo.Control"),
+    ('py:class', 'argparse.HelpFormatter'),
+    ('py:class', 'contextlib.contextmanager'),
+    ('py:class', 'module'),
+    ('py:class', '_io.BufferedReader'),
+    ('py:class', 'unittest.case.TestCase'),
+    ('py:class', '_frozen_importlib_external.SourceFileLoader'),
    # Spack classes that are private and we don't want to expose
-    ("py:class", "spack.provider_index._IndexBase"),
-    ("py:class", "spack.repo._PrependFileLoader"),
+    ('py:class', 'spack.provider_index._IndexBase'),
 ]

 # The reST default role (used for this markup: `text`) to use for all documents.
-# default_role = None
+#default_role = None

 # If true, '()' will be appended to :func: etc. cross-reference text.
-# add_function_parentheses = True
+#add_function_parentheses = True

 # If true, the current module name will be prepended to all description
 # unit titles (such as .. function::).
-# add_module_names = True
+#add_module_names = True

 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
-# show_authors = False
+#show_authors = False

 # The name of the Pygments (syntax highlighting) style to use.
 # We use our own extension of the default style with a few modifications
@@ -229,151 +204,156 @@ def setup(sphinx):

 class SpackStyle(DefaultStyle):
    styles = DefaultStyle.styles.copy()
-    background_color = "#f4f4f8"
+    background_color       = "#f4f4f8"
    styles[Generic.Output] = "#355"
    styles[Generic.Prompt] = "bold #346ec9"

-
 import pkg_resources

 dist = pkg_resources.Distribution(__file__)
-sys.path.append(".")  # make 'conf' module findable
-ep = pkg_resources.EntryPoint.parse("spack = conf:SpackStyle", dist=dist)
-dist._ep_map = {"pygments.styles": {"plugin1": ep}}
+sys.path.append('.')  # make 'conf' module findable
+ep = pkg_resources.EntryPoint.parse('spack = conf:SpackStyle', dist=dist)
+dist._ep_map = {'pygments.styles': {'plugin1': ep}}
 pkg_resources.working_set.add(dist)

-pygments_style = "spack"
+pygments_style = 'spack'

 # A list of ignored prefixes for module index sorting.
-# modindex_common_prefix = []
+#modindex_common_prefix = []


 # -- Options for HTML output ---------------------------------------------------

 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = "sphinx_rtd_theme"
+html_theme = 'sphinx_rtd_theme'

 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-html_theme_options = {"logo_only": True}
+html_theme_options = { 'logo_only' : True }

 # Add any paths that contain custom themes here, relative to this directory.
 # html_theme_path = ["_themes"]

 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-# html_title = None
+#html_title = None

 # A shorter title for the navigation bar.  Default is the same as html_title.
-# html_short_title = None
+#html_short_title = None

 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-html_logo = "_spack_root/share/spack/logo/spack-logo-white-text.svg"
+html_logo = '_spack_root/share/spack/logo/spack-logo-white-text.svg'

 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
 # pixels large.
-html_favicon = "_spack_root/share/spack/logo/favicon.ico"
+html_favicon = '_spack_root/share/spack/logo/favicon.ico'

 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ["_static"]
+html_static_path = ['_static']

 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-html_last_updated_fmt = "%b %d, %Y"
+html_last_updated_fmt = '%b %d, %Y'

 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
-# html_use_smartypants = True
+#html_use_smartypants = True

 # Custom sidebar templates, maps document names to template names.
-# html_sidebars = {}
+#html_sidebars = {}

 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-# html_additional_pages = {}
+#html_additional_pages = {}

 # If false, no module index is generated.
-# html_domain_indices = True
+#html_domain_indices = True

 # If false, no index is generated.
-# html_use_index = True
+#html_use_index = True

 # If true, the index is split into individual pages for each letter.
-# html_split_index = False
+#html_split_index = False

 # If true, links to the reST sources are added to the pages.
-# html_show_sourcelink = True
+#html_show_sourcelink = True

 # If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
-# html_show_sphinx = False
+#html_show_sphinx = False

 # If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
-# html_show_copyright = True
+#html_show_copyright = True

 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-# html_use_opensearch = ''
+#html_use_opensearch = ''

 # This is the file name suffix for HTML files (e.g. ".xhtml").
-# html_file_suffix = None
+#html_file_suffix = None

 # Output file base name for HTML help builder.
-htmlhelp_basename = "Spackdoc"
+htmlhelp_basename = 'Spackdoc'


 # -- Options for LaTeX output --------------------------------------------------

 latex_elements = {
-    # The paper size ('letterpaper' or 'a4paper').
-    #'papersize': 'letterpaper',
-    # The font size ('10pt', '11pt' or '12pt').
-    #'pointsize': '10pt',
-    # Additional stuff for the LaTeX preamble.
-    #'preamble': '',
+# The paper size ('letterpaper' or 'a4paper').
+#'papersize': 'letterpaper',
+
+# The font size ('10pt', '11pt' or '12pt').
+#'pointsize': '10pt',
+
+# Additional stuff for the LaTeX preamble.
+#'preamble': '',
 }

 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
 latex_documents = [
-    ("index", "Spack.tex", u"Spack Documentation", u"Todd Gamblin", "manual"),
+  ('index', 'Spack.tex', u'Spack Documentation',
+   u'Todd Gamblin', 'manual'),
 ]

 # The name of an image file (relative to this directory) to place at the top of
 # the title page.
-# latex_logo = None
+#latex_logo = None

 # For "manual" documents, if this is true, then toplevel headings are parts,
 # not chapters.
-# latex_use_parts = False
+#latex_use_parts = False

 # If true, show page references after internal links.
-# latex_show_pagerefs = False
+#latex_show_pagerefs = False

 # If true, show URL addresses after external links.
-# latex_show_urls = False
+#latex_show_urls = False

 # Documents to append as an appendix to all manuals.
-# latex_appendices = []
+#latex_appendices = []

 # If false, no module index is generated.
-# latex_domain_indices = True
+#latex_domain_indices = True


 # -- Options for manual page output --------------------------------------------

 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [("index", "spack", u"Spack Documentation", [u"Todd Gamblin"], 1)]
+man_pages = [
+    ('index', 'spack', u'Spack Documentation',
+     [u'Todd Gamblin'], 1)
+]

 # If true, show URL addresses after external links.
-# man_show_urls = False
+#man_show_urls = False


 # -- Options for Texinfo output ------------------------------------------------
@@ -382,25 +362,19 @@ class SpackStyle(DefaultStyle):
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    (
-        "index",
-        "Spack",
-        u"Spack Documentation",
-        u"Todd Gamblin",
-        "Spack",
-        "One line description of project.",
-        "Miscellaneous",
-    ),
+  ('index', 'Spack', u'Spack Documentation',
+   u'Todd Gamblin', 'Spack', 'One line description of project.',
+   'Miscellaneous'),
 ]

 # Documents to append as an appendix to all manuals.
-# texinfo_appendices = []
+#texinfo_appendices = []

 # If false, no module index is generated.
-# texinfo_domain_indices = True
+#texinfo_domain_indices = True

 # How to display URL addresses: 'footnote', 'no', or 'inline'.
-# texinfo_show_urls = 'footnote'
+#texinfo_show_urls = 'footnote'


 # -- Extension configuration -------------------------------------------------
--- a/lib/spack/docs/config_yaml.rst
+++ b/lib/spack/docs/config_yaml.rst
@@ -1,13 +1,13 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)

 .. _config-yaml:

-============================
-Spack Settings (config.yaml)
-============================
+==============
+Basic Settings
+==============

 Spack's basic configuration options are set in ``config.yaml``.  You can
 see the default settings by looking at
@@ -72,6 +72,21 @@ used to configure module names.
   packages have been installed will prevent Spack from being
   able to find the old installation directories.

+--------------------
+``module_roots``
+--------------------
+
+Controls where Spack installs generated module files.  You can customize
+the location for each type of module.  e.g.:
+
+.. code-block:: yaml
+
+   module_roots:
+     tcl:    $spack/share/spack/modules
+     lmod:   $spack/share/spack/lmod
+
+See :ref:`modules` for details.
+
 --------------------
 ``build_stage``
 --------------------
@@ -244,16 +259,3 @@ and ld.so will ONLY search for dependencies in the ``RUNPATH`` of
 the loading object.

 DO NOT MIX the two options within the same install tree.
-
----------------------
-``terminal_title``
----------------------
-
-By setting this option to ``true``, Spack will update the terminal's title to
-provide information about its current progress as well as the current and
-total package numbers.
-
-To work properly, this requires your terminal to reset its title after
-Spack has finished its work, otherwise Spack's status information will
-remain in the terminal's title indefinitely. Most terminals should already
-be set up this way and clear Spack's status information.
--- a/lib/spack/docs/configuration.rst
+++ b/lib/spack/docs/configuration.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -13,16 +13,12 @@ Spack has many configuration files.  Here is a quick list of them, in
 case you want to skip directly to specific docs:

 * :ref:`compilers.yaml <compiler-config>`
-* :ref:`concretizer.yaml <concretizer-options>`
 * :ref:`config.yaml <config-yaml>`
 * :ref:`mirrors.yaml <mirrors>`
 * :ref:`modules.yaml <modules>`
 * :ref:`packages.yaml <build-settings>`
 * :ref:`repos.yaml <repositories>`

-You can also add any of these as inline configuration in ``spack.yaml``
-in an :ref:`environment <environment-configuration>`.
-
 -----------
 YAML Format
 -----------
@@ -37,6 +33,8 @@ Here is an example ``config.yaml`` file:

   config:
     install_tree: $spack/opt/spack
+     module_roots:
+       lmod: $spack/share/spack/lmod
     build_stage:
       - $tempdir/$user/spack-stage
       - ~/.spack/stage
@@ -251,6 +249,8 @@ your configurations look like this:

   config:
     install_tree: $spack/opt/spack
+     module_roots:
+       lmod: $spack/share/spack/lmod
     build_stage:
       - $tempdir/$user/spack-stage
       - ~/.spack/stage
@@ -274,6 +274,8 @@ command:
   $ spack config get config
   config:
     install_tree: /some/other/directory
+     module_roots:
+       lmod: $spack/share/spack/lmod
     build_stage:
       - $tempdir/$user/spack-stage
       - ~/.spack/stage
@@ -339,11 +341,13 @@ higher-precedence scope is *prepended* to the defaults. ``spack config
 get config`` shows the result:

 .. code-block:: console
-   :emphasize-lines: 5-8
+   :emphasize-lines: 7-10

   $ spack config get config
   config:
     install_tree: /some/other/directory
+     module_roots:
+       lmod: $spack/share/spack/lmod
     build_stage:
       - /lustre-scratch/$user/spack
       - ~/mystage
@@ -367,11 +371,13 @@ user config looked like this:
 The merged configuration would look like this:

 .. code-block:: console
-   :emphasize-lines: 5-6
+   :emphasize-lines: 7-8

   $ spack config get config
   config:
     install_tree: /some/other/directory
+     module_roots:
+       lmod: $spack/share/spack/lmod
     build_stage:
       - /lustre-scratch/$user/spack
       - ~/mystage
@@ -396,15 +402,12 @@ Spack-specific variables

 Spack understands several special variables. These are:

-* ``$env``: name of the currently active :ref:`environment <environments>`
 * ``$spack``: path to the prefix of this Spack installation
 * ``$tempdir``: default system temporary directory (as specified in
  Python's `tempfile.tempdir
  <https://docs.python.org/2/library/tempfile.html#tempfile.tempdir>`_
  variable.
 * ``$user``: name of the current user
-* ``$user_cache_path``: user cache directory (``~/.spack`` unless
-  :ref:`overridden <local-config-overrides>`)

 Note that, as with shell variables, you can write these as ``$varname``
 or with braces to distinguish the variable from surrounding characters:
@@ -492,6 +495,9 @@ account all scopes. For example, to see the fully merged
     template_dirs:
     - $spack/templates
     directory_layout: {architecture}/{compiler.name}-{compiler.version}/{name}-{version}-{hash}
+     module_roots:
+       tcl: $spack/share/spack/modules
+       lmod: $spack/share/spack/lmod
     build_stage:
     - $tempdir/$user/spack-stage
     - ~/.spack/stage
@@ -539,6 +545,9 @@ down the problem:
   /home/myuser/spack/etc/spack/defaults/config.yaml:23    template_dirs:
   /home/myuser/spack/etc/spack/defaults/config.yaml:24    - $spack/templates
   /home/myuser/spack/etc/spack/defaults/config.yaml:28    directory_layout: {architecture}/{compiler.name}-{compiler.version}/{name}-{version}-{hash}
+   /home/myuser/spack/etc/spack/defaults/config.yaml:32    module_roots:
+   /home/myuser/spack/etc/spack/defaults/config.yaml:33      tcl: $spack/share/spack/modules
+   /home/myuser/spack/etc/spack/defaults/config.yaml:34      lmod: $spack/share/spack/lmod
   /home/myuser/spack/etc/spack/defaults/config.yaml:49    build_stage:
   /home/myuser/spack/etc/spack/defaults/config.yaml:50    - $tempdir/$user/spack-stage
   /home/myuser/spack/etc/spack/defaults/config.yaml:51    - ~/.spack/stage
@@ -553,39 +562,3 @@ built in and are not overridden by a configuration file. The
 command line. ``dirty`` and ``install_tree`` come from the custom
 scopes ``./my-scope`` and ``./my-scope-2``, and all other configuration
 options come from the default configuration files that ship with Spack.
-
-.. _local-config-overrides:
-
------------------------------
-Overriding Local Configuration
------------------------------
-
-Spack's ``system`` and ``user`` scopes provide ways for administrators and users to set
-global defaults for all Spack instances, but for use cases where one wants a clean Spack
-installation, these scopes can be undesirable. For example, users may want to opt out of
-global system configuration, or they may want to ignore their own home directory
-settings when running in a continuous integration environment.
-
-Spack also, by default, keeps various caches and user data in ``~/.spack``, but
-users may want to override these locations.
-
-Spack provides three environment variables that allow you to override or opt out of
-configuration locations:
-
-* ``SPACK_USER_CONFIG_PATH``: Override the path to use for the
-  ``user`` scope (``~/.spack`` by default).
-* ``SPACK_SYSTEM_CONFIG_PATH``: Override the path to use for the
-  ``system`` scope (``/etc/spack`` by default).
-* ``SPACK_DISABLE_LOCAL_CONFIG``: set this environment variable to completely disable
-  **both** the system and user configuration directories. Spack will only consider its
-  own defaults and ``site`` configuration locations.
-
-And one that allows you to move the default cache location:
-
-* ``SPACK_USER_CACHE_PATH``: Override the default path to use for user data
-  (misc_cache, tests, reports, etc.)
-
-With these settings, if you want to isolate Spack in a CI environment, you can do this::
-
-  export SPACK_DISABLE_LOCAL_CONFIG=true
-  export SPACK_USER_CACHE_PATH=/tmp/spack
--- a/lib/spack/docs/containers.rst
+++ b/lib/spack/docs/containers.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -59,8 +59,7 @@ other techniques to minimize the size of the final image:
   &&   echo "  specs:" \
   &&   echo "  - gromacs+mpi" \
   &&   echo "  - mpich" \
-   &&   echo "  concretizer:" \
-   &&   echo "    unify: true" \
+   &&   echo "  concretization: together" \
   &&   echo "  config:" \
   &&   echo "    install_tree: /opt/software" \
   &&   echo "  view: /opt/view") > /opt/spack-environment/spack.yaml
@@ -109,10 +108,9 @@ Spack Images on Docker Hub
 --------------------------

 Docker images with Spack preinstalled and ready to be used are
-built when a release is tagged, or nightly on ``develop``. The images
-are then pushed both to `Docker Hub <https://hub.docker.com/u/spack>`_
-and to `GitHub Container Registry <https://github.com/orgs/spack/packages?repo_name=spack>`_.
-The OS that are currently supported are summarized in the table below:
+built on `Docker Hub <https://hub.docker.com/u/spack>`_
+at every push to ``develop`` or to a release branch. The OS that
+are currently supported are summarized in the table below:

 .. _containers-supported-os:

@@ -122,31 +120,22 @@ The OS that are currently supported are summarized in the table below:
   * - Operating System
     - Base Image
     - Spack Image
+   * - Ubuntu 16.04
+     - ``ubuntu:16.04``
+     - ``spack/ubuntu-xenial``
   * - Ubuntu 18.04
     - ``ubuntu:18.04``
     - ``spack/ubuntu-bionic``
-   * - Ubuntu 20.04
-     - ``ubuntu:20.04``
-     - ``spack/ubuntu-focal``
-   * - Ubuntu 22.04
-     - ``ubuntu:22.04``
-     - ``spack/ubuntu-jammy``
+   * - CentOS 6
+     - ``centos:6``
+     - ``spack/centos6``
   * - CentOS 7
     - ``centos:7``
     - ``spack/centos7``
-   * - CentOS Stream
-     - ``quay.io/centos/centos:stream``
-     - ``spack/centos-stream``
-   * - openSUSE Leap
-     - ``opensuse/leap``
-     - ``spack/leap15``
-   * - Amazon Linux 2
-     - ``amazonlinux:2``
-     - ``spack/amazon-linux``

 All the images are tagged with the corresponding release of Spack:

-.. image:: images/ghcr_spack.png
+.. image:: dockerhub_spack.png

 with the exception of the ``latest`` tag that points to the HEAD
 of the ``develop`` branch. These images are available for anyone
@@ -211,7 +200,7 @@ Setting Base Images

 The ``images`` subsection is used to select both the image where
 Spack builds the software and the image where the built software
-is installed. This attribute can be set in different ways and
+is installed. This attribute can be set in two different ways and
 which one to use depends on the use case at hand.

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -256,8 +245,7 @@ software is respectively built and installed:
   &&   echo "  specs:" \
   &&   echo "  - gromacs+mpi" \
   &&   echo "  - mpich" \
-   &&   echo "  concretizer:" \
-   &&   echo "    unify: true" \
+   &&   echo "  concretization: together" \
   &&   echo "  config:" \
   &&   echo "    install_tree: /opt/software" \
   &&   echo "  view: /opt/view") > /opt/spack-environment/spack.yaml
@@ -272,54 +260,10 @@ software is respectively built and installed:

   ENTRYPOINT ["/bin/bash", "--rcfile", "/etc/profile", "-l"]

-This is the simplest available method of selecting base images, and we advise
+This method of selecting base images is the simplest of the two, and we advise
 to use it whenever possible. There are cases though where using Spack official
-images is not enough to fit production needs. In these situations users can
-extend the recipe to start with the bootstrapping of Spack at a certain pinned
-version or manually select which base image to start from in the recipe,
-as we'll see next.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Use a Bootstrap Stage for Spack
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-In some cases users may want to pin the commit sha that is used for Spack, to ensure later
-reproducibility, or start from a fork of the official Spack repository to try a bugfix or
-a feature in the early stage of development. This is possible by being just a little more
-verbose when specifying information about Spack in the ``spack.yaml`` file:
-
-.. code-block:: yaml
-
-   images:
-     os: amazonlinux:2
-     spack:
-       # URL of the Spack repository to be used in the container image
-       url: <to-use-a-fork>
-       # Either a commit sha, a branch name or a tag
-       ref: <sha/tag/branch>
-       # If true turn a branch name or a tag into the corresponding commit
-       # sha at the time of recipe generation
-       resolve_sha: <true/false>
-
-``url`` specifies the URL from which to clone Spack and defaults to https://github.com/spack/spack.
-The ``ref`` attribute can be either a commit sha, a branch name or a tag. The default value in
-this case is to use the ``develop`` branch, but it may change in the future to point to the latest stable
-release. Finally ``resolve_sha`` transform branch names or tags into the corresponding commit
-shas at the time of recipe generation, to allow for a greater reproducibility of the results
-at a later time.
-
-The list of operating systems that can be used to bootstrap Spack can be
-obtained with:
-
-.. command-output:: spack containerize --list-os
-
-.. note::
-
-   The ``resolve_sha`` option uses ``git rev-parse`` under the hood and thus it requires
-   to checkout the corresponding Spack repository in a temporary folder before generating
-   the recipe. Recipe generation may take longer when this option is set to true because
-   of this additional step.
-
+images is not enough to fit production needs. In these situations users can manually
+select which base image to start from in the recipe, as we'll see next.

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Use Custom Images Provided by Users
@@ -378,8 +322,7 @@ produces, for instance, the following ``Dockerfile``:
   &&   echo "      externals:" \
   &&   echo "      - spec: cuda%gcc" \
   &&   echo "        prefix: /usr/local/cuda" \
-   &&   echo "  concretizer:" \
-   &&   echo "    unify: true" \
+   &&   echo "  concretization: together" \
   &&   echo "  config:" \
   &&   echo "    install_tree: /opt/software" \
   &&   echo "  view: /opt/view") > /opt/spack-environment/spack.yaml
@@ -472,18 +415,6 @@ to customize the generation of container recipes:
     - Version of Spack use in the ``build`` stage
     - Valid tags for ``base:image``
     - Yes, if using constrained selection of base images
-   * - ``images:spack:url``
-     - Repository from which Spack is cloned
-     - Any fork of Spack
-     - No
-   * - ``images:spack:ref``
-     - Reference for the checkout of Spack
-     - Either a commit sha, a branch name or a tag
-     - No
-   * - ``images:spack:resolve_sha``
-     - Resolve branches and tags in ``spack.yaml`` to commits in the generated recipe
-     - True or False (default: False)
-     - No
   * - ``images:build``
     - Image to be used in the ``build`` stage
     - Any valid container image
--- a/lib/spack/docs/contribution_guide.rst
+++ b/lib/spack/docs/contribution_guide.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -71,7 +71,7 @@ locally to speed up the review process.
   new release that is causing problems. If this is the case, please file an issue.


