WIP

Previously, we only searched for `patch` inside of whatever Git
installation was available because the most common installation of Git
available on Windows had `patch`. That's not true for all possible
installations of Git though, so this updates the search to also check
PATH.

.github/dependabot.yml

@@ -10,3 +10,8 @@ updates:
     directory: "/lib/spack/docs"
     schedule:
       interval: "daily"
+  # Requirements to run style checks
+  - package-ecosystem: "pip"
+    directory: "/.github/workflows/style"
+    schedule:
+      interval: "daily"

.github/workflows/audit.yaml

@@ -22,8 +22,8 @@ jobs:
       matrix:
         operating_system: ["ubuntu-latest", "macos-latest"]
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236 # @v2
       with:
         python-version: ${{inputs.python_version}}
     - name: Install Python packages
@@ -34,6 +34,7 @@ jobs:
       run: |
           . share/spack/setup-env.sh
           coverage run $(which spack) audit packages
+          coverage run $(which spack) audit externals        
           coverage combine
           coverage xml
     - name: Package audits (without coverage)
@@ -41,6 +42,7 @@ jobs:
       run: |
           . share/spack/setup-env.sh
           $(which spack) audit packages
+          $(which spack) audit externals
     - uses: codecov/codecov-action@eaaf4bedf32dbdc6b720b63067d99c4d77d6047d # @v2.1.0
       if: ${{ inputs.with_coverage == 'true' }}
       with:

.github/workflows/bootstrap.yml

@@ -24,7 +24,7 @@ jobs:
               make patch unzip which xz python3 python3-devel tree \
               cmake bison bison-devel libstdc++-static
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup non-root user
@@ -42,8 +42,8 @@ jobs:
         shell: runuser -u spack-test -- bash {0}
         run: |
           source share/spack/setup-env.sh
+          spack bootstrap disable github-actions-v0.5
           spack bootstrap disable github-actions-v0.4
-          spack bootstrap disable github-actions-v0.3
           spack external find cmake bison
           spack -d solve zlib
           tree ~/.spack/bootstrap/store/
@@ -62,7 +62,7 @@ jobs:
               make patch unzip xz-utils python3 python3-dev tree \
               cmake bison
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup non-root user
@@ -80,8 +80,8 @@ jobs:
         shell: runuser -u spack-test -- bash {0}
         run: |
           source share/spack/setup-env.sh
+          spack bootstrap disable github-actions-v0.5
           spack bootstrap disable github-actions-v0.4
-          spack bootstrap disable github-actions-v0.3
           spack external find cmake bison
           spack -d solve zlib
           tree ~/.spack/bootstrap/store/
@@ -99,7 +99,7 @@ jobs:
               bzip2 curl file g++ gcc gfortran git gnupg2 gzip \
               make patch unzip xz-utils python3 python3-dev tree
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup non-root user
@@ -133,7 +133,7 @@ jobs:
               make patch unzip which xz python3 python3-devel tree \
               cmake bison
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup repo
@@ -145,8 +145,8 @@ jobs:
       - name: Bootstrap clingo
         run: |
           source share/spack/setup-env.sh
+          spack bootstrap disable github-actions-v0.5
           spack bootstrap disable github-actions-v0.4
-          spack bootstrap disable github-actions-v0.3
           spack external find cmake bison
           spack -d solve zlib
           tree ~/.spack/bootstrap/store/
@@ -158,13 +158,13 @@ jobs:
         run: |
           brew install cmake bison@2.7 tree
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       - name: Bootstrap clingo
         run: |
           source share/spack/setup-env.sh
           export PATH=/usr/local/opt/bison@2.7/bin:$PATH
+          spack bootstrap disable github-actions-v0.5
           spack bootstrap disable github-actions-v0.4
-          spack bootstrap disable github-actions-v0.3
           spack external find --not-buildable cmake bison
           spack -d solve zlib
           tree ~/.spack/bootstrap/store/
@@ -179,11 +179,11 @@ jobs:
         run: |
           brew install tree
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       - name: Bootstrap clingo
         run: |
           set -ex
-          for ver in '3.6' '3.7' '3.8' '3.9' '3.10' ; do
+          for ver in '3.7' '3.8' '3.9' '3.10' '3.11' ; do
             not_found=1
             ver_dir="$(find $RUNNER_TOOL_CACHE/Python -wholename "*/${ver}.*/*/bin" | grep . || true)"
             echo "Testing $ver_dir"
@@ -204,7 +204,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup repo
@@ -214,7 +214,7 @@ jobs:
       - name: Bootstrap clingo
         run: |
           set -ex
-          for ver in '3.6' '3.7' '3.8' '3.9' '3.10' ; do
+          for ver in '3.7' '3.8' '3.9' '3.10' '3.11' ; do
             not_found=1
             ver_dir="$(find $RUNNER_TOOL_CACHE/Python -wholename "*/${ver}.*/*/bin" | grep . || true)"
             echo "Testing $ver_dir"
@@ -247,7 +247,7 @@ jobs:
               bzip2 curl file g++ gcc patchelf gfortran git gzip \
               make patch unzip xz-utils python3 python3-dev tree
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup non-root user
@@ -265,6 +265,7 @@ jobs:
         shell: runuser -u spack-test -- bash {0}
         run: |
           source share/spack/setup-env.sh
+          spack bootstrap disable github-actions-v0.4
           spack bootstrap disable spack-install
           spack -d gpg list
           tree ~/.spack/bootstrap/store/
@@ -283,7 +284,7 @@ jobs:
               make patch unzip xz-utils python3 python3-dev tree \
               gawk
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
           fetch-depth: 0
       - name: Setup non-root user
@@ -302,8 +303,8 @@ jobs:
         run: |
           source share/spack/setup-env.sh
           spack solve zlib
+          spack bootstrap disable github-actions-v0.5
           spack bootstrap disable github-actions-v0.4
-          spack bootstrap disable github-actions-v0.3
           spack -d gpg list
           tree ~/.spack/bootstrap/store/
 
@@ -316,10 +317,11 @@ jobs:
           # Remove GnuPG since we want to bootstrap it
           sudo rm -rf /usr/local/bin/gpg
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       - name: Bootstrap GnuPG
         run: |
           source share/spack/setup-env.sh
+          spack bootstrap disable github-actions-v0.4
           spack bootstrap disable spack-install
           spack -d gpg list
           tree ~/.spack/bootstrap/store/
@@ -333,13 +335,13 @@ jobs:
           # Remove GnuPG since we want to bootstrap it
           sudo rm -rf /usr/local/bin/gpg
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       - name: Bootstrap GnuPG
         run: |
           source share/spack/setup-env.sh
           spack solve zlib
+          spack bootstrap disable github-actions-v0.5
           spack bootstrap disable github-actions-v0.4
-          spack bootstrap disable github-actions-v0.3
           spack -d gpg list
           tree ~/.spack/bootstrap/store/
 

.github/workflows/build-containers.yml

@@ -56,7 +56,7 @@ jobs:
     if: github.repository == 'spack/spack'
     steps:
       - name: Checkout
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
 
       - name: Set Container Tag Normal (Nightly)
         run: |
@@ -92,13 +92,13 @@ jobs:
           path: dockerfiles
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@2b82ce82d56a2a04d2637cd93a637ae1b359c0a7 # @v1
+        uses: docker/setup-qemu-action@68827325e0b33c7199eb31dd4e31fbe9023e06e3 # @v1
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@885d1462b80bc1c1c7f0b00334ad271f09369c55 # @v1
+        uses: docker/setup-buildx-action@f95db51fddba0c2d1ec667646a06c2ce06100226 # @v1
 
       - name: Log in to GitHub Container Registry
-        uses: docker/login-action@465a07811f14bebb1938fbed4728c6a1ff8901fc # @v1
+        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # @v1
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -106,13 +106,13 @@ jobs:
 
       - name: Log in to DockerHub
         if: github.event_name != 'pull_request'
-        uses: docker/login-action@465a07811f14bebb1938fbed4728c6a1ff8901fc # @v1
+        uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # @v1
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Build & Deploy ${{ matrix.dockerfile[0] }}
-        uses: docker/build-push-action@0a97817b6ade9f46837855d676c4cca3a2471fc9 # @v2
+        uses: docker/build-push-action@0565240e2d4ab88bba5387d719585280857ece09 # @v2
         with:
           context: dockerfiles/${{ matrix.dockerfile[0] }}
           platforms: ${{ matrix.dockerfile[1] }}

.github/workflows/ci.yaml

@@ -35,7 +35,7 @@ jobs:
       core: ${{ steps.filter.outputs.core }}
       packages: ${{ steps.filter.outputs.packages }}
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
         if: ${{ github.event_name == 'push' }}
         with:
           fetch-depth: 0

.github/workflows/nightly-win-builds.yml

@@ -14,10 +14,10 @@ jobs:
   build-paraview-deps:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236
       with:
         python-version: 3.9
     - name: Install Python packages

.github/workflows/style/requirements.txt

@@ -0,0 +1,7 @@
+black==23.9.1
+clingo==5.6.2
+flake8==6.1.0
+isort==5.12.0
+mypy==1.6.1
+types-six==1.16.21.9
+vermin==1.5.2

.github/workflows/unit_tests.yaml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
         concretizer: ['clingo']
         on_develop:
         - ${{ github.ref == 'refs/heads/develop' }}
@@ -45,12 +45,16 @@ jobs:
           os: ubuntu-latest
           concretizer: 'clingo'
           on_develop: false
+        - python-version: '3.11'
+          os: ubuntu-latest
+          concretizer: 'clingo'
+          on_develop: false
 
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236 # @v2
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install System packages
@@ -94,10 +98,10 @@ jobs:
   shell:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236 # @v2
       with:
         python-version: '3.11'
     - name: Install System packages
@@ -133,7 +137,7 @@ jobs:
           dnf install -y \
               bzip2 curl file gcc-c++ gcc gcc-gfortran git gnupg2 gzip \
               make patch tcl unzip which xz
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
     - name: Setup repo and non-root user
       run: |
           git --version
@@ -152,10 +156,10 @@ jobs:
   clingo-cffi:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236 # @v2
       with:
         python-version: '3.11'
     - name: Install System packages
@@ -185,12 +189,12 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        python-version: ["3.10"]
+        python-version: ["3.11"]
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236 # @v2
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install Python packages

.github/workflows/valid-style.yml

@@ -18,15 +18,15 @@ jobs:
   validate:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236
       with:
         python-version: '3.11'
         cache: 'pip'
     - name: Install Python Packages
       run: |
-        pip install --upgrade pip
-        pip install --upgrade vermin
+        pip install --upgrade pip setuptools
+        pip install -r .github/workflows/style/requirements.txt
     - name: vermin (Spack's Core)
       run: vermin --backport importlib --backport argparse --violations --backport typing -t=3.6- -vvv lib/spack/spack/ lib/spack/llnl/ bin/
     - name: vermin (Repositories)
@@ -35,16 +35,17 @@ jobs:
   style:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # @v2
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236
       with:
         python-version: '3.11'
         cache: 'pip'
     - name: Install Python packages
       run: |
-        python3 -m pip install --upgrade pip setuptools types-six black==23.1.0 mypy isort clingo flake8
+        pip install --upgrade pip setuptools
+        pip install -r .github/workflows/style/requirements.txt
     - name: Setup git configuration
       run: |
         # Need this for the git tests to succeed.
@@ -68,7 +69,7 @@ jobs:
           dnf install -y \
               bzip2 curl file gcc-c++ gcc gcc-gfortran git gnupg2 gzip \
               make patch tcl unzip which xz
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # @v2
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # @v2
       - name: Setup repo and non-root user
         run: |
           git --version

.github/workflows/windows_python.yml

@@ -15,10 +15,10 @@ jobs:
   unit-tests:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236
       with:
         python-version: 3.9
     - name: Install Python packages
@@ -39,10 +39,10 @@ jobs:
   unit-tests-cmd:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236
       with:
         python-version: 3.9
     - name: Install Python packages
@@ -63,10 +63,10 @@ jobs:
   build-abseil:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1
+    - uses: actions/setup-python@65d7f2d534ac1bc67fcd62888c5f4f3d2cb2b236
       with:
         python-version: 3.9
     - name: Install Python packages

CITATION.cff

@@ -27,12 +27,53 @@
 # And here's the CITATION.cff format:
 #
 cff-version: 1.2.0
+type: software
 message: "If you are referencing Spack in a publication, please cite the paper below."
+title: "The Spack Package Manager: Bringing Order to HPC Software Chaos"
+abstract: >-
+  Large HPC centers spend considerable time supporting software for thousands of users, but the complexity of HPC software is quickly outpacing the capabilities of existing software management tools.
+  Scientific applications require specific versions of compilers, MPI, and other dependency libraries, so using a single, standard software stack is infeasible.
+  However, managing many configurations is difficult because the configuration space is combinatorial in size.
+  We introduce Spack, a tool used at Lawrence Livermore National Laboratory to manage this complexity.
+  Spack provides a novel, re- cursive specification syntax to invoke parametric builds of packages and dependencies.
+  It allows any number of builds to coexist on the same system, and it ensures that installed packages can find their dependencies, regardless of the environment.
+  We show through real-world use cases that Spack supports diverse and demanding applications, bringing order to HPC software chaos.
 preferred-citation:
+  title: "The Spack Package Manager: Bringing Order to HPC Software Chaos"
   type: conference-paper
-  doi: "10.1145/2807591.2807623"
-  url: "https://github.com/spack/spack"
+  url: "https://tgamblin.github.io/pubs/spack-sc15.pdf"
   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"
+  conference:
+    name: "Supercomputing 2015 (SC’15)"
+    city: "Austin"
+    region: "Texas"
+    country: "US"
+    date-start: 2015-11-15
+    date-end: 2015-11-20
+  month: 11
+  year: 2015
+  identifiers:
+    - description: "The concept DOI of the work."
+      type: doi
+      value: 10.1145/2807591.2807623
+    - description: "The DOE Document Release Number of the work"
+      type: other 
+      value: "LLNL-CONF-669890"
+authors:
   - family-names: "Gamblin"
     given-names: "Todd"
   - family-names: "LeGendre"
@@ -47,12 +88,3 @@ preferred-citation:
     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

README.md

@@ -7,6 +7,7 @@
 [![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)
+[![Matrix](https://img.shields.io/matrix/spack-space%3Amatrix.org?label=Matrix)](https://matrix.to/#/#spack-space:matrix.org)
 
 Spack is a multi-platform package manager that builds and installs
 multiple versions and configurations of software. It works on Linux,
@@ -62,7 +63,10 @@ Resources:
 
 * **Slack workspace**: [spackpm.slack.com](https://spackpm.slack.com).
   To get an invitation, visit [slack.spack.io](https://slack.spack.io).
-* [**Github Discussions**](https://github.com/spack/spack/discussions): not just for discussions, also Q&A.
+* **Matrix space**: [#spack-space:matrix.org](https://matrix.to/#/#spack-space:matrix.org):
+  [bridged](https://github.com/matrix-org/matrix-appservice-slack#matrix-appservice-slack) to Slack.
+* [**Github Discussions**](https://github.com/spack/spack/discussions):
+  not just for discussions, also Q&A.
 * **Mailing list**: [groups.google.com/d/forum/spack](https://groups.google.com/d/forum/spack)
 * **Twitter**: [@spackpm](https://twitter.com/spackpm). Be sure to
   `@mention` us!

etc/spack/defaults/bootstrap.yaml

@@ -9,15 +9,15 @@ bootstrap:
   # may not be able to bootstrap all the software that Spack needs,
   # depending on its type.
   sources:
+  - name: 'github-actions-v0.5'
+    metadata: $spack/share/spack/bootstrap/github-actions-v0.5
   - name: 'github-actions-v0.4'
     metadata: $spack/share/spack/bootstrap/github-actions-v0.4
-  - name: 'github-actions-v0.3'
-    metadata: $spack/share/spack/bootstrap/github-actions-v0.3
   - name: 'spack-install'
     metadata: $spack/share/spack/bootstrap/spack-install
   trusted:
     # By default we trust bootstrapping from sources and from binaries
     # produced on Github via the workflow
+    github-actions-v0.5: true
     github-actions-v0.4: true
-    github-actions-v0.3: true
     spack-install: true

etc/spack/defaults/concretizer.yaml

@@ -41,4 +41,4 @@ concretizer:
     # "none": allows a single node for any package in the DAG.
     # "minimal": allows the duplication of 'build-tools' nodes only (e.g. py-setuptools, cmake etc.)
     # "full" (experimental): allows separation of the entire build-tool stack (e.g. the entire "cmake" subDAG)
-    strategy: none
+    strategy: minimal

lib/spack/docs/.gitignore

@@ -1,4 +1,3 @@
-package_list.html
 command_index.rst
 spack*.rst
 llnl*.rst

lib/spack/docs/basic_usage.rst

@@ -45,7 +45,8 @@ Listing available packages
 
 To install software with Spack, you need to know what software is
 available.  You can see a list of available package names at the
-:ref:`package-list` webpage, or using the ``spack list`` command.
+`packages.spack.io <https://packages.spack.io>`_ website, or
+using the ``spack list`` command.
 
 .. _cmd-spack-list:
 
@@ -60,7 +61,7 @@ can install:
    :ellipsis: 10
 
 There are thousands of them, so we've truncated the output above, but you
-can find a :ref:`full list here <package-list>`.
+can find a `full list here <https://packages.spack.io>`_.
 Packages are listed by name in alphabetical order.
 A pattern to match with no wildcards, ``*`` or ``?``,
 will be treated as though it started and ended with

lib/spack/docs/build_settings.rst

@@ -3,6 +3,103 @@
 
    SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
+
+.. _concretizer-options:
+
+==========================================
+Concretization Settings (concretizer.yaml)
+==========================================
+
+The ``concretizer.yaml`` configuration file allows to customize aspects of the
+algorithm used to select the dependencies you install. The default configuration
+is the following:
+
+.. 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 ``concretizer.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.
+
+---------------
+Duplicate nodes
+---------------
+
+The ``duplicates`` attribute controls whether the DAG can contain multiple configurations of
+the same package. This is mainly relevant for build dependencies, which may have their version
+pinned by some nodes, and thus be required at different versions by different nodes in the same
+DAG.
+
+The ``strategy`` option controls how the solver deals with duplicates. If the value is ``none``,
+then a single configuration per package is allowed in the DAG. This means, for instance, that only
+a single ``cmake`` or a single ``py-setuptools`` version is allowed. The result would be a slightly
+faster concretization, at the expense of making a few specs unsolvable.
+
+If the value is ``minimal`` Spack will allow packages tagged as ``build-tools`` to have duplicates.
+This allows, for instance, to concretize specs whose nodes require different, and incompatible, ranges
+of some build tool. For instance, in the figure below the latest `py-shapely` requires a newer `py-setuptools`,
+while `py-numpy` still needs an older version:
+
+.. figure::  images/shapely_duplicates.svg
+   :scale: 70 %
+   :align: center
+
+Up to Spack v0.20 ``duplicates:strategy:none`` was the default (and only) behavior. From Spack v0.21 the
+default behavior is ``duplicates:strategy:minimal``.
+
 .. _build-settings:
 
 ================================
@@ -232,76 +329,6 @@ Specific limitations include:
   then Spack will not add a new external entry (``spack config blame packages``
   can help locate all external entries).
 