-We currently test against Python 2.7 and 3.6-3.10 on both macOS and Linux and
+We currently test against Python 2.6, 2.7, and 3.5-3.7 on both macOS and Linux and
 perform 3 types of tests:

 .. _cmd-spack-unit-test:
@@ -338,6 +338,15 @@ Once all of the dependencies are installed, you can try building the documentati
 If you see any warning or error messages, you will have to correct those before
 your PR is accepted.

+.. note::
+
+   There is also a ``run-doc-tests`` script in ``share/spack/qa``. The only
+   difference between running this script and running ``make`` by hand is that
+   the script will exit immediately if it encounters an error or warning. This
+   is necessary for CI. If you made a lot of documentation changes, it is
+   much quicker to run ``make`` by hand so that you can see all of the warnings
+   at once.
+
 If you are editing the documentation, you should obviously be running the
 documentation tests. But even if you are simply adding a new package, your
 changes could cause the documentation tests to fail:
--- a/lib/spack/docs/developer_guide.rst
+++ b/lib/spack/docs/developer_guide.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -107,6 +107,7 @@ with a high level view of Spack's directory structure:
            llnl/          <- some general-use libraries

            spack/                <- spack module; contains Python code
+               analyzers/         <- modules to run analysis on installed packages
               build_systems/     <- modules for different build systems
               cmd/               <- each file in here is a spack subcommand
               compilers/         <- compiler description files
@@ -150,7 +151,7 @@ Package-related modules
 ^^^^^^^^^^^^^^^^^^^^^^^

 :mod:`spack.package`
-  Contains the :class:`~spack.package_base.Package` class, which
+  Contains the :class:`~spack.package.Package` class, which
  is the superclass for all packages in Spack.  Methods on ``Package``
  implement all phases of the :ref:`package lifecycle
  <package-lifecycle>` and manage the build process.
@@ -209,6 +210,15 @@ Spec-related modules
     but compilers aren't fully integrated with the build process
     yet.

+:mod:`spack.architecture`
+  :func:`architecture.default_arch <spack.architecture.default_arch>` is used
+  to determine the host architecture while building.
+
+  .. warning::
+
+     Not yet implemented.  Should eventually have architecture
+     descriptions for cross-compiling.
+
 ^^^^^^^^^^^^^^^^^
 Build environment
 ^^^^^^^^^^^^^^^^^
@@ -241,6 +251,22 @@ Unit tests
  Implements Spack's test suite.  Add a module and put its name in
  the test suite in ``__init__.py`` to add more unit tests.

+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Research and Monitoring Modules
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+:mod:`spack.monitor`
+  Contains :class:`~spack.monitor.SpackMonitorClient`. This is accessed from
+  the ``spack install`` and ``spack analyze`` commands to send build and
+  package metadata up to a `Spack Monitor
+  <https://github.com/spack/spack-monitor>`_ server.
+
+
+:mod:`spack.analyzers`
+  A module folder with a :class:`~spack.analyzers.analyzer_base.AnalyzerBase`
+  that provides base functions to run, save, and (optionally) upload analysis
+  results to a `Spack Monitor <https://github.com/spack/spack-monitor>`_ server.
+

 ^^^^^^^^^^^^^
 Other Modules
@@ -284,6 +310,240 @@ Most spack commands look something like this:
 The information in Package files is used at all stages in this
 process.

+Conceptually, packages are overloaded.  They contain:
+
+-------------
+Stage objects
+-------------
+
+
+.. _writing-analyzers:
+
+-----------------
+Writing analyzers
+-----------------
+
+To write an analyzer, you should add a new python file to the
+analyzers module directory at ``lib/spack/spack/analyzers`` .
+Your analyzer should be a subclass of the :class:`AnalyzerBase <spack.analyzers.analyzer_base.AnalyzerBase>`. For example, if you want
+to add an analyzer class ``Myanalyzer`` you would write to
+``spack/analyzers/myanalyzer.py`` and import and
+use the base as follows:
+
+.. code-block:: python
+
+    from .analyzer_base import AnalyzerBase
+
+    class Myanalyzer(AnalyzerBase):
+
+
+Note that the class name is your module file name, all lowercase
+except for the first capital letter. You can  look at other analyzers in
+that analyzer directory for examples. The guide here will tell you about the basic functions needed.
+
+^^^^^^^^^^^^^^^^^^^^^^^^^
+Analyzer Output Directory
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+By default, when you run ``spack analyze run`` an analyzer output directory will
+be created in your spack user directory in your ``$HOME``. The reason we output here
+is because the install directory might not always be writable.
+
+.. code-block:: console
+
+    ~/.spack/
+      analyzers
+
+Result files will be written here, organized in subfolders in the same structure
+as the package, with each analyzer owning it's own subfolder. for example:
+
+
+.. code-block:: console
+
+    $ tree ~/.spack/analyzers/
+    /home/spackuser/.spack/analyzers/
+    └── linux-ubuntu20.04-skylake
+        └── gcc-9.3.0
+            └── zlib-1.2.11-sl7m27mzkbejtkrajigj3a3m37ygv4u2
+                ├── environment_variables
+                │   └── spack-analyzer-environment-variables.json
+                ├── install_files
+                │   └── spack-analyzer-install-files.json
+                └── libabigail
+                    └── lib
+                        └── spack-analyzer-libabigail-libz.so.1.2.11.xml
+
+
+Notice that for the libabigail analyzer, since results are generated per object,
+we honor the object's folder in case there are equivalently named files in
+different folders. The result files are typically written as json so they can be easily read and  uploaded in a future interaction with a monitor.
+
+
+^^^^^^^^^^^^^^^^^
+Analyzer Metadata
+^^^^^^^^^^^^^^^^^
+
+Your analyzer is required to have the class attributes ``name``, ``outfile``,
+and ``description``. These are printed to the user with they use the subcommand
+``spack analyze list-analyzers``.  Here is an example.
+As we mentioned above, note that this analyzer would live in a module named
+``libabigail.py`` in the analyzers folder so that the class can be discovered.
+
+
+.. code-block:: python
+
+    class Libabigail(AnalyzerBase):
+
+        name = "libabigail"
+        outfile = "spack-analyzer-libabigail.json"
+        description = "Application Binary Interface (ABI) features for objects"
+
+
+This means that the name and output file should be unique for your analyzer.
+Note that "all" cannot be the name of an analyzer, as this key is used to indicate
+that the user wants to run all analyzers.
+
+.. _analyzer_run_function:
+
+
+^^^^^^^^^^^^^^^^^^^^^^^^
+An analyzer run Function
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+The core of an analyzer is its ``run()`` function, which should accept no
+arguments. You can assume your analyzer has the package spec of interest at ``self.spec``
+and it's up to the run function to generate whatever analysis data you need,
+and then return the object with a key as the analyzer name. The result data
+should be a list of objects, each with a name, ``analyzer_name``, ``install_file``,
+and one of ``value`` or ``binary_value``. The install file should be for a relative
+path, and not the absolute path. For example, let's say we extract a metric called
+``metric`` for ``bin/wget`` using our analyzer ``thebest-analyzer``.
+We might have data that looks like this:
+
+.. code-block:: python
+
+    result = {"name": "metric", "analyzer_name": "thebest-analyzer", "value": "1", "install_file": "bin/wget"}
+
+
+We'd then return it as follows - note that they key is the analyzer name at ``self.name``.
+
+.. code-block:: python
+
+    return {self.name: result}
+
+This will save the complete result to the analyzer metadata folder, as described
+previously. If you want support for adding a different kind of metadata (e.g.,
+not associated with an install file) then the monitor server would need to be updated
+to support this first.
+
+
+^^^^^^^^^^^^^^^^^^^^^^^^^
+An analyzer init Function
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If you don't need any extra dependencies or checks, you can skip defining an analyzer
+init function, as the base class will handle it. Typically, it will accept
+a spec, and an optional output directory (if the user does not want the default
+metadata folder for analyzer results). The analyzer init function should call
+it's parent init, and then do any extra checks or validation that are required to
+work. For example:
+
+.. code-block:: python
+
+    def __init__(self, spec, dirname=None):
+        super(Myanalyzer, self).__init__(spec, dirname)
+
+        # install extra dependencies, do extra preparation and checks here
+
+
+At the end of the init, you will have available to you:
+
+ - **self.spec**: the spec object
+ - **self.dirname**: an optional directory name the user as provided at init to save
+ - **self.output_dir**: the analyzer metadata directory, where we save by default
+ - **self.meta_dir**: the path to the package metadata directory (.spack) if you need it
+
+And can proceed to write your analyzer.
+
+
+^^^^^^^^^^^^^^^^^^^^^^^
+Saving Analyzer Results
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The analyzer will have ``save_result`` called, with the result object generated
+to save it to the filesystem, and if the user has added the ``--monitor`` flag
+to upload it to a monitor server. If your result follows an accepted result
+format and you don't need to parse it further, you don't need to add this
+function to your class. However, if your result data is large or otherwise
+needs additional parsing, you can define it. If you define the function, it
+is useful to know about the ``output_dir`` property, which you can join
+with your output file relative path of choice:
+
+.. code-block:: python
+
+    outfile = os.path.join(self.output_dir, "my-output-file.txt")
+
+
+The directory will be provided by the ``output_dir`` property but it won't exist,
+so you should create it:
+
+
+.. code::block:: python
+
+    # Create the output directory
+    if not os.path.exists(self._output_dir):
+        os.makedirs(self._output_dir)
+
+
+If you are generating results that match to specific files in the package
+install directory, you should try to maintain those paths in the case that
+there are equivalently named files in different directories that would
+overwrite one another. As an example of an analyzer with a custom save,
+the Libabigail analyzer saves ``*.xml`` files to the analyzer metadata
+folder in ``run()``, as they are either binaries, or as xml (text) would
+usually be too big to pass in one request. For this reason, the files
+are saved during ``run()`` and the filenames added to the result object,
+and then when the result object is passed back into ``save_result()``,
+we skip saving to the filesystem, and instead read the file and send
+each one (separately) to the monitor:
+
+
+.. code-block:: python
+
+    def save_result(self, result, monitor=None, overwrite=False):
+        """ABI results are saved to individual files, so each one needs to be
+        read and uploaded. Result here should be the lookup generated in run(),
+        the key is the analyzer name, and each value is the result file.
+        We currently upload the entire xml as text because libabigail can't
+        easily read gzipped xml, but this will be updated when it can.
+        """
+        if not monitor:
+            return
+
+        name = self.spec.package.name
+
+        for obj, filename in result.get(self.name, {}).items():
+
+            # Don't include the prefix
+            rel_path = obj.replace(self.spec.prefix + os.path.sep, "")
+
+            # We've already saved the results to file during run
+            content = spack.monitor.read_file(filename)
+
+            # A result needs an analyzer, value or binary_value, and name
+            data = {"value": content, "install_file": rel_path, "name": "abidw-xml"}
+            tty.info("Sending result for %s %s to monitor." % (name, rel_path))
+            monitor.send_analyze_metadata(self.spec.package, {"libabigail": [data]})
+
+
+
+Notice that this function, if you define it, requires a result object (generated by
+``run()``, a monitor (if you want to send), and a boolean ``overwrite`` to be used
+to check if a result exists first, and not write to it if the result exists and
+overwrite is False. Also notice that since we already saved these files to the analyzer metadata folder, we return early if a monitor isn't defined, because this function serves to send  results to the monitor. If you haven't saved anything to the analyzer metadata folder
+yet, you might want to do that here. You should also use ``tty.info`` to give
+the user a message of "Writing result to $DIRNAME."
+

 .. _writing-commands:

@@ -420,13 +680,6 @@ If you need to write a hook that is relevant to a failure within a build
 process, you would want to instead use ``on_phase_failure``.


-"""""""""""""""""""""""""""
-``on_install_cancel(spec)``
-"""""""""""""""""""""""""""
-
-The same, but triggered if a spec install is cancelled for any reason.
-
-
 """""""""""""""""""""""""""""""""""""""""""""""
 ``on_phase_success(pkg, phase_name, log_file)``
 """""""""""""""""""""""""""""""""""""""""""""""
@@ -448,6 +701,23 @@ with a hook, and this is the purpose of this particular hook. Akin to
 ``on_phase_success`` we require the same variables - the package that failed,
 the name of the phase, and the log file where we might find errors.

+"""""""""""""""""""""""""""""""""
+``on_analyzer_save(pkg, result)``
+"""""""""""""""""""""""""""""""""
+
+After an analyzer has saved some result for a package, this hook is called,
+and it provides the package that we just ran the analysis for, along with
+the loaded result. Typically, a result is structured to have the name
+of the analyzer as key, and the result object that is defined in detail in
+:ref:`analyzer_run_function`.
+
+.. code-block:: python
+
+    def on_analyzer_save(pkg, result):
+        """given a package and a result...
+        """
+        print('Do something extra with a package analysis result here')
+

 ^^^^^^^^^^^^^^^^^^^^^^
 Adding a New Hook Type
@@ -789,39 +1059,39 @@ Release branches
 ^^^^^^^^^^^^^^^^

 There are currently two types of Spack releases: :ref:`major releases
-<major-releases>` (``0.17.0``, ``0.18.0``, etc.) and :ref:`point releases
-<point-releases>` (``0.17.1``, ``0.17.2``, ``0.17.3``, etc.). Here is a
+<major-releases>` (``0.13.0``, ``0.14.0``, etc.) and :ref:`point releases
+<point-releases>` (``0.13.1``, ``0.13.2``, ``0.13.3``, etc.). Here is a
 diagram of how Spack release branches work::

-    o    branch: develop  (latest version, v0.19.0.dev0)
+    o    branch: develop  (latest version)
    |
-    o
-    | o  branch: releases/v0.18, tag: v0.18.1
-    o |
-    | o  tag: v0.18.0
-    o |
-    | o
+    o    merge v0.14.1 into develop
+    |\
+    | o  branch: releases/v0.14, tag: v0.14.1
+    o |  merge v0.14.0 into develop
+    |\|
+    | o  tag: v0.14.0
    |/
-    o
-    |
-    o
-    | o  branch: releases/v0.17, tag: v0.17.2
-    o |
-    | o  tag: v0.17.1
-    o |
-    | o  tag: v0.17.0
+    o    merge v0.13.2 into develop
+    |\
+    | o  branch: releases/v0.13, tag: v0.13.2
+    o |  merge v0.13.1 into develop
+    |\|
+    | o  tag: v0.13.1
+    o |  merge v0.13.0 into develop
+    |\|
+    | o  tag: v0.13.0
    o |
    | o
    |/
    o

 The ``develop`` branch has the latest contributions, and nearly all pull
-requests target ``develop``. The ``develop`` branch will report that its
-version is that of the next **major** release with a ``.dev0`` suffix.
+requests target ``develop``.

 Each Spack release series also has a corresponding branch, e.g.
-``releases/v0.18`` has ``0.18.x`` versions of Spack, and
-``releases/v0.17`` has ``0.17.x`` versions. A major release is the first
+``releases/v0.14`` has ``0.14.x`` versions of Spack, and
+``releases/v0.13`` has ``0.13.x`` versions. A major release is the first
 tagged version on a release branch. Minor releases are back-ported from
 develop onto release branches. This is typically done by cherry-picking
 bugfix commits off of ``develop``.
@@ -832,20 +1102,12 @@ packages. They should generally only contain fixes to the Spack core.
 However, sometimes priorities are such that new functionality needs to
 be added to a minor release.

-Both major and minor releases are tagged. As a convenience, we also tag
-the latest release as ``releases/latest``, so that users can easily check
-it out to get the latest stable version. See :ref:`updating-latest-release`
-for more details.
-
-.. note::
-
-   Older spack releases were merged **back** into develop so that we could
-   do fancy things with tags, but since tarballs and many git checkouts do
-   not have tags, this proved overly complex and confusing.
-
-   We have since converted to using `PEP 440 <https://peps.python.org/pep-0440/>`_
-   compliant versions.  `See here <https://github.com/spack/spack/pull/25267>`_ for
-   details.
+Both major and minor releases are tagged. After each release, we merge
+the release branch back into ``develop`` so that the version bump and any
+other release-specific changes are visible in the mainline. As a
+convenience, we also tag the latest release as ``releases/latest``,
+so that users can easily check it out to get the latest
+stable version. See :ref:`merging-releases` for more details.

 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Scheduling work for releases
@@ -903,11 +1165,10 @@ completed, the steps to make the major release are:
   ``releases/vX.Y``. That is, you should create a ``releases/vX.Y``
   branch if you are preparing the ``X.Y.0`` release.

-#. Remove the ``dev0`` development release segment from the version tuple in
-   ``lib/spack/spack/__init__.py``.
+#. Bump the version in ``lib/spack/spack/__init__.py``.

-   The version number itself should already be correct and should not be
-   modified.
+   See `this example from 0.13.0
+   <https://github.com/spack/spack/commit/8eeb64096c98b8a43d1c587f13ece743c864fba9>`_

 #. Update ``CHANGELOG.md`` with major highlights in bullet form.

@@ -925,20 +1186,9 @@ completed, the steps to make the major release are:
   If CI is not passing, submit pull requests to ``develop`` as normal
   and keep rebasing the release branch on ``develop`` until CI passes.

-#. Make sure the entire documentation is up to date. If documentation
-   is outdated submit pull requests to ``develop`` as normal
-   and keep rebasing the release branch on ``develop``.
-
-#. Bump the major version in the ``develop`` branch.
-
-   Create a pull request targeting the ``develop`` branch, bumping the major
-   version in ``lib/spack/spack/__init__.py`` with a ``dev0`` release segment.
-   For instance when you have just released ``v0.15.0``, set the version
-   to ``(0, 16, 0, 'dev0')`` on ``develop``.
-
 #. Follow the steps in :ref:`publishing-releases`.

-#. Follow the steps in :ref:`updating-latest-release`.
+#. Follow the steps in :ref:`merging-releases`.

 #. Follow the steps in :ref:`announcing-releases`.

@@ -965,13 +1215,8 @@ completed, the steps to make the point release are:

      $ git checkout releases/v0.15

-#. If a pull request to the release branch named ``Backports vX.Y.Z`` is not already
-   in the project, create it. This pull request ought to be created as early as
-   possible when working on a release project, so that we can build the release
-   commits incrementally, and identify potential conflicts at an early stage.
-
 #. Cherry-pick each pull request in the ``Done`` column of the release
-   project board onto the ``Backports vX.Y.Z`` pull request.
+   project board onto the release branch.

   This is **usually** fairly simple since we squash the commits from the
   vast majority of pull requests. That means there is only one commit
@@ -996,7 +1241,7 @@ completed, the steps to make the point release are:

      It is important to cherry-pick commits in the order they happened,
      otherwise you can get conflicts while cherry-picking. When
-      cherry-picking look at the merge date,
+      cherry-picking onto a point release, look at the merge date,
      **not** the number of the pull request or the date it was opened.

      Sometimes you may **still** get merge conflicts even if you have
@@ -1017,19 +1262,18 @@ completed, the steps to make the point release are:
         branch if neither of the above options makes sense, but this can
         require a lot of work. It's seldom the right choice.

-#. When all the commits from the project board are cherry-picked into
-   the ``Backports vX.Y.Z`` pull request, you can push a commit to:
+#. Bump the version in ``lib/spack/spack/__init__.py``.

-   1. Bump the version in ``lib/spack/spack/__init__.py``.
-   2. Update ``CHANGELOG.md`` with a list of the changes.
+   See `this example from 0.14.1
+   <https://github.com/spack/spack/commit/ff0abb9838121522321df2a054d18e54b566b44a>`_.
+
+#. Update ``CHANGELOG.md`` with a list of the changes.

   This is typically a summary of the commits you cherry-picked onto the
   release branch. See `the changelog from 0.14.1
   <https://github.com/spack/spack/commit/ff0abb9838121522321df2a054d18e54b566b44a>`_.

-#. Merge the ``Backports vX.Y.Z`` PR with the **Rebase and merge** strategy. This
-   is needed to keep track in the release branch of all the commits that were
-   cherry-picked.
+#. Push the release branch to GitHub.

 #. Make sure CI passes on the release branch, including:

@@ -1044,12 +1288,10 @@ completed, the steps to make the point release are:

 #. Follow the steps in :ref:`publishing-releases`.

-#. Follow the steps in :ref:`updating-latest-release`.
+#. Follow the steps in :ref:`merging-releases`.

 #. Follow the steps in :ref:`announcing-releases`.

-#. Submit a PR to update the CHANGELOG in the `develop` branch
-   with the addition of this point release.

 .. _publishing-releases:

@@ -1107,11 +1349,11 @@ Publishing a release on GitHub
   selectable in the versions menu.


-.. _updating-latest-release:
+.. _merging-releases:

-^^^^^^^^^^^^^^^^^^^^^^^^^^
-Updating `releases/latest`
-^^^^^^^^^^^^^^^^^^^^^^^^^^
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Updating `releases/latest` and `develop`
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 If the new release is the **highest** Spack release yet, you should
 also tag it as ``releases/latest``. For example, suppose the highest
@@ -1135,6 +1377,40 @@ To tag ``releases/latest``, do this:
 The ``--force`` argument to ``git tag`` makes ``git`` overwrite the existing
 ``releases/latest`` tag with the new one.

+We also merge each release that we tag as ``releases/latest`` into ``develop``.
+Make sure to do this with a merge commit:
+
+.. code-block:: console
+
+   $ git checkout develop
+   $ git merge --no-ff -s ours vX.Y.Z  # vX.Y.Z is the new release's tag
+   $ git push
+
+We merge back to ``develop`` because it:
+
+  * updates the version and ``CHANGELOG.md`` on ``develop``; and
+  * ensures that your release tag is reachable from the head of
+    ``develop``.
+
+We *must* use a real merge commit (via the ``--no-ff`` option) to
+ensure that the release tag is reachable from the tip of ``develop``.
+This is necessary for ``spack -V`` to work properly -- it uses ``git
+describe --tags`` to find the last reachable tag in the repository and
+reports how far we are from it. For example:
+
+.. code-block:: console
+
+   $ spack -V
+   0.14.2-1486-b80d5e74e5
+
+This says that we are at commit ``b80d5e74e5``, which is 1,486 commits
+ahead of the ``0.14.2`` release.
+
+We put this step last in the process because it's best to do it only once
+the release is complete and tagged. If you do it before you've tagged the
+release and later decide you want to tag some later commit, you'll need
+to merge again.
+

 .. _announcing-releases:

--- a/lib/spack/docs/dockerhub_spack.png
+++ b/lib/spack/docs/dockerhub_spack.png
--- a/lib/spack/docs/environments.rst
+++ b/lib/spack/docs/environments.rst
@@ -1,13 +1,13 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)

 .. _environments:

-=========================
-Environments (spack.yaml)
-=========================
+============
+Environments
+============

 An environment is used to group together a set of specs for the
 purpose of building, rebuilding and deploying in a coherent fashion.
@@ -273,9 +273,19 @@ or
 Concretizing
 ^^^^^^^^^^^^

-Once some user specs have been added to an environment, they can be concretized.
-There are at the moment three different modes of operation to concretize an environment,
-which are explained in details in :ref:`environments_concretization_config`.
+Once some user specs have been added to an environment, they can be
+concretized. *By default specs are concretized separately*, one after
+the other. This mode of operation permits to deploy a full
+software stack where multiple configurations of the same package
+need to be installed alongside each other. Central installations done
+at HPC centers by system administrators or user support groups
+are a common case that fits in this behavior.
+Environments *can also be configured to concretize all
+the root specs in a self-consistent way* to ensure that
+each package in the environment comes with a single configuration. This
+mode of operation is usually what is required by software developers that
+want to deploy their development environment.
+
 Regardless of which mode of operation has been chosen, the following
 command will ensure all the root specs are concretized according to the
 constraints that are prescribed in the configuration:
@@ -339,24 +349,6 @@ If the Environment has been concretized, Spack will install the
 concretized specs. Otherwise, ``spack install`` will first concretize
 the Environment and then install the concretized specs.

-.. note::
-
-   Every ``spack install`` process builds one package at a time with multiple build
-   jobs, controlled by the ``-j`` flag and the ``config:build_jobs`` option
-   (see :ref:`build-jobs`). To speed up environment builds further, independent
-   packages can be installed in parallel by launching more Spack instances. For
-   example, the following will build at most four packages in parallel using
-   three background jobs: 
-
-   .. code-block:: console
-
-      [myenv]$ spack install & spack install & spack install & spack install
-
-   Another option is to generate a ``Makefile`` and run ``make -j<N>`` to control
-   the number of parallel install processes. See :ref:`env-generate-depfile`
-   for details.
-
-
 As it installs, ``spack install`` creates symbolic links in the
 ``logs/`` directory in the Environment, allowing for easy inspection
 of build logs related to that environment. The ``spack install``
@@ -376,30 +368,6 @@ from being added again.  At the same time, a spec that already exists in the
 environment, but only as a dependency, will be added to the environment as a
 root spec without the ``--no-add`` option.

-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Developing Packages in a Spack Environment
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The ``spack develop`` command allows one to develop Spack packages in
-an environment. It requires a spec containing a concrete version, and
-will configure Spack to install the package from local source. By
-default, it will also clone the package to a subdirectory in the
-environment. This package will have a special variant ``dev_path``
-set, and Spack will ensure the package and its dependents are rebuilt
-any time the environment is installed if the package's local source
-code has been modified. Spack ensures that all instances of a
-developed package in the environment are concretized to match the
-version (and other constraints) passed as the spec argument to the
-``spack develop`` command.
-
-For packages with ``git`` attributes, git branches, tags, and commits can
-also be used as valid concrete versions (see :ref:`version-specifier`).
-This means that for a package ``foo``, ``spack develop foo@git.main`` will clone 
-the ``main`` branch of the package, and ``spack install`` will install from
-that git clone if ``foo`` is in the environment.
-Further development on ``foo`` can be tested by reinstalling the environment,
-and eventually committed and pushed to the upstream git repo.
-
 ^^^^^^^
 Loading
 ^^^^^^^
@@ -416,11 +384,18 @@ Sourcing that file in Bash will make the environment available to the
 user; and can be included in ``.bashrc`` files, etc.  The ``loads``
 file may also be copied out of the environment, renamed, etc.

+----------
+spack.yaml
+----------
+
+Spack environments can be customized at finer granularity by editing
+the ``spack.yaml`` manifest file directly.
+
 .. _environment-configuration:

------------------------
+^^^^^^^^^^^^^^^^^^^^^^^^
 Configuring Environments
------------------------
+^^^^^^^^^^^^^^^^^^^^^^^^

 A variety of Spack behaviors are changed through Spack configuration
 files, covered in more detail in the :ref:`configuration`
@@ -442,9 +417,9 @@ environment can be specified by ``env:NAME`` (to affect environment
 ``foo``, set ``--scope env:foo``). These commands will automatically
 manipulate configuration inline in the ``spack.yaml`` file.

-^^^^^^^^^^^^^^^^^^^^^
+"""""""""""""""""""""
 Inline configurations
-^^^^^^^^^^^^^^^^^^^^^
+"""""""""""""""""""""

 Inline Environment-scope configuration is done using the same yaml
 format as standard Spack configuration scopes, covered in the
@@ -465,9 +440,9 @@ a ``packages.yaml`` file) could contain:
 This configuration sets the default compiler for all packages to
 ``intel``.

-^^^^^^^^^^^^^^^^^^^^^^^
+"""""""""""""""""""""""
 Included configurations
-^^^^^^^^^^^^^^^^^^^^^^^
+"""""""""""""""""""""""

 Spack environments allow an ``include`` heading in their yaml
 schema. This heading pulls in external configuration files and applies
@@ -487,9 +462,9 @@ to make small changes to an individual Environment. Included configs
 listed earlier will have higher precedence, as the included configs are
 applied in reverse order.

-------------------------------
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Manually Editing the Specs List
-------------------------------
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 The list of abstract/root specs in the Environment is maintained in
 the ``spack.yaml`` manifest under the heading ``specs``.
@@ -507,81 +482,37 @@ Appending to this list in the yaml is identical to using the ``spack
 add`` command from the command line. However, there is more power
 available from the yaml file.

-.. _environments_concretization_config:
-
-^^^^^^^^^^^^^^^^^^^
+"""""""""""""""""""
 Spec concretization
-^^^^^^^^^^^^^^^^^^^
-An environment can be concretized in three different modes and the behavior active under any environment
-is determined by the ``concretizer:unify`` property. By default specs are concretized *separately*, one after the other:
+"""""""""""""""""""
+
+Specs can be concretized separately or together, as already
+explained in :ref:`environments_concretization`. The behavior active
+under any environment is determined by the ``concretization`` property:

 .. code-block:: yaml

   spack:
       specs:
-         - hdf5~mpi
-         - hdf5+mpi
-         - zlib@1.2.8
-       concretizer:
-         unify: false
+         - ncview
+         - netcdf
+         - nco
+         - py-sphinx
+       concretization: together

-This mode of operation permits to deploy a full software stack where multiple configurations of the same package
-need to be installed alongside each other using the best possible selection of transitive dependencies. The downside
-is that redundancy of installations is disregarded completely, and thus environments might be more bloated than
-strictly needed. In the example above, for instance, if a version of ``zlib`` newer than ``1.2.8`` is known to Spack,
-then it will be used for both ``hdf5`` installations.
-
-If redundancy of the environment is a concern, Spack provides a way to install it *together where possible*,
-i.e. trying to maximize reuse of dependencies across different specs:
-
-.. code-block:: yaml
-
-   spack:
-       specs:
-         - hdf5~mpi
-         - hdf5+mpi
-         - zlib@1.2.8
-       concretizer:
-         unify: when_possible
-
-Also in this case Spack allows having multiple configurations of the same package, but privileges the reuse of
-specs over other factors. Going back to our example, this means that both ``hdf5`` installations will use
-``zlib@1.2.8`` as a dependency even if newer versions of that library are available.
-Central installations done at HPC centers by system administrators or user support groups are a common case
-that fits either of these two modes.
-
-Environments can also be configured to concretize all the root specs *together*, in a self-consistent way, to
-ensure that each package in the environment comes with a single configuration:
-
-.. code-block:: yaml
-
-   spack:
-       specs:
-         - hdf5+mpi
-         - zlib@1.2.8
-       concretizer:
-         unify: true
-
-This mode of operation is usually what is required by software developers that want to deploy their development
-environment and have a single view of it in the filesystem.
-
-.. note::
-
-   The ``concretizer:unify`` config option was introduced in Spack 0.18 to
-   replace the ``concretization`` property. For reference,
-   ``concretization: together`` is replaced by ``concretizer:unify:true``,
-   and ``concretization: separately`` is replaced by ``concretizer:unify:false``.
+which can currently take either one of the two allowed values ``together`` or ``separately``
+(the default).

 .. admonition:: Re-concretization of user specs

-   When concretizing specs *together* or *together where possible* the entire set of specs will be
+   When concretizing specs together the entire set of specs will be
   re-concretized after any addition of new user specs, to ensure that
-   the environment remains consistent / minimal. When instead the specs are concretized
+   the environment remains consistent. When instead the specs are concretized
   separately only the new specs will be re-concretized after any addition.

-^^^^^^^^^^^^^
+"""""""""""""
 Spec Matrices
-^^^^^^^^^^^^^
+"""""""""""""

 Entries in the ``specs`` list can be individual abstract specs or a
 spec matrix.
@@ -641,9 +572,9 @@ This allows one to create toolchains out of combinations of
 constraints and apply them somewhat indiscriminately to packages,
 without regard for the applicability of the constraint.

-^^^^^^^^^^^^^^^^^^^^
+""""""""""""""""""""
 Spec List References
-^^^^^^^^^^^^^^^^^^^^
+""""""""""""""""""""

 The last type of possible entry in the specs list is a reference.

@@ -743,9 +674,9 @@ The valid variables for a ``when`` clause are:
 #. ``hostname``. The hostname of the system (if ``hostname`` is an
   executable in the user's PATH).

-^^^^^^^^^^^^^^^^^^^^^^^^
+""""""""""""""""""""""""
 SpecLists as Constraints
-^^^^^^^^^^^^^^^^^^^^^^^^
+""""""""""""""""""""""""

 Dependencies and compilers in Spack can be both packages in an
 environment and constraints on other packages. References to SpecLists
@@ -777,41 +708,41 @@ For example, the following environment has three root packages:
 This allows for a much-needed reduction in redundancy between packages
 and constraints.

----------------
-Filesystem Views
----------------
+^^^^^^^^^^^^^^^^^^^^^^^^^
+Environment-managed Views
+^^^^^^^^^^^^^^^^^^^^^^^^^

-Spack Environments can define filesystem views, which provide a direct access point
-for software similar to the directory hierarchy that might exist under ``/usr/local``.
-Filesystem views are updated every time the environment is written out to the lock
-file ``spack.lock``, so the concrete environment and the view are always compatible.
-The files of the view's installed packages are brought into the view by symbolic or
-hard links, referencing the original Spack installation, or by copy.
+Spack Environments can define filesystem views of their software,
+which are maintained as packages and can be installed and uninstalled from
+the Environment. Filesystem views provide an access point for packages
+from the filesystem for users who want to access those packages
+directly. For more information on filesystem views, see the section
+:ref:`filesystem-views`.
+
+Spack Environment managed views are updated every time the environment
+is written out to the lock file ``spack.lock``, so the concrete
+environment and the view are always compatible.

 .. _configuring_environment_views:

-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Configuration in ``spack.yaml``
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+"""""""""""""""""""""""""""""
+Configuring environment views
+"""""""""""""""""""""""""""""

 The Spack Environment manifest file has a top-level keyword
-``view``. Each entry under that heading is a **view descriptor**, headed
-by a name. Any number of views may be defined under the ``view`` heading.
-The view descriptor contains the root of the view, and
+``view``. Each entry under that heading is a view descriptor, headed
+by a name. The view descriptor contains the root of the view, and
 optionally the projections for the view, ``select`` and
 ``exclude`` lists for the view and link information via ``link`` and
-``link_type``.
-
-For example, in the following manifest
+``link_type``. For example, in the following manifest
 file snippet we define a view named ``mpis``, rooted at
 ``/path/to/view`` in which all projections use the package name,
 version, and compiler name to determine the path for a given
 package. This view selects all packages that depend on MPI, and
 excludes those built with the PGI compiler at version 18.5.
-The root specs with their (transitive) link and run type dependencies
-will be put in the view due to the  ``link: all`` option,
-and the files in the view will be symlinks to the spack install
-directories.
+All the dependencies of each root spec in the environment will be linked
+in the view due to the command ``link: all`` and the files in the view will
+be symlinks to the spack install directories.

 .. code-block:: yaml

@@ -823,30 +754,20 @@ directories.
         select: [^mpi]
         exclude: ['%pgi@18.5']
         projections:
-           all: '{name}/{version}-{compiler.name}'
+           all: {name}/{version}-{compiler.name}
         link: all
         link_type: symlink

-The default for the ``select`` and
+For more information on using view projections, see the section on
+:ref:`adding_projections_to_views`. The default for the ``select`` and
 ``exclude`` values is to select everything and exclude nothing. The
 default projection is the default view projection (``{}``). The ``link``
-attribute allows the following values:
-
-#. ``link: all`` include root specs with their transitive run and link type
-   dependencies (default);
-#. ``link: run`` include root specs with their transitive run type dependencies;
-#. ``link: roots`` include root specs without their dependencies.
-
-The ``link_type`` defaults to ``symlink`` but can also take the value
-of ``hardlink`` or ``copy``.
-
-.. tip::
-
-   The option ``link: run`` can be used to create small environment views for
-   Python packages. Python will be able to import packages *inside* of the view even
-   when the environment is not activated, and linked libraries will be located
-   *outside* of the view thanks to rpaths.
+defaults to ``all`` but can also be ``roots`` when only the root specs
+in the environment are desired in the view. The ``link_type`` defaults
+to ``symlink`` but can also take the value of ``hardlink`` or ``copy``.

+Any number of views may be defined under the ``view`` heading in a
+Spack Environment.

 There are two shorthands for environments with a single view. If the
 environment at ``/path/to/env`` has a single view, with a root at
@@ -912,47 +833,9 @@ regenerate`` will regenerate the views for the environment. This will
 apply any updates in the environment configuration that have not yet
 been applied.

-.. _view_projections:
-
-""""""""""""""""
-View Projections
-""""""""""""""""
-The default projection into a view is to link every package into the
-root of the view. The projections attribute is a mapping of partial specs to
-spec format strings, defined by the :meth:`~spack.spec.Spec.format`
-function, as shown in the example below:
-
-.. code-block:: yaml
-
-   projections:
-     zlib: {name}-{version}
-     ^mpi: {name}-{version}/{^mpi.name}-{^mpi.version}-{compiler.name}-{compiler.version}
-     all: {name}-{version}/{compiler.name}-{compiler.version}
-
-The entries in the projections configuration file must all be either
-specs or the keyword ``all``. For each spec, the projection used will
-be the first non-``all`` entry that the spec satisfies, or ``all`` if
-there is an entry for ``all`` and no other entry is satisfied by the
-spec. Where the keyword ``all`` appears in the file does not
-matter.
-
-Given the example above, the spec ``zlib@1.2.8``
-will be linked into ``/my/view/zlib-1.2.8/``, the spec
-``hdf5@1.8.10+mpi %gcc@4.9.3 ^mvapich2@2.2`` will be linked into
-``/my/view/hdf5-1.8.10/mvapich2-2.2-gcc-4.9.3``, and the spec
-``hdf5@1.8.10~mpi %gcc@4.9.3`` will be linked into
-``/my/view/hdf5-1.8.10/gcc-4.9.3``.
-
-If the keyword ``all`` does not appear in the projections
-configuration file, any spec that does not satisfy any entry in the
-file will be linked into the root of the view as in a single-prefix
-view. Any entries that appear below the keyword ``all`` in the
-projections configuration file will not be used, as all specs will use
-the projection under ``all`` before reaching those entries.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+""""""""""""""""""""""""""""
 Activating environment views
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+""""""""""""""""""""""""""""

 The ``spack env activate`` command will put the default view for the
 environment into the user's path, in addition to activating the
@@ -972,6 +855,9 @@ Variable            Paths
 PATH                bin
 MANPATH             man, share/man
 ACLOCAL_PATH        share/aclocal
+LD_LIBRARY_PATH     lib, lib64
+LIBRARY_PATH        lib, lib64
+CPATH               include
 PKG_CONFIG_PATH     lib/pkgconfig, lib64/pkgconfig, share/pkgconfig
 CMAKE_PREFIX_PATH   .
 =================== =========
@@ -983,89 +869,3 @@ environment.

 The ``spack env deactivate`` command will remove the default view of
 the environment from the user's path.
-
-
-.. _env-generate-depfile:
-
-
------------------------------------------
-Generating Depfiles from Environments
------------------------------------------
-
-Spack can generate ``Makefile``\s to make it easier to build multiple
-packages in an environment in parallel. Generated ``Makefile``\s expose
-targets that can be included in existing ``Makefile``\s, to allow
-other targets to depend on the environment installation.
-
-A typical workflow is as follows:
-
-.. code:: console
-
-   spack env create -d .
-   spack -e . add perl
-   spack -e . concretize
-   spack -e . env depfile > Makefile
-   make -j64
-
-This generates a ``Makefile`` from a concretized environment in the
-current working directory, and ``make -j64`` installs the environment,
-exploiting parallelism across packages as much as possible. Spack
-respects the Make jobserver and forwards it to the build environment
-of packages, meaning that a single ``-j`` flag is enough to control the
-load, even when packages are built in parallel.
-
-By default the following phony convenience targets are available:
-
- ``make all``: installs the environment (default target);
- ``make fetch-all``: only fetch sources of all packages;
- ``make clean``: cleans files used by make, but does not uninstall packages.
-
-.. tip::
-
-   GNU Make version 4.3 and above have great support for output synchronization
-   through the ``-O`` and ``--output-sync`` flags, which ensure that output is
-   printed orderly per package install. To get synchronized output with colors,
-   use ``make -j<N> SPACK_COLOR=always --output-sync=recurse``.
-
-The following advanced example shows how generated targets can be used in a
-``Makefile``:
-
-.. code:: Makefile
-
-   SPACK ?= spack
-
-   .PHONY: all clean env
-
-   all: env
-
-   spack.lock: spack.yaml
-   	$(SPACK) -e . concretize -f
-
-   env.mk: spack.lock
-   	$(SPACK) -e . env depfile -o $@ --make-target-prefix spack
-
-   env: spack/env
-   	$(info Environment installed!)
-
-   clean:
-   	rm -rf spack.lock env.mk spack/
-
-   ifeq (,$(filter clean,$(MAKECMDGOALS)))
-   include env.mk
-   endif
-
-When ``make`` is invoked, it first "remakes" the missing include ``env.mk``
-from its rule, which triggers concretization. When done, the generated target
-``spack/env`` is available. In the above example, the ``env`` target uses this generated
-target as a prerequisite, meaning that it can make use of the installed packages in
-its commands.
-
-As it is typically undesirable to remake ``env.mk`` as part of ``make clean``,
-the include is conditional.
-
-.. note::
-
-   When including generated ``Makefile``\s, it is important to use
-   the ``--make-target-prefix`` flag and use the non-phony target
-   ``<target-prefix>/env`` as prerequisite, instead of the phony target
-   ``<target-prefix>/all``.
--- a/lib/spack/docs/extensions.rst
+++ b/lib/spack/docs/extensions.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -38,7 +38,8 @@ obtained by cloning the corresponding git repository:

 .. code-block:: console

-   $ cd ~/
+   $ pwd
+   /home/user
   $ mkdir tmp && cd tmp
   $ git clone https://github.com/alalazo/spack-scripting.git
   Cloning into 'spack-scripting'...
@@ -61,7 +62,7 @@ paths to ``config.yaml``. In the case of our example this means ensuring that:

   config:
     extensions:
-     - ~/tmp/spack-scripting
+     - /home/user/tmp/spack-scripting

 is part of your configuration file. Once this is setup any command that the extension provides
 will be available from the command line:
--- a/lib/spack/docs/features.rst
+++ b/lib/spack/docs/features.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/getting_started.rst
+++ b/lib/spack/docs/getting_started.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -35,7 +35,7 @@ Getting Spack is easy.  You can clone it from the `github repository

 .. code-block:: console

-   $ git clone -c feature.manyFiles=true https://github.com/spack/spack.git
+   $ git clone https://github.com/spack/spack.git

 This will create a directory called ``spack``.