-.. _concretizer-options:
-
-----------------------
-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 ``concretizer.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-requirements:
 
 --------------------

lib/spack/docs/build_systems/autotoolspackage.rst

@@ -127,9 +127,9 @@ check out a commit from the ``master`` 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')
+   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.
@@ -145,7 +145,7 @@ example, the ``bash`` shell is used to run the ``autogen.sh`` script.
 .. code-block:: python
 
    def autoreconf(self, spec, prefix):
-       which('bash')('autogen.sh')
+       which("bash")("autogen.sh")
 
 """""""""""""""""""""""""""""""""""""""
 patching configure or Makefile.in files
@@ -186,9 +186,9 @@ To opt out of this feature, use the following setting:
 To enable it conditionally on different architectures, define a property and
 make the package depend on ``gnuconfig`` as a build dependency:
 
-.. code-block
+.. code-block:: python
 
-   depends_on('gnuconfig', when='@1.0:')
+   depends_on("gnuconfig", when="@1.0:")
 
    @property
    def patch_config_files(self):
@@ -230,7 +230,7 @@ version, this can be done like so:
 
    @property
    def force_autoreconf(self):
-       return self.version == Version('1.2.3')
+       return self.version == Version("1.2.3")
 
 ^^^^^^^^^^^^^^^^^^^^^^^
 Finding configure flags
@@ -278,13 +278,22 @@ function like so:
    def configure_args(self):
        args = []
 
-       if '+mpi' in self.spec:
-           args.append('--enable-mpi')
+       if self.spec.satisfies("+mpi"):
+           args.append("--enable-mpi")
        else:
-           args.append('--disable-mpi')
+           args.append("--disable-mpi")
 
        return args
 
+
+Alternatively, you can use the :ref:`enable_or_disable  <autotools_enable_or_disable>` helper:
+
+.. code-block:: python
+
+   def configure_args(self):
+       return [self.enable_or_disable("mpi")]
+
+
 Note that we are explicitly disabling MPI support if it is not
 requested. This is important, as many Autotools packages will enable
 options by default if the dependencies are found, and disable them
@@ -295,9 +304,11 @@ and `here <https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Automagic_depe
 for a rationale as to why these so-called "automagic" dependencies
 are a problem.
 
-By default, Autotools installs packages to ``/usr``. We don't want this,
-so Spack automatically adds ``--prefix=/path/to/installation/prefix``
-to your list of ``configure_args``. You don't need to add this yourself.
+.. note::
+
+   By default, Autotools installs packages to ``/usr``. We don't want this,
+   so Spack automatically adds ``--prefix=/path/to/installation/prefix``
+   to your list of ``configure_args``. You don't need to add this yourself.
 
 ^^^^^^^^^^^^^^^^
 Helper functions
@@ -308,6 +319,8 @@ You may have noticed that most of the Autotools flags are of the form
 ``--without-baz``. Since these flags are so common, Spack provides a
 couple of helper functions to make your life easier.
 
+.. _autotools_enable_or_disable:
+
 """""""""""""""""
 enable_or_disable
 """""""""""""""""
@@ -319,11 +332,11 @@ typically used to enable or disable some feature within the package.
 .. code-block:: python
 
    variant(
-       'memchecker',
+       "memchecker",
        default=False,
-       description='Memchecker support for debugging [degrades performance]'
+       description="Memchecker support for debugging [degrades performance]"
    )
-   config_args.extend(self.enable_or_disable('memchecker'))
+   config_args.extend(self.enable_or_disable("memchecker"))
 
 In this example, specifying the variant ``+memchecker`` will generate
 the following configuration options:
@@ -343,15 +356,15 @@ the ``with_or_without`` method.
 .. code-block:: python
 
    variant(
-       'schedulers',
+       "schedulers",
        values=disjoint_sets(
-           ('auto',), ('alps', 'lsf', 'tm', 'slurm', 'sge', 'loadleveler')
-       ).with_non_feature_values('auto', 'none'),
+           ("auto",), ("alps", "lsf", "tm", "slurm", "sge", "loadleveler")
+       ).with_non_feature_values("auto", "none"),
        description="List of schedulers for which support is enabled; "
        "'auto' lets openmpi determine",
    )
-   if 'schedulers=auto' not in spec:
-       config_args.extend(self.with_or_without('schedulers'))
+   if not spec.satisfies("schedulers=auto"):
+       config_args.extend(self.with_or_without("schedulers"))
 
 In this example, specifying the variant ``schedulers=slurm,sge`` will
 generate the following configuration options:
@@ -376,16 +389,16 @@ generated, using the ``activation_value`` argument to
 .. code-block:: python
 
    variant(
-      'fabrics',
+      "fabrics",
        values=disjoint_sets(
-           ('auto',), ('psm', 'psm2', 'verbs', 'mxm', 'ucx', 'libfabric')
-       ).with_non_feature_values('auto', 'none'),
+           ("auto",), ("psm", "psm2", "verbs", "mxm", "ucx", "libfabric")
+       ).with_non_feature_values("auto", "none"),
        description="List of fabrics that are enabled; "
        "'auto' lets openmpi determine",
    )
-   if 'fabrics=auto' not in spec:
-       config_args.extend(self.with_or_without('fabrics',
-           activation_value='prefix'))
+   if not spec.satisfies("fabrics=auto"):
+       config_args.extend(self.with_or_without("fabrics",
+           activation_value="prefix"))
 
 ``activation_value`` accepts a callable that generates the configure
 parameter value given the variant value; but the special value
@@ -409,16 +422,16 @@ When Spack variants and configure flags do not correspond one-to-one, the
 
 .. code-block:: python
 
-   variant('debug_tools', default=False)
-   config_args += self.enable_or_disable('debug-tools', variant='debug_tools')
+   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')
+   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")
 
 
 """"""""""""""""""""
@@ -432,8 +445,8 @@ For example:
 
 .. code-block:: python
 
-   variant('profiler', when='@2.0:')
-   config_args += self.with_or_without('profiler')
+   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``.
@@ -452,10 +465,10 @@ the variant values require atypical behavior.
    def with_or_without_verbs(self, activated):
        # Up through version 1.6, this option was named --with-openib.
        # In version 1.7, it was renamed to be --with-verbs.
-       opt = 'verbs' if self.spec.satisfies('@1.7:') else 'openib'
+       opt = "verbs" if self.spec.satisfies("@1.7:") else "openib"
        if not activated:
-           return '--without-{0}'.format(opt)
-       return '--with-{0}={1}'.format(opt, self.spec['rdma-core'].prefix)
+           return f"--without-{opt}"
+       return f"--with-{opt}={self.spec['rdma-core'].prefix}"
 
 Defining ``with_or_without_verbs`` overrides the behavior of a
 ``fabrics=verbs`` variant, changing the configure-time option to
@@ -479,7 +492,7 @@ do this like so:
 
 .. code-block:: python
 
-   configure_directory = 'src'
+   configure_directory = "src"
 
 ^^^^^^^^^^^^^^^^^^^^^^
 Building out of source
@@ -491,7 +504,7 @@ This can be done using the ``build_directory`` variable:
 
 .. code-block:: python
 
-   build_directory = 'spack-build'
+   build_directory = "spack-build"
 
 By default, Spack will build the package in the same directory that
 contains the ``configure`` script
@@ -514,8 +527,8 @@ library or build the documentation, you can add these like so:
 
 .. code-block:: python
 
-   build_targets = ['all', 'docs']
-   install_targets = ['install', 'docs']
+   build_targets = ["all", "docs"]
+   install_targets = ["install", "docs"]
 
 ^^^^^^^
 Testing

lib/spack/docs/build_systems/cachedcmakepackage.rst

@@ -87,7 +87,7 @@ A typical usage of these methods may look something like this:
 
 .. code-block:: python
 
-   def initconfig_mpi_entries(self)
+   def initconfig_mpi_entries(self):
        # Get existing MPI configurations
        entries = super(self, Foo).initconfig_mpi_entries()
 
@@ -95,25 +95,25 @@ A typical usage of these methods may look something like this:
        # 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"))
+       if self.spec.satisfies("+mpi"):
+           entries.append(cmake_cache_option("FOO_MPI", True, "enable mpi"))
        else:
-           entries.append(cmake_cache_option('FOO_MPI', False, "disable mpi"))
+           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')
+       entries.append("#Entries for build options")
 
-       bar_on = '+bar' in self.spec
-       entries.append(cmake_cache_option('FOO_BAR', bar_on, 'toggle bar'))
+       bar_on = self.spec.satisfies("+bar")
+       entries.append(cmake_cache_option("FOO_BAR", bar_on, "toggle bar"))
 
-       entries.append('#Entries for dependencies')
+       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))
+       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

lib/spack/docs/build_systems/cudapackage.rst

@@ -54,8 +54,8 @@ to terminate such build attempts with a suitable message:
 
 .. code-block:: python
 
-    conflicts('cuda_arch=none', when='+cuda',
-              msg='CUDA architecture is required')
+    conflicts("cuda_arch=none", when="+cuda",
+              msg="CUDA architecture is required")
 
 Similarly, if your software does not support all versions of the property,
 you could add ``conflicts`` to your package for those versions.  For example,
@@ -66,13 +66,13 @@ custom message should a user attempt such a build:
 .. code-block:: python
 
     unsupported_cuda_archs = [
-        '10', '11', '12', '13',
-        '20', '21',
-        '30', '32', '35', '37'
+        "10", "11", "12", "13",
+        "20", "21",
+        "30", "32", "35", "37"
     ]
     for value in unsupported_cuda_archs:
-        conflicts('cuda_arch={0}'.format(value), when='+cuda',
-                  msg='CUDA architecture {0} is not supported'.format(value))
+        conflicts(f"cuda_arch={value}", when="+cuda",
+                  msg=f"CUDA architecture {value} is not supported")
 
 ^^^^^^^
 Methods
@@ -107,16 +107,16 @@ class of your package.  For example, you can add it to your
             spec = self.spec
             args = []
             ...
-            if '+cuda' in spec:
+            if spec.satisfies("+cuda"):
                 # Set up the cuda macros needed by the build
-                args.append('-DWITH_CUDA=ON')
-                cuda_arch_list = spec.variants['cuda_arch'].value
+                args.append("-DWITH_CUDA=ON")
+                cuda_arch_list = spec.variants["cuda_arch"].value
                 cuda_arch = cuda_arch_list[0]
-                if cuda_arch != 'none':
-                    args.append('-DCUDA_FLAGS=-arch=sm_{0}'.format(cuda_arch))
+                if cuda_arch != "none":
+                    args.append(f"-DCUDA_FLAGS=-arch=sm_{cuda_arch}")
             else:
                 # Ensure build with cuda is disabled
-                args.append('-DWITH_CUDA=OFF')
+                args.append("-DWITH_CUDA=OFF")
             ...
             return args
 
@@ -125,7 +125,7 @@ You will need to customize options as needed for your build.
 
 This example also illustrates how to check for the ``cuda`` variant using
 ``self.spec`` and how to retrieve the ``cuda_arch`` variant's value, which
-is a list, using ``self.spec.variants['cuda_arch'].value``.
+is a list, using ``self.spec.variants["cuda_arch"].value``.
 
 With over 70 packages using ``CudaPackage`` as of January 2021 there are
 lots of examples to choose from to get more ideas for using this package.

lib/spack/docs/build_systems/custompackage.rst

@@ -57,13 +57,13 @@ If you look at the ``perl`` package, you'll see:
 
 .. code-block:: python
 
-   phases = ['configure', 'build', 'install']
+   phases = ["configure", "build", "install"]
 
 Similarly, ``cmake`` defines:
 
 .. code-block:: python
 
-   phases = ['bootstrap', 'build', 'install']
+   phases = ["bootstrap", "build", "install"]
 
 If we look at the ``cmake`` example, this tells Spack's ``PackageBase``
 class to run the ``bootstrap``, ``build``, and ``install`` functions
@@ -78,7 +78,7 @@ If we look at ``perl``, we see that it defines a ``configure`` method:
 .. code-block:: python
 
    def configure(self, spec, prefix):
-       configure = Executable('./Configure')
+       configure = Executable("./Configure")
        configure(*self.configure_args())
 
 There is also a corresponding ``configure_args`` function that handles
@@ -92,7 +92,7 @@ phases are pretty simple:
        make()
 
    def install(self, spec, prefix):
-       make('install')
+       make("install")
 
 The ``cmake`` package looks very similar, but with a ``bootstrap``
 function instead of ``configure``:
@@ -100,14 +100,14 @@ function instead of ``configure``:
 .. code-block:: python
 
    def bootstrap(self, spec, prefix):
-       bootstrap = Executable('./bootstrap')
+       bootstrap = Executable("./bootstrap")
        bootstrap(*self.bootstrap_args())
 
    def build(self, spec, prefix):
        make()
 
    def install(self, spec, prefix):
-       make('install')
+       make("install")
 
 Again, there is a ``boostrap_args`` function that determines the
 correct bootstrap flags to use.
@@ -128,16 +128,16 @@ before or after a particular phase. For example, in ``perl``, we see:
 
 .. code-block:: python
 
-   @run_after('install')
+   @run_after("install")
    def install_cpanm(self):
        spec = self.spec
 
-       if '+cpanm' in spec:
-           with working_dir(join_path('cpanm', 'cpanm')):
-               perl = spec['perl'].command
-               perl('Makefile.PL')
+       if spec.satisfies("+cpanm"):
+           with working_dir(join_path("cpanm", "cpanm")):
+               perl = spec["perl"].command
+               perl("Makefile.PL")
                make()
-               make('install')
+               make("install")
 
 This extra step automatically installs ``cpanm`` in addition to the
 base Perl installation.
@@ -174,10 +174,10 @@ In the ``perl`` package, we can see:
 
 .. code-block:: python
 
-   @run_after('build')
+   @run_after("build")
    @on_package_attributes(run_tests=True)
    def test(self):
-       make('test')
+       make("test")
 
 As you can guess, this runs ``make test`` *after* building the package,
 if and only if testing is requested. Again, this is not specific to
@@ -189,7 +189,7 @@ custom build systems, it can be added to existing build systems as well.
 
    .. code-block:: python
 
-      @run_after('install')
+      @run_after("install")
       @on_package_attributes(run_tests=True)
 
    works as expected. However, if you reverse the ordering:
@@ -197,7 +197,7 @@ custom build systems, it can be added to existing build systems as well.
    .. code-block:: python
 
       @on_package_attributes(run_tests=True)
-      @run_after('install')
+      @run_after("install")
 
    the tests will always be run regardless of whether or not
    ``--test=root`` is requested. See https://github.com/spack/spack/issues/3833

lib/spack/docs/build_systems/inteloneapipackage.rst

@@ -25,8 +25,8 @@ use Spack to build packages with the tools.
 The Spack Python class ``IntelOneapiPackage`` is a base class that is
 used by ``IntelOneapiCompilers``, ``IntelOneapiMkl``,
 ``IntelOneapiTbb`` and other classes to implement the oneAPI
-packages. See the :ref:`package-list` for the full list of available
-oneAPI packages or use::
+packages. Search for ``oneAPI`` at `<packages.spack.io>`_ for the full
+list of available oneAPI packages, or use::
 
   spack list -d oneAPI
 

lib/spack/docs/build_systems/makefilepackage.rst

@@ -59,7 +59,7 @@ using GNU Make, you should add a dependency on ``gmake``:
 
 .. code-block:: python
 
-   depends_on('gmake', type='build')
+   depends_on("gmake", type="build")
 
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -93,8 +93,8 @@ there are any other variables you need to set, you can do this in the
 .. code-block:: python
 
    def edit(self, spec, prefix):
-       env['PREFIX'] = prefix
-       env['BLASLIB'] = spec['blas'].libs.ld_flags
+       env["PREFIX"] = prefix
+       env["BLASLIB"] = spec["blas"].libs.ld_flags
 
 
 `cbench <https://github.com/spack/spack/blob/develop/var/spack/repos/builtin/packages/cbench/package.py>`_
@@ -113,7 +113,7 @@ you can do this like so:
 
 .. code-block:: python
 
-   build_targets = ['CC=cc']
+   build_targets = ["CC=cc"]
 
 
 If you do need access to the spec, you can create a property like so:
@@ -125,8 +125,8 @@ If you do need access to the spec, you can create a property like so:
        spec = self.spec
 
        return [
-           'CC=cc',
-           'BLASLIB={0}'.format(spec['blas'].libs.ld_flags),
+           "CC=cc",
+           f"BLASLIB={spec['blas'].libs.ld_flags}",
        ]
 
 
@@ -145,12 +145,12 @@ and a ``filter_file`` method to help with this. For example:
 .. code-block:: python
 
    def edit(self, spec, prefix):
-       makefile = FileFilter('Makefile')
+       makefile = FileFilter("Makefile")
 
-       makefile.filter(r'^\s*CC\s*=.*',  'CC = '  + spack_cc)
-       makefile.filter(r'^\s*CXX\s*=.*', 'CXX = ' + spack_cxx)
-       makefile.filter(r'^\s*F77\s*=.*', 'F77 = ' + spack_f77)
-       makefile.filter(r'^\s*FC\s*=.*',  'FC = '  + spack_fc)
+       makefile.filter(r"^\s*CC\s*=.*",  f"CC = {spack_cc}")
+       makefile.filter(r"^\s*CXX\s*=.*", f"CXX = {spack_cxx}")
+       makefile.filter(r"^\s*F77\s*=.*", f"F77 = {spack_f77}")
+       makefile.filter(r"^\s*FC\s*=.*",  f"FC = {spack_fc}")
 