@@ -88,89 +88,91 @@ the environment.
 Bootstrapping clingo
 ^^^^^^^^^^^^^^^^^^^^

-Spack uses ``clingo`` under the hood to resolve optimal versions and variants of
-dependencies when installing a package. Since ``clingo`` itself is a binary,
-Spack has to install it on initial use, which is called bootstrapping.
-
-Spack provides two ways of bootstrapping ``clingo``: from pre-built binaries
-(default), or from sources. The fastest way to get started is to bootstrap from
-pre-built binaries.
-
-.. note::
-
-   When bootstrapping from pre-built binaries, Spack currently requires 
-   ``patchelf`` on Linux and ``otool`` on macOS. If ``patchelf`` is not in the
-   ``PATH``, Spack will build it from sources, and a C++ compiler is required.
-
-The first time you concretize a spec, Spack will bootstrap in the background:
+Spack supports using ``clingo`` as an external solver to compute which software
+needs to be installed. The default configuration allows Spack to install
+``clingo`` from a public buildcache, created by a Github Action workflow. In this
+case the bootstrapping procedure is transparent to the user, except for a
+slightly long waiting time on the first concretization of a spec:

 .. code-block:: console

-   $ time spack spec zlib
-   Input spec
-   --------------------------------
-   zlib
+   $ spack find -b
+   ==> Showing internal bootstrap store at "/home/spack/.spack/bootstrap/store"
+   ==> 0 installed packages

-   Concretized
-   --------------------------------
-   zlib@1.2.11%gcc@7.5.0+optimize+pic+shared arch=linux-ubuntu18.04-zen
+   $ time spack solve zlib
+   ==> Best of 2 considered solutions.
+   ==> Optimization Criteria:
+     Priority  Criterion                                 Value
+     1         deprecated versions used                      0
+     2         version weight                                0
+     3         number of non-default variants (roots)        0
+     4         multi-valued variants                         0
+     5         preferred providers for roots                 0
+     6         number of non-default variants (non-roots)    0
+     7         preferred providers (non-roots)               0
+     8         compiler mismatches                           0
+     9         version badness                               0
+     10        count of non-root multi-valued variants       0
+     11        non-preferred compilers                       0
+     12        target mismatches                             0
+     13        non-preferred targets                         0

-   real	0m20.023s
-   user	0m18.351s
-   sys	0m0.784s
+   zlib@1.2.11%gcc@11.1.0+optimize+pic+shared arch=linux-ubuntu18.04-broadwell
+
+   real	0m30,618s
+   user	0m27,278s
+   sys	0m1,549s

 After this command you'll see that ``clingo`` has been installed for Spack's own use:

 .. code-block:: console

   $ spack find -b
-   ==> Showing internal bootstrap store at "/root/.spack/bootstrap/store"
-   ==> 3 installed packages
+   ==> Showing internal bootstrap store at "/home/spack/.spack/bootstrap/store"
+   ==> 2 installed packages
   -- linux-rhel5-x86_64 / gcc@9.3.0 -------------------------------
   clingo-bootstrap@spack  python@3.6

-   -- linux-ubuntu18.04-zen / gcc@7.5.0 ----------------------------
-   patchelf@0.13
-
 Subsequent calls to the concretizer will then be much faster:

 .. code-block:: console

-   $ time spack spec zlib
+   $ time spack solve zlib
   [ ... ]
-   real	0m0.490s
-   user	0m0.431s
-   sys	0m0.041s
+   real	0m1,222s
+   user	0m1,146s
+   sys	0m0,059s

-
-If for security concerns you cannot bootstrap ``clingo`` from pre-built
-binaries, you have to mark this bootstrapping method as untrusted. This makes
-Spack fall back to bootstrapping from sources:
+If for security or for other reasons you don't want to or can't install precompiled
+binaries, Spack can fall-back to bootstrap ``clingo`` from source files. To forbid
+Spack from retrieving binaries from the bootstrapping buildcache, the following
+command must be given:

 .. code-block:: console

-   $ spack bootstrap untrust github-actions-v0.2
-   ==> "github-actions-v0.2" is now untrusted and will not be used for bootstrapping
+   $ spack bootstrap untrust github-actions
+   ==> "github-actions" is now untrusted and will not be used for bootstrapping

-You can verify that the new settings are effective with:
+since an "untrusted" way of bootstrapping software will not be considered
+by Spack. You can verify the new settings are effective with:

 .. code-block:: console

   $ spack bootstrap list
-   Name: github-actions-v0.2 UNTRUSTED
+   Name: github-actions UNTRUSTED

     Type: buildcache

     Info:
-       url: https://mirror.spack.io/bootstrap/github-actions/v0.2
-       homepage: https://github.com/spack/spack-bootstrap-mirrors
-       releases: https://github.com/spack/spack-bootstrap-mirrors/releases
+       url: https://mirror.spack.io/bootstrap/github-actions/v0.1
+       homepage: https://github.com/alalazo/spack-bootstrap-mirrors
+       releases: https://github.com/alalazo/spack-bootstrap-mirrors/releases

     Description:
       Buildcache generated from a public workflow using Github Actions.
       The sha256 checksum of binaries is checked before installation.

-   [ ... ]

   Name: spack-install TRUSTED

@@ -179,25 +181,33 @@ You can verify that the new settings are effective with:
     Description:
       Specs built from sources by Spack. May take a long time.

-.. note::
-
-   When bootstrapping from sources, Spack requires a full install of Python
-   including header files (e.g. ``python3-dev`` on Debian), and a compiler
-   with support for C++14 (GCC on Linux, Apple Clang on macOS) and static C++
-   standard libraries on Linux.
-
-Spack will build the required software on the first request to concretize a spec:
+When bootstrapping from sources, Spack requires a compiler with support
+for C++14 (GCC on ``linux``, Apple Clang on ``darwin``) and static C++
+standard libraries on ``linux``. Spack will build the required software
+on the first request to concretize a spec:

 .. code-block:: console

-   $ spack spec zlib
+   $ spack solve zlib
   [+] /usr (external bison-3.0.4-wu5pgjchxzemk5ya2l3ddqug2d7jv6eb)
   [+] /usr (external cmake-3.19.4-a4kmcfzxxy45mzku4ipmj5kdiiz5a57b)
   [+] /usr (external python-3.6.9-x4fou4iqqlh5ydwddx3pvfcwznfrqztv)
   ==> Installing re2c-1.2.1-e3x6nxtk3ahgd63ykgy44mpuva6jhtdt
   [ ... ]
+   ==> Optimization: [0, 0, 0, 0, 0, 1, 0, 0, 0]
   zlib@1.2.11%gcc@10.1.0+optimize+pic+shared arch=linux-ubuntu18.04-broadwell

+.. tip::
+
+   If you want to speed-up bootstrapping ``clingo`` from sources, you may try to
+   search for ``cmake`` and ``bison`` on your system:
+
+   .. code-block:: console
+
+      $ spack external find cmake bison
+      ==> The following specs have been detected on this system and added to /home/spack/.spack/packages.yaml
+      bison@3.0.4  cmake@3.19.4
+
 """""""""""""""""""
 The Bootstrap Store
 """""""""""""""""""
@@ -272,10 +282,9 @@ Compiler configuration
 ----------------------

 Spack has the ability to build packages with multiple compilers and
-compiler versions. Compilers can be made available to Spack by
-specifying them manually in ``compilers.yaml``, or automatically by
-running ``spack compiler find``, but for convenience Spack will
-automatically detect compilers the first time it needs them.
+compiler versions. Spack searches for compilers on your machine
+automatically the first time it is run. It does this by inspecting
+your ``PATH``.

 .. _cmd-spack-compilers:

@@ -283,7 +292,7 @@ automatically detect compilers the first time it needs them.
 ``spack compilers``
 ^^^^^^^^^^^^^^^^^^^

-You can see which compilers are available to Spack by running ``spack
+You can see which compilers spack has found by running ``spack
 compilers`` or ``spack compiler list``:

 .. code-block:: console
@@ -322,10 +331,9 @@ An alias for ``spack compiler find``.
 ``spack compiler find``
 ^^^^^^^^^^^^^^^^^^^^^^^

-Lists the compilers currently available to Spack. If you do not see
-a compiler in this list, but you want to use it with Spack, you can
-simply run ``spack compiler find`` with the path to where the
-compiler is installed.  For example:
+If you do not see a compiler in this list, but you want to use it with
+Spack, you can simply run ``spack compiler find`` with the path to
+where the compiler is installed.  For example:

 .. code-block:: console

@@ -1517,238 +1525,3 @@ To ensure that Spack does not autodetect the Cray programming
 environment, unset the environment variable ``MODULEPATH``. This
 will cause Spack to treat a linux container on a Cray system as a base
 linux distro.
-
-.. _windows_support:
-
----------------
-Spack On Windows
----------------
-
-Windows support for Spack is currently under development. While this work is still in an early stage,
-it is currently possible to set up Spack and perform a few operations on Windows.  This section will guide
-you through the steps needed to install Spack and start running it on a fresh Windows machine. 
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Step 1: Install prerequisites
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-To use Spack on Windows, you will need the following packages:
-
-Required:
-* Microsoft Visual Studio
-* Python 
-* Git
-
-Optional:
-* Intel Fortran (needed for some packages)
-
-.. note::
-
-  Currently MSVC is the only compiler tested for C/C++ projects. Intel OneAPI provides Fortran support.
-
-"""""""""""""""""""""""
-Microsoft Visual Studio
-"""""""""""""""""""""""
-
-Microsoft Visual Studio provides the only Windows C/C++ compiler that is currently supported by Spack.
-
-We require several specific components to be included in the Visual Studio installation.
-One is the C/C++ toolset, which can be selected as "Desktop development with C++" or "C++ build tools,"
-depending on installation type (Professional, Build Tools, etc.)  The other required component is
-"C++ CMake tools for Windows," which can be selected from among the optional packages.
-This provides CMake and Ninja for use during Spack configuration.
-
-If you already have Visual Studio installed, you can make sure these components are installed by
-rerunning the installer.  Next to your installation, select "Modify" and look at the
-"Installation details" pane on the right.
-
-"""""""""""""
-Intel Fortran
-"""""""""""""
-
-For Fortran-based packages on Windows, we strongly recommend Intel's oneAPI Fortran compilers.
-The suite is free to download from Intel's website, located at 
-https://software.intel.com/content/www/us/en/develop/tools/oneapi/components/fortran-compiler.html#gs.70t5tw.
-The executable of choice for Spack will be Intel's Beta Compiler, ifx, which supports the classic
-compiler's (ifort's) frontend and runtime libraries by using LLVM.
-
-""""""
-Python
-""""""
-
-As Spack is a Python-based package, an installation of Python will be needed to run it.
-Python 3 can be downloaded and installed from the Windows Store, and will be automatically added
-to your ``PATH`` in this case.
-
-.. note::
-   Spack currently supports Python versions later than 3.2 inclusive.
-
-"""
-Git
-"""
-
-A bash console and GUI can be downloaded from https://git-scm.com/downloads.
-If you are unfamiliar with Git, there are a myriad of resources online to help
-guide you through checking out repositories and switching development branches.
-
-When given the option of adjusting your ``PATH``, choose the ``Git from the
-command line and also from 3rd-party software`` option. This will automatically
-update your ``PATH`` variable to include the ``git`` command.
-
-Spack support on Windows is currently dependent on installing the Git for Windows project
-as the project providing Git support on Windows. This is additionally the recommended method
-for installing Git on Windows, a link to which can be found above. Spack requires the
-utilities vendored by this project.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Step 2: Install and setup Spack
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-We are now ready to get the Spack environment set up on our machine. We
-begin by using Git to clone the Spack repo, hosted at https://github.com/spack/spack.git
-into a desired directory, for our purposes today, called ``spack_install``.
-
-In order to install Spack with Windows support, run the following one liner
-in a Windows CMD prompt.
-
-.. code-block:: console
-
-   git clone https://github.com/spack/spack.git
-
-.. note::
-   If you chose to install Spack into a directory on Windows that is set up to require Administrative
-   Privleges, Spack will require elevated privleges to run.
-   Administrative Privleges can be denoted either by default such as
-   ``C:\Program Files``, or aministrator applied administrative restrictions
-   on a directory that spack installs files to such as ``C:\Users``
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Step 3: Run and configure Spack
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-To use Spack, run ``bin\spack_cmd.bat`` (you may need to Run as Administrator) from the top-level spack
-directory. This will provide a Windows command prompt with an environment properly set up with Spack
-and its prerequisites. If you receive a warning message that Python is not in your ``PATH``
-(which may happen if you installed Python from the website and not the Windows Store) add the location
-of the Python executable to your ``PATH`` now. You can permanently add Python to your ``PATH`` variable
-by using the ``Edit the system environment variables`` utility in Windows Control Panel.
-
-.. note::
-   Alternatively, Powershell can be used in place of CMD
-
-To configure Spack, first run the following command inside the Spack console:
-
-.. code-block:: console
-
-   spack compiler find
-
-This creates a ``.staging`` directory in our Spack prefix, along with a ``windows`` subdirectory
-containing a ``compilers.yaml`` file. On a fresh Windows install with the above packages
-installed, this command should only detect Microsoft Visual Studio and the Intel Fortran
-compiler will be integrated within the first version of MSVC present in the ``compilers.yaml``
-output.
-
-Spack provides a default ``config.yaml`` file for Windows that it will use unless overridden.
-This file is located at ``etc\spack\defaults\windows\config.yaml``. You can read more on how to
-do this and write your own configuration files in the :ref:`Configuration Files<configuration>` section of our
-documentation. If you do this, pay particular attention to the ``build_stage`` block of the file
-as this specifies the directory that will temporarily hold the source code for the packages to
-be installed. This path name must be sufficiently short for compliance with cmd, otherwise you
-will see build errors during installation (particularly with CMake) tied to long path names.
-
-To allow Spack use of external tools and dependencies already on your system, the
-external pieces of software must be described in the ``packages.yaml`` file.
-There are two methods to populate this file:
-
-The first and easiest choice is to use Spack to find installation on your system. In
-the Spack terminal, run the following commands:
-
-.. code-block:: console
-
-   spack external find cmake
-   spack external find ninja
-
-The ``spack external find <name>`` will find executables on your system
-with the same name given. The command will store the items found in
-``packages.yaml`` in the ``.staging\`` directory.
-
-Assuming that the command found CMake and Ninja executables in the previous
-step, continue to Step 4. If no executables were found, we may need to manually direct spack towards the CMake
-and Ninja installations we set up with Visual Studio. Therefore, your ``packages.yaml`` file will look something
-like this, with possibly slight variants in the paths to CMake and Ninja:
-
-.. code-block:: yaml
-
-   packages:
-     cmake:
-       externals:
-       - spec: cmake@3.19
-         prefix: 'c:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake'
-       buildable: False
-     ninja:
-       externals:
-       - spec: ninja@1.8.2
-         prefix: 'c:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja'
-       buildable: False
-
-You can also use an separate installation of CMake if you have one and prefer
-to use it. If you don't have a path to Ninja analogous to the above, then you can
-obtain it by running the Visual Studio Installer and following the instructions
-at the start of this section. Also note that .yaml files use spaces for indentation
-and not tabs, so ensure that this is the case when editing one directly.
-
-
-.. note:: Cygwin
-   The use of Cygwin is not officially supported by Spack and is not tested.
-   However Spack will not throw an error, so use if choosing to use Spack
-   with Cygwin, know that no functionality is garunteed.
-
-^^^^^^^^^^^^^^^^^
-Step 4: Use Spack
-^^^^^^^^^^^^^^^^^
-
-Once the configuration is complete, it is time to give the installation a test.  Install a basic package though the
-Spack console via:
-
-.. code-block:: console
-
-   spack install cpuinfo
-
-If in the previous step, you did not have CMake or Ninja installed, running the command above should boostrap both packages
-
-"""""""""""""""""""""""""""
-Windows Compatible Packages
-"""""""""""""""""""""""""""
-
-Many Spack packages are not currently compatible with Windows, due to Unix
-dependencies or incompatible build tools like autoconf. Here are several
-packages known to work on Windows:
-
-* abseil-cpp
-* clingo
-* cpuinfo
-* cmake
-* glm
-* nasm
-* netlib-lapack (requires Intel Fortran)
-* ninja
-* openssl
-* perl
-* python
-* ruby
-* wrf
-* zlib
-
-.. note::
-   This is by no means a comprehensive list
-
-^^^^^^^^^^^^^^
-For developers
-^^^^^^^^^^^^^^
-
-The intent is to provide a Windows installer that will automatically set up
-Python, Git, and Spack, instead of requiring the user to do so manually.
-Instructions for creating the installer are at
-https://github.com/spack/spack/blob/develop/lib/spack/spack/cmd/installer/README.md
-
-Alternatively a pre-built copy of the Windows installer is available as an artifact of Spack's Windows CI
--- a/lib/spack/docs/images/ghcr_spack.png
+++ b/lib/spack/docs/images/ghcr_spack.png
--- a/lib/spack/docs/index.rst
+++ b/lib/spack/docs/index.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -39,7 +39,7 @@ package:

 .. code-block:: console

-   $ git clone -c feature.manyFiles=true https://github.com/spack/spack.git
+   $ git clone https://github.com/spack/spack.git
   $ cd spack/bin
   $ ./spack install libelf

@@ -54,8 +54,8 @@ or refer to the full manual below.
   features
   getting_started
   basic_usage
+   workflows
   Tutorial: Spack 101 <https://spack-tutorial.readthedocs.io>
-   replace_conda_homebrew
   known_issues

 .. toctree::
@@ -64,7 +64,6 @@ or refer to the full manual below.

   configuration
   config_yaml
-   bootstrapping
   build_settings
   environments
   containers
--- a/lib/spack/docs/known_issues.rst
+++ b/lib/spack/docs/known_issues.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -7,34 +7,71 @@
 Known Issues
 ============

-This is a list of known issues in Spack. It provides ways of getting around these
+This is a list of known bugs in Spack. It provides ways of getting around these
 problems if you encounter them.

------------------------------------------------
-Spack does not seem to respect ``packages.yaml``
------------------------------------------------
+---------------------------------------------------
+Variants are not properly forwarded to dependencies
+---------------------------------------------------

-.. note::
+**Status:** Expected to be fixed by Spack's new concretizer

-   This issue is **resolved** as of v0.19.0.dev0 commit
-   `8281a0c5feabfc4fe180846d6fe95cfe53420bc5`, through the introduction of package
-   requirements. See :ref:`package-requirements`.
+Sometimes, a variant of a package can also affect how its dependencies are
+built. For example, in order to build MPI support for a package, it may
+require that its dependencies are also built with MPI support. In the
+``package.py``, this looks like:

-A common problem in Spack v0.18.0 up to v0.19.0.dev0 is that package, compiler and target
-preferences specified in ``packages.yaml`` do not seem to be respected. Spack picks the
-"wrong" compilers and their versions, package versions and variants, and
-micro-architectures.
+.. code-block:: python

-This is however not a bug. In order to reduce the number of builds of the same
-packages, the concretizer values reuse of installed packages higher than preferences
-set in ``packages.yaml``. Note that ``packages.yaml`` specifies only preferences, not
-hard constraints.
+   depends_on('hdf5~mpi', when='~mpi')
+   depends_on('hdf5+mpi', when='+mpi')

-There are multiple workarounds:
+Spack handles this situation properly for *immediate* dependencies, and
+builds ``hdf5`` with the same variant you used for the package that
+depends on it. However, for *indirect* dependencies (dependencies of
+dependencies), Spack does not backtrack up the DAG far enough to handle
+this. Users commonly run into this situation when trying to build R with
+X11 support:

-1. Disable reuse during concretization: ``spack install --fresh <spec>`` when installing
-   from the command line, or ``spack concretize --fresh --force`` when using
-   environments.  
-2. Turn preferences into constrains, by moving them to the input spec. For example,
-   use ``spack spec zlib%gcc@12`` when you want to force GCC 12 even if ``zlib`` was
-   already installed with GCC 10.
+.. code-block:: console
+
+   $ spack install r+X
+   ...
+   ==> Error: Invalid spec: 'cairo@1.14.8%gcc@6.2.1+X arch=linux-fedora25-x86_64 ^bzip2@1.0.6%gcc@6.2.1+shared arch=linux-fedora25-x86_64 ^font-util@1.3.1%gcc@6.2.1 arch=linux-fedora25-x86_64 ^fontconfig@2.12.1%gcc@6.2.1 arch=linux-fedora25-x86_64 ^freetype@2.7.1%gcc@6.2.1 arch=linux-fedora25-x86_64 ^gettext@0.19.8.1%gcc@6.2.1+bzip2+curses+git~libunistring+libxml2+tar+xz arch=linux-fedora25-x86_64 ^glib@2.53.1%gcc@6.2.1~libmount arch=linux-fedora25-x86_64 ^inputproto@2.3.2%gcc@6.2.1 arch=linux-fedora25-x86_64 ^kbproto@1.0.7%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libffi@3.2.1%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libpng@1.6.29%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libpthread-stubs@0.4%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libx11@1.6.5%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libxau@1.0.8%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libxcb@1.12%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libxdmcp@1.1.2%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libxext@1.3.3%gcc@6.2.1 arch=linux-fedora25-x86_64 ^libxml2@2.9.4%gcc@6.2.1~python arch=linux-fedora25-x86_64 ^libxrender@0.9.10%gcc@6.2.1 arch=linux-fedora25-x86_64 ^ncurses@6.0%gcc@6.2.1~symlinks arch=linux-fedora25-x86_64 ^openssl@1.0.2k%gcc@6.2.1 arch=linux-fedora25-x86_64 ^pcre@8.40%gcc@6.2.1+utf arch=linux-fedora25-x86_64 ^pixman@0.34.0%gcc@6.2.1 arch=linux-fedora25-x86_64 ^pkg-config@0.29.2%gcc@6.2.1+internal_glib arch=linux-fedora25-x86_64 ^python@2.7.13%gcc@6.2.1+shared~tk~ucs4 arch=linux-fedora25-x86_64 ^readline@7.0%gcc@6.2.1 arch=linux-fedora25-x86_64 ^renderproto@0.11.1%gcc@6.2.1 arch=linux-fedora25-x86_64 ^sqlite@3.18.0%gcc@6.2.1 arch=linux-fedora25-x86_64 ^tar^util-macros@1.19.1%gcc@6.2.1 arch=linux-fedora25-x86_64 ^xcb-proto@1.12%gcc@6.2.1 arch=linux-fedora25-x86_64 ^xextproto@7.3.0%gcc@6.2.1 arch=linux-fedora25-x86_64 ^xproto@7.0.31%gcc@6.2.1 arch=linux-fedora25-x86_64 ^xtrans@1.3.5%gcc@6.2.1 arch=linux-fedora25-x86_64 ^xz@5.2.3%gcc@6.2.1 arch=linux-fedora25-x86_64 ^zlib@1.2.11%gcc@6.2.1+pic+shared arch=linux-fedora25-x86_64'.
+   Package cairo requires variant ~X, but spec asked for +X
+
+A workaround is to explicitly activate the variants of dependencies as well:
+
+.. code-block:: console
+
+   $ spack install r+X ^cairo+X ^pango+X
+
+See https://github.com/spack/spack/issues/267 and
+https://github.com/spack/spack/issues/2546 for further details.
+
+-----------------------------------------------
+depends_on cannot handle recursive dependencies
+-----------------------------------------------
+
+**Status:** Not yet a work in progress
+
+Although ``depends_on`` can handle any aspect of Spack's spec syntax,
+it currently cannot handle recursive dependencies. If the ``^`` sigil
+appears in a ``depends_on`` statement, the concretizer will hang.
+For example, something like:
+
+.. code-block:: python
+
+   depends_on('mfem+cuda ^hypre+cuda', when='+cuda')
+
+
+should be rewritten as:
+
+.. code-block:: python
+
+   depends_on('mfem+cuda', when='+cuda')
+   depends_on('hypre+cuda', when='+cuda')
+
+
+See https://github.com/spack/spack/issues/17660 and
+https://github.com/spack/spack/issues/11160 for more details.
--- a/lib/spack/docs/mirrors.rst
+++ b/lib/spack/docs/mirrors.rst
@@ -1,13 +1,13 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)

 .. _mirrors:

-======================
-Mirrors (mirrors.yaml)
-======================
+=======
+Mirrors
+=======

 Some sites may not have access to the internet for fetching packages.
 These sites will need a local repository of tarballs from which they
--- a/lib/spack/docs/module_file_support.rst
+++ b/lib/spack/docs/module_file_support.rst
@@ -1,13 +1,13 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)

 .. _modules:

-======================
-Modules (modules.yaml)
-======================
+=======
+Modules
+=======

 The use of module systems to manage user environment in a controlled way
 is a common practice at HPC centers that is often embraced also by
@@ -113,8 +113,6 @@ from language interpreters into their extensions. The latter two instead permit
 fine tune the filesystem layout, content and creation of module files to meet
 site specific conventions.