 
 `stream <https://github.com/spack/spack/blob/develop/var/spack/repos/builtin/packages/stream/package.py>`_
@@ -181,16 +181,16 @@ well for storing variables:
 
    def edit(self, spec, prefix):
        config = {
-           'CC': 'cc',
-           'MAKE': 'make',
+           "CC": "cc",
+           "MAKE": "make",
        }
 
-       if '+blas' in spec:
-           config['BLAS_LIBS'] = spec['blas'].libs.joined()
+       if spec.satisfies("+blas"):
+           config["BLAS_LIBS"] = spec["blas"].libs.joined()
 
-       with open('make.inc', 'w') as inc:
+       with open("make.inc", "w") as inc:
            for key in config:
-               inc.write('{0} = {1}\n'.format(key, config[key]))
+               inc.write(f"{key} = {config[key]}\n")
 
 
 `elk <https://github.com/spack/spack/blob/develop/var/spack/repos/builtin/packages/elk/package.py>`_
@@ -204,14 +204,14 @@ them in a list:
 
    def edit(self, spec, prefix):
        config = [
-           'INSTALL_DIR = {0}'.format(prefix),
-           'INCLUDE_DIR = $(INSTALL_DIR)/include',
-           'LIBRARY_DIR = $(INSTALL_DIR)/lib',
+           f"INSTALL_DIR = {prefix}",
+           "INCLUDE_DIR = $(INSTALL_DIR)/include",
+           "LIBRARY_DIR = $(INSTALL_DIR)/lib",
        ]
 
-       with open('make.inc', 'w') as inc:
+       with open("make.inc", "w") as inc:
            for var in config:
-               inc.write('{0}\n'.format(var))
+               inc.write(f"{var}\n")
 
 
 `hpl <https://github.com/spack/spack/blob/develop/var/spack/repos/builtin/packages/hpl/package.py>`_
@@ -284,7 +284,7 @@ can tell Spack where to locate it like so:
 
 .. code-block:: python
 
-   build_directory = 'src'
+   build_directory = "src"
 
 
 ^^^^^^^^^^^^^^^^^^^
@@ -299,8 +299,8 @@ install the package:
 
    def install(self, spec, prefix):
        mkdir(prefix.bin)
-       install('foo', prefix.bin)
-       install_tree('lib', prefix.lib)
+       install("foo", prefix.bin)
+       install_tree("lib", prefix.lib)
 
 
 ^^^^^^^^^^^^^^^^^^^^^^

lib/spack/docs/build_systems/pythonpackage.rst

@@ -152,16 +152,16 @@ set. Once set, ``pypi`` will be used to define the ``homepage``,
 
 .. code-block:: python
 
-   homepage = 'https://pypi.org/project/setuptools/'
-   url      = 'https://pypi.org/packages/source/s/setuptools/setuptools-49.2.0.zip'
-   list_url = 'https://pypi.org/simple/setuptools/'
+   homepage = "https://pypi.org/project/setuptools/"
+   url      = "https://pypi.org/packages/source/s/setuptools/setuptools-49.2.0.zip"
+   list_url = "https://pypi.org/simple/setuptools/"
 
 
 is equivalent to:
 
 .. code-block:: python
 
-   pypi = 'setuptools/setuptools-49.2.0.zip'
+   pypi = "setuptools/setuptools-49.2.0.zip"
 
 
 If a package has a different homepage listed on PyPI, you can
@@ -208,7 +208,7 @@ dependencies to your package:
 
 .. code-block:: python
 
-   depends_on('py-setuptools@42:', type='build')
+   depends_on("py-setuptools@42:", type="build")
 
 
 Note that ``py-wheel`` is already listed as a build dependency in the
@@ -232,7 +232,7 @@ Look for dependencies under the following keys:
 * ``dependencies`` under ``[project]``
 
   These packages are required for building and installation. You can
-  add them with ``type=('build', 'run')``.
+  add them with ``type=("build", "run")``.
 
 * ``[project.optional-dependencies]``
 
@@ -279,12 +279,12 @@ distutils library, and has almost the exact same API. In addition to
 * ``setup_requires``
 
   These packages are usually only needed at build-time, so you can
-  add them with ``type='build'``.
+  add them with ``type="build"``.
 
 * ``install_requires``
 
   These packages are required for building and installation. You can
-  add them with ``type=('build', 'run')``.
+  add them with ``type=("build", "run")``.
 
 * ``extras_require``
 
@@ -296,7 +296,7 @@ distutils library, and has almost the exact same API. In addition to
 
   These are packages that are required to run the unit tests for the
   package. These dependencies can be specified using the
-  ``type='test'`` dependency type. However, the PyPI tarballs rarely
+  ``type="test"`` dependency type. However, the PyPI tarballs rarely
   contain unit tests, so there is usually no reason to add these.
 
 See https://setuptools.pypa.io/en/latest/userguide/dependency_management.html
@@ -321,7 +321,7 @@ older versions of flit may use the following keys:
 * ``requires`` under ``[tool.flit.metadata]``
 
   These packages are required for building and installation. You can
-  add them with ``type=('build', 'run')``.
+  add them with ``type=("build", "run")``.
 
 * ``[tool.flit.metadata.requires-extra]``
 
@@ -434,12 +434,12 @@ the BLAS/LAPACK library you want pkg-config to search for:
 
 .. code-block:: python
 
-   depends_on('py-pip@22.1:', type='build')
+   depends_on("py-pip@22.1:", type="build")
 
    def config_settings(self, spec, prefix):
        return {
-           'blas': spec['blas'].libs.names[0],
-           'lapack': spec['lapack'].libs.names[0],
+           "blas": spec["blas"].libs.names[0],
+           "lapack": spec["lapack"].libs.names[0],
        }
 
 
@@ -463,10 +463,10 @@ has an optional dependency on ``libyaml`` that can be enabled like so:
 
    def global_options(self, spec, prefix):
        options = []
-       if '+libyaml' in spec:
-           options.append('--with-libyaml')
+       if spec.satisfies("+libyaml"):
+           options.append("--with-libyaml")
        else:
-           options.append('--without-libyaml')
+           options.append("--without-libyaml")
        return options
 
 
@@ -492,10 +492,10 @@ allows you to specify the directories to search for ``libyaml``:
 
    def install_options(self, spec, prefix):
        options = []
-       if '+libyaml' in spec:
+       if spec.satisfies("+libyaml"):
            options.extend([
-               spec['libyaml'].libs.search_flags,
-               spec['libyaml'].headers.include_flags,
+               spec["libyaml"].libs.search_flags,
+               spec["libyaml"].headers.include_flags,
            ])
        return options
 
@@ -556,7 +556,7 @@ detected are wrong, you can provide the names yourself by overriding
 
 .. code-block:: python
 
-   import_modules = ['six']
+   import_modules = ["six"]
 
 
 Sometimes the list of module names to import depends on how the
@@ -571,9 +571,9 @@ This can be expressed like so:
 
    @property
    def import_modules(self):
-       modules = ['yaml']
-       if '+libyaml' in self.spec:
-           modules.append('yaml.cyaml')
+       modules = ["yaml"]
+       if self.spec.satisfies("+libyaml"):
+           modules.append("yaml.cyaml")
        return modules
 
 
@@ -586,14 +586,14 @@ Instead of defining the ``import_modules`` explicitly, only the subset
 of module names to be skipped can be defined by using ``skip_modules``.
 If a defined module has submodules, they are skipped as well, e.g.,
 in case the ``plotting`` modules should be excluded from the
-automatically detected ``import_modules`` ``['nilearn', 'nilearn.surface',
-'nilearn.plotting', 'nilearn.plotting.data']`` set:
+automatically detected ``import_modules`` ``["nilearn", "nilearn.surface",
+"nilearn.plotting", "nilearn.plotting.data"]`` set:
 
 .. code-block:: python
 
-        skip_modules = ['nilearn.plotting']
+        skip_modules = ["nilearn.plotting"]
 
-This will set ``import_modules`` to ``['nilearn', 'nilearn.surface']``
+This will set ``import_modules`` to ``["nilearn", "nilearn.surface"]``
 
 Import tests can be run during the installation using ``spack install
 --test=root`` or at any time after the installation using
@@ -612,11 +612,11 @@ after the ``install`` phase:
 
 .. code-block:: python
 
-   @run_after('install')
+   @run_after("install")
    @on_package_attributes(run_tests=True)
    def install_test(self):
-       with working_dir('spack-test', create=True):
-           python('-c', 'import numpy; numpy.test("full", verbose=2)')
+       with working_dir("spack-test", create=True):
+           python("-c", "import numpy; numpy.test('full', verbose=2)")
 
 
 when testing is enabled during the installation (i.e., ``spack install
@@ -638,7 +638,7 @@ provides Python bindings in a ``python`` directory, you can use:
 
 .. code-block:: python
 
-   build_directory = 'python'
+   build_directory = "python"
 
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

lib/spack/docs/build_systems/rocmpackage.rst

@@ -81,28 +81,27 @@ class of your package.  For example, you can add it to your
     class MyRocmPackage(CMakePackage, ROCmPackage):
         ...
         # Ensure +rocm and amdgpu_targets are passed to dependencies
-        depends_on('mydeppackage', when='+rocm')
+        depends_on("mydeppackage", when="+rocm")
         for val in ROCmPackage.amdgpu_targets:
-            depends_on('mydeppackage amdgpu_target={0}'.format(val),
-                       when='amdgpu_target={0}'.format(val))
+            depends_on(f"mydeppackage amdgpu_target={val}",
+                       when=f"amdgpu_target={val}")
         ...
 
         def cmake_args(self):
             spec = self.spec
             args = []
             ...
-            if '+rocm' in spec:
+            if spec.satisfies("+rocm"):
                 # Set up the hip macros needed by the build
                 args.extend([
-                    '-DENABLE_HIP=ON',
-                    '-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}'
-                                .format(",".join(rocm_archs)))
+                    "-DENABLE_HIP=ON",
+                    f"-DHIP_ROOT_DIR={spec['hip'].prefix}"])
+                rocm_archs = spec.variants["amdgpu_target"].value
+                if "none" not in rocm_archs:
+                    args.append(f"-DHIP_HIPCC_FLAGS=--amdgpu-target={','.join(rocm_archs}")
             else:
                 # Ensure build with hip is disabled
-                args.append('-DENABLE_HIP=OFF')
+                args.append("-DENABLE_HIP=OFF")
             ...
             return args
         ...
@@ -114,7 +113,7 @@ build.
 
 This example also illustrates how to check for the ``rocm`` variant using
 ``self.spec`` and how to retrieve the ``amdgpu_target`` variant's value
-using ``self.spec.variants['amdgpu_target'].value``.
+using ``self.spec.variants["amdgpu_target"].value``.
 
 All five packages using ``ROCmPackage`` as of January 2021 also use the
 :ref:`CudaPackage <cudapackage>`. So it is worth looking at those packages

lib/spack/docs/build_systems/sconspackage.rst

@@ -57,7 +57,7 @@ overridden like so:
 .. code-block:: python
 
    def test(self):
-       scons('check')
+       scons("check")
 
 
 ^^^^^^^^^^^^^^^
@@ -88,7 +88,7 @@ base class already contains:
 
 .. code-block:: python
 
-   depends_on('scons', type='build')
+   depends_on("scons", type="build")
 
 
 If you want to specify a particular version requirement, you can override
@@ -96,7 +96,7 @@ this in your package:
 
 .. code-block:: python
 
-   depends_on('scons@2.3.0:', type='build')
+   depends_on("scons@2.3.0:", type="build")
 
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -238,14 +238,14 @@ the package build phase. This is done by overriding ``build_args`` like so:
 
    def build_args(self, spec, prefix):
        args = [
-         'PREFIX={0}'.format(prefix),
-         'ZLIB={0}'.format(spec['zlib'].prefix),
+         f"PREFIX={prefix}",
+         f"ZLIB={spec['zlib'].prefix}",
        ]
 
-       if '+debug' in spec:
-           args.append('DEBUG=yes')
+       if spec.satisfies("+debug"):
+           args.append("DEBUG=yes")
        else:
-           args.append('DEBUG=no')
+           args.append("DEBUG=no")
 
        return args
 
@@ -275,8 +275,8 @@ environment variables. For example, cantera has the following option:
    * env_vars: [ string ]
        Environment variables to propagate through to SCons. Either the
        string "all" or a comma separated list of variable names, e.g.
-       'LD_LIBRARY_PATH,HOME'.
-       - default: 'LD_LIBRARY_PATH,PYTHONPATH'
+       "LD_LIBRARY_PATH,HOME".
+       - default: "LD_LIBRARY_PATH,PYTHONPATH"
 
 
 In the case of cantera, using ``env_vars=all`` allows us to use

lib/spack/docs/conf.py

@@ -48,9 +48,6 @@
 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"])
-
 # Generate a command index if an update is needed
 subprocess.call(
     [

lib/spack/docs/containers.rst

@@ -212,18 +212,12 @@ under the ``container`` attribute of environments:
          final:
          - libgomp
 
-       # Extra instructions
-       extra_instructions:
-         final: |
-           RUN echo 'export PS1="\[$(tput bold)\]\[$(tput setaf 1)\][gromacs]\[$(tput setaf 2)\]\u\[$(tput sgr0)\]:\w $ "' >> ~/.bashrc
-
        # Labels for the image
        labels:
          app: "gromacs"
          mpi: "mpich"
 
-A detailed description of the options available can be found in the
-:ref:`container_config_options` section.
+A detailed description of the options available can be found in the :ref:`container_config_options` section.
 
 -------------------
 Setting Base Images
@@ -525,6 +519,13 @@ the example below:
    COPY data /share/myapp/data
    {% endblock %}
 
+The Dockerfile is generated by running:
+
+.. code-block:: console
+
+   $ spack -e /opt/environment containerize
+
+Note that the environment must be active for spack to read the template.
 The recipe that gets generated contains the two extra instruction that we added in our template extension:
 
 .. code-block:: Dockerfile

lib/spack/docs/contribution_guide.rst

@@ -310,53 +310,11 @@ Once all of the dependencies are installed, you can try building the documentati
    $ make clean
    $ make
 
-If you see any warning or error messages, you will have to correct those before
-your PR is accepted.
-
-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:
-
-.. code-block:: console
-
-   package_list.rst:8745: WARNING: Block quote ends without a blank line; unexpected unindent.
-
-At first, this error message will mean nothing to you, since you didn't edit
-that file. Until you look at line 8745 of the file in question:
-
-.. code-block:: rst
-
-   Description:
-      NetCDF is a set of software libraries and self-describing, machine-
-     independent data formats that support the creation, access, and sharing
-     of array-oriented scientific data.
-
-Our documentation includes :ref:`a list of all Spack packages <package-list>`.
-If you add a new package, its docstring is added to this page. The problem in
-this case was that the docstring looked like:
-
-.. code-block:: python
-
-   class Netcdf(Package):
-       """
-       NetCDF is a set of software libraries and self-describing,
-       machine-independent data formats that support the creation,
-       access, and sharing of array-oriented scientific data.
-       """
-
-Docstrings cannot start with a newline character, or else Sphinx will complain.
-Instead, they should look like:
-
-.. code-block:: python
-
-   class Netcdf(Package):
-       """NetCDF is a set of software libraries and self-describing,
-       machine-independent data formats that support the creation,
-       access, and sharing of array-oriented scientific data."""
-
-Documentation changes can result in much more obfuscated warning messages.
-If you don't understand what they mean, feel free to ask when you submit
-your PR.
+If you see any warning or error messages, you will have to correct those before your PR
+is accepted. If you are editing the documentation, you should be running the
+documentation tests to make sure there are no errors. Documentation changes can result
+in some obfuscated warning messages. If you don't understand what they mean, feel free
+to ask when you submit your PR.
 
 --------
 Coverage

lib/spack/docs/index.rst

@@ -54,9 +54,16 @@ or refer to the full manual below.
    features
    getting_started
    basic_usage
-   Tutorial: Spack 101 <https://spack-tutorial.readthedocs.io>
    replace_conda_homebrew
 
+.. toctree::
+   :maxdepth: 2
+   :caption: Links
+
+   Tutorial (spack-tutorial.rtfd.io) <https://spack-tutorial.readthedocs.io>
+   Packages (packages.spack.io) <https://packages.spack.io>
+   Binaries (binaries.spack.io) <https://cache.spack.io>
+
 .. toctree::
    :maxdepth: 2
    :caption: Reference
@@ -72,7 +79,6 @@ or refer to the full manual below.
    repositories
    binary_caches
    command_index
-   package_list
    chain
    extensions
    pipelines

lib/spack/docs/package_list.rst

@@ -1,17 +0,0 @@
-.. Copyright 2013-2023 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)
-
-.. _package-list:
-
-============
-Package List
-============
-
-This is a list of things you can install using Spack.  It is
-automatically generated based on the packages in this Spack
-version.
-
-.. raw:: html
-   :file: package_list.html

lib/spack/docs/packaging_guide.rst

@@ -1549,7 +1549,7 @@ its value:
 
     def configure_args(self):
         ...
-        if "+shared" in self.spec:
+        if self.spec.satisfies("+shared"):
             extra_args.append("--enable-shared")
         else:
             extra_args.append("--disable-shared")
@@ -1636,7 +1636,7 @@ Within a package recipe a multi-valued variant is tested using a ``key=value`` s
 
   .. code-block:: python
 
-    if "languages=jit" in spec:
+    if spec.satisfies("languages=jit"):
         options.append("--enable-host-shared")
 
 """""""""""""""""""""""""""""""""""""""""""
@@ -2557,9 +2557,10 @@ Conditional dependencies
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
 You may have a package that only requires a dependency under certain
-conditions. For example, you may have a package that has optional MPI support,
-- MPI is only a dependency when you want to enable MPI support for the
-package. In that case, you could say something like:
+conditions. For example, you may have a package with optional MPI support.
+You would then provide a variant to reflect that the feature is optional
+and specify the MPI dependency only applies when MPI support is enabled.
+In that case, you could say something like:
 
 .. code-block:: python
 
@@ -2567,13 +2568,39 @@ package. In that case, you could say something like:
 
    depends_on("mpi", when="+mpi")
 
-``when`` can include constraints on the variant, version, compiler, etc. and
-the :mod:`syntax<spack.spec>` is the same as for Specs written on the command
-line.
 
-If a dependency/feature of a package isn't typically used, you can save time
-by making it conditional (since Spack will not build the dependency unless it
-is required for the Spec).
+Suppose the above package also has, since version 3, optional `Trilinos`
+support and you want them both to build either with or without MPI. Further
+suppose you require a version of `Trilinos` no older than 12.6. In that case,
+the `trilinos` variant and dependency directives would be:
+
+.. code-block:: python
+
+   variant("trilinos", default=False, description="Enable Trilinos support")
+
+   depends_on("trilinos@12.6:", when="@3: +trilinos")
+   depends_on("trilinos@12.6: +mpi", when="@3: +trilinos +mpi")
+
+
+Alternatively, you could use the `when` context manager to equivalently specify
+the `trilinos` variant dependencies as follows:
+
+.. code-block:: python
+
+   with when("@3: +trilinos"):
+       depends_on("trilinos@12.6:")
+       depends_on("trilinos +mpi", when="+mpi")
+
+
+The argument to ``when`` in either case can include any Spec constraints that
+are supported on the command line using the same :ref:`syntax <sec-specs>`.
+
+.. note::
+
+   If a dependency isn't typically used, you can save time by making it
+   conditional since Spack will not build the dependency unless it is
+   required for the Spec.
+
 
 .. _dependency_dependency_patching:
 
@@ -3501,7 +3528,7 @@ need to override methods like ``configure_args``:
 
    def configure_args(self):
         args = ["--enable-cxx"] + self.enable_or_disable("libs")
-        if "libs=static" in self.spec:
+        if self.spec.satisfies("libs=static"):
             args.append("--with-pic")
         return args
 
@@ -3635,7 +3662,8 @@ regardless of the build system. The arguments for the phase are:
 The arguments ``spec`` and ``prefix`` are passed only for convenience, as they always
 correspond to ``self.spec`` and ``self.spec.prefix`` respectively.
 
-If the ``package.py`` encodes builders explicitly, the signature for a phase changes slightly:
+If the ``package.py`` has build instructions in a separate
+:ref:`builder class <multiple_build_systems>`, the signature for a phase changes slightly:
 
 .. code-block:: python
 
@@ -3645,56 +3673,6 @@ If the ``package.py`` encodes builders explicitly, the signature for a phase cha
 
 In this case the package is passed as the second argument, and ``self`` is the builder instance.
 
-.. _multiple_build_systems:
-
-^^^^^^^^^^^^^^^^^^^^^^
-Multiple build systems
-^^^^^^^^^^^^^^^^^^^^^^
-
-There are cases where a software actively supports two build systems, or changes build systems
-as it evolves, or needs different build systems on different platforms. Spack allows dealing with
-these cases natively, if a recipe is written using builders explicitly.
-
-For instance, software that supports two build systems unconditionally should derive from
-both ``*Package`` base classes, and declare the possible use of multiple build systems using
-a directive:
-
-.. code-block:: python
-
-   class ArpackNg(CMakePackage, AutotoolsPackage):
-
-       build_system("cmake", "autotools", default="cmake")
-
-In this case the software can be built with both ``autotools`` and ``cmake``. Since the package
-supports multiple build systems, it is necessary to declare which one is the default. The ``package.py``
-will likely contain some overriding of default builder methods:
-
-.. code-block:: python
-
-   class CMakeBuilder(spack.build_systems.cmake.CMakeBuilder):
-       def cmake_args(self):
-           pass
-
-   class AutotoolsBuilder(spack.build_systems.autotools.AutotoolsBuilder):
-       def configure_args(self):
-           pass
-
-In more complex cases it might happen that the build system changes according to certain conditions,
-for instance across versions. That can be expressed with conditional variant values:
-
-.. code-block:: python
-
-   class ArpackNg(CMakePackage, AutotoolsPackage):
-
-       build_system(
-           conditional("cmake", when="@0.64:"),
-           conditional("autotools", when="@:0.63"),
-           default="cmake",
-       )
-
-In the example the directive impose a change from ``Autotools`` to ``CMake`` going
-from ``v0.63`` to ``v0.64``.
-
 ^^^^^^^^^^^^^^^^^^
 Mixin base classes
 ^^^^^^^^^^^^^^^^^^
@@ -3741,6 +3719,106 @@ for instance:
 
 In the example above ``Cp2k`` inherits all the conflicts and variants that ``CudaPackage`` defines.
 
+.. _multiple_build_systems:
+
+----------------------
+Multiple build systems
+----------------------
+
+There are cases where a package actively supports two build systems, or changes build systems
+as it evolves, or needs different build systems on different platforms. Spack allows dealing with
+these cases by splitting the build instructions into separate builder classes.
+
+For instance, software that supports two build systems unconditionally should derive from
+both ``*Package`` base classes, and declare the possible use of multiple build systems using
+a directive:
+
+.. code-block:: python
+
+   class Example(CMakePackage, AutotoolsPackage):
+
+       variant("my_feature", default=True)
+
+       build_system("cmake", "autotools", default="cmake")
+
+In this case the software can be built with both ``autotools`` and ``cmake``. Since the package
+supports multiple build systems, it is necessary to declare which one is the default.
+
+Additional build instructions are split into separate builder classes:
+
+.. code-block:: python
+
+   class CMakeBuilder(spack.build_systems.cmake.CMakeBuilder):
+       def cmake_args(self):
+           return [
+               self.define_from_variant("MY_FEATURE", "my_feature")
+           ]
+
+   class AutotoolsBuilder(spack.build_systems.autotools.AutotoolsBuilder):
+       def configure_args(self):
+           return self.with_or_without("my-feature", variant="my_feature")
+
+In this example, ``spack install example +feature build_sytem=cmake``  will
+pick the ``CMakeBuilder`` and invoke ``cmake -DMY_FEATURE:BOOL=ON``.
+
+Similarly, ``spack install example +feature build_system=autotools`` will pick
+the  ``AutotoolsBuilder`` and invoke ``./configure --with-my-feature``.
+
+Dependencies are always specified in the package class. When some dependencies
+depend on the choice of the build system, it is possible to use when conditions as 
+usual:
+
+.. code-block:: python
+
+   class Example(CMakePackage, AutotoolsPackage):
+
+       build_system("cmake", "autotools", default="cmake")
+
+       # Runtime dependencies
+       depends_on("ncurses")
+       depends_on("libxml2")
+
+       # Lowerbounds for cmake only apply when using cmake as the build system
+       with when("build_system=cmake"):
+           depends_on("cmake@3.18:", when="@2.0:", type="build")
+           depends_on("cmake@3:", type="build")
+
+       # Specify extra build dependencies used only in the configure script 
+       with when("build_system=autotools"):
+           depends_on("perl", type="build")
+           depends_on("pkgconfig", type="build")
+
+Very often projects switch from one build system to another, or add support
+for a new build system from a certain version, which means that the choice
+of the build system typically depends on a version range. Those situations can
+be handled by using conditional values in the ``build_system`` directive:
+
+.. code-block:: python
+
+   class Example(CMakePackage, AutotoolsPackage):
+
+       build_system(
+           conditional("cmake", when="@0.64:"),
+           conditional("autotools", when="@:0.63"),
+           default="cmake",
+       )
+
+In the example the directive impose a change from ``Autotools`` to ``CMake`` going
+from ``v0.63`` to ``v0.64``.
+
+The ``build_system`` can be used as an ordinary variant, which also means that it can
+be used in ``depends_on`` statements. This can be useful when a package *requires* that
+its dependency has a CMake config file, meaning that the dependent can only build when the
+dependency is built with CMake, and not Autotools. In that case, you can force the choice
+of the build system in the dependent:
+
+.. code-block:: python
+
+   class Dependent(CMakePackage):
+
+       depends_on("example build_system=cmake")
+
+
 .. _install-environment:
 
 -----------------------
@@ -4313,7 +4391,7 @@ for supported features, for instance:
 
 .. code-block:: python
 
-   if "avx512" in spec.target:
+   if spec.satisfies("target=avx512"):
        args.append("--with-avx512")
 
 The snippet above will append the ``--with-avx512`` item to a list of arguments only if the corresponding
@@ -6196,7 +6274,100 @@ follows:
                "foo-package@{0}".format(version_str)
            )
 
-.. _package-lifecycle:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Add detection tests to packages
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+To ensure that software is detected correctly for multiple configurations
+and on different systems users can write a ``detection_test.yaml`` file and
+put it in the package directory alongside the ``package.py`` file.
+This YAML file contains enough information for Spack to mock an environment
+and try to check if the detection logic yields the results that are expected.
+
+As a general rule, attributes at the top-level of ``detection_test.yaml``
+represent search mechanisms and they each map to a list of tests that should confirm
+the validity of the package's detection logic.
+
+The detection tests can be run with the following command:
+
+.. code-block:: console
+
+   $ spack audit externals
+
+Errors that have been detected are reported to screen.
+
+""""""""""""""""""""""""""
+Tests for PATH inspections
+""""""""""""""""""""""""""
+
+Detection tests insisting on ``PATH`` inspections are listed under
+the ``paths`` attribute:
+
+.. code-block:: yaml
+
+   paths:
+   - layout:
+     - executables:
+       - "bin/clang-3.9"
+       - "bin/clang++-3.9"
+       script: |
+         echo "clang version 3.9.1-19ubuntu1 (tags/RELEASE_391/rc2)"
+         echo "Target: x86_64-pc-linux-gnu"
+         echo "Thread model: posix"
+         echo "InstalledDir: /usr/bin"
+     results:
+     - spec: 'llvm@3.9.1 +clang~lld~lldb'
+
+Each test is performed by first creating a temporary directory structure as
+specified in the corresponding ``layout`` and by then running
+package detection and checking that the outcome matches the expected
+``results``. The exact details on how to specify both the ``layout`` and the
+``results`` are reported in the table below:
+
+.. list-table:: Test based on PATH inspections
+   :header-rows: 1
+
+   * - Option Name
+     - Description
+     - Allowed Values
+     - Required Field
+   * - ``layout``
+     - Specifies the filesystem tree used for the test
+     - List of objects
+     - Yes
+   * - ``layout:[0]:executables``
+     - Relative paths for the mock executables to be created
+     - List of strings
+     - Yes
+   * - ``layout:[0]:script``
+     - Mock logic for the executable
+     - Any valid shell script
+     - Yes
+   * - ``results``
+     - List of expected results
+     - List of objects (empty if no result is expected)
+     - Yes
+   * - ``results:[0]:spec``
+     - A spec that is expected from detection
+     - Any valid spec
+     - Yes
+
+"""""""""""""""""""""""""""""""
+Reuse tests from other packages
+"""""""""""""""""""""""""""""""
+
+When using a custom repository, it is possible to customize a package that already exists in ``builtin``
+and reuse its external tests. To do so, just write a ``detection_tests.yaml`` alongside the customized
+``package.py`` with an ``includes`` attribute. For instance the ``detection_tests.yaml`` for
+``myrepo.llvm`` might look like:
+
+.. code-block:: yaml
+
+   includes:
+   - "builtin.llvm"
+
+This YAML file instructs Spack to run the detection tests defined in ``builtin.llvm`` in addition to
+those locally defined in the file.
 
 -----------------------------
 Style guidelines for packages
@@ -6655,3 +6826,30 @@ To achieve backward compatibility with the single-class format Spack creates in
 Overall the role of the adapter is to route access to attributes of methods first through the ``*Package``
 hierarchy, and then back to the base class builder. This is schematically shown in the diagram above, where
 the adapter role is to "emulate" a method resolution order like the one represented by the red arrows.
+
+------------------------------
+Specifying License Information
+------------------------------
+
+A significant portion of software that Spack packages is open source. Most open
+source software is released under one or more common open source licenses.
+Specifying the specific license that a package is released under in a project's
+`package.py` is good practice. To specify a license, find the SPDX identifier for
+a project and then add it using the license directive:
+
+.. code-block:: python
+
+   license("<SPDX Identifier HERE>")
+
+Note that specifying a license without a when clause makes it apply to all
+versions and variants of the package, which might not actually be the case.
+For example, a project might have switched licenses at some point or have
+certain build configurations that include files that are licensed differently.
+To account for this, you can specify when licenses should be applied. For
+example, to specify that a specific license identifier should only apply
+to versionup to and including 1.5, you could write the following directive:
+
+.. code-block:: python
+
+   license("...", when="@:1.5")
+

lib/spack/docs/pipelines.rst

@@ -213,6 +213,16 @@ pipeline jobs.
 ``spack ci generate``
 ^^^^^^^^^^^^^^^^^^^^^
 
+Throughout this documentation, references to the "mirror" mean the target
+mirror which is checked for the presence of up-to-date specs, and where
+any scheduled jobs should push built binary packages.  In the past, this
+defaulted to the mirror at index 0 in the mirror configs, and could be
+overridden using the ``--buildcache-destination`` argument. Starting with
+Spack 0.23, ``spack ci generate`` will require you to identify this mirror
+by the name "buildcache-destination".  While you can configure any number
+of mirrors as sources for your pipelines, you will need to identify the
+destination mirror by name.
+
 Concretizes the specs in the active environment, stages them (as described in
 :ref:`staging_algorithm`), and writes the resulting ``.gitlab-ci.yml`` to disk.
 During concretization of the environment, ``spack ci generate`` also writes a

lib/spack/docs/replace_conda_homebrew.rst

@@ -4,7 +4,7 @@
    SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 =====================================
-Using Spack to Replace Homebrew/Conda
+Spack for Homebrew/Conda Users
 =====================================
 
 Spack is an incredibly powerful package manager, designed for supercomputers
@@ -191,18 +191,18 @@ The ``--fresh`` flag tells Spack to use the latest version of every package
 where possible instead of trying to optimize for reuse of existing installed
 packages.
 
-The ``--force`` flag in addition 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`` 
+The ``--force`` flag in addition 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.
 
 -----------------------------------
 Updating & Cleaning Up Old Packages
 -----------------------------------
 
-If you're looking to mimic the behavior of Homebrew, you may also want to 
-clean up out-of-date packages from your environment after an upgrade. To 
-upgrade your entire software stack within an environment and clean up old 
+If you're looking to mimic the behavior of Homebrew, you may also want to
+clean up out-of-date packages from your environment after an upgrade. To
+upgrade your entire software stack within an environment and clean up old
 package versions, simply run the following commands:
 
 .. code-block:: console
@@ -212,9 +212,9 @@ package versions, simply run the following commands:
    $ spack concretize --fresh --force
    $ spack install
    $ spack gc
-   
-Running ``spack mark -i --all`` tells Spack to mark all of the existing 
-packages within an environment as "implicitly" installed. This tells 
+
+Running ``spack mark -i --all`` tells Spack to mark all of the existing
+packages within an environment as "implicitly" installed. This tells
 spack's garbage collection system that these packages should be cleaned up.
 
 Don't worry however, this will not remove your entire environment.
@@ -223,8 +223,8 @@ a fresh concretization and will re-mark any packages that should remain
 installed as "explicitly" installed.
 
 **Note:** if you use multiple spack environments you should re-run ``spack install``
-in each of your environments prior to running ``spack gc`` to prevent spack 
-from uninstalling any shared packages that are no longer required by the 
+in each of your environments prior to running ``spack gc`` to prevent spack
+from uninstalling any shared packages that are no longer required by the
 environment you just upgraded.
 
 --------------

lib/spack/docs/requirements.txt

@@ -2,12 +2,12 @@ sphinx==7.2.6
 sphinxcontrib-programoutput==0.17
 sphinx_design==0.5.0
 sphinx-rtd-theme==1.3.0
-python-levenshtein==0.21.1
+python-levenshtein==0.23.0
 docutils==0.18.1
 pygments==2.16.1
-urllib3==2.0.4
+urllib3==2.0.7
 pytest==7.4.2
 isort==5.12.0
 black==23.9.1
 flake8==6.1.0
-mypy==1.5.1
+mypy==1.6.1

lib/spack/docs/tables/system_prerequisites.csv

@@ -1,9 +1,7 @@
 Name, Supported Versions, Notes, Requirement Reason
-Python, 3.6--3.11, , Interpreter for Spack
+Python, 3.6--3.12, , Interpreter for Spack
 C/C++ Compilers, , , Building software
-make, , , Build software
 patch, , , Build software
-bash, , , Compiler wrappers
 tar, , , Extract/create archives
 gzip, , , Compress/Decompress archives
 unzip, , , Compress/Decompress archives

lib/spack/llnl/path.py

@@ -0,0 +1,105 @@
+# Copyright 2013-2023 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)
+"""Path primitives that just require Python standard library."""
+import functools
+import sys
+from typing import List, Optional
+from urllib.parse import urlparse
+
+
+class Path:
+    """Enum to identify the path-style."""
+
+    unix: int = 0
+    windows: int = 1
+    platform_path: int = windows if sys.platform == "win32" else unix
+
+
+def format_os_path(path: str, mode: int = Path.unix) -> str:
+    """Formats the input path to use consistent, platform specific separators.
+
+    Absolute paths are converted between drive letters and a prepended '/' as per platform
+    requirement.
+
+    Parameters:
+        path: the path to be normalized, must be a string or expose the replace method.
+        mode: the path file separator style to normalize the passed path to.
+            Default is unix style, i.e. '/'
+    """
+    if not path:
+        return path
+    if mode == Path.windows:
+        path = path.replace("/", "\\")
+    else:
+        path = path.replace("\\", "/")
+    return path
+
+
+def convert_to_posix_path(path: str) -> str:
+    """Converts the input path to POSIX style."""
+    return format_os_path(path, mode=Path.unix)
+
+
+def convert_to_windows_path(path: str) -> str:
+    """Converts the input path to Windows style."""
+    return format_os_path(path, mode=Path.windows)
+
+
+def convert_to_platform_path(path: str) -> str:
+    """Converts the input path to the current platform's native style."""
+    return format_os_path(path, mode=Path.platform_path)
+
+
+def path_to_os_path(*parameters: str) -> List[str]:
+    """Takes an arbitrary number of positional parameters, converts each argument of type
+    string to use a normalized filepath separator, and returns a list of all values.
+    """
+
+    def _is_url(path_or_url: str) -> bool:
+        if "\\" in path_or_url:
+            return False
+        url_tuple = urlparse(path_or_url)
+        return bool(url_tuple.scheme) and len(url_tuple.scheme) > 1
+
+    result = []
+    for item in parameters:
+        if isinstance(item, str) and not _is_url(item):
+            item = convert_to_platform_path(item)
+        result.append(item)
+    return result
+
+
+def system_path_filter(_func=None, arg_slice: Optional[slice] = None):
+    """Filters function arguments to account for platform path separators.
+    Optional slicing range can be specified to select specific arguments
+
+    This decorator takes all (or a slice) of a method's positional arguments
+    and normalizes usage of filepath separators on a per platform basis.
+
+    Note: `**kwargs`, urls, and any type that is not a string are ignored
+    so in such cases where path normalization is required, that should be
+    handled by calling path_to_os_path directly as needed.
+
+    Parameters:
+        arg_slice: a slice object specifying the slice of arguments
+            in the decorated method over which filepath separators are
+            normalized
+    """
+
+    def holder_func(func):
+        @functools.wraps(func)
+        def path_filter_caller(*args, **kwargs):
+            args = list(args)
+            if arg_slice:
+                args[arg_slice] = path_to_os_path(*args[arg_slice])
+            else:
+                args = path_to_os_path(*args)
+            return func(*args, **kwargs)
+
+        return path_filter_caller
+
+    if _func:
+        return holder_func(_func)
+    return holder_func