-.. _overide-api-calls-in-package-py:
-
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Override API calls in ``package.py``
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -136,7 +134,7 @@ The second method:
       pass

 can instead inject run-time environment modifications in the module files of packages
-that depend on it. In both cases you need to fill ``env`` with the desired
+that depend on it. In both cases you need to fill ``run_env`` with the desired
 list of environment modifications.

 .. admonition:: The ``r`` package and callback APIs
@@ -183,7 +181,10 @@ to the environment variables listed below the folder name.
 Spack modules can be configured for multiple module sets. The default
 module set is named ``default``. All Spack commands which operate on
 modules default to apply the ``default`` module set, but can be
-applied to any module set in the configuration.
+applied to any module set in the configuration. Settings applied at
+the root of the configuration (e.g. ``modules:enable`` rather than
+``modules:default:enable``) are applied to the default module set for
+backwards compatibility.

 """""""""""""""""""""""""
 Changing the modules root
@@ -212,18 +213,6 @@ location). The set ``my_custom_lmod_modules`` will install its lmod
 modules to ``/path/to/install/custom/lmod/modules`` (and still install
 its tcl modules, if any, to the default location).

-By default, an architecture-specific directory is added to the root
-directory. A module set may override that behavior by setting the
-``arch_folder`` config value to ``False``.
-
-.. code-block:: yaml
-
-   modules:
-     default:
-       roots:
-         tcl: /path/to/install/tcl/modules
-       arch_folder: false
-
 Obviously, having multiple module sets install modules to the default
 location could be confusing to users of your modules. In the next
 section, we will discuss enabling and disabling module types (module
@@ -272,30 +261,29 @@ of the installed software. For instance, in the snippet below:
 .. code-block:: yaml

   modules:
-     default:
-       tcl:
-         # The keyword `all` selects every package
-         all:
-           environment:
-             set:
-               BAR: 'bar'
-         # This anonymous spec selects any package that
-         # depends on openmpi. The double colon at the
-         # end clears the set of rules that matched so far.
-         ^openmpi::
-           environment:
-             set:
-               BAR: 'baz'
-         # Selects any zlib package
-         zlib:
-           environment:
-             prepend_path:
-               LD_LIBRARY_PATH: 'foo'
-         # Selects zlib compiled with gcc@4.8
-         zlib%gcc@4.8:
-           environment:
-             unset:
-             - FOOBAR
+     tcl:
+       # The keyword `all` selects every package
+       all:
+         environment:
+           set:
+             BAR: 'bar'
+       # This anonymous spec selects any package that
+       # depends on openmpi. The double colon at the
+       # end clears the set of rules that matched so far.
+       ^openmpi::
+         environment:
+           set:
+             BAR: 'baz'
+       # Selects any zlib package
+       zlib:
+         environment:
+           prepend_path:
+             LD_LIBRARY_PATH: 'foo'
+       # Selects zlib compiled with gcc@4.8
+       zlib%gcc@4.8:
+         environment:
+           unset:
+           - FOOBAR

 you are instructing Spack to set the environment variable ``BAR=bar`` for every module,
 unless the associated spec satisfies ``^openmpi`` in which case ``BAR=baz``.
@@ -310,7 +298,7 @@ the variable ``FOOBAR`` will be unset.
     spec constraints are instead evaluated top to bottom.

 """"""""""""""""""""""""""""""""""""""""""""
-Exclude or include specific module files
+Blacklist or whitelist specific module files
 """"""""""""""""""""""""""""""""""""""""""""

 You can use anonymous specs also to prevent module files from being written or
@@ -322,10 +310,9 @@ your system. If you write a configuration file like:
 .. code-block:: yaml

   modules:
-     default:
-       tcl:
-         include: ['gcc', 'llvm']  # include will have precedence over exclude
-         exclude: ['%gcc@4.4.7']   # Assuming gcc@4.4.7 is the system compiler
+     tcl:
+       whitelist: ['gcc', 'llvm']  # Whitelist will have precedence over blacklist
+       blacklist: ['%gcc@4.4.7']   # Assuming gcc@4.4.7 is the system compiler

 you will prevent the generation of module files for any package that
 is compiled with ``gcc@4.4.7``, with the only exception of any ``gcc``
@@ -350,9 +337,8 @@ shows how to set hash length in the module file names:
 .. code-block:: yaml

   modules:
-     default:
-       tcl:
-         hash_length: 7
+     tcl:
+       hash_length: 7

 To help make module names more readable, and to help alleviate name conflicts
 with a short hash, one can use the ``suffixes`` option in the modules
@@ -362,12 +348,11 @@ For instance, the following config options,
 .. code-block:: yaml

   modules:
-     default:
-       tcl:
-         all:
-           suffixes:
-             ^python@2.7.12: 'python-2.7.12'
-             ^openblas: 'openblas'
+     tcl:
+       all:
+         suffixes:
+           ^python@2.7.12: 'python-2.7.12'
+           ^openblas: 'openblas'

 will add a ``python-2.7.12`` version string to any packages compiled with
 python matching the spec, ``python@2.7.12``. This is useful to know which
@@ -377,16 +362,15 @@ most likely via the ``+blas`` variant specification.

 The most heavyweight solution to module naming is to change the entire
 naming convention for module files. This uses the projections format
-covered in :ref:`view_projections`.
+covered in :ref:`adding_projections_to_views`.

 .. code-block:: yaml

  modules:
-    default:
-      tcl:
-        projections:
-          all: '{name}/{version}-{compiler.name}-{compiler.version}-module'
-          ^mpi: '{name}/{version}-{^mpi.name}-{^mpi.version}-{compiler.name}-{compiler.version}-module'
+    tcl:
+      projections:
+        all: '{name}/{version}-{compiler.name}-{compiler.version}-module'
+        ^mpi: '{name}/{version}-{^mpi.name}-{^mpi.version}-{compiler.name}-{compiler.version}-module'

 will create module files that are nested in directories by package
 name, contain the version and compiler name and version, and have the
@@ -407,16 +391,15 @@ that are already in the LMod hierarchy.
     .. code-block:: yaml

        modules:
-          default:
-            enable:
-              - tcl
-            tcl:
-              projections:
-                all: '{name}/{version}-{compiler.name}-{compiler.version}'
-              all:
-                conflict:
-                  - '{name}'
-                  - 'intel/14.0.1'
+          enable:
+            - tcl
+          tcl:
+            projections:
+              all: '{name}/{version}-{compiler.name}-{compiler.version}'
+            all:
+              conflict:
+                - '{name}'
+                - 'intel/14.0.1'

     will create module files that will conflict with ``intel/14.0.1`` and with the
     base directory of the same module, effectively preventing the possibility to
@@ -436,17 +419,16 @@ that are already in the LMod hierarchy.
     .. code-block:: yaml

       modules:
-         default:
-           enable:
-             - lmod
-           lmod:
-             core_compilers:
-               - 'gcc@4.8'
-             core_specs:
-               - 'python'
-             hierarchy:
-               - 'mpi'
-               - 'lapack'
+         enable:
+           - lmod
+         lmod:
+           core_compilers:
+             - 'gcc@4.8'
+           core_specs:
+             - 'python'
+           hierarchy:
+             - 'mpi'
+             - 'lapack'

     that will generate a hierarchy in which the ``lapack`` and ``mpi`` layer can be switched
     independently. This allows a site to build the same libraries or applications against different
@@ -467,36 +449,6 @@ that are already in the LMod hierarchy.
   For hierarchies that are deeper than three layers ``lmod spider`` may have some issues.
   See `this discussion on the LMod project <https://github.com/TACC/Lmod/issues/114>`_.

-""""""""""""""""""""""
-Select default modules
-""""""""""""""""""""""
-
-By default, when multiple modules of the same name share a directory,
-the highest version number will be the default module. This behavior
-of the ``module`` command can be overridden with a symlink named
-``default`` to the desired default module. If you wish to configure
-default modules with Spack, add a ``defaults`` key to your modules
-configuration:
-
-.. code-block:: yaml
-
-  modules:
-    my-module-set:
-      tcl:
-        defaults:
-        - gcc@10.2.1
-        - hdf5@1.2.10+mpi+hl%gcc
-
-These defaults may be arbitrarily specific. For any package that
-satisfies a default, Spack will generate the module file in the
-appropriate path, and will generate a default symlink to the module
-file as well.
-
-.. warning::
-  If Spack is configured to generate multiple default packages in the
-  same directory, the last modulefile to be generated will be the
-  default module.
-
 .. _customize-env-modifications:

 """""""""""""""""""""""""""""""""""
@@ -520,33 +472,18 @@ inspections and customize them per-module-set.
    prefix_inspections:
      bin:
        - PATH
-      man:
-        - MANPATH
+      lib:
+        - LIBRARY_PATH
      '':
        - CMAKE_PREFIX_PATH

 Prefix inspections are only applied if the relative path inside the
 installation prefix exists. In this case, for a Spack package ``foo``
 installed to ``/spack/prefix/foo``, if ``foo`` installs executables to
-``bin`` but no manpages in ``man``, the generated module file for
+``bin`` but no libraries in ``lib``, the generated module file for
 ``foo`` would update ``PATH`` to contain ``/spack/prefix/foo/bin`` and
 ``CMAKE_PREFIX_PATH`` to contain ``/spack/prefix/foo``, but would not
-update ``MANPATH``.
-
-The default list of environment variables in this config section
-inludes ``PATH``, ``MANPATH``, ``ACLOCAL_PATH``, ``PKG_CONFIG_PATH``
-and ``CMAKE_PREFIX_PATH``, as well as ``DYLD_FALLBACK_LIBRARY_PATH``
-on macOS. On Linux however, the corresponding ``LD_LIBRARY_PATH``
-variable is *not* set, because it affects the behavior of
-system executables too.
-
-.. note::
-
-   In general, the ``LD_LIBRARY_PATH`` variable is not required
-   when using packages built with Spack, thanks to the use of RPATH.
-   Some packages may still need the variable, which is best handled
-   on a per-package basis instead of globally, as explained in
-   :ref:`overide-api-calls-in-package-py`.
+update ``LIBRARY_PATH``.

 There is a special case for prefix inspections relative to environment
 views. If all of the following conditions hold for a module set
@@ -554,7 +491,8 @@ configuration:

 #. The configuration is for an :ref:`environment <environments>` and
   will never be applied outside the environment,
-#. The environment in question is configured to use a view,
+#. The environment in question is configured to use a :ref:`view
+   <filesystem-views>`,
 #. The :ref:`environment view is configured
   <configuring_environment_views>` with a projection that ensures
   every package is linked to a unique directory,
@@ -606,17 +544,16 @@ Filter out environment modifications
 Modifications to certain environment variables in module files are there by
 default, for instance because they are generated by prefix inspections.
 If you want to prevent modifications to some environment variables, you can
-do so by using the ``exclude_env_vars``:
+do so by using the environment blacklist:

 .. code-block:: yaml

   modules:
-     default:
-       tcl:
-         all:
-           filter:
-             # Exclude changes to any of these variables
-             exclude_env_vars: ['CPATH', 'LIBRARY_PATH']
+     tcl:
+       all:
+         filter:
+           # Exclude changes to any of these variables
+           environment_blacklist: ['CPATH', 'LIBRARY_PATH']

 The configuration above will generate module files that will not contain
 modifications to either ``CPATH`` or ``LIBRARY_PATH``.
@@ -628,39 +565,42 @@ modifications to either ``CPATH`` or ``LIBRARY_PATH``.
 Autoload dependencies
 """""""""""""""""""""

-Often it is required for a module to have its (transient) dependencies loaded as well.
-One example where this is useful is when one package needs to use executables provided
-by its dependency; when the dependency is autoloaded, the executable will be in the
-PATH. Similarly for scripting languages such as Python, packages and their dependencies
-have to be loaded together.
-
-Autoloading is enabled by default for LMod, as it has great builtin support for through
-the ``depends_on`` function. For Environment Modules it is disabled by default.
-
-Autoloading can also be enabled conditionally:
+In some cases it can be useful to have module files that automatically load
+their dependencies.  This may be the case for Python extensions, if not
+activated using ``spack activate``:

 .. code-block:: yaml

-    modules:
-      default:
-        tcl:
-          all:
-            autoload: none
-          ^python:
-            autoload: direct
+   modules:
+     tcl:
+       ^python:
+         autoload: 'direct'

 The configuration file above will produce module files that will
 load their direct dependencies if the package installed depends on ``python``.
 The allowed values for the ``autoload`` statement are either ``none``,
-``direct`` or ``all``.
+``direct`` or ``all``.  The default is ``none``.
+
+.. tip::
+  Building external software
+     Setting ``autoload`` to ``direct`` for all packages can be useful
+     when building software outside of a Spack installation that depends on
+     artifacts in that installation.  E.g. (adjust ``lmod`` vs ``tcl``
+     as appropriate):
+
+  .. code-block:: yaml
+
+     modules:
+       lmod:
+         all:
+           autoload: 'direct'

 .. note::
  TCL prerequisites
     In the ``tcl`` section of the configuration file it is possible to use
     the ``prerequisites`` directive that accepts the same values as
     ``autoload``. It will produce module files that have a ``prereq``
-     statement, which can be used to autoload dependencies in some versions
-     of Environment Modules.
+     statement instead of automatically loading other modules.

 ------------------------
 Maintaining Module Files
--- a/lib/spack/docs/monitoring.rst
+++ b/lib/spack/docs/monitoring.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/package_list.rst
+++ b/lib/spack/docs/package_list.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
--- a/lib/spack/docs/packaging_guide.rst
+++ b/lib/spack/docs/packaging_guide.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -126,7 +126,7 @@ generates a boilerplate template for your package, and opens up the new
   # If you submit this package back to Spack as a pull request,
   # please first remove this boilerplate and all FIXME comments.
   #
-   from spack.package import *
+   from spack import *


   class Gmp(AutotoolsPackage):
@@ -695,24 +695,20 @@ example, ``py-sphinx-rtd-theme@0.1.10a0``.  In this case, numbers are
 always considered to be "newer" than letters.  This is for consistency
 with `RPM <https://bugzilla.redhat.com/show_bug.cgi?id=50977>`_.

-Spack versions may also be arbitrary non-numeric strings, for example
-``@develop``, ``@master``, ``@local``.
+Spack versions may also be arbitrary non-numeric strings; any string
+here will suffice; for example, ``@develop``, ``@master``, ``@local``.
+Versions are compared as follows. First, a version string is split into
+multiple fields based on delimiters such as ``.``, ``-`` etc. Then
+matching fields are compared using the rules below:

-The order on versions is defined as follows. A version string is split
-into a list of components based on delimiters such as ``.``, ``-`` etc.
-Lists are then ordered lexicographically, where components are ordered
-as follows:
+#. The following develop-like strings are greater (newer) than all
+   numbers and are ordered as ``develop > main > master > head > trunk``.

-#. The following special strings are considered larger than any other
-   numeric or non-numeric version component, and satisfy the following
-   order between themselves:
-   ``develop > main > master > head > trunk > stable``.
+#. Numbers are all less than the chosen develop-like strings above,
+   and are sorted numerically.

-#. Numbers are ordered numerically, are less than special strings, and
-   larger than other non-numeric components.
-
-#. All other non-numeric components are less than numeric components,
-   and are ordered alphabetically.
+#. All other non-numeric versions are less than numeric versions, and
+   are sorted alphabetically.

 The logic behind this sort order is two-fold:

@@ -733,7 +729,7 @@ Version selection
 When concretizing, many versions might match a user-supplied spec.
 For example, the spec ``python`` matches all available versions of the
 package ``python``.  Similarly, ``python@3:`` matches all versions of
-Python 3 and above.  Given a set of versions that match a spec, Spack
+Python3.  Given a set of versions that match a spec, Spack
 concretization uses the following priorities to decide which one to
 use:

@@ -1070,32 +1066,13 @@ Commits

 Submodules
  You can supply ``submodules=True`` to cause Spack to fetch submodules
-  recursively along with the repository at fetch time.
+  recursively along with the repository at fetch time. For more information
+  about git submodules see the manpage of git: ``man git-submodule``.

  .. code-block:: python

     version('1.0.1', tag='v1.0.1', submodules=True)

-  If a package has needs more fine-grained control over submodules, define
-  ``submodules`` to be a callable function that takes the package instance as
-  its only argument.  The function should return a list of submodules to be fetched.
-
-  .. code-block:: python
-
-     def submodules(package):
-         submodules = []
-         if "+variant-1" in package.spec:
-             submodules.append("submodule_for_variant_1")
-         if "+variant-2" in package.spec:
-             submodules.append("submodule_for_variant_2")
-         return submodules
-
-
-      class MyPackage(Package):
-          version("0.1.0", submodules=submodules)
-
-  For more information about git submodules see the manpage of git: ``man
-  git-submodule``.