lib/spack/llnl/string.py

@@ -0,0 +1,67 @@
+# Copyright 2013-2023 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)
+"""String manipulation functions that do not have other dependencies than Python
+standard library
+"""
+from typing import List, Optional
+
+
+def comma_list(sequence: List[str], article: str = "") -> str:
+    if type(sequence) is not list:
+        sequence = list(sequence)
+
+    if not sequence:
+        return ""
+    if len(sequence) == 1:
+        return sequence[0]
+
+    out = ", ".join(str(s) for s in sequence[:-1])
+    if len(sequence) != 2:
+        out += ","  # oxford comma
+    out += " "
+    if article:
+        out += article + " "
+    out += str(sequence[-1])
+    return out
+
+
+def comma_or(sequence: List[str]) -> str:
+    """Return a string with all the elements of the input joined by comma, but the last
+    one (which is joined by 'or').
+    """
+    return comma_list(sequence, "or")
+
+
+def comma_and(sequence: List[str]) -> str:
+    """Return a string with all the elements of the input joined by comma, but the last
+    one (which is joined by 'and').
+    """
+    return comma_list(sequence, "and")
+
+
+def quote(sequence: List[str], q: str = "'") -> List[str]:
+    """Quotes each item in the input list with the quote character passed as second argument."""
+    return [f"{q}{e}{q}" for e in sequence]
+
+
+def plural(n: int, singular: str, plural: Optional[str] = None, show_n: bool = True) -> str:
+    """Pluralize <singular> word by adding an s if n != 1.
+
+    Arguments:
+        n: number of things there are
+        singular: singular form of word
+        plural: optional plural form, for when it's not just singular + 's'
+        show_n: whether to include n in the result string (default True)
+
+    Returns:
+        "1 thing" if n == 1 or "n things" if n != 1
+    """
+    number = f"{n} " if show_n else ""
+    if n == 1:
+        return f"{number}{singular}"
+    elif plural is not None:
+        return f"{number}{plural}"
+    else:
+        return f"{number}{singular}s"

lib/spack/llnl/util/filesystem.py

@@ -28,7 +28,8 @@
 from llnl.util.symlink import islink, readlink, resolve_link_target_relative_to_the_link, symlink
 
 from spack.util.executable import Executable, which
-from spack.util.path import path_to_os_path, system_path_filter
+
+from ..path import path_to_os_path, system_path_filter
 
 if sys.platform != "win32":
     import grp
@@ -155,6 +156,37 @@ def lookup(name):
     shutil.copystat = copystat
 
 
+def polite_path(components: Iterable[str]):
+    """
+    Given a list of strings which are intended to be path components,
+    generate a path, and format each component to avoid generating extra
+    path entries.
+
+    For example all "/", "\", and ":" characters will be replaced with
+    "_". Other characters like "=" will also be replaced.
+    """
+    return os.path.join(*[polite_filename(x) for x in components])
+
+
+@memoized
+def _polite_antipattern():
+    # A regex of all the characters we don't want in a filename
+    return re.compile(r"[^A-Za-z0-9_.-]")
+
+
+def polite_filename(filename: str) -> str:
+    """
+    Replace generally problematic filename characters with underscores.
+
+    This differs from sanitize_filename in that it is more aggressive in
+    changing characters in the name. For example it removes "=" which can
+    confuse path parsing in external tools.
+    """
+    # This character set applies for both Windows and Linux. It does not
+    # account for reserved filenames in Windows.
+    return _polite_antipattern().sub("_", filename)
+
+
 def getuid():
     if sys.platform == "win32":
         import ctypes
@@ -336,8 +368,7 @@ def groupid_to_group(x):
 
     if string:
         regex = re.escape(regex)
-    filenames = path_to_os_path(*filenames)
-    for filename in filenames:
+    for filename in path_to_os_path(*filenames):
         msg = 'FILTER FILE: {0} [replacing "{1}"]'
         tty.debug(msg.format(filename, regex))
 

lib/spack/llnl/util/lock.py

@@ -14,7 +14,7 @@
 
 from llnl.util import lang, tty
 
-import spack.util.string
+from ..string import plural
 
 if sys.platform != "win32":
     import fcntl
@@ -169,7 +169,7 @@ def _attempts_str(wait_time, nattempts):
     if nattempts <= 1:
         return ""
 
-    attempts = spack.util.string.plural(nattempts, "attempt")
+    attempts = plural(nattempts, "attempt")
     return " after {} and {}".format(lang.pretty_seconds(wait_time), attempts)
 
 

lib/spack/llnl/util/symlink.py

@@ -11,8 +11,7 @@
 
 from llnl.util import lang, tty
 
-from spack.error import SpackError
-from spack.util.path import system_path_filter
+from ..path import system_path_filter
 
 if sys.platform == "win32":
     from win32file import CreateHardLink
@@ -338,7 +337,7 @@ def resolve_link_target_relative_to_the_link(link):
     return os.path.join(link_dir, target)
 
 
-class SymlinkError(SpackError):
+class SymlinkError(RuntimeError):
     """Exception class for errors raised while creating symlinks,
     junctions and hard links
     """

lib/spack/spack/abi.py

@@ -8,8 +8,8 @@
 from llnl.util.lang import memoized
 
 import spack.spec
+import spack.version
 from spack.compilers.clang import Clang
-from spack.spec import CompilerSpec
 from spack.util.executable import Executable, ProcessError
 
 
@@ -17,7 +17,9 @@ class ABI:
     """This class provides methods to test ABI compatibility between specs.
     The current implementation is rather rough and could be improved."""
 
-    def architecture_compatible(self, target, constraint):
+    def architecture_compatible(
+        self, target: spack.spec.Spec, constraint: spack.spec.Spec
+    ) -> bool:
         """Return true if architecture of target spec is ABI compatible
         to the architecture of constraint spec. If either the target
         or constraint specs have no architecture, target is also defined
@@ -34,7 +36,7 @@ def _gcc_get_libstdcxx_version(self, version):
         a compiler's libstdc++ or libgcc_s"""
         from spack.build_environment import dso_suffix
 
-        spec = CompilerSpec("gcc", version)
+        spec = spack.spec.CompilerSpec("gcc", version)
         compilers = spack.compilers.compilers_for_spec(spec)
         if not compilers:
             return None
@@ -77,16 +79,20 @@ def _gcc_compiler_compare(self, pversion, cversion):
             return False
         return plib == clib
 
-    def _intel_compiler_compare(self, pversion, cversion):
+    def _intel_compiler_compare(
+        self, pversion: spack.version.ClosedOpenRange, cversion: spack.version.ClosedOpenRange
+    ) -> bool:
         """Returns true iff the intel version pversion and cversion
         are ABI compatible"""
 
         # Test major and minor versions.  Ignore build version.
-        if len(pversion.version) < 2 or len(cversion.version) < 2:
-            return False
-        return pversion.version[:2] == cversion.version[:2]
+        pv = pversion.lo
+        cv = cversion.lo
+        return pv.up_to(2) == cv.up_to(2)
 
-    def compiler_compatible(self, parent, child, **kwargs):
+    def compiler_compatible(
+        self, parent: spack.spec.Spec, child: spack.spec.Spec, loose: bool = False
+    ) -> bool:
         """Return true if compilers for parent and child are ABI compatible."""
         if not parent.compiler or not child.compiler:
             return True
@@ -95,7 +101,7 @@ def compiler_compatible(self, parent, child, **kwargs):
             # Different compiler families are assumed ABI incompatible
             return False
 
-        if kwargs.get("loose", False):
+        if loose:
             return True
 
         # TODO: Can we move the specialized ABI matching stuff
@@ -116,9 +122,10 @@ def compiler_compatible(self, parent, child, **kwargs):
                     return True
         return False
 
-    def compatible(self, target, constraint, **kwargs):
+    def compatible(
+        self, target: spack.spec.Spec, constraint: spack.spec.Spec, loose: bool = False
+    ) -> bool:
         """Returns true if target spec is ABI compatible to constraint spec"""
-        loosematch = kwargs.get("loose", False)
         return self.architecture_compatible(target, constraint) and self.compiler_compatible(
-            target, constraint, loose=loosematch
+            target, constraint, loose=loose
         )

lib/spack/spack/audit.py

@@ -38,10 +38,13 @@ def _search_duplicate_compilers(error_cls):
 import ast
 import collections
 import collections.abc
+import glob
 import inspect
 import itertools
+import pathlib
 import pickle
 import re
+import warnings
 from urllib.request import urlopen
 
 import llnl.util.lang
@@ -304,10 +307,17 @@ def _check_build_test_callbacks(pkgs, error_cls):
 
 @package_directives
 def _check_patch_urls(pkgs, error_cls):
-    """Ensure that patches fetched from GitHub have stable sha256 hashes."""
+    """Ensure that patches fetched from GitHub and GitLab have stable sha256
+    hashes."""
     github_patch_url_re = (
         r"^https?://(?:patch-diff\.)?github(?:usercontent)?\.com/"
-        ".+/.+/(?:commit|pull)/[a-fA-F0-9]*.(?:patch|diff)"
+        r".+/.+/(?:commit|pull)/[a-fA-F0-9]+\.(?:patch|diff)"
+    )
+    # Only .diff URLs have stable/full hashes:
+    # https://forum.gitlab.com/t/patches-with-full-index/29313
+    gitlab_patch_url_re = (
+        r"^https?://(?:.+)?gitlab(?:.+)/"
+        r".+/.+/-/(?:commit|merge_requests)/[a-fA-F0-9]+\.(?:patch|diff)"
     )
 
     errors = []
@@ -318,19 +328,27 @@ def _check_patch_urls(pkgs, error_cls):
                 if not isinstance(patch, spack.patch.UrlPatch):
                     continue
 
-                if not re.match(github_patch_url_re, patch.url):
-                    continue
-
-                full_index_arg = "?full_index=1"
-                if not patch.url.endswith(full_index_arg):
-                    errors.append(
-                        error_cls(
-                            "patch URL in package {0} must end with {1}".format(
-                                pkg_cls.name, full_index_arg
-                            ),
-                            [patch.url],
+                if re.match(github_patch_url_re, patch.url):
+                    full_index_arg = "?full_index=1"
+                    if not patch.url.endswith(full_index_arg):
+                        errors.append(
+                            error_cls(
+                                "patch URL in package {0} must end with {1}".format(
+                                    pkg_cls.name, full_index_arg
+                                ),
+                                [patch.url],
+                            )
+                        )
+                elif re.match(gitlab_patch_url_re, patch.url):
+                    if not patch.url.endswith(".diff"):
+                        errors.append(
+                            error_cls(
+                                "patch URL in package {0} must end with .diff".format(
+                                    pkg_cls.name
+                                ),
+                                [patch.url],
+                            )
                         )
-                    )
 
     return errors
 
@@ -798,3 +816,76 @@ def _analyze_variants_in_directive(pkg, constraint, directive, error_cls):
             errors.append(err)
 
     return errors
+
+
+#: Sanity checks on package directives
+external_detection = AuditClass(
+    group="externals",
+    tag="PKG-EXTERNALS",
+    description="Sanity checks for external software detection",
+    kwargs=("pkgs",),
+)
+
+
+def packages_with_detection_tests():
+    """Return the list of packages with a corresponding detection_test.yaml file."""
+    import spack.config
+    import spack.util.path
+
+    to_be_tested = []
+    for current_repo in spack.repo.PATH.repos:
+        namespace = current_repo.namespace
+        packages_dir = pathlib.PurePath(current_repo.packages_path)
+        pattern = packages_dir / "**" / "detection_test.yaml"
+        pkgs_with_tests = [
+            f"{namespace}.{str(pathlib.PurePath(x).parent.name)}" for x in glob.glob(str(pattern))
+        ]
+        to_be_tested.extend(pkgs_with_tests)
+
+    return to_be_tested
+
+
+@external_detection
+def _test_detection_by_executable(pkgs, error_cls):
+    """Test drive external detection for packages"""
+    import spack.detection
+
+    errors = []
+
+    # Filter the packages and retain only the ones with detection tests
+    pkgs_with_tests = packages_with_detection_tests()
+    selected_pkgs = []
+    for current_package in pkgs_with_tests:
+        _, unqualified_name = spack.repo.partition_package_name(current_package)
+        # Check for both unqualified name and qualified name
+        if unqualified_name in pkgs or current_package in pkgs:
+            selected_pkgs.append(current_package)
+    selected_pkgs.sort()
+
+    if not selected_pkgs:
+        summary = "No detection test to run"
+        details = [f'  "{p}" has no detection test' for p in pkgs]
+        warnings.warn("\n".join([summary] + details))
+        return errors
+
+    for pkg_name in selected_pkgs:
+        for idx, test_runner in enumerate(
+            spack.detection.detection_tests(pkg_name, spack.repo.PATH)
+        ):
+            specs = test_runner.execute()
+            expected_specs = test_runner.expected_specs
+
+            not_detected = set(expected_specs) - set(specs)
+            if not_detected:
+                summary = pkg_name + ": cannot detect some specs"
+                details = [f'"{s}" was not detected [test_id={idx}]' for s in sorted(not_detected)]
+                errors.append(error_cls(summary=summary, details=details))
+
+            not_expected = set(specs) - set(expected_specs)
+            if not_expected:
+                summary = pkg_name + ": detected unexpected specs"
+                msg = '"{0}" was detected, but was not expected [test_id={1}]'
+                details = [msg.format(s, idx) for s in sorted(not_expected)]
+                errors.append(error_cls(summary=summary, details=details))
+
+    return errors

lib/spack/spack/binary_distribution.py

@@ -23,7 +23,7 @@
 import warnings
 from contextlib import closing, contextmanager
 from gzip import GzipFile
-from typing import List, NamedTuple, Optional, Union
+from typing import Dict, List, NamedTuple, Optional, Tuple, Union
 from urllib.error import HTTPError, URLError
 
 import llnl.util.filesystem as fsys
@@ -34,6 +34,7 @@
 import spack.cmd
 import spack.config as config
 import spack.database as spack_db
+import spack.error
 import spack.hooks
 import spack.hooks.sbang
 import spack.mirror
@@ -215,11 +216,11 @@ def _associate_built_specs_with_mirror(self, cache_key, mirror_url):
                 with self._index_file_cache.read_transaction(cache_key):
                     db._read_from_file(cache_path)
             except spack_db.InvalidDatabaseVersionError as e:
-                msg = (
+                tty.warn(
                     f"you need a newer Spack version to read the buildcache index for the "
                     f"following mirror: '{mirror_url}'. {e.database_version_message}"
                 )
-                raise BuildcacheIndexError(msg) from e
+                return
 
             spec_list = db.query_local(installed=False, in_buildcache=True)
 
@@ -624,8 +625,7 @@ def buildinfo_file_name(prefix):
     """
     Filename of the binary package meta-data file
     """
-    name = os.path.join(prefix, ".spack/binary_distribution")
-    return name
+    return os.path.join(prefix, ".spack/binary_distribution")
 
 
 def read_buildinfo_file(prefix):
@@ -646,8 +646,7 @@ class BuildManifestVisitor(BaseDirectoryVisitor):
     directories."""
 
     def __init__(self):
-        # Save unique identifiers of files to avoid
-        # relocating hardlink files for each path.
+        # Save unique identifiers of hardlinks to avoid relocating them multiple times
         self.visited = set()
 
         # Lists of files we will check
@@ -656,6 +655,8 @@ def __init__(self):
 
     def seen_before(self, root, rel_path):
         stat_result = os.lstat(os.path.join(root, rel_path))
+        if stat_result.st_nlink == 1:
+            return False
         identifier = (stat_result.st_dev, stat_result.st_ino)
         if identifier in self.visited:
             return True
@@ -796,11 +797,7 @@ def tarball_directory_name(spec):
     Return name of the tarball directory according to the convention
     <os>-<architecture>/<compiler>/<package>-<version>/
     """
-    return os.path.join(
-        str(spec.architecture),
-        f"{spec.compiler.name}-{spec.compiler.version}",
-        f"{spec.name}-{spec.version}",
-    )
+    return spec.format_path("{architecture}/{compiler.name}-{compiler.version}/{name}-{version}")
 
 
 def tarball_name(spec, ext):
@@ -808,10 +805,10 @@ def tarball_name(spec, ext):
     Return the name of the tarfile according to the convention
     <os>-<architecture>-<package>-<dag_hash><ext>
     """
-    return (
-        f"{spec.architecture}-{spec.compiler.name}-{spec.compiler.version}-"
-        f"{spec.name}-{spec.version}-{spec.dag_hash()}{ext}"
+    spec_formatted = spec.format_path(
+        "{architecture}-{compiler.name}-{compiler.version}-{name}-{version}-{hash}"
     )
+    return f"{spec_formatted}{ext}"
 
 
 def tarball_path_name(spec, ext):
@@ -912,7 +909,7 @@ def _read_specs_and_push_index(file_list, read_method, cache_prefix, db, temp_di
         index_json_path,
         url_util.join(cache_prefix, "index.json"),
         keep_original=False,
-        extra_args={"ContentType": "application/json"},
+        extra_args={"ContentType": "application/json", "CacheControl": "no-cache"},
     )
 