 .. _github-fetch:

@@ -1442,117 +1419,6 @@ other similar operations:
            ).with_default('auto').with_non_feature_values('auto'),
        )

-"""""""""""""""""""""""""""
-Conditional Possible Values
-"""""""""""""""""""""""""""
-
-There are cases where a variant may take multiple values, and the list of allowed values
-expand over time. Think for instance at the C++ standard with which we might compile
-Boost, which can take one of multiple possible values with the latest standards
-only available from a certain version on.
-
-To model a similar situation we can use *conditional possible values* in the variant declaration:
-
-.. code-block:: python
-
-   variant(
-       'cxxstd', default='98',
-       values=(
-           '98', '11', '14',
-           # C++17 is not supported by Boost < 1.63.0.
-           conditional('17', when='@1.63.0:'),
-           # C++20/2a is not support by Boost < 1.73.0
-           conditional('2a', '2b', when='@1.73.0:')
-       ),
-       multi=False,
-       description='Use the specified C++ standard when building.',
-   )
-
-The snippet above allows ``98``, ``11`` and ``14`` as unconditional possible values for the
-``cxxstd`` variant, while ``17`` requires a version greater or equal to ``1.63.0``
-and both ``2a`` and ``2b`` require a version greater or equal to ``1.73.0``.
-
-
-^^^^^^^^^^^^^^^^^^^^
-Conditional Variants
-^^^^^^^^^^^^^^^^^^^^
-
-The variant directive accepts a ``when`` clause. The variant will only
-be present on specs that otherwise satisfy the spec listed as the
-``when`` clause. For example, the following class has a variant
-``bar`` when it is at version 2.0 or higher.
-
-.. code-block:: python
-
-   class Foo(Package):
-       ...
-       variant('bar', default=False, when='@2.0:', description='help message')
-
-The ``when`` clause follows the same syntax and accepts the same
-values as the ``when`` argument of
-:py:func:`spack.directives.depends_on`
-
-^^^^^^^^^^^^^^^
-Sticky Variants
-^^^^^^^^^^^^^^^
-
-The variant directive can be marked as ``sticky`` by setting to ``True`` the
-corresponding argument:
-
-.. code-block:: python
-
-   variant('bar', default=False, sticky=True)
-
-A ``sticky`` variant differs from a regular one in that it is always set
-to either:
-
-#. An explicit value appearing in a spec literal or
-#. Its default value
-
-The concretizer thus is not free to pick an alternate value to work
-around conflicts, but will error out instead.
-Setting this property on a variant is useful in cases where the
-variant allows some dangerous or controversial options (e.g. using unsupported versions
-of a compiler for a library) and the packager wants to ensure that
-allowing these options is done on purpose by the user, rather than
-automatically by the solver.
-
-
-^^^^^^^^^^^^^^^^^^^
-Overriding Variants
-^^^^^^^^^^^^^^^^^^^
-
-Packages may override variants for several reasons, most often to
-change the default from a variant defined in a parent class or to
-change the conditions under which a variant is present on the spec.
-
-When a variant is defined multiple times, whether in the same package
-file or in a subclass and a superclass, the last definition is used
-for all attributes **except** for the ``when`` clauses. The ``when``
-clauses are accumulated through all invocations, and the variant is
-present on the spec if any of the accumulated conditions are
-satisfied.
-
-For example, consider the following package:
-
-.. code-block:: python
-
-   class Foo(Package):
-       ...
-       variant('bar', default=False, when='@1.0', description='help1')
-       variant('bar', default=True, when='platform=darwin', description='help2')
-       ...
-
-This package ``foo`` has a variant ``bar`` when the spec satisfies
-either ``@1.0`` or ``platform=darwin``, but not for other platforms at
-other versions. The default for this variant, when it is present, is
-always ``True``, regardless of which condition of the variant is
-satisfied. This allows packages to override variants in packages or
-build system classes from which they inherit, by modifying the variant
-values without modifying the ``when`` clause. It also allows a package
-to implement ``or`` semantics for a variant ``when`` clause by
-duplicating the variant definition.
-
 ------------------------------------
 Resources (expanding extra tarballs)
 ------------------------------------
@@ -2197,7 +2063,7 @@ Version ranges
 ^^^^^^^^^^^^^^

 Although some packages require a specific version for their dependencies,
-most can be built with a range of versions. For example, if you are
+most can be built with a range of version. For example, if you are
 writing a package for a legacy Python module that only works with Python
 2.4 through 2.6, this would look like:

@@ -2206,9 +2072,9 @@ writing a package for a legacy Python module that only works with Python
   depends_on('python@2.4:2.6')

 Version ranges in Spack are *inclusive*, so ``2.4:2.6`` means any version
-greater than or equal to ``2.4`` and up to and including any ``2.6.x``. If
-you want to specify that a package works with any version of Python 3 (or
-higher), this would look like:
+greater than or equal to ``2.4`` and up to and including ``2.6``. If you
+want to specify that a package works with any version of Python 3, this
+would look like:

 .. code-block:: python

@@ -2219,30 +2085,29 @@ requires Python 2, you can similarly leave out the lower bound:

 .. code-block:: python

-   depends_on('python@:2')
+   depends_on('python@:2.9')

 Notice that we didn't use ``@:3``. Version ranges are *inclusive*, so
-``@:3`` means "up to and including any 3.x version".
+``@:3`` means "up to and including 3".

-What if a package can only be built with Python 2.7? You might be
+What if a package can only be built with Python 2.6? You might be
 inclined to use:

 .. code-block:: python

-   depends_on('python@2.7')
+   depends_on('python@2.6')

 However, this would be wrong. Spack assumes that all version constraints
-are exact, so it would try to install Python not at ``2.7.18``, but
-exactly at ``2.7``, which is a non-existent version. The correct way to
-specify this would be:
+are absolute, so it would try to install Python at exactly ``2.6``. The
+correct way to specify this would be:

 .. code-block:: python

-   depends_on('python@2.7.0:2.7')
+   depends_on('python@2.6.0:2.6.999')

-A spec can contain a version list of ranges and individual versions
-separated by commas. For example, if you need Boost 1.59.0 or newer,
-but there are known issues with 1.64.0, 1.65.0, and 1.66.0, you can say:
+A spec can contain multiple version ranges separated by commas.
+For example, if you need Boost 1.59.0 or newer, but there are known
+issues with 1.64.0, 1.65.0, and 1.66.0, you can say:

 .. code-block:: python

@@ -2283,17 +2148,9 @@ The following dependency types are available:
 One of the advantages of the ``build`` dependency type is that although the
 dependency needs to be installed in order for the package to be built, it
 can be uninstalled without concern afterwards. ``link`` and ``run`` disallow
-this because uninstalling the dependency would break the package.
-
-``build``, ``link``, and ``run`` dependencies all affect the hash of Spack
-packages (along with ``sha256`` sums of patches and archives used to build the
-package, and a [canonical hash](https://github.com/spack/spack/pull/28156) of
-the ``package.py`` recipes). ``test`` dependencies do not affect the package
-hash, as they are only used to construct a test environment *after* building and
-installing a given package installation. Older versions of Spack did not include
-build dependencies in the hash, but this has been
-[fixed](https://github.com/spack/spack/pull/28504) as of [Spack
-``v0.18``](https://github.com/spack/spack/releases/tag/v0.18.0)
+this because uninstalling the dependency would break the package. Another
+consequence of this is that ``build``-only dependencies do not affect the
+hash of the package. The same is true for ``test`` dependencies.

 If the dependency type is not specified, Spack uses a default of
 ``('build', 'link')``. This is the common case for compiler languages.
@@ -2420,9 +2277,9 @@ Influence how dependents are built or run

 Spack provides a mechanism for dependencies to influence the
 environment of their dependents by overriding  the
-:meth:`setup_dependent_run_environment <spack.package_base.PackageBase.setup_dependent_run_environment>`
+:meth:`setup_dependent_run_environment <spack.package.PackageBase.setup_dependent_run_environment>`
 or the
-:meth:`setup_dependent_build_environment <spack.package_base.PackageBase.setup_dependent_build_environment>`
+:meth:`setup_dependent_build_environment <spack.package.PackageBase.setup_dependent_build_environment>`
 methods.
 The Qt package, for instance, uses this call:

@@ -2444,7 +2301,7 @@ will have the ``PYTHONPATH``, ``PYTHONHOME`` and ``PATH`` environment
 variables set appropriately before starting the installation. To make things
 even simpler the ``python setup.py`` command is also inserted into the module
 scope of dependents by overriding a third method called
-:meth:`setup_dependent_package <spack.package_base.PackageBase.setup_dependent_package>`
+:meth:`setup_dependent_package <spack.package.PackageBase.setup_dependent_package>`
 :

 .. literalinclude:: _spack_root/var/spack/repos/builtin/packages/python/package.py
@@ -2528,24 +2385,6 @@ Now, the ``py-numpy`` package can be used as an argument to ``spack
 activate``.  When it is activated, all the files in its prefix will be
 symbolically linked into the prefix of the python package.

-A package can only extend one other package at a time.  To support packages
-that may extend one of a list of other packages, Spack supports multiple
-``extends`` directives as long as at most one of them is selected as
-a dependency during concretization.  For example, a lua package could extend
-either lua or luajit, but not both:
-
-.. code-block:: python
-
-   class LuaLpeg(Package):
-       ...
-       variant('use_lua', default=True)
-       extends('lua', when='+use_lua')
-       extends('lua-luajit', when='~use_lua')
-       ...
-
-Now, a user can install, and activate, the ``lua-lpeg`` package for either
-lua or luajit.
-
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Adding additional constraints
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -2601,7 +2440,7 @@ from being linked in at activation time.
 Views
 -----

-The ``spack view`` command can be
+As covered in :ref:`filesystem-views`, the ``spack view`` command can be
 used to symlink a number of packages into a merged prefix. The methods of
 ``PackageViewMixin`` can be overridden to customize how packages are added
 to views. Generally this can be used to create copies of specific files rather
@@ -2802,256 +2641,6 @@ Suppose a user invokes ``spack install`` like this:
 Spack will fail with a constraint violation, because the version of
 MPICH requested is too low for the ``mpi`` requirement in ``foo``.

-.. _custom-attributes:
-
------------------
-Custom attributes
------------------
-
-Often a package will need to provide attributes for dependents to query
-various details about what it provides.  While any number of custom defined
-attributes can be implemented by a package, the four specific attributes
-described below are always available on every package with default
-implementations and the ability to customize with alternate implementations
-in the case of virtual packages provided:
-
-=========== =========================================== =====================
-Attribute   Purpose                                     Default
-=========== =========================================== =====================
-``home``    The installation path for the package       ``spec.prefix``
-``command`` An executable command for the package       | ``spec.name`` found
-                                                          in
-                                                        | ``.home.bin``
-``headers`` A list of headers provided by the package   | All headers
-                                                          searched
-                                                        | recursively in
-                                                          ``.home.include``
-``libs``    A list of libraries provided by the package | ``lib{spec.name}``
-                                                          searched
-                                                        | recursively in
-                                                          ``.home`` starting
-                                                        | with ``lib``,
-                                                          ``lib64``, then the
-                                                        | rest of ``.home``
-=========== =========================================== =====================
-
-Each of these can be customized by implementing the relevant attribute
-as a ``@property`` in the package's class:
-
-.. code-block:: python
-   :linenos:
-
-   class Foo(Package):
-       ...
-       @property
-       def libs(self):
-           # The library provided by Foo is libMyFoo.so
-           return find_libraries('libMyFoo', root=self.home, recursive=True)
-
-A package may also provide a custom implementation of each attribute
-for the virtual packages it provides by implementing the
-``virtualpackagename_attributename`` property in the package's class.
-The implementation used is the first one found from:
-
-#. Specialized virtual: ``Package.virtualpackagename_attributename``
-#. Generic package: ``Package.attributename``
-#. Default
-
-The use of customized attributes is demonstrated in the next example.
-
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Example: Customized attributes for virtual packages
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Consider a package ``foo`` that can optionally provide two virtual
-packages ``bar`` and ``baz``.  When both are enabled the installation tree
-appears as follows:
-
-.. code-block:: console
-
-   include/foo.h
-   include/bar/bar.h
-   lib64/libFoo.so
-   lib64/libFooBar.so
-   baz/include/baz/baz.h
-   baz/lib/libFooBaz.so
-
-The install tree shows that ``foo`` is providing the header ``include/foo.h``
-and library ``lib64/libFoo.so`` in it's install prefix.  The virtual
-package ``bar`` is providing ``include/bar/bar.h`` and library
-``lib64/libFooBar.so``, also in ``foo``'s install prefix.  The ``baz``
-package, however, is provided in the ``baz`` subdirectory of ``foo``'s
-prefix with the ``include/baz/baz.h`` header and ``lib/libFooBaz.so``
-library.  Such a package could implement the optional attributes as
-follows:
-
-.. code-block:: python
-   :linenos:
-
-   class Foo(Package):
-       ...
-       variant('bar', default=False, description='Enable the Foo implementation of bar')
-       variant('baz', default=False, description='Enable the Foo implementation of baz')
-       ...
-       provides('bar', when='+bar')
-       provides('baz', when='+baz')
-       ....
-
-       # Just the foo headers
-       @property
-       def headers(self):
-           return find_headers('foo', root=self.home.include, recursive=False)
-
-       # Just the foo libraries
-       @property
-       def libs(self):
-           return find_libraries('libFoo', root=self.home, recursive=True)
-
-       # The header provided by the bar virutal package
-       @property
-       def bar_headers(self):
-           return find_headers('bar/bar.h', root=self.home.include, recursive=False)
-
-       # The libary provided by the bar virtual package
-       @property
-       def bar_libs(self):
-           return find_libraries('libFooBar', root=sef.home, recursive=True)
-
-       # The baz virtual package home
-       @property
-       def baz_home(self):
-           return self.prefix.baz
-
-       # The header provided by the baz virtual package
-       @property
-       def baz_headers(self):
-           return find_headers('baz/baz', root=self.baz_home.include, recursive=False)
-
-       # The library provided by the baz virtual package
-       @property
-       def baz_libs(self):
-           return find_libraries('libFooBaz', root=self.baz_home, recursive=True)
-
-Now consider another package, ``foo-app``, depending on all three:
-
-.. code-block:: python
-   :linenos:
-
-   class FooApp(CMakePackage):
-       ...
-       depends_on('foo')
-       depends_on('bar')
-       depends_on('baz')
-
-The resulting spec objects for it's dependencies shows the result of
-the above attribute implementations:
-
-.. code-block:: python
-
-   # The core headers and libraries of the foo package
-
-   >>> spec['foo']
-   foo@1.0%gcc@11.3.1+bar+baz arch=linux-fedora35-haswell
-   >>> spec['foo'].prefix
-   '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6'
-
-   # home defaults to the package install prefix without an explicit implementation
-   >>> spec['foo'].home
-   '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6'
-
-   # foo headers from the foo prefix
-   >>> spec['foo'].headers
-   HeaderList([
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/include/foo.h',
-   ])
-
-   # foo include directories from the foo prefix
-   >>> spec['foo'].headers.directories
-   ['/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/include']
-
-   # foo libraries from the foo prefix
-   >>> spec['foo'].libs
-   LibraryList([
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/lib64/libFoo.so',
-   ])
-
-   # foo library directories from the foo prefix
-   >>> spec['foo'].libs.directories
-   ['/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/lib64']
-
-.. code-block:: python
-
-   # The virtual bar package in the same prefix as foo
-
-   # bar resolves to the foo package
-   >>> spec['bar']
-   foo@1.0%gcc@11.3.1+bar+baz arch=linux-fedora35-haswell
-   >>> spec['bar'].prefix
-   '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6'
-
-   # home defaults to the foo prefix without either a Foo.bar_home
-   # or Foo.home implementation
-   >>> spec['bar'].home
-   '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6'
-
-   # bar header in the foo prefix
-   >>> spec['bar'].headers
-   HeaderList([
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/include/bar/bar.h'
-   ])
-
-   # bar include dirs from the foo prefix
-   >>> spec['bar'].headers.directories
-   ['/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/include']
-
-   # bar library from the foo prefix
-   >>> spec['bar'].libs
-   LibraryList([
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/lib64/libFooBar.so'
-   ])
-
-   # bar library directories from the foo prefix
-   >>> spec['bar'].libs.directories
-   ['/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/lib64']
-
-.. code-block:: python
-
-   # The virtual baz package in a subdirectory of foo's prefix
-
-   # baz resolves to the foo package
-   >>> spec['baz']
-   foo@1.0%gcc@11.3.1+bar+baz arch=linux-fedora35-haswell
-   >>> spec['baz'].prefix
-   '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6'
-
-   # baz_home implementation provides the subdirectory inside the foo prefix
-   >>> spec['baz'].home
-   '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/baz'
-
-   # baz headers in the baz subdirectory of the foo prefix
-   >>> spec['baz'].headers
-   HeaderList([
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/baz/include/baz/baz.h'
-   ])
-
-   # baz include directories in the baz subdirectory of the foo prefix
-   >>> spec['baz'].headers.directories
-   [
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/baz/include'
-   ]
-
-   # baz libraries in the baz subdirectory of the foo prefix
-   >>> spec['baz'].libs
-   LibraryList([
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/baz/lib/libFooBaz.so'
-   ])
-
-   # baz library directories in the baz subdirectory of the foo porefix
-   >>> spec['baz'].libs.directories
-   [
-       '/opt/spack/linux-fedora35-haswell/gcc-11.3.1/foo-1.0-ca3rczp5omy7dfzoqw4p7oc2yh3u7lt6/baz/lib'
-   ]
-
 .. _abstract-and-concrete:

 -------------------------
@@ -3185,7 +2774,7 @@ be concretized on their system.  For example, one user may prefer packages
 built with OpenMPI and the Intel compiler.  Another user may prefer
 packages be built with MVAPICH and GCC.

-See the :ref:`package-preferences` section for more details.
+See the :ref:`concretization-preferences` section for more details.


 .. _group_when_spec:
@@ -3235,7 +2824,7 @@ is equivalent to:

   depends_on('elpa+openmp', when='+openmp+elpa')

-Constraints from nested context managers are also combined together, but they are rarely
+Constraints from nested context managers are also added together, but they are rarely
 needed or recommended.

 .. _install-method:
@@ -3296,10 +2885,10 @@ The package base class, usually specialized for a given build system, determines
 actual set of entities available for overriding.
 The classes that are currently provided by Spack are:

-+----------------------------------------------------------+----------------------------------+
+-------------------------=--------------------------------+----------------------------------+
 |     **Base Class**                                       |           **Purpose**            |
 +==========================================================+==================================+
-| :class:`~spack.package_base.Package`                     | General base class not           |
+| :class:`~spack.package.Package`                          | General base class not           |
 |                                                          | specialized for any build system |
 +----------------------------------------------------------+----------------------------------+
 | :class:`~spack.build_systems.makefile.MakefilePackage`   | Specialized class for packages   |
@@ -3430,7 +3019,7 @@ for the install phase is:
    For those not used to Python instance methods, this is the
    package itself.  In this case it's an instance of ``Foo``, which
    extends ``Package``.  For API docs on Package objects, see
-    :py:class:`Package <spack.package_base.Package>`.
+    :py:class:`Package <spack.package.Package>`.

 ``spec``
    This is the concrete spec object created by Spack from an
@@ -5753,24 +5342,6 @@ Version Lists

 Spack packages should list supported versions with the newest first.

-^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-Using ``home`` vs ``prefix``
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-``home`` and ``prefix`` are both attributes that can be queried on a
-package's dependencies, often when passing configure arguments pointing to the
-location of a dependency.  The difference is that while ``prefix`` is the
-location on disk where a concrete package resides, ``home`` is the `logical`
-location that a package resides, which may be different than ``prefix`` in
-the case of virtual packages or other special circumstances.  For most use
-cases inside a package, it's dependency locations can be accessed via either
-``self.spec['foo'].home`` or ``self.spec['foo'].prefix``.  Specific packages
-that should be consumed by dependents via ``.home`` instead of ``.prefix``
-should be noted in their respective documentation.
-
-See :ref:`custom-attributes` for more details and an example implementing
-a custom ``home`` attribute.
-
 ---------------------------
 Packaging workflow commands
 ---------------------------
--- a/lib/spack/docs/pipelines.rst
+++ b/lib/spack/docs/pipelines.rst
@@ -1,4 +1,4 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -48,9 +48,9 @@ or Amazon Elastic Kubernetes Service (`EKS <https://aws.amazon.com/eks>`_), thou
 topics are outside the scope of this document.

 Spack's pipelines are now making use of the
-`trigger <https://docs.gitlab.com/ee/ci/yaml/#trigger>`_ syntax to run
+`trigger <https://docs.gitlab.com/12.9/ee/ci/yaml/README.html#trigger>`_ syntax to run
 dynamically generated
-`child pipelines <https://docs.gitlab.com/ee/ci/pipelines/parent_child_pipelines.html>`_.
+`child pipelines <https://docs.gitlab.com/12.9/ee/ci/parent_child_pipelines.html>`_.
 Note that the use of dynamic child pipelines requires running Gitlab version
 ``>= 12.9``.

@@ -115,8 +115,7 @@ And here's the spack environment built by the pipeline represented as a

   spack:
     view: false
-     concretizer:
-       unify: false
+     concretization: separately

     definitions:
     - pkgs:
--- a/lib/spack/docs/replace_conda_homebrew.rst
+++ b/lib/spack/docs/replace_conda_homebrew.rst
@@ -1,207 +0,0 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
-   Spack Project Developers. See the top-level COPYRIGHT file for details.
-
-   SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-=====================================
-Using Spack to Replace Homebrew/Conda
-=====================================
-
-Spack is an incredibly powerful package manager, designed for supercomputers
-where users have diverse installation needs. But Spack can also be used to
-handle simple single-user installations on your laptop. Most macOS users are
-already familiar with package managers like Homebrew and Conda, where all
-installed packages are symlinked to a single central location like ``/usr/local``.
-In this section, we will show you how to emulate the behavior of Homebrew/Conda
-using :ref:`environments`!
-
-----
-Setup
-----
-
-First, let's create a new environment. We'll assume that Spack is already set up
-correctly, and that you've already sourced the setup script for your shell.
-To create a new environment, simply run:
-
-.. code-block:: console
-
-   $ spack env create myenv
-
-Here, *myenv* can be anything you want to name your environment. Next, we can add
-a list of packages we would like to install into our environment. Let's say we
-want a newer version of Bash than the one that comes with macOS, and we want a
-few Python libraries. We can run:
-
-.. code-block:: console
-
-   $ spack -e myenv add bash@5 python py-numpy py-scipy py-matplotlib
-
-Each package can be listed on a separate line, or combined into a single line like we did above.
-Notice that we're explicitly asking for Bash 5 here. You can use any spec
-you would normally use on the command line with other Spack commands.
-
-Next, we want to manually configure a couple of things:
-
-.. code-block:: console
-
-   $ spack -e myenv config edit
-
-.. code-block:: yaml
-
-   # This is a Spack Environment file.
-   #
-   # It describes a set of packages to be installed, along with
-   # configuration settings.
-   spack:
-     # add package specs to the `specs` list
-     specs: [bash@5, python, py-numpy, py-scipy, py-matplotlib]
-     view: true
-
-You can see the packages we added earlier in the ``specs:`` section. If you
-ever want to add more packages, you can either use ``spack add`` or manually
-edit this file.
-
-We also need to change the ``concretizer:unify`` option. By default, Spack
-concretizes each spec *separately*, allowing multiple versions of the same
-package to coexist. Since we want a single consistent environment, we want to
-concretize all of the specs *together*.
-
-Here is what your ``spack.yaml`` looks like with this new setting:
-
-.. code-block:: yaml
-
-   # This is a Spack Environment file.
-   #
-   # It describes a set of packages to be installed, along with
-   # configuration settings.
-   spack:
-     # add package specs to the `specs` list
-     specs: [bash@5, python, py-numpy, py-scipy, py-matplotlib]
-     view: true
-     concretizer:
-       unify: true
-
-^^^^^^^^^^^^^^^^
-Symlink location
-^^^^^^^^^^^^^^^^
-
-Spack symlinks all installations to ``/Users/me/spack/var/spack/environments/myenv/.spack-env/view``,
-which is the default when ``view: true``.
-You can actually change this to any directory you want. For example, Homebrew
-uses ``/usr/local``, while Conda uses ``/Users/me/anaconda``. In order to access
-files in these locations, you need to update ``PATH`` and other environment variables
-to point to them. Activating the Spack environment does this automatically, but
-you can also manually set them in your ``.bashrc``.
-
-.. warning::
-
-   There are several reasons why you shouldn't use ``/usr/local``:
-
-   1. If you are on macOS 10.11+ (El Capitan and newer), Apple makes it hard
-      for you. You may notice permissions issues on ``/usr/local`` due to their
-      `System Integrity Protection <https://support.apple.com/en-us/HT204899>`_.
-      By default, users don't have permissions to install anything in ``/usr/local``,
-      and you can't even change this using ``sudo chown`` or ``sudo chmod``.
-   2. Other package managers like Homebrew will try to install things to the
-      same directory. If you plan on using Homebrew in conjunction with Spack,
-      don't symlink things to ``/usr/local``.
-   3. If you are on a shared workstation, or don't have sudo privileges, you
-      can't do this.
-
-   If you still want to do this anyway, there are several ways around SIP.
-   You could disable SIP by booting into recovery mode and running
-   ``csrutil disable``, but this is not recommended, as it can open up your OS
-   to security vulnerabilities. Another technique is to run ``spack concretize``
-   and ``spack install`` using ``sudo``. This is also not recommended.
-
-   The safest way I've found is to create your installation directories using
-   sudo, then change ownership back to the user like so:
-
-   .. code-block:: bash
-
-      for directory in .spack bin contrib include lib man share
-      do
-          sudo mkdir -p /usr/local/$directory
-          sudo chown $(id -un):$(id -gn) /usr/local/$directory
-      done
-
-   Depending on the packages you install in your environment, the exact list of
-   directories you need to create may vary. You may also find some packages
-   like Java libraries that install a single file to the installation prefix
-   instead of in a subdirectory. In this case, the action is the same, just replace
-   ``mkdir -p`` with ``touch`` in the for-loop above.
-
-   But again, it's safer just to use the default symlink location.
-
-
------------
-Installation
------------
-
-To actually concretize the environment, run:
-
-.. code-block:: console
-
-   $ spack -e myenv concretize
-
-This will tell you which if any packages are already installed, and alert you
-to any conflicting specs.
-
-To actually install these packages and symlink them to your ``view:``
-directory, simply run:
-
-.. code-block:: console
-
-   $ spack -e myenv install
-   $ spack env activate myenv
-
-Now, when you type ``which python3``, it should find the one you just installed.
-
-In order to change the default shell to our newer Bash installation, we first
-need to add it to this list of acceptable shells. Run:
-
-.. code-block:: console
-
-   $ sudo vim /etc/shells
-
-and add the absolute path to your bash executable. Then run:
-
-.. code-block:: console
-
-   $ chsh -s /path/to/bash
-
-Now, when you log out and log back in, ``echo $SHELL`` should point to the
-newer version of Bash.
-
---------------------------
-Updating Installed Packages
---------------------------
-
-Let's say you upgraded to a new version of macOS, or a new version of Python
-was released, and you want to rebuild your entire software stack. To do this,
-simply run the following commands:
-
-.. code-block:: console
-
-   $ spack env activate myenv
-   $ spack concretize --force
-   $ spack install
-
-The ``--force`` flag tells Spack to overwrite its previous concretization
-decisions, allowing you to choose a new version of Python. If any of the new
-packages like Bash are already installed, ``spack install`` won't re-install
-them, it will keep the symlinks in place.
-
--------------
-Uninstallation
--------------
-
-If you decide that Spack isn't right for you, uninstallation is simple.
-Just run:
-
-.. code-block:: console
-
-   $ spack env activate myenv
-   $ spack uninstall --all
-
-This will uninstall all packages in your environment and remove the symlinks.
--- a/lib/spack/docs/repositories.rst
+++ b/lib/spack/docs/repositories.rst
@@ -1,13 +1,13 @@
-.. Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+.. Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
   Spack Project Developers. See the top-level COPYRIGHT file for details.

   SPDX-License-Identifier: (Apache-2.0 OR MIT)

 .. _repositories:

-=================================
-Package Repositories (repos.yaml)
-=================================
+=============================
+Package Repositories
+=============================

 Spack comes with thousands of built-in package recipes in
 ``var/spack/repos/builtin/``.  This is a **package repository** -- a
@@ -335,7 +335,7 @@ merged YAML from all configuration files, use ``spack config get repos``:
   - ~/myrepo
   - $spack/var/spack/repos/builtin

-Note that, unlike ``spack repo list``, this does not include the
+mNote that, unlike ``spack repo list``, this does not include the
 namespace, which is read from each repo's ``repo.yaml``.

 ^^^^^^^^^^^^^^^^^^^^^
--- a/lib/spack/docs/requirements.txt
+++ b/lib/spack/docs/requirements.txt
@@ -1,11 +1,7 @@
 # These dependencies should be installed using pip in order
 # to build the documentation.

-sphinx>=3.4,!=4.1.2,!=5.1.0
+sphinx>=3.4,!=4.1.2
 sphinxcontrib-programoutput
 sphinx-rtd-theme
 python-levenshtein
-# Restrict to docutils <0.17 to workaround a list rendering issue in sphinx.
-# https://stackoverflow.com/questions/67542699
-docutils <0.17
-pygments <2.13
--- a/lib/spack/docs/spack.yaml
+++ b/lib/spack/docs/spack.yaml
@@ -1,4 +1,4 @@
-# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -17,7 +17,6 @@ spack:
  # Sphinx
  - "py-sphinx@3.4:4.1.1,4.1.3:"
  - py-sphinxcontrib-programoutput
-  - py-docutils@:0.16
  - py-sphinx-rtd-theme
  # VCS
  - git
@@ -25,5 +24,4 @@ spack:
  - subversion
  # Plotting
  - graphviz
-  concretizer:
-    unify: true
+  concretization: together
--- a/lib/spack/docs/tables/system_prerequisites.csv
+++ b/lib/spack/docs/tables/system_prerequisites.csv
@@ -1,5 +1,5 @@
 Name, Supported Versions, Notes, Requirement Reason
-Python, 2.7/3.6-3.10, , Interpreter for Spack
+Python, 2.6/2.7/3.5-3.9, , Interpreter for Spack
 C/C++ Compilers, , , Building software
 make, , , Build software
 patch, , , Build software
@@ -7,7 +7,7 @@ bash, , , Compiler wrappers
 tar, , , Extract/create archives
 gzip, , , Compress/Decompress archives
 unzip, , , Compress/Decompress archives
-bzip2, , , Compress/Decompress archives
+bzip, , , Compress/Decompress archives
 xz, , , Compress/Decompress archives
 zstd, , Optional, Compress/Decompress archives
 file, , , Create/Use Buildcaches
@@ -15,4 +15,3 @@ gnupg2, , , Sign/Verify Buildcaches
 git, , , Manage Software Repositories
 svn, , Optional, Manage Software Repositories
 hg, , Optional, Manage Software Repositories
-Python header files, , Optional (e.g. ``python3-dev`` on Debian), Bootstrapping from sources
--- a/lib/spack/docs/workflows.rst
+++ b/lib/spack/docs/workflows.rst
--- a/lib/spack/env/cc
+++ b/lib/spack/env/cc
@@ -1,7 +1,6 @@
-#!/bin/sh -f
-# shellcheck disable=SC2034  # evals in this script fool shellcheck
+#!/bin/bash
 #
-# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
@@ -21,33 +20,25 @@
 #      -Wl,-rpath         arguments for dependency /lib directories.
 #

-# Reset IFS to the default: whitespace-separated lists. When we use
-# other separators, we set and reset it.
-unset IFS
-
-# Separator for lists whose names end with `_list`.
-# We pick the alarm bell character, which is highly unlikely to
-# conflict with anything. This is a literal bell character (which
-# we have to use since POSIX sh does not convert escape sequences
-# like '\a' outside of the format argument of `printf`).
-# NOTE: Depending on your editor this may look empty, but it is not.
-readonly lsep=''
-
 # This is an array of environment variables that need to be set before
 # the script runs. They are set by routines in spack.build_environment
 # as part of the package installation process.
-readonly params="\
-SPACK_ENV_PATH
-SPACK_DEBUG_LOG_DIR
-SPACK_DEBUG_LOG_ID
-SPACK_COMPILER_SPEC
-SPACK_CC_RPATH_ARG
-SPACK_CXX_RPATH_ARG
-SPACK_F77_RPATH_ARG
-SPACK_FC_RPATH_ARG
-SPACK_LINKER_ARG
-SPACK_SHORT_SPEC
-SPACK_SYSTEM_DIRS"
+parameters=(
+    SPACK_ENV_PATH
+    SPACK_DEBUG_LOG_DIR
+    SPACK_DEBUG_LOG_ID
+    SPACK_COMPILER_SPEC
+    SPACK_CC_RPATH_ARG
+    SPACK_CXX_RPATH_ARG
+    SPACK_F77_RPATH_ARG
+    SPACK_FC_RPATH_ARG
+    SPACK_TARGET_ARGS
+    SPACK_DTAGS_TO_ADD
+    SPACK_DTAGS_TO_STRIP
+    SPACK_LINKER_ARG
+    SPACK_SHORT_SPEC
+    SPACK_SYSTEM_DIRS
+)

 # Optional parameters that aren't required to be set

@@ -67,157 +58,60 @@ SPACK_SYSTEM_DIRS"
 # Test command is used to unit test the compiler script.
 #   SPACK_TEST_COMMAND

-# die MESSAGE
-# Print a message and exit with error code 1.
-die() {
-    echo "[spack cc] ERROR: $*"
+# die()
+# Prints a message and exits with error 1.
+function die {
+    echo "$@"
    exit 1
 }

-# empty VARNAME
-# Return whether the variable VARNAME is unset or set to the empty string.
-empty() {
-    eval "test -z \"\${$1}\""
-}
+# read input parameters into proper bash arrays.
+# SYSTEM_DIRS is delimited by :
+IFS=':' read -ra SPACK_SYSTEM_DIRS <<< "${SPACK_SYSTEM_DIRS}"

-# setsep LISTNAME
-# Set the global variable 'sep' to the separator for a list with name LISTNAME.
-# There are three types of lists:
-#   1. regular lists end with _list and are separated by $lsep
-#   2. directory lists end with _dirs/_DIRS/PATH(S) and are separated by ':'
-#   3. any other list is assumed to be separated by spaces: " "
-setsep() {
-    case "$1" in
-        *_dirs|*_DIRS|*PATH|*PATHS)
-            sep=':'
-            ;;
-        *_list)
-            sep="$lsep"
-            ;;
-        *)
-            sep=" "
-            ;;
-    esac
-}
+# SPACK_<LANG>FLAGS and SPACK_LDLIBS are split by ' '
+IFS=' ' read -ra SPACK_FFLAGS   <<< "$SPACK_FFLAGS"
+IFS=' ' read -ra SPACK_CPPFLAGS <<< "$SPACK_CPPFLAGS"
+IFS=' ' read -ra SPACK_CFLAGS   <<< "$SPACK_CFLAGS"
+IFS=' ' read -ra SPACK_CXXFLAGS <<< "$SPACK_CXXFLAGS"
+IFS=' ' read -ra SPACK_LDFLAGS  <<< "$SPACK_LDFLAGS"
+IFS=' ' read -ra SPACK_LDLIBS   <<< "$SPACK_LDLIBS"

-# prepend LISTNAME ELEMENT [SEP]
-#
-# Prepend ELEMENT to the list stored in the variable LISTNAME,
-# assuming the list is separated by SEP.
-# Handles empty lists and single-element lists.
-prepend() {
-    varname="$1"
-    elt="$2"
-
-    if empty "$varname"; then
-        eval "$varname=\"\${elt}\""
-    else
-        # Get the appropriate separator for the list we're appending to.
-        setsep "$varname"
-        eval "$varname=\"\${elt}${sep}\${$varname}\""
-    fi
-}
-
-# append LISTNAME ELEMENT [SEP]
-#
-# Append ELEMENT to the list stored in the variable LISTNAME,
-# assuming the list is separated by SEP.
-# Handles empty lists and single-element lists.
-append() {
-    varname="$1"
-    elt="$2"
-
-    if empty "$varname"; then
-        eval "$varname=\"\${elt}\""
-    else
-        # Get the appropriate separator for the list we're appending to.
-        setsep "$varname"
-        eval "$varname=\"\${$varname}${sep}\${elt}\""
-    fi
-}
-
-# extend LISTNAME1 LISTNAME2 [PREFIX]
-#
-# Append the elements stored in the variable LISTNAME2
-# to the list stored in LISTNAME1.
-# If PREFIX is provided, prepend it to each element.
-extend() {
-    # Figure out the appropriate IFS for the list we're reading.
-    setsep "$2"
-    if [ "$sep" != " " ]; then
-        IFS="$sep"
-    fi
-    eval "for elt in \${$2}; do append $1 \"$3\${elt}\"; done"
-    unset IFS
-}
-
-# preextend LISTNAME1 LISTNAME2 [PREFIX]
-#
-# Prepend the elements stored in the list at LISTNAME2
-# to the list at LISTNAME1, preserving order.
-# If PREFIX is provided, prepend it to each element.
-preextend() {
-    # Figure out the appropriate IFS for the list we're reading.
-    setsep "$2"
-    if [ "$sep" != " " ]; then
-        IFS="$sep"
-    fi
-
-    # first, reverse the list to prepend
-    _reversed_list=""
-    eval "for elt in \${$2}; do prepend _reversed_list \"$3\${elt}\"; done"
-
-    # prepend reversed list to preextend in order
-    IFS="${lsep}"
-    for elt in $_reversed_list; do prepend "$1" "$3${elt}"; done
-    unset IFS
-}
-
-# system_dir PATH
 # test whether a path is a system directory
-system_dir() {
-    IFS=':'  # SPACK_SYSTEM_DIRS is colon-separated
+function system_dir {
    path="$1"
-    for sd in $SPACK_SYSTEM_DIRS; do
-        if [ "${path}" = "${sd}" ] || [ "${path}" = "${sd}/" ]; then
+    for sd in "${SPACK_SYSTEM_DIRS[@]}"; do
+        if [ "${path}" == "${sd}" ] || [ "${path}" == "${sd}/" ]; then
            # success if path starts with a system prefix
-            unset IFS
            return 0
        fi
    done
-    unset IFS
    return 1  # fail if path starts no system prefix
 }

-# Fail with a clear message if the input contains any bell characters.
-if eval "[ \"\${*#*${lsep}}\" != \"\$*\" ]"; then
-    die "Compiler command line contains our separator ('${lsep}'). Cannot parse."
-fi
-
-# ensure required variables are set
-for param in $params; do
-    if eval "test -z \"\${${param}:-}\""; then
+for param in "${parameters[@]}"; do
+    if [[ -z ${!param+x} ]]; then
        die "Spack compiler must be run from Spack! Input '$param' is missing."
    fi
 done

 # Check if optional parameters are defined
 # If we aren't asking for debug flags, don't add them
-if [ -z "${SPACK_ADD_DEBUG_FLAGS:-}" ]; then
+if [[ -z ${SPACK_ADD_DEBUG_FLAGS+x} ]]; then
    SPACK_ADD_DEBUG_FLAGS="false"
 fi

 # SPACK_ADD_DEBUG_FLAGS must be true/false/custom
 is_valid="false"
 for param in "true" "false" "custom"; do
-  if [ "$param" = "$SPACK_ADD_DEBUG_FLAGS" ];  then
+  if [ "$param" == "$SPACK_ADD_DEBUG_FLAGS" ];  then
      is_valid="true"
  fi
 done

 # Exit with error if we are given an incorrect value
-if [ "$is_valid" = "false" ]; then
-    die "SPACK_ADD_DEBUG_FLAGS, if defined, must be one of 'true', 'false', or 'custom'."
+if [ "$is_valid" == "false" ]; then
+    die "SPACK_ADD_DEBUG_FLAGS, if defined, must be one of 'true' 'false' or 'custom'"
 fi

 # Figure out the type of compiler, the language, and the mode so that
@@ -234,35 +128,35 @@ fi
 #    ld      link
 #    ccld    compile & link

-command="${0##*/}"
+command=$(basename "$0")
 comp="CC"
 case "$command" in
    cpp)
        mode=cpp
        debug_flags="-g"
        ;;
-    cc|c89|c99|gcc|clang|armclang|icc|icx|pgcc|nvc|xlc|xlc_r|fcc|amdclang|cl.exe)
+    cc|c89|c99|gcc|clang|armclang|icc|icx|pgcc|nvc|xlc|xlc_r|fcc)
        command="$SPACK_CC"
        language="C"
        comp="CC"
        lang_flags=C
        debug_flags="-g"
        ;;
-    c++|CC|g++|clang++|armclang++|icpc|icpx|dpcpp|pgc++|nvc++|xlc++|xlc++_r|FCC|amdclang++)
+    c++|CC|g++|clang++|armclang++|icpc|icpx|pgc++|nvc++|xlc++|xlc++_r|FCC)
        command="$SPACK_CXX"
        language="C++"
        comp="CXX"
        lang_flags=CXX
        debug_flags="-g"
        ;;
-    ftn|f90|fc|f95|gfortran|flang|armflang|ifort|ifx|pgfortran|nvfortran|xlf90|xlf90_r|nagfor|frt|amdflang)
+    ftn|f90|fc|f95|gfortran|flang|armflang|ifort|ifx|pgfortran|nvfortran|xlf90|xlf90_r|nagfor|frt)
        command="$SPACK_FC"
        language="Fortran 90"
        comp="FC"
        lang_flags=F
        debug_flags="-g"
        ;;
-    f77|xlf|xlf_r|pgf77|amdflang)
+    f77|xlf|xlf_r|pgf77)
        command="$SPACK_F77"
        language="Fortran 77"
        comp="F77"
@@ -280,7 +174,7 @@ esac
 # If any of the arguments below are present, then the mode is vcheck.
 # In vcheck mode, nothing is added in terms of extra search paths or
 # libraries.
-if [ -z "$mode" ] || [ "$mode" = ld ]; then
+if [[ -z $mode ]] || [[ $mode == ld ]]; then
    for arg in "$@"; do
        case $arg in
            -v|-V|--version|-dumpversion)
@@ -292,16 +186,16 @@ if [ -z "$mode" ] || [ "$mode" = ld ]; then
 fi

 # Finish setting up the mode.
-if [ -z "$mode" ]; then
+if [[ -z $mode ]]; then
    mode=ccld
    for arg in "$@"; do
-        if [ "$arg" = "-E" ]; then
+        if [[ $arg == -E ]]; then
            mode=cpp
            break
-        elif [ "$arg" = "-S" ]; then
+        elif [[ $arg == -S ]]; then
            mode=as
            break
-        elif [ "$arg" = "-c" ]; then
+        elif [[ $arg == -c ]]; then
            mode=cc
            break
        fi
@@ -328,46 +222,42 @@ dtags_to_strip="${SPACK_DTAGS_TO_STRIP}"
 linker_arg="${SPACK_LINKER_ARG}"

 # Set up rpath variable according to language.
-rpath="ERROR: RPATH ARG WAS NOT SET"
-eval "rpath=\${SPACK_${comp}_RPATH_ARG:?${rpath}}"
+eval rpath=\$SPACK_${comp}_RPATH_ARG

 # Dump the mode and exit if the command is dump-mode.
-if [ "$SPACK_TEST_COMMAND" = "dump-mode" ]; then
+if [[ $SPACK_TEST_COMMAND == dump-mode ]]; then
    echo "$mode"
    exit
 fi

-# If, say, SPACK_CC is set but SPACK_FC is not, we want to know. Compilers do not
-# *have* to set up Fortran executables, so we need to tell the user when a build is
-# about to attempt to use them unsuccessfully.
-if [ -z "$command" ]; then
-    die "Compiler '$SPACK_COMPILER_SPEC' does not have a $language compiler configured."
+# Check that at least one of the real commands was actually selected,
+# otherwise we don't know what to execute.
+if [[ -z $command ]]; then
+    die "ERROR: Compiler '$SPACK_COMPILER_SPEC' does not support compiling $language programs."
 fi