     # Push the hash
@@ -920,7 +917,7 @@ def _read_specs_and_push_index(file_list, read_method, cache_prefix, db, temp_di
         index_hash_path,
         url_util.join(cache_prefix, "index.json.hash"),
         keep_original=False,
-        extra_args={"ContentType": "text/plain"},
+        extra_args={"ContentType": "text/plain", "CacheControl": "no-cache"},
     )
 
 
@@ -1156,57 +1153,99 @@ def gzip_compressed_tarfile(path):
         yield tar
 
 
-def deterministic_tarinfo(tarinfo: tarfile.TarInfo):
-    # We only add files, symlinks, hardlinks, and directories
-    # No character devices, block devices and FIFOs should ever enter a tarball.
-    if tarinfo.isdev():
-        return None
-
-    # For distribution, it makes no sense to user/group data; since (a) they don't exist
-    # on other machines, and (b) they lead to surprises as `tar x` run as root will change
-    # ownership if it can. We want to extract as the current user. By setting owner to root,
-    # root will extract as root, and non-privileged user will extract as themselves.
-    tarinfo.uid = 0
-    tarinfo.gid = 0
-    tarinfo.uname = ""
-    tarinfo.gname = ""
-
-    # Reset mtime to epoch time, our prefixes are not truly immutable, so files may get
-    # touched; as long as the content does not change, this ensures we get stable tarballs.
-    tarinfo.mtime = 0
-
-    # Normalize mode
-    if tarinfo.isfile() or tarinfo.islnk():
-        # If user can execute, use 0o755; else 0o644
-        # This is to avoid potentially unsafe world writable & exeutable files that may get
-        # extracted when Python or tar is run with privileges
-        tarinfo.mode = 0o644 if tarinfo.mode & 0o100 == 0 else 0o755
-    else:  # symbolic link and directories
-        tarinfo.mode = 0o755
-
-    return tarinfo
+def _tarinfo_name(p: str):
+    return p.lstrip("/")
 
 
-def tar_add_metadata(tar: tarfile.TarFile, path: str, data: dict):
-    # Serialize buildinfo for the tarball
-    bstring = syaml.dump(data, default_flow_style=True).encode("utf-8")
-    tarinfo = tarfile.TarInfo(name=path)
-    tarinfo.size = len(bstring)
-    tar.addfile(deterministic_tarinfo(tarinfo), io.BytesIO(bstring))
+def tarfile_of_spec_prefix(tar: tarfile.TarFile, prefix: str) -> None:
+    """Create a tarfile of an install prefix of a spec. Skips existing buildinfo file.
+    Only adds regular files, symlinks and dirs. Skips devices, fifos. Preserves hardlinks.
+    Normalizes permissions like git. Tar entries are added in depth-first pre-order, with
+    dir entries partitioned by file | dir, and sorted alphabetically, for reproducibility.
+    Partitioning ensures only one dir is in memory at a time, and sorting improves compression.
+
+    Args:
+        tar: tarfile object to add files to
+        prefix: absolute install prefix of spec"""
+    if not os.path.isabs(prefix) or not os.path.isdir(prefix):
+        raise ValueError(f"prefix '{prefix}' must be an absolute path to a directory")
+    hardlink_to_tarinfo_name: Dict[Tuple[int, int], str] = dict()
+    stat_key = lambda stat: (stat.st_dev, stat.st_ino)
+
+    try:  # skip buildinfo file if it exists
+        files_to_skip = [stat_key(os.lstat(buildinfo_file_name(prefix)))]
+    except OSError:
+        files_to_skip = []
+
+    dir_stack = [prefix]
+    while dir_stack:
+        dir = dir_stack.pop()
+
+        # Add the dir before its contents
+        dir_info = tarfile.TarInfo(_tarinfo_name(dir))
+        dir_info.type = tarfile.DIRTYPE
+        dir_info.mode = 0o755
+        tar.addfile(dir_info)
+
+        # Sort by name: reproducible & improves compression
+        with os.scandir(dir) as it:
+            entries = sorted(it, key=lambda entry: entry.name)
+
+        new_dirs = []
+        for entry in entries:
+            if entry.is_dir(follow_symlinks=False):
+                new_dirs.append(entry.path)
+                continue
+
+            file_info = tarfile.TarInfo(_tarinfo_name(entry.path))
+
+            s = entry.stat(follow_symlinks=False)
+
+            # Skip existing binary distribution files.
+            id = stat_key(s)
+            if id in files_to_skip:
+                continue
+
+            # Normalize the mode
+            file_info.mode = 0o644 if s.st_mode & 0o100 == 0 else 0o755
+
+            if entry.is_symlink():
+                file_info.type = tarfile.SYMTYPE
+                file_info.linkname = os.readlink(entry.path)
+                tar.addfile(file_info)
+
+            elif entry.is_file(follow_symlinks=False):
+                # Deduplicate hardlinks
+                if s.st_nlink > 1:
+                    if id in hardlink_to_tarinfo_name:
+                        file_info.type = tarfile.LNKTYPE
+                        file_info.linkname = hardlink_to_tarinfo_name[id]
+                        tar.addfile(file_info)
+                        continue
+                    hardlink_to_tarinfo_name[id] = file_info.name
+
+                # If file not yet seen, copy it.
+                file_info.type = tarfile.REGTYPE
+                file_info.size = s.st_size
+
+                with open(entry.path, "rb") as f:
+                    tar.addfile(file_info, f)
+
+        dir_stack.extend(reversed(new_dirs))  # we pop, so reverse to stay alphabetical
 
 
-def deterministic_tarinfo_without_buildinfo(tarinfo: tarfile.TarInfo):
-    """Skip buildinfo file when creating a tarball, and normalize other tarinfo fields."""
-    if tarinfo.name.endswith("/.spack/binary_distribution"):
-        return None
-
-    return deterministic_tarinfo(tarinfo)
-
-
-def _do_create_tarball(tarfile_path: str, binaries_dir: str, pkg_dir: str, buildinfo: dict):
+def _do_create_tarball(tarfile_path: str, binaries_dir: str, buildinfo: dict):
     with gzip_compressed_tarfile(tarfile_path) as tar:
-        tar.add(name=binaries_dir, arcname=pkg_dir, filter=deterministic_tarinfo_without_buildinfo)
-        tar_add_metadata(tar, buildinfo_file_name(pkg_dir), buildinfo)
+        # Tarball the install prefix
+        tarfile_of_spec_prefix(tar, binaries_dir)
+
+        # Serialize buildinfo for the tarball
+        bstring = syaml.dump(buildinfo, default_flow_style=True).encode("utf-8")
+        tarinfo = tarfile.TarInfo(name=_tarinfo_name(buildinfo_file_name(binaries_dir)))
+        tarinfo.type = tarfile.REGTYPE
+        tarinfo.size = len(bstring)
+        tarinfo.mode = 0o644
+        tar.addfile(tarinfo, io.BytesIO(bstring))
 
 
 class PushOptions(NamedTuple):
@@ -1278,14 +1317,12 @@ def _build_tarball_in_stage_dir(spec: Spec, out_url: str, stage_dir: str, option
     ):
         raise NoOverwriteException(url_util.format(remote_specfile_path))
 
-    pkg_dir = os.path.basename(spec.prefix.rstrip(os.path.sep))
-
     binaries_dir = spec.prefix
 
     # create info for later relocation and create tar
     buildinfo = get_buildinfo_dict(spec)
 
-    _do_create_tarball(tarfile_path, binaries_dir, pkg_dir, buildinfo)
+    _do_create_tarball(tarfile_path, binaries_dir, buildinfo)
 
     # get the sha256 checksum of the tarball
     checksum = checksum_tarball(tarfile_path)
@@ -1417,7 +1454,7 @@ def try_fetch(url_to_fetch):
 
     try:
         stage.fetch()
-    except web_util.FetchError:
+    except spack.error.FetchError:
         stage.destroy()
         return None
 
@@ -1580,9 +1617,10 @@ def dedupe_hardlinks_if_necessary(root, buildinfo):
         for rel_path in buildinfo[key]:
             stat_result = os.lstat(os.path.join(root, rel_path))
             identifier = (stat_result.st_dev, stat_result.st_ino)
-            if identifier in visited:
-                continue
-            visited.add(identifier)
+            if stat_result.st_nlink > 1:
+                if identifier in visited:
+                    continue
+                visited.add(identifier)
             new_list.append(rel_path)
         buildinfo[key] = new_list
 
@@ -2144,7 +2182,7 @@ def get_keys(install=False, trust=False, force=False, mirrors=None):
                 if not os.path.exists(stage.save_filename):
                     try:
                         stage.fetch()
-                    except web_util.FetchError:
+                    except spack.error.FetchError:
                         continue
 
             tty.debug("Found key {0}".format(fingerprint))
@@ -2296,7 +2334,7 @@ def _download_buildcache_entry(mirror_root, descriptions):
             try:
                 stage.fetch()
                 break
-            except web_util.FetchError as e:
+            except spack.error.FetchError as e:
                 tty.debug(e)
         else:
             if fail_if_missing:

lib/spack/spack/bootstrap/core.py

@@ -228,7 +228,7 @@ def _install_and_test(
                 if not abstract_spec.intersects(candidate_spec):
                     continue
 
-                if python_spec is not None and python_spec not in abstract_spec:
+                if python_spec is not None and not abstract_spec.intersects(f"^{python_spec}"):
                     continue
 
                 for _, pkg_hash, pkg_sha256 in item["binaries"]:
@@ -446,16 +446,11 @@ def ensure_executables_in_path_or_raise(
                     current_bootstrapper.last_search["spec"],
                     current_bootstrapper.last_search["command"],
                 )
-                env_mods = spack.util.environment.EnvironmentModifications()
-                for dep in concrete_spec.traverse(
-                    root=True, order="post", deptype=("link", "run")
-                ):
-                    env_mods.extend(
-                        spack.user_environment.environment_modifications_for_spec(
-                            dep, set_package_py_globals=False
-                        )
+                cmd.add_default_envmod(
+                    spack.user_environment.environment_modifications_for_specs(
+                        concrete_spec, set_package_py_globals=False
                     )
-                cmd.add_default_envmod(env_mods)
+                )
                 return cmd
 
     assert exception_handler, (

lib/spack/spack/build_environment.py

@@ -40,11 +40,15 @@
 import sys
 import traceback
 import types
+from collections import defaultdict
+from enum import Flag, auto
+from itertools import chain
 from typing import List, Tuple
 
 import llnl.util.tty as tty
+from llnl.string import plural
 from llnl.util.filesystem import join_path
-from llnl.util.lang import dedupe
+from llnl.util.lang import dedupe, stable_partition
 from llnl.util.symlink import symlink
 from llnl.util.tty.color import cescape, colorize
 from llnl.util.tty.log import MultiProcessFd
@@ -54,17 +58,21 @@
 import spack.build_systems.python
 import spack.builder
 import spack.config
+import spack.deptypes as dt
 import spack.main
 import spack.package_base
 import spack.paths
 import spack.platforms
 import spack.repo
 import spack.schema.environment
+import spack.spec
 import spack.store
 import spack.subprocess_context
 import spack.user_environment
 import spack.util.path
 import spack.util.pattern
+from spack import traverse
+from spack.context import Context
 from spack.error import NoHeadersError, NoLibrariesError
 from spack.install_test import spack_install_test_log
 from spack.installer import InstallError
@@ -75,14 +83,12 @@
     env_flag,
     filter_system_paths,
     get_path,
-    inspect_path,
     is_system_path,
     validate,
 )
 from spack.util.executable import Executable
 from spack.util.log_parse import make_log_context, parse_log_events
 from spack.util.module_cmd import load_module, module, path_from_modules
-from spack.util.string import plural
 
 #
 # This can be set by the user to globally disable parallel builds.
@@ -109,7 +115,6 @@
 SPACK_CCACHE_BINARY = "SPACK_CCACHE_BINARY"
 SPACK_SYSTEM_DIRS = "SPACK_SYSTEM_DIRS"
 
-
 # Platform-specific library suffix.
 if sys.platform == "darwin":
     dso_suffix = "dylib"
@@ -406,19 +411,13 @@ def set_compiler_environment_variables(pkg, env):
 
 
 def set_wrapper_variables(pkg, env):
-    """Set environment variables used by the Spack compiler wrapper
-    (which have the prefix `SPACK_`) and also add the compiler wrappers
-    to PATH.
+    """Set environment variables used by the Spack compiler wrapper (which have the prefix
+    `SPACK_`) and also add the compiler wrappers to PATH.
 
-    This determines the injected -L/-I/-rpath options; each
-    of these specifies a search order and this function computes these
-    options in a manner that is intended to match the DAG traversal order
-    in `modifications_from_dependencies`: that method uses a post-order
-    traversal so that `PrependPath` actions from dependencies take lower
-    precedence; we use a post-order traversal here to match the visitation
-    order of `modifications_from_dependencies` (so we are visiting the
-    lowest priority packages first).
-    """
+    This determines the injected -L/-I/-rpath options; each of these specifies a search order and
+    this function computes these options in a manner that is intended to match the DAG traversal
+    order in `SetupContext`. TODO: this is not the case yet, we're using post order, SetupContext
+    is using topo order."""
     # Set environment variables if specified for
     # the given compiler
     compiler = pkg.compiler
@@ -537,45 +536,42 @@ def update_compiler_args_for_dep(dep):
     env.set(SPACK_RPATH_DIRS, ":".join(rpath_dirs))
 
 
-def set_module_variables_for_package(pkg):
+def set_package_py_globals(pkg, context: Context = Context.BUILD):
     """Populate the Python module of a package with some useful global names.
     This makes things easier for package writers.
     """
-    # Put a marker on this module so that it won't execute the body of this
-    # function again, since it is not needed
-    marker = "_set_run_already_called"
-    if getattr(pkg.module, marker, False):
-        return
-
     module = ModuleChangePropagator(pkg)
 
-    jobs = determine_number_of_jobs(parallel=pkg.parallel)
-
     m = module
-    m.make_jobs = jobs
 
-    # TODO: make these build deps that can be installed if not found.
-    m.make = MakeExecutable("make", jobs)
-    m.ninja = MakeExecutable("ninja", jobs, supports_jobserver=False)
-    # TODO: johnwparent: add package or builder support to define these build tools
-    # for now there is no entrypoint for builders to define these on their
-    # own
-    if sys.platform == "win32":
-        m.nmake = Executable("nmake")
-        m.msbuild = Executable("msbuild")
-        # analog to configure for win32
-        m.cscript = Executable("cscript")
+    if context == Context.BUILD:
+        jobs = determine_number_of_jobs(parallel=pkg.parallel)
+        m.make_jobs = jobs
 
-    # Find the configure script in the archive path
-    # Don't use which for this; we want to find it in the current dir.
-    m.configure = Executable("./configure")
+        # TODO: make these build deps that can be installed if not found.
+        m.make = MakeExecutable("make", jobs)
+        m.gmake = MakeExecutable("gmake", jobs)
+        m.ninja = MakeExecutable("ninja", jobs, supports_jobserver=False)
+        # TODO: johnwparent: add package or builder support to define these build tools
+        # for now there is no entrypoint for builders to define these on their
+        # own
+        if sys.platform == "win32":
+            m.nmake = Executable("nmake")
+            m.msbuild = Executable("msbuild")
+            # analog to configure for win32
+            m.cscript = Executable("cscript")
 
-    # Standard CMake arguments
-    m.std_cmake_args = spack.build_systems.cmake.CMakeBuilder.std_args(pkg)
-    m.std_meson_args = spack.build_systems.meson.MesonBuilder.std_args(pkg)
-    m.std_pip_args = spack.build_systems.python.PythonPipBuilder.std_args(pkg)
+        # Find the configure script in the archive path
+        # Don't use which for this; we want to find it in the current dir.
+        m.configure = Executable("./configure")
 
-    # Put spack compiler paths in module scope.
+        # Standard CMake arguments
+        m.std_cmake_args = spack.build_systems.cmake.CMakeBuilder.std_args(pkg)
+        m.std_meson_args = spack.build_systems.meson.MesonBuilder.std_args(pkg)
+        m.std_pip_args = spack.build_systems.python.PythonPipBuilder.std_args(pkg)
+
+    # Put spack compiler paths in module scope. (Some packages use it
+    # in setup_run_environment etc, so don't put it context == build)
     link_dir = spack.paths.build_env_path
     m.spack_cc = os.path.join(link_dir, pkg.compiler.link_paths["cc"])
     m.spack_cxx = os.path.join(link_dir, pkg.compiler.link_paths["cxx"])
@@ -599,9 +595,6 @@ def static_to_shared_library(static_lib, shared_lib=None, **kwargs):
 
     m.static_to_shared_library = static_to_shared_library
 
-    # Put a marker on this module so that it won't execute the body of this
-    # function again, since it is not needed
-    setattr(m, marker, True)
     module.propagate_changes_to_mro()
 
 
@@ -727,12 +720,15 @@ def load_external_modules(pkg):
             load_module(external_module)
 
 
-def setup_package(pkg, dirty, context="build"):
+def setup_package(pkg, dirty, context: Context = Context.BUILD):
     """Execute all environment setup routines."""
-    if context not in ["build", "test"]:
-        raise ValueError("'context' must be one of ['build', 'test'] - got: {0}".format(context))
+    if context not in (Context.BUILD, Context.TEST):
+        raise ValueError(f"'context' must be Context.BUILD or Context.TEST - got {context}")
 
-    set_module_variables_for_package(pkg)
+    # First populate the package.py's module with the relevant globals that could be used in any
+    # of the setup_* functions.
+    setup_context = SetupContext(pkg.spec, context=context)
+    setup_context.set_all_package_py_globals()
 
     # Keep track of env changes from packages separately, since we want to
     # issue warnings when packages make "suspicious" modifications.
@@ -740,13 +736,15 @@ def setup_package(pkg, dirty, context="build"):
     env_mods = EnvironmentModifications()
 
     # setup compilers for build contexts
-    need_compiler = context == "build" or (context == "test" and pkg.test_requires_compiler)
+    need_compiler = context == Context.BUILD or (
+        context == Context.TEST and pkg.test_requires_compiler
+    )
     if need_compiler:
         set_compiler_environment_variables(pkg, env_mods)
         set_wrapper_variables(pkg, env_mods)
 
     tty.debug("setup_package: grabbing modifications from dependencies")
-    env_mods.extend(modifications_from_dependencies(pkg.spec, context, custom_mods_only=False))
+    env_mods.extend(setup_context.get_env_modifications())
     tty.debug("setup_package: collected all modifications from dependencies")
 
     # architecture specific setup
@@ -754,7 +752,7 @@ def setup_package(pkg, dirty, context="build"):
     target = platform.target(pkg.spec.architecture.target)
     platform.setup_platform_environment(pkg, env_mods)
 
-    if context == "build":
+    if context == Context.BUILD:
         tty.debug("setup_package: setup build environment for root")
         builder = spack.builder.create(pkg)
         builder.setup_build_environment(env_mods)
@@ -765,16 +763,7 @@ def setup_package(pkg, dirty, context="build"):
                 "config to assume that the package is part of the system"
                 " includes and omit it when invoked with '--cflags'."
             )
-    elif context == "test":
-        tty.debug("setup_package: setup test environment for root")
-        env_mods.extend(
-            inspect_path(
-                pkg.spec.prefix,
-                spack.user_environment.prefix_inspections(pkg.spec.platform),
-                exclude=is_system_path,
-            )
-        )
-        pkg.setup_run_environment(env_mods)
+    elif context == Context.TEST:
         env_mods.prepend_path("PATH", ".")
 