 #
 # Filter '.' and Spack environment directories out of PATH so that
 # this script doesn't just call itself
 #
-new_dirs=""
-IFS=':'
-for dir in $PATH; do
+IFS=':' read -ra env_path <<< "$PATH"
+IFS=':' read -ra spack_env_dirs <<< "$SPACK_ENV_PATH"
+spack_env_dirs+=("" ".")
+export PATH=""
+for dir in "${env_path[@]}"; do
    addpath=true
-    for spack_env_dir in $SPACK_ENV_PATH; do
-        case "${dir%%/}" in
-            "$spack_env_dir"|'.'|'')
-                addpath=false
-                break
-                ;;
-        esac
+    for env_dir in "${spack_env_dirs[@]}"; do
+        if [[ "${dir%%/}" == "$env_dir" ]]; then
+            addpath=false
+            break
+        fi
    done
-    if [ $addpath = true ]; then
-        append new_dirs "$dir"
+    if $addpath; then
+        export PATH="${PATH:+$PATH:}$dir"
    fi
 done
-unset IFS
-export PATH="$new_dirs"

-if [ "$mode" = vcheck ]; then
+if [[ $mode == vcheck ]]; then
    exec "${command}" "$@"
 fi

@@ -375,20 +265,16 @@ fi
 # It doesn't work with -rpath.
 # This variable controls whether they are added.
 add_rpaths=true
-if [ "$mode" = ld ] || [ "$mode" = ccld ]; then
-    if [ "${SPACK_SHORT_SPEC#*darwin}" != "${SPACK_SHORT_SPEC}" ]; then
-        for arg in "$@"; do
-            if [ "$arg" = "-r" ]; then
-                if [ "$mode" = ld ] || [ "$mode" = ccld ]; then
-                    add_rpaths=false
-                    break
-                fi
-            elif [ "$arg" = "-Wl,-r" ] && [ "$mode" = ccld ]; then
-                add_rpaths=false
-                break
-            fi
-        done
-    fi
+if [[ ($mode == ld || $mode == ccld) && "$SPACK_SHORT_SPEC" =~ "darwin" ]];
+then
+    for arg in "$@"; do
+        if [[ ($arg == -r && $mode == ld) ||
+              ($arg == -r && $mode == ccld) ||
+              ($arg == -Wl,-r && $mode == ccld) ]]; then
+            add_rpaths=false
+            break
+        fi
+    done
 fi

 # Save original command for debug logging
@@ -411,22 +297,17 @@ input_command="$*"
 # The libs variable is initialized here for completeness, and it is also
 # used later to inject flags supplied via `ldlibs` on the command
 # line. These come into the wrappers via SPACK_LDLIBS.
-
-# The loop below breaks up the command line into these lists of components.
-# The lists are all bell-separated to be as flexible as possible, as their
-# contents may come from the command line, from ' '-separated lists,
-# ':'-separated lists, etc.
-include_dirs_list=""
-lib_dirs_list=""
-rpath_dirs_list=""
-system_include_dirs_list=""
-system_lib_dirs_list=""
-system_rpath_dirs_list=""
-isystem_system_include_dirs_list=""
-isystem_include_dirs_list=""
-libs_list=""
-other_args_list=""
-
+#
+includes=()
+libdirs=()
+rpaths=()
+system_includes=()
+system_libdirs=()
+system_rpaths=()
+libs=()
+other_args=()
+isystem_system_includes=()
+isystem_includes=()

 while [ $# -ne 0 ]; do

@@ -446,32 +327,32 @@ while [ $# -ne 0 ]; do
            isystem_was_used=true
            if [ -z "$arg" ]; then shift; arg="$1"; fi
            if system_dir "$arg"; then
-                append isystem_system_include_dirs_list "$arg"
+                isystem_system_includes+=("$arg")
            else
-                append isystem_include_dirs_list "$arg"
+                isystem_includes+=("$arg")
            fi
            ;;
        -I*)
            arg="${1#-I}"
            if [ -z "$arg" ]; then shift; arg="$1"; fi
            if system_dir "$arg"; then
-                append system_include_dirs_list "$arg"
+                system_includes+=("$arg")
            else
-                append include_dirs_list "$arg"
+                includes+=("$arg")
            fi
            ;;
        -L*)
            arg="${1#-L}"
            if [ -z "$arg" ]; then shift; arg="$1"; fi
            if system_dir "$arg"; then
-                append system_lib_dirs_list "$arg"
+                system_libdirs+=("$arg")
            else
-                append lib_dirs_list "$arg"
+                libdirs+=("$arg")
            fi
            ;;
        -l*)
            # -loopopt=0 is generated erroneously in autoconf <= 2.69,
-            # and passed by ifx to the linker, which confuses it with a
+            # and passed by ifx to the linker, which confuses it with a 
            # library. Filter it out.
            # TODO: generalize filtering of args with an env var, so that
            # TODO: we do not have to special case this here.
@@ -482,76 +363,66 @@ while [ $# -ne 0 ]; do
            fi
            arg="${1#-l}"
            if [ -z "$arg" ]; then shift; arg="$1"; fi
-            append other_args_list "-l$arg"
+            other_args+=("-l$arg")
            ;;
        -Wl,*)
            arg="${1#-Wl,}"
            if [ -z "$arg" ]; then shift; arg="$1"; fi
-            case "$arg" in
-                -rpath=*)  rp="${arg#-rpath=}"  ;;
-                --rpath=*) rp="${arg#--rpath=}" ;;
-                -rpath,*)  rp="${arg#-rpath,}"  ;;
-                --rpath,*) rp="${arg#--rpath,}" ;;
-                -rpath|--rpath)
-                    shift; arg="$1"
-                    case "$arg" in
-                        -Wl,*)
-                            rp="${arg#-Wl,}"
-                            ;;
-                        *)
-                            die "-Wl,-rpath was not followed by -Wl,*"
-                            ;;
-                    esac
-                    ;;
-                "$dtags_to_strip")
-                    :  # We want to remove explicitly this flag
-                    ;;
-                *)
-                    append other_args_list "-Wl,$arg"
-                    ;;
-            esac
+            if [[ "$arg" = -rpath=* ]]; then
+                rp="${arg#-rpath=}"
+            elif [[ "$arg" = --rpath=* ]]; then
+                rp="${arg#--rpath=}"
+            elif [[ "$arg" = -rpath,* ]]; then
+                rp="${arg#-rpath,}"
+            elif [[ "$arg" = --rpath,* ]]; then
+                rp="${arg#--rpath,}"
+            elif [[ "$arg" =~ ^-?-rpath$ ]]; then
+                shift; arg="$1"
+                if [[ "$arg" != -Wl,* ]]; then
+                    die "-Wl,-rpath was not followed by -Wl,*"
+                fi
+                rp="${arg#-Wl,}"
+            elif [[ "$arg" = "$dtags_to_strip" ]] ; then
+                :  # We want to remove explicitly this flag
+            else
+                other_args+=("-Wl,$arg")
+            fi
            ;;
        -Xlinker,*)
            arg="${1#-Xlinker,}"
            if [ -z "$arg" ]; then shift; arg="$1"; fi
-
-            case "$arg" in
-                -rpath=*)  rp="${arg#-rpath=}"  ;;
-                --rpath=*) rp="${arg#--rpath=}" ;;
-                -rpath|--rpath)
-                    shift; arg="$1"
-                    case "$arg" in
-                        -Xlinker,*)
-                            rp="${arg#-Xlinker,}"
-                        ;;
-                        *)
-                            die "-Xlinker,-rpath was not followed by -Xlinker,*"
-                            ;;
-                    esac
-                    ;;
-                *)
-                    append other_args_list "-Xlinker,$arg"
-                    ;;
-            esac
+            if [[ "$arg" = -rpath=* ]]; then
+                rp="${arg#-rpath=}"
+            elif [[ "$arg" = --rpath=* ]]; then
+                rp="${arg#--rpath=}"
+            elif [[ "$arg" = -rpath  ]] || [[ "$arg" = --rpath ]]; then
+                shift; arg="$1"
+                if [[ "$arg" != -Xlinker,* ]]; then
+                    die "-Xlinker,-rpath was not followed by -Xlinker,*"
+                fi
+                rp="${arg#-Xlinker,}"
+            else
+                other_args+=("-Xlinker,$arg")
+            fi
            ;;
        -Xlinker)
-            if [ "$2" = "-rpath" ]; then
-                if [ "$3" != "-Xlinker" ]; then
+            if [[ "$2" == "-rpath" ]]; then
+                if [[ "$3" != "-Xlinker" ]]; then
                    die "-Xlinker,-rpath was not followed by -Xlinker,*"
                fi
                shift 3;
                rp="$1"
-            elif [ "$2" = "$dtags_to_strip" ]; then
+            elif [[ "$2" = "$dtags_to_strip" ]] ; then
                shift  # We want to remove explicitly this flag
            else
-                append other_args_list "$1"
+                other_args+=("$1")
            fi
            ;;
        *)
-            if [ "$1" = "$dtags_to_strip" ]; then
+            if [[ "$1" = "$dtags_to_strip" ]] ; then
                :  # We want to remove explicitly this flag
            else
-                append other_args_list "$1"
+                other_args+=("$1")
            fi
            ;;
    esac
@@ -559,9 +430,9 @@ while [ $# -ne 0 ]; do
    # test rpaths against system directories in one place.
    if [ -n "$rp" ]; then
        if system_dir "$rp"; then
-            append system_rpath_dirs_list "$rp"
+            system_rpaths+=("$rp")
        else
-            append rpath_dirs_list "$rp"
+            rpaths+=("$rp")
        fi
    fi
    shift
@@ -574,15 +445,16 @@ done
 # See the gmake manual on implicit rules for details:
 # https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html
 #
-flags_list=""
+flags=()

 # Add debug flags
-if [ "${SPACK_ADD_DEBUG_FLAGS}" = "true" ]; then
-    extend flags_list debug_flags
+if [ "${SPACK_ADD_DEBUG_FLAGS}" == "true" ]; then
+    flags=("${flags[@]}" "${debug_flags}")

 # If a custom flag is requested, derive from environment
-elif [ "$SPACK_ADD_DEBUG_FLAGS" = "custom" ]; then
-    extend flags_list SPACK_DEBUG_FLAGS
+elif [ "$SPACK_ADD_DEBUG_FLAGS" == "custom" ]; then
+    IFS=' ' read -ra SPACK_DEBUG_FLAGS <<< "$SPACK_DEBUG_FLAGS"
+    flags=("${flags[@]}" "${SPACK_DEBUG_FLAGS[@]}")
 fi

 # Fortran flags come before CPPFLAGS
@@ -590,8 +462,7 @@ case "$mode" in
    cc|ccld)
        case $lang_flags in
            F)
-                extend flags_list SPACK_FFLAGS
-                ;;
+                flags=("${flags[@]}" "${SPACK_FFLAGS[@]}") ;;
        esac
        ;;
 esac
@@ -599,8 +470,7 @@ esac
 # C preprocessor flags come before any C/CXX flags
 case "$mode" in
    cpp|as|cc|ccld)
-        extend flags_list SPACK_CPPFLAGS
-        ;;
+        flags=("${flags[@]}" "${SPACK_CPPFLAGS[@]}") ;;
 esac


@@ -609,67 +479,67 @@ case "$mode" in
    cc|ccld)
        case $lang_flags in
            C)
-                extend flags_list SPACK_CFLAGS
-                ;;
+                flags=("${flags[@]}" "${SPACK_CFLAGS[@]}") ;;
            CXX)
-                extend flags_list SPACK_CXXFLAGS
-                ;;
+                flags=("${flags[@]}" "${SPACK_CXXFLAGS[@]}") ;;
        esac
-
-        # prepend target args
-        preextend flags_list SPACK_TARGET_ARGS
+        flags=(${SPACK_TARGET_ARGS[@]} "${flags[@]}")
        ;;
 esac

 # Linker flags
 case "$mode" in
    ld|ccld)
-        extend flags_list SPACK_LDFLAGS
-        ;;
+        flags=("${flags[@]}" "${SPACK_LDFLAGS[@]}") ;;
 esac

 # On macOS insert headerpad_max_install_names linker flag
-if [ "$mode" = ld ] || [ "$mode" = ccld ]; then
-    if [ "${SPACK_SHORT_SPEC#*darwin}" != "${SPACK_SHORT_SPEC}" ]; then
-        case "$mode" in
-            ld)
-                append flags_list "-headerpad_max_install_names" ;;
-            ccld)
-                append flags_list "-Wl,-headerpad_max_install_names" ;;
-        esac
-    fi
+if [[ ($mode == ld || $mode == ccld) && "$SPACK_SHORT_SPEC" =~ "darwin" ]];
+then
+    case "$mode" in
+        ld)
+            flags=("${flags[@]}" -headerpad_max_install_names) ;;
+        ccld)
+            flags=("${flags[@]}" "-Wl,-headerpad_max_install_names") ;;
+    esac
 fi

-if [ "$mode" = ccld ] || [ "$mode" = ld ]; then
-    if [ "$add_rpaths" != "false" ]; then
+IFS=':' read -ra rpath_dirs <<< "$SPACK_RPATH_DIRS"
+if [[ $mode == ccld || $mode == ld ]]; then
+
+    if [[ "$add_rpaths" != "false" ]] ; then
        # Append RPATH directories. Note that in the case of the
        # top-level package these directories may not exist yet. For dependencies
        # it is assumed that paths have already been confirmed.
-        extend rpath_dirs_list SPACK_RPATH_DIRS
+        rpaths=("${rpaths[@]}" "${rpath_dirs[@]}")
    fi
+
 fi

-if [ "$mode" = ccld ] || [ "$mode" = ld ]; then
-    extend lib_dirs_list SPACK_LINK_DIRS
+IFS=':' read -ra link_dirs <<< "$SPACK_LINK_DIRS"
+if [[ $mode == ccld || $mode == ld ]]; then
+    libdirs=("${libdirs[@]}" "${link_dirs[@]}")
 fi

 # add RPATHs if we're in in any linking mode
 case "$mode" in
    ld|ccld)
        # Set extra RPATHs
-        extend lib_dirs_list SPACK_COMPILER_EXTRA_RPATHS
-        if [ "$add_rpaths" != "false" ]; then
-            extend rpath_dirs_list SPACK_COMPILER_EXTRA_RPATHS
+        IFS=':' read -ra extra_rpaths <<< "$SPACK_COMPILER_EXTRA_RPATHS"
+        libdirs+=("${extra_rpaths[@]}")
+        if [[ "$add_rpaths" != "false" ]] ; then
+            rpaths+=("${extra_rpaths[@]}")
        fi

        # Set implicit RPATHs
-        if [ "$add_rpaths" != "false" ]; then
-            extend rpath_dirs_list SPACK_COMPILER_IMPLICIT_RPATHS
+        IFS=':' read -ra implicit_rpaths <<< "$SPACK_COMPILER_IMPLICIT_RPATHS"
+        if [[ "$add_rpaths" != "false" ]] ; then
+            rpaths+=("${implicit_rpaths[@]}")
        fi

        # Add SPACK_LDLIBS to args
-        for lib in $SPACK_LDLIBS; do
-            append libs_list "${lib#-l}"
+        for lib in "${SPACK_LDLIBS[@]}"; do
+            libs+=("${lib#-l}")
        done
        ;;
 esac
@@ -677,62 +547,63 @@ esac
 #
 # Finally, reassemble the command line.
 #
-args_list="$flags_list"
+
+# Includes and system includes first
+args=()
+
+# flags assembled earlier
+args+=("${flags[@]}")

 # Insert include directories just prior to any system include directories
-# NOTE: adding ${lsep} to the prefix here turns every added element into two
-extend args_list include_dirs_list "-I"
-extend args_list isystem_include_dirs_list "-isystem${lsep}"

-case "$mode" in
-    cpp|cc|as|ccld)
-        if [ "$isystem_was_used" = "true" ]; then
-            extend args_list SPACK_INCLUDE_DIRS "-isystem${lsep}"
-        else
-            extend args_list SPACK_INCLUDE_DIRS "-I"
-        fi
-        ;;
-esac
+for dir in "${includes[@]}";         do args+=("-I$dir"); done
+for dir in "${isystem_includes[@]}";         do args+=("-isystem" "$dir"); done

-extend args_list system_include_dirs_list -I
-extend args_list isystem_system_include_dirs_list "-isystem${lsep}"
+IFS=':' read -ra spack_include_dirs <<< "$SPACK_INCLUDE_DIRS"
+if [[ $mode == cpp || $mode == cc || $mode == as || $mode == ccld ]]; then
+    if [[ "$isystem_was_used" == "true" ]] ; then
+        for dir in "${spack_include_dirs[@]}";  do args+=("-isystem" "$dir"); done
+    else
+        for dir in "${spack_include_dirs[@]}";  do args+=("-I$dir"); done
+    fi
+fi
+
+for dir in "${system_includes[@]}";  do args+=("-I$dir"); done
+for dir in "${isystem_system_includes[@]}";  do args+=("-isystem" "$dir"); done

 # Library search paths
-extend args_list lib_dirs_list "-L"
-extend args_list system_lib_dirs_list "-L"
+for dir in "${libdirs[@]}";          do args+=("-L$dir"); done
+for dir in "${system_libdirs[@]}";   do args+=("-L$dir"); done

 # RPATHs arguments
 case "$mode" in
    ccld)
-        if [ -n "$dtags_to_add" ] ; then
-            append args_list "$linker_arg$dtags_to_add"
-        fi
-        extend args_list rpath_dirs_list "$rpath"
-        extend args_list system_rpath_dirs_list "$rpath"
+        if [ -n "$dtags_to_add" ] ; then args+=("$linker_arg$dtags_to_add") ; fi
+        for dir in "${rpaths[@]}";        do args+=("$rpath$dir"); done
+        for dir in "${system_rpaths[@]}"; do args+=("$rpath$dir"); done
        ;;
    ld)
-        if [ -n "$dtags_to_add" ] ; then
-            append args_list "$dtags_to_add"
-        fi
-        extend args_list rpath_dirs_list "-rpath${lsep}"
-        extend args_list system_rpath_dirs_list "-rpath${lsep}"
+        if [ -n "$dtags_to_add" ] ; then args+=("$dtags_to_add") ; fi
+        for dir in "${rpaths[@]}";        do args+=("-rpath" "$dir"); done
+        for dir in "${system_rpaths[@]}"; do args+=("-rpath" "$dir"); done
        ;;
 esac

 # Other arguments from the input command
-extend args_list other_args_list
+args+=("${other_args[@]}")

 # Inject SPACK_LDLIBS, if supplied
-extend args_list libs_list "-l"
+for lib in "${libs[@]}"; do
+    args+=("-l$lib");
+done

-full_command_list="$command"
-extend full_command_list args_list
+full_command=("$command" "${args[@]}")

 # prepend the ccache binary if we're using ccache
 if [ -n "$SPACK_CCACHE_BINARY" ]; then
    case "$lang_flags" in
        C|CXX)  # ccache only supports C languages
-            prepend full_command_list "${SPACK_CCACHE_BINARY}"
+            full_command=("${SPACK_CCACHE_BINARY}" "${full_command[@]}")
            # workaround for stage being a temp folder
            # see #3761#issuecomment-294352232
            export CCACHE_NOHASHDIR=yes
@@ -741,38 +612,25 @@ if [ -n "$SPACK_CCACHE_BINARY" ]; then
 fi

 # dump the full command if the caller supplies SPACK_TEST_COMMAND=dump-args
-if [ -n "${SPACK_TEST_COMMAND=}" ]; then
-    case "$SPACK_TEST_COMMAND" in
-        dump-args)
-            IFS="$lsep"
-            for arg in $full_command_list; do
-                echo "$arg"
-            done
-            unset IFS
-            exit
-            ;;
-        dump-env-*)
-            var=${SPACK_TEST_COMMAND#dump-env-}
-            eval "printf '%s\n' \"\$0: \$var: \$$var\""
-            ;;
-        *)
-            die "Unknown test command: '$SPACK_TEST_COMMAND'"
-            ;;
-    esac
+if [[ $SPACK_TEST_COMMAND == dump-args ]]; then
+    IFS="
+" && echo "${full_command[*]}"
+    exit
+elif [[ $SPACK_TEST_COMMAND =~ dump-env-* ]]; then
+    var=${SPACK_TEST_COMMAND#dump-env-}
+    echo "$0: $var: ${!var}"
+elif [[ -n $SPACK_TEST_COMMAND ]]; then
+    die "ERROR: Unknown test command"
 fi

 #
 # Write the input and output commands to debug logs if it's asked for.
 #
-if [ "$SPACK_DEBUG" = TRUE ]; then
+if [[ $SPACK_DEBUG == TRUE ]]; then
    input_log="$SPACK_DEBUG_LOG_DIR/spack-cc-$SPACK_DEBUG_LOG_ID.in.log"
    output_log="$SPACK_DEBUG_LOG_DIR/spack-cc-$SPACK_DEBUG_LOG_ID.out.log"
    echo "[$mode] $command $input_command" >> "$input_log"
-    IFS="$lsep"
-    echo "[$mode] "$full_command_list >> "$output_log"
-    unset IFS
+    echo "[$mode] ${full_command[*]}" >> "$output_log"
 fi

-# Execute the full command, preserving spaces with IFS set
-# to the alarm bell separator.
-IFS="$lsep"; exec $full_command_list
+exec "${full_command[@]}"
--- a/lib/spack/env/oneapi/dpcpp
+++ b/lib/spack/env/oneapi/dpcpp
@@ -1 +0,0 @@
-../cc
--- a/lib/spack/env/rocmcc/amdclang
+++ b/lib/spack/env/rocmcc/amdclang
@@ -1 +0,0 @@
-../cc
--- a/lib/spack/env/rocmcc/amdclang++
+++ b/lib/spack/env/rocmcc/amdclang++
@@ -1 +0,0 @@
-../cpp
--- a/lib/spack/env/rocmcc/amdflang
+++ b/lib/spack/env/rocmcc/amdflang
@@ -1 +0,0 @@
-../fc
--- a/Show More
+++ b/Show More