     # First apply the clean environment changes
@@ -813,158 +802,245 @@ def setup_package(pkg, dirty, context="build"):
     return env_base
 
 
-def _make_runnable(pkg, env):
-    # Helper method which prepends a Package's bin/ prefix to the PATH
-    # environment variable
-    prefix = pkg.prefix
+class EnvironmentVisitor:
+    def __init__(self, *roots: spack.spec.Spec, context: Context):
+        # For the roots (well, marked specs) we follow different edges
+        # than for their deps, depending on the context.
+        self.root_hashes = set(s.dag_hash() for s in roots)
 
-    for dirname in ["bin", "bin64"]:
-        bin_dir = os.path.join(prefix, dirname)
-        if os.path.isdir(bin_dir):
-            env.prepend_path("PATH", bin_dir)
+        if context == Context.BUILD:
+            # Drop direct run deps in build context
+            # We don't really distinguish between install and build time test deps,
+            # so we include them here as build-time test deps.
+            self.root_depflag = dt.BUILD | dt.TEST | dt.LINK
+        elif context == Context.TEST:
+            # This is more of an extended run environment
+            self.root_depflag = dt.TEST | dt.RUN | dt.LINK
+        elif context == Context.RUN:
+            self.root_depflag = dt.RUN | dt.LINK
+
+    def neighbors(self, item):
+        spec = item.edge.spec
+        if spec.dag_hash() in self.root_hashes:
+            depflag = self.root_depflag
+        else:
+            depflag = dt.LINK | dt.RUN
+        return traverse.sort_edges(spec.edges_to_dependencies(depflag=depflag))
 
 
-def modifications_from_dependencies(
-    spec, context, custom_mods_only=True, set_package_py_globals=True
-):
-    """Returns the environment modifications that are required by
-    the dependencies of a spec and also applies modifications
-    to this spec's package at module scope, if need be.
+class UseMode(Flag):
+    #: Entrypoint spec (a spec to be built; an env root, etc)
+    ROOT = auto()
 
-    Environment modifications include:
+    #: A spec used at runtime, but no executables in PATH
+    RUNTIME = auto()
 
-    - Updating PATH so that executables can be found
-    - Updating CMAKE_PREFIX_PATH and PKG_CONFIG_PATH so that their respective
-      tools can find Spack-built dependencies
-    - Running custom package environment modifications
+    #: A spec used at runtime, with executables in PATH
+    RUNTIME_EXECUTABLE = auto()
 
-    Custom package modifications can conflict with the default PATH changes
-    we make (specifically for the PATH, CMAKE_PREFIX_PATH, and PKG_CONFIG_PATH
-    environment variables), so this applies changes in a fixed order:
+    #: A spec that's a direct build or test dep
+    BUILDTIME_DIRECT = auto()
 
-    - All modifications (custom and default) from external deps first
-    - All modifications from non-external deps afterwards
+    #: A spec that should be visible in search paths in a build env.
+    BUILDTIME = auto()
 
-    With that order, `PrependPath` actions from non-external default
-    environment modifications will take precedence over custom modifications
-    from external packages.
+    #: Flag is set when the (node, mode) is finalized
+    ADDED = auto()
 
-    A secondary constraint is that custom and default modifications are
-    grouped on a per-package basis: combined with the post-order traversal this
-    means that default modifications of dependents can override custom
-    modifications of dependencies (again, this would only occur for PATH,
-    CMAKE_PREFIX_PATH, or PKG_CONFIG_PATH).
 
-    Args:
-        spec (spack.spec.Spec): spec for which we want the modifications
-        context (str): either 'build' for build-time modifications or 'run'
-            for run-time modifications
-        custom_mods_only (bool): if True returns only custom modifications, if False
-            returns custom and default modifications
-        set_package_py_globals (bool): whether or not to set the global variables in the
-            package.py files (this may be problematic when using buildcaches that have
-            been built on a different but compatible OS)
-    """
-    if context not in ["build", "run", "test"]:
-        raise ValueError(
-            "Expecting context to be one of ['build', 'run', 'test'], " "got: {0}".format(context)
+def effective_deptypes(
+    *specs: spack.spec.Spec, context: Context = Context.BUILD
+) -> List[Tuple[spack.spec.Spec, UseMode]]:
+    """Given a list of input specs and a context, return a list of tuples of
+    all specs that contribute to (environment) modifications, together with
+    a flag specifying in what way they do so. The list is ordered topologically
+    from root to leaf, meaning that environment modifications should be applied
+    in reverse so that dependents override dependencies, not the other way around."""
+    visitor = traverse.TopoVisitor(
+        EnvironmentVisitor(*specs, context=context),
+        key=lambda x: x.dag_hash(),
+        root=True,
+        all_edges=True,
+    )
+    traverse.traverse_depth_first_with_visitor(traverse.with_artificial_edges(specs), visitor)
+
+    # Dictionary with "no mode" as default value, so it's easy to write modes[x] |= flag.
+    use_modes = defaultdict(lambda: UseMode(0))
+    nodes_with_type = []
+
+    for edge in visitor.edges:
+        parent, child, depflag = edge.parent, edge.spec, edge.depflag
+
+        # Mark the starting point
+        if parent is None:
+            use_modes[child] = UseMode.ROOT
+            continue
+
+        parent_mode = use_modes[parent]
+
+        # Nothing to propagate.
+        if not parent_mode:
+            continue
+
+        # Dependending on the context, include particular deps from the root.
+        if UseMode.ROOT & parent_mode:
+            if context == Context.BUILD:
+                if (dt.BUILD | dt.TEST) & depflag:
+                    use_modes[child] |= UseMode.BUILDTIME_DIRECT
+                if dt.LINK & depflag:
+                    use_modes[child] |= UseMode.BUILDTIME
+
+            elif context == Context.TEST:
+                if (dt.RUN | dt.TEST) & depflag:
+                    use_modes[child] |= UseMode.RUNTIME_EXECUTABLE
+                elif dt.LINK & depflag:
+                    use_modes[child] |= UseMode.RUNTIME
+
+            elif context == Context.RUN:
+                if dt.RUN & depflag:
+                    use_modes[child] |= UseMode.RUNTIME_EXECUTABLE
+                elif dt.LINK & depflag:
+                    use_modes[child] |= UseMode.RUNTIME
+
+        # Propagate RUNTIME and RUNTIME_EXECUTABLE through link and run deps.
+        if (UseMode.RUNTIME | UseMode.RUNTIME_EXECUTABLE | UseMode.BUILDTIME_DIRECT) & parent_mode:
+            if dt.LINK & depflag:
+                use_modes[child] |= UseMode.RUNTIME
+            if dt.RUN & depflag:
+                use_modes[child] |= UseMode.RUNTIME_EXECUTABLE
+
+        # Propagate BUILDTIME through link deps.
+        if UseMode.BUILDTIME & parent_mode:
+            if dt.LINK & depflag:
+                use_modes[child] |= UseMode.BUILDTIME
+
+        # Finalize the spec; the invariant is that all in-edges are processed
+        # before out-edges, meaning that parent is done.
+        if not (UseMode.ADDED & parent_mode):
+            use_modes[parent] |= UseMode.ADDED
+            nodes_with_type.append((parent, parent_mode))
+
+    # Attach the leaf nodes, since we only added nodes with out-edges.
+    for spec, parent_mode in use_modes.items():
+        if parent_mode and not (UseMode.ADDED & parent_mode):
+            nodes_with_type.append((spec, parent_mode))
+
+    return nodes_with_type
+
+
+class SetupContext:
+    """This class encapsulates the logic to determine environment modifications, and is used as
+    well to set globals in modules of package.py."""
+
+    def __init__(self, *specs: spack.spec.Spec, context: Context) -> None:
+        """Construct a ModificationsFromDag object.
+        Args:
+            specs: single root spec for build/test context, possibly more for run context
+            context: build, run, or test"""
+        if (context == Context.BUILD or context == Context.TEST) and not len(specs) == 1:
+            raise ValueError("Cannot setup build environment for multiple specs")
+        specs_with_type = effective_deptypes(*specs, context=context)
+
+        self.specs = specs
+        self.context = context
+        self.external: List[Tuple[spack.spec.Spec, UseMode]]
+        self.nonexternal: List[Tuple[spack.spec.Spec, UseMode]]
+        # Reverse so we go from leaf to root
+        self.nodes_in_subdag = set(id(s) for s, _ in specs_with_type)
+
+        # Split into non-external and external, maintaining topo order per group.
+        self.external, self.nonexternal = stable_partition(
+            reversed(specs_with_type), lambda t: t[0].external
         )
+        self.should_be_runnable = UseMode.BUILDTIME_DIRECT | UseMode.RUNTIME_EXECUTABLE
+        self.should_setup_run_env = UseMode.RUNTIME | UseMode.RUNTIME_EXECUTABLE
+        self.should_setup_dependent_build_env = UseMode.BUILDTIME | UseMode.BUILDTIME_DIRECT
 
-    env = EnvironmentModifications()
+        if context == Context.RUN or context == Context.TEST:
+            self.should_be_runnable |= UseMode.ROOT
+            self.should_setup_run_env |= UseMode.ROOT
 
-    # Note: see computation of 'custom_mod_deps' and 'exe_deps' later in this
-    # function; these sets form the building blocks of those collections.
-    build_deps = set(spec.dependencies(deptype=("build", "test")))
-    link_deps = set(spec.traverse(root=False, deptype="link"))
-    build_link_deps = build_deps | link_deps
-    build_and_supporting_deps = set()
-    for build_dep in build_deps:
-        build_and_supporting_deps.update(build_dep.traverse(deptype="run"))
-    run_and_supporting_deps = set(spec.traverse(root=False, deptype=("run", "link")))
-    test_and_supporting_deps = set()
-    for test_dep in set(spec.dependencies(deptype="test")):
-        test_and_supporting_deps.update(test_dep.traverse(deptype="run"))
+        # Everything that calls setup_run_environment and setup_dependent_* needs globals set.
+        self.should_set_package_py_globals = (
+            self.should_setup_dependent_build_env | self.should_setup_run_env | UseMode.ROOT
+        )
+        # In a build context, the root and direct build deps need build-specific globals set.
+        self.needs_build_context = UseMode.ROOT | UseMode.BUILDTIME_DIRECT
 
-    # All dependencies that might have environment modifications to apply
-    custom_mod_deps = set()
-    if context == "build":
-        custom_mod_deps.update(build_and_supporting_deps)
-        # Tests may be performed after build
-        custom_mod_deps.update(test_and_supporting_deps)
-    else:
-        # test/run context
-        custom_mod_deps.update(run_and_supporting_deps)
-        if context == "test":
-            custom_mod_deps.update(test_and_supporting_deps)
-    custom_mod_deps.update(link_deps)
+    def set_all_package_py_globals(self):
+        """Set the globals in modules of package.py files."""
+        for dspec, flag in chain(self.external, self.nonexternal):
+            pkg = dspec.package
 
-    # Determine 'exe_deps': the set of packages with binaries we want to use
-    if context == "build":
-        exe_deps = build_and_supporting_deps | test_and_supporting_deps
-    elif context == "run":
-        exe_deps = set(spec.traverse(deptype="run"))
-    elif context == "test":
-        exe_deps = test_and_supporting_deps
+            if self.should_set_package_py_globals & flag:
+                if self.context == Context.BUILD and self.needs_build_context & flag:
+                    set_package_py_globals(pkg, context=Context.BUILD)
+                else:
+                    # This includes runtime dependencies, also runtime deps of direct build deps.
+                    set_package_py_globals(pkg, context=Context.RUN)
 
-    def default_modifications_for_dep(dep):
-        if dep in build_link_deps and not is_system_path(dep.prefix) and context == "build":
-            prefix = dep.prefix
+            for spec in dspec.dependents():
+                # Note: some specs have dependents that are unreachable from the root, so avoid
+                # setting globals for those.
+                if id(spec) not in self.nodes_in_subdag:
+                    continue
+                dependent_module = ModuleChangePropagator(spec.package)
+                pkg.setup_dependent_package(dependent_module, spec)
+                dependent_module.propagate_changes_to_mro()
 
-            env.prepend_path("CMAKE_PREFIX_PATH", prefix)
+    def get_env_modifications(self) -> EnvironmentModifications:
+        """Returns the environment variable modifications for the given input specs and context.
+        Environment modifications include:
+        - Updating PATH for packages that are required at runtime
+        - Updating CMAKE_PREFIX_PATH and PKG_CONFIG_PATH so that their respective
+        tools can find Spack-built dependencies (when context=build)
+        - Running custom package environment modifications (setup_run_environment,
+        setup_dependent_build_environment, setup_dependent_run_environment)
 
-            for directory in ("lib", "lib64", "share"):
-                pcdir = os.path.join(prefix, directory, "pkgconfig")
-                if os.path.isdir(pcdir):
-                    env.prepend_path("PKG_CONFIG_PATH", pcdir)
+        The (partial) order imposed on the specs is externals first, then topological
+        from leaf to root. That way externals cannot contribute search paths that would shadow
+        Spack's prefixes, and dependents override variables set by dependencies."""
+        env = EnvironmentModifications()
+        for dspec, flag in chain(self.external, self.nonexternal):
+            tty.debug(f"Adding env modifications for {dspec.name}")
+            pkg = dspec.package
 
-        if dep in exe_deps and not is_system_path(dep.prefix):
-            _make_runnable(dep, env)
+            if self.should_setup_dependent_build_env & flag:
+                self._make_buildtime_detectable(dspec, env)
 
-    def add_modifications_for_dep(dep):
-        tty.debug("Adding env modifications for {0}".format(dep.name))
-        # Some callers of this function only want the custom modifications.
-        # For callers that want both custom and default modifications, we want
-        # to perform the default modifications here (this groups custom
-        # and default modifications together on a per-package basis).
-        if not custom_mods_only:
-            default_modifications_for_dep(dep)
+                for spec in self.specs:
+                    builder = spack.builder.create(pkg)
+                    builder.setup_dependent_build_environment(env, spec)
 
-        # Perform custom modifications here (PrependPath actions performed in
-        # the custom method override the default environment modifications
-        # we do to help the build, namely for PATH, CMAKE_PREFIX_PATH, and
-        # PKG_CONFIG_PATH)
-        if dep in custom_mod_deps:
-            dpkg = dep.package
-            if set_package_py_globals:
-                set_module_variables_for_package(dpkg)
+            if self.should_be_runnable & flag:
+                self._make_runnable(dspec, env)
 
-            current_module = ModuleChangePropagator(spec.package)
-            dpkg.setup_dependent_package(current_module, spec)
-            current_module.propagate_changes_to_mro()
+            if self.should_setup_run_env & flag:
+                # TODO: remove setup_dependent_run_environment...
+                for spec in dspec.dependents(deptype=dt.RUN):
+                    if id(spec) in self.nodes_in_subdag:
+                        pkg.setup_dependent_run_environment(env, spec)
+                pkg.setup_run_environment(env)
+        return env
 
-            if context == "build":
-                builder = spack.builder.create(dpkg)
-                builder.setup_dependent_build_environment(env, spec)
-            else:
-                dpkg.setup_dependent_run_environment(env, spec)
-        tty.debug("Added env modifications for {0}".format(dep.name))
+    def _make_buildtime_detectable(self, dep: spack.spec.Spec, env: EnvironmentModifications):
+        if is_system_path(dep.prefix):
+            return
 
-    # Note that we want to perform environment modifications in a fixed order.
-    # The Spec.traverse method provides this: i.e. in addition to
-    # the post-order semantics, it also guarantees a fixed traversal order
-    # among dependencies which are not constrained by post-order semantics.
-    for dspec in spec.traverse(root=False, order="post"):
-        if dspec.external:
-            add_modifications_for_dep(dspec)
+        env.prepend_path("CMAKE_PREFIX_PATH", dep.prefix)
+        for d in ("lib", "lib64", "share"):
+            pcdir = os.path.join(dep.prefix, d, "pkgconfig")
+            if os.path.isdir(pcdir):
+                env.prepend_path("PKG_CONFIG_PATH", pcdir)
 
-    for dspec in spec.traverse(root=False, order="post"):
-        # Default env modifications for non-external packages can override
-        # custom modifications of external packages (this can only occur
-        # for modifications to PATH, CMAKE_PREFIX_PATH, and PKG_CONFIG_PATH)
-        if not dspec.external:
-            add_modifications_for_dep(dspec)
+    def _make_runnable(self, dep: spack.spec.Spec, env: EnvironmentModifications):
+        if is_system_path(dep.prefix):
+            return
 
-    return env
+        for d in ("bin", "bin64"):
+            bin_dir = os.path.join(dep.prefix, d)
+            if os.path.isdir(bin_dir):
+                env.prepend_path("PATH", bin_dir)
 
 
 def get_cmake_prefix_path(pkg):
@@ -996,7 +1072,7 @@ def get_cmake_prefix_path(pkg):
 def _setup_pkg_and_run(
     serialized_pkg, function, kwargs, write_pipe, input_multiprocess_fd, jsfd1, jsfd2
 ):
-    context = kwargs.get("context", "build")
+    context: str = kwargs.get("context", "build")
 
     try:
         # We are in the child process. Python sets sys.stdin to
@@ -1012,7 +1088,7 @@ def _setup_pkg_and_run(
         if not kwargs.get("fake", False):
             kwargs["unmodified_env"] = os.environ.copy()
             kwargs["env_modifications"] = setup_package(
-                pkg, dirty=kwargs.get("dirty", False), context=context
+                pkg, dirty=kwargs.get("dirty", False), context=Context.from_string(context)
             )
         return_value = function(pkg, kwargs)
         write_pipe.send(return_value)

lib/spack/spack/build_systems/autotools.py

@@ -46,6 +46,7 @@ class AutotoolsPackage(spack.package_base.PackageBase):
         depends_on("gnuconfig", type="build", when="target=ppc64le:")
         depends_on("gnuconfig", type="build", when="target=aarch64:")
         depends_on("gnuconfig", type="build", when="target=riscv64:")
+        depends_on("gmake", type="build")
         conflicts("platform=windows")
 
     def flags_to_build_system_args(self, flags):

lib/spack/spack/build_systems/cmake.py

@@ -142,10 +142,10 @@ def flags_to_build_system_args(self, flags):
         # We specify for each of them.
         if flags["ldflags"]:
             ldflags = " ".join(flags["ldflags"])
-            ld_string = "-DCMAKE_{0}_LINKER_FLAGS={1}"
             # cmake has separate linker arguments for types of builds.
-            for type in ["EXE", "MODULE", "SHARED", "STATIC"]:
-                self.cmake_flag_args.append(ld_string.format(type, ldflags))
+            self.cmake_flag_args.append(f"-DCMAKE_EXE_LINKER_FLAGS={ldflags}")
+            self.cmake_flag_args.append(f"-DCMAKE_MODULE_LINKER_FLAGS={ldflags}")
+            self.cmake_flag_args.append(f"-DCMAKE_SHARED_LINKER_FLAGS={ldflags}")
 
         # CMake has libs options separated by language. Apply ours to each.
         if flags["ldlibs"]:

lib/spack/spack/build_systems/makefile.py

@@ -9,7 +9,8 @@
 
 import spack.builder
 import spack.package_base
-from spack.directives import build_system, conflicts
+from spack.directives import build_system, conflicts, depends_on
+from spack.multimethod import when
 
 from ._checks import (
     BaseBuilder,
@@ -29,7 +30,10 @@ class MakefilePackage(spack.package_base.PackageBase):
     legacy_buildsystem = "makefile"
 
     build_system("makefile")
-    conflicts("platform=windows", when="build_system=makefile")
+
+    with when("build_system=makefile"):
+        conflicts("platform=windows")
+        depends_on("gmake", type="build")
 
 
 @spack.builder.builder("makefile")

lib/spack/spack/build_systems/meson.py

@@ -10,7 +10,7 @@
 
 import spack.builder
 import spack.package_base
-from spack.directives import build_system, depends_on, variant
+from spack.directives import build_system, conflicts, depends_on, variant
 from spack.multimethod import when
 
 from ._checks import BaseBuilder, execute_build_time_tests
@@ -47,6 +47,13 @@ class MesonPackage(spack.package_base.PackageBase):
         variant("strip", default=False, description="Strip targets on install")
         depends_on("meson", type="build")
         depends_on("ninja", type="build")
+        # Python detection in meson requires distutils to be importable, but distutils no longer
+        # exists in Python 3.12. In Spack, we can't use setuptools as distutils replacement,
+        # because the distutils-precedence.pth startup file that setuptools ships with is not run
+        # when setuptools is in PYTHONPATH; it has to be in system site-packages. In a future meson
+        # release, the distutils requirement will be dropped, so this conflict can be relaxed.
+        # We have patches to make it work with meson 1.1 and above.
+        conflicts("^python@3.12:", when="^meson@:1.0")
 
     def flags_to_build_system_args(self, flags):
         """Produces a list of all command line arguments to pass the specified

lib/spack/spack/build_systems/oneapi.py

@@ -61,6 +61,11 @@ def component_prefix(self):
         """Path to component <prefix>/<component>/<version>."""
         return self.prefix.join(join_path(self.component_dir, self.spec.version))
 
+    @property
+    def env_script_args(self):
+        """Additional arguments to pass to vars.sh script."""
+        return ()
+
     def install(self, spec, prefix):
         self.install_component(basename(self.url_for_version(spec.version)))
 
@@ -124,7 +129,7 @@ def setup_run_environment(self, env):
         if "~envmods" not in self.spec:
             env.extend(
                 EnvironmentModifications.from_sourcing_file(
-                    join_path(self.component_prefix, "env", "vars.sh")
+                    join_path(self.component_prefix, "env", "vars.sh"), *self.env_script_args
                 )
             )
 

lib/spack/spack/build_systems/python.py

@@ -6,6 +6,7 @@
 import os
 import re
 import shutil
+import stat
 from typing import Optional
 
 import archspec
@@ -25,6 +26,7 @@
 from spack.directives import build_system, depends_on, extends, maintainers
 from spack.error import NoHeadersError, NoLibrariesError, SpecError
 from spack.install_test import test_part
+from spack.util.executable import Executable
 from spack.version import Version
 
 from ._checks import BaseBuilder, execute_install_time_tests
@@ -319,9 +321,12 @@ def list_url(cls):
     def headers(self):
         """Discover header files in platlib."""
 
+        # Remove py- prefix in package name
+        name = self.spec.name[3:]
+
         # Headers may be in either location
-        include = self.prefix.join(self.spec["python"].package.include)
-        platlib = self.prefix.join(self.spec["python"].package.platlib)
+        include = self.prefix.join(self.spec["python"].package.include).join(name)
+        platlib = self.prefix.join(self.spec["python"].package.platlib).join(name)
         headers = fs.find_all_headers(include) + fs.find_all_headers(platlib)
 
         if headers:
@@ -335,18 +340,64 @@ def libs(self):
         """Discover libraries in platlib."""
 
         # Remove py- prefix in package name
-        library = "lib" + self.spec.name[3:].replace("-", "?")
-        root = self.prefix.join(self.spec["python"].package.platlib)
+        name = self.spec.name[3:]
 
-        for shared in [True, False]:
-            libs = fs.find_libraries(library, root, shared=shared, recursive=True)
-            if libs:
-                return libs
+        root = self.prefix.join(self.spec["python"].package.platlib).join(name)
+
+        libs = fs.find_all_libraries(root, recursive=True)
+
+        if libs:
+            return libs
 
         msg = "Unable to recursively locate {} libraries in {}"
         raise NoLibrariesError(msg.format(self.spec.name, root))
 
 
+def fixup_shebangs(path: str, old_interpreter: bytes, new_interpreter: bytes):
+    # Recurse into the install prefix and fixup shebangs
+    exe = stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
+    dirs = [path]
+    hardlinks = set()
+
+    while dirs:
+        with os.scandir(dirs.pop()) as entries:
+            for entry in entries:
+                if entry.is_dir(follow_symlinks=False):
+                    dirs.append(entry.path)
+                    continue
+
+                # Only consider files, not symlinks
+                if not entry.is_file(follow_symlinks=False):
+                    continue
+
+                lstat = entry.stat(follow_symlinks=False)
+
+                # Skip over files that are not executable
+                if not (lstat.st_mode & exe):
+                    continue
+
+                # Don't modify hardlinks more than once
+                if lstat.st_nlink > 1:
+                    key = (lstat.st_ino, lstat.st_dev)
+                    if key in hardlinks:
+                        continue
+                    hardlinks.add(key)
+
+                # Finally replace shebangs if any.
+                with open(entry.path, "rb+") as f:
+                    contents = f.read(2)
+                    if contents != b"#!":
+                        continue
+                    contents += f.read()
+
+                    if old_interpreter not in contents:
+                        continue
+
+                    f.seek(0)
+                    f.write(contents.replace(old_interpreter, new_interpreter))
+                    f.truncate()
+
+
 @spack.builder.builder("python_pip")
 class PythonPipBuilder(BaseBuilder):
     phases = ("install",)
@@ -443,8 +494,36 @@ def global_options(self, spec, prefix):
         """
         return []
 
+    @property
+    def _build_venv_path(self):
+        """Return the path to the virtual environment used for building when
+        python is external."""
+        return os.path.join(self.spec.package.stage.path, "build_env")
+
+    @property
+    def _build_venv_python(self) -> Executable:
+        """Return the Python executable in the build virtual environment when
+        python is external."""
+        return Executable(os.path.join(self._build_venv_path, "bin", "python"))
+
     def install(self, pkg, spec, prefix):
         """Install everything from build directory."""
+        python: Executable = spec["python"].command
+        # Since we invoke pip with --no-build-isolation, we have to make sure that pip cannot
+        # execute hooks from user and system site-packages.
+        if spec["python"].external:
+            # There are no environment variables to disable the system site-packages, so we use a
+            # virtual environment instead. The downside of this approach is that pip produces
+            # incorrect shebangs that refer to the virtual environment, which we have to fix up.
+            python("-m", "venv", "--without-pip", self._build_venv_path)
+            pip = self._build_venv_python
+        else:
+            # For a Spack managed Python, system site-packages is empty/unused by design, so it
+            # suffices to disable user site-packages, for which there is an environment variable.
+            pip = python
+            pip.add_default_env("PYTHONNOUSERSITE", "1")
+        pip.add_default_arg("-m")
+        pip.add_default_arg("pip")
 
         args = PythonPipBuilder.std_args(pkg) + ["--prefix=" + prefix]
 
@@ -468,8 +547,31 @@ def install(self, pkg, spec, prefix):
         else:
             args.append(".")
 
-        pip = inspect.getmodule(pkg).pip
         with fs.working_dir(self.build_directory):
             pip(*args)
 
+    @spack.builder.run_after("install")
+    def fixup_shebangs_pointing_to_build(self):
+        """When installing a package using an external python, we use a temporary virtual
+        environment which improves build isolation. The downside is that pip produces shebangs
+        that point to the temporary virtual environment. This method fixes them up to point to the
+        underlying Python."""
+        # No need to fixup shebangs if no build venv was used. (this post install function also
+        # runs when install was overridden in another package, so check existence of the venv path)
+        if not os.path.exists(self._build_venv_path):
+            return
+
+        # Use sys.executable, since that's what pip uses.
+        interpreter = (
+            lambda python: python("-c", "import sys; print(sys.executable)", output=str)
+            .strip()
+            .encode("utf-8")
+        )
+
+        fixup_shebangs(
+            path=self.spec.prefix,
+            old_interpreter=interpreter(self._build_venv_python),
+            new_interpreter=interpreter(self.spec["python"].command),
+        )
+
     spack.builder.run_after("install")(execute_install_time_tests)

lib/spack/spack/build_systems/racket.py

@@ -64,7 +64,7 @@ class RacketBuilder(spack.builder.Builder):
 
     @property
     def subdirectory(self):
-        if self.racket_name:
+        if self.pkg.racket_name:
             return "pkgs/{0}".format(self.pkg.racket_name)
         return None
 

lib/spack/spack/ci.py

@@ -49,7 +49,11 @@
 
 TEMP_STORAGE_MIRROR_NAME = "ci_temporary_mirror"
 SPACK_RESERVED_TAGS = ["public", "protected", "notary"]
+# TODO: Remove this in Spack 0.23
 SHARED_PR_MIRROR_URL = "s3://spack-binaries-prs/shared_pr_mirror"
+JOB_NAME_FORMAT = (
+    "{name}{@version} {/hash:7} {%compiler.name}{@compiler.version}{arch=architecture}"
+)
 
 spack_gpg = spack.main.SpackCommand("gpg")
 spack_compiler = spack.main.SpackCommand("compiler")
@@ -69,48 +73,23 @@ def __exit__(self, exc_type, exc_value, exc_traceback):
         return False
 
 
-def get_job_name(spec, osarch, build_group):
-    """Given the necessary parts, format the gitlab job name
+def get_job_name(spec: spack.spec.Spec, build_group: str = ""):
+    """Given a spec and possibly a build group, return the job name. If the
+    resulting name is longer than 255 characters, it will be truncated.
 
     Arguments:
         spec (spack.spec.Spec): Spec job will build
-        osarch: Architecture TODO: (this is a spack.spec.ArchSpec,
-            but sphinx doesn't recognize the type and fails).
         build_group (str): Name of build group this job belongs to (a CDash
         notion)
 
     Returns: The job name
     """
-    item_idx = 0
-    format_str = ""
-    format_args = []
-
-    format_str += "{{{0}}}".format(item_idx)
-    format_args.append(spec.name)
-    item_idx += 1
-
-    format_str += "/{{{0}}}".format(item_idx)
-    format_args.append(spec.dag_hash(7))
-    item_idx += 1
-
-    format_str += " {{{0}}}".format(item_idx)
-    format_args.append(spec.version)
-    item_idx += 1
-
-    format_str += " {{{0}}}".format(item_idx)
-    format_args.append(spec.compiler)
-    item_idx += 1
-
-    format_str += " {{{0}}}".format(item_idx)
-    format_args.append(osarch)
-    item_idx += 1
+    job_name = spec.format(JOB_NAME_FORMAT)
 
     if build_group:
-        format_str += " {{{0}}}".format(item_idx)
-        format_args.append(build_group)
-        item_idx += 1
+        job_name = "{0} {1}".format(job_name, build_group)
 
-    return format_str.format(*format_args)
+    return job_name[:255]
 
 
 def _remove_reserved_tags(tags):
@@ -337,7 +316,7 @@ def _spec_matches(spec, match_string):
 
 
 def _format_job_needs(
-    dep_jobs, osname, build_group, prune_dag, rebuild_decisions, enable_artifacts_buildcache
+    dep_jobs, build_group, prune_dag, rebuild_decisions, enable_artifacts_buildcache
 ):
     needs_list = []
     for dep_job in dep_jobs:
@@ -347,7 +326,7 @@ def _format_job_needs(
         if not prune_dag or rebuild:
             needs_list.append(
                 {
-                    "job": get_job_name(dep_job, dep_job.architecture, build_group),
+                    "job": get_job_name(dep_job, build_group),
                     "artifacts": enable_artifacts_buildcache,
                 }
             )
@@ -700,7 +679,7 @@ def generate_gitlab_ci_yaml(
         remote_mirror_override (str): Typically only needed when one spack.yaml
             is used to populate several mirrors with binaries, based on some
             criteria.  Spack protected pipelines populate different mirrors based
-            on branch name, facilitated by this option.
+            on branch name, facilitated by this option.  DEPRECATED
     """
     with spack.concretize.disable_compiler_existence_check():
         with env.write_transaction():
@@ -797,17 +776,39 @@ def generate_gitlab_ci_yaml(
             "instead.",
         )
 
-    if "mirrors" not in yaml_root or len(yaml_root["mirrors"].values()) < 1:
-        tty.die("spack ci generate requires an env containing a mirror")
+    pipeline_mirrors = spack.mirror.MirrorCollection(binary=True)
+    deprecated_mirror_config = False
+    buildcache_destination = None
+    if "buildcache-destination" in pipeline_mirrors:
+        if remote_mirror_override:
+            tty.die(
+                "Using the deprecated --buildcache-destination cli option and "
+                "having a mirror named 'buildcache-destination' at the same time "
+                "is not allowed"
+            )
+        buildcache_destination = pipeline_mirrors["buildcache-destination"]
+    else:
+        deprecated_mirror_config = True
+        # TODO: This will be an error in Spack 0.23
 
-    ci_mirrors = yaml_root["mirrors"]
-    mirror_urls = [url for url in ci_mirrors.values()]
-    remote_mirror_url = mirror_urls[0]
+    # TODO: Remove this block in spack 0.23
+    remote_mirror_url = None
+    if deprecated_mirror_config:
+        if "mirrors" not in yaml_root or len(yaml_root["mirrors"].values()) < 1:
+            tty.die("spack ci generate requires an env containing a mirror")
+
+        ci_mirrors = yaml_root["mirrors"]
+        mirror_urls = [url for url in ci_mirrors.values()]
+        remote_mirror_url = mirror_urls[0]
 
     spack_buildcache_copy = os.environ.get("SPACK_COPY_BUILDCACHE", None)
     if spack_buildcache_copy:
         buildcache_copies = {}
-        buildcache_copy_src_prefix = remote_mirror_override or remote_mirror_url
+        buildcache_copy_src_prefix = (
+            buildcache_destination.fetch_url
+            if buildcache_destination
+            else remote_mirror_override or remote_mirror_url
+        )
         buildcache_copy_dest_prefix = spack_buildcache_copy
 
     # Check for a list of "known broken" specs that we should not bother
@@ -819,6 +820,7 @@ def generate_gitlab_ci_yaml(
 
     enable_artifacts_buildcache = False
     if "enable-artifacts-buildcache" in ci_config:
+        tty.warn("Support for enable-artifacts-buildcache will be removed in Spack 0.23")
         enable_artifacts_buildcache = ci_config["enable-artifacts-buildcache"]
 
     rebuild_index_enabled = True
@@ -827,13 +829,15 @@ def generate_gitlab_ci_yaml(
 
     temp_storage_url_prefix = None
     if "temporary-storage-url-prefix" in ci_config:
+        tty.warn("Support for temporary-storage-url-prefix will be removed in Spack 0.23")
         temp_storage_url_prefix = ci_config["temporary-storage-url-prefix"]
 
     # If a remote mirror override (alternate buildcache destination) was
     # specified, add it here in case it has already built hashes we might
     # generate.
+    # TODO: Remove this block in Spack 0.23
     mirrors_to_check = None
-    if remote_mirror_override:
+    if deprecated_mirror_config and remote_mirror_override:
         if spack_pipeline_type == "spack_protected_branch":
             # Overriding the main mirror in this case might result
             # in skipping jobs on a release pipeline because specs are
@@ -853,8 +857,9 @@ def generate_gitlab_ci_yaml(
             cfg.default_modify_scope(),
         )
 
+    # TODO: Remove this block in Spack 0.23
     shared_pr_mirror = None
-    if spack_pipeline_type == "spack_pull_request":
+    if deprecated_mirror_config and spack_pipeline_type == "spack_pull_request":
         stack_name = os.environ.get("SPACK_CI_STACK_NAME", "")
         shared_pr_mirror = url_util.join(SHARED_PR_MIRROR_URL, stack_name)
         spack.mirror.add(
@@ -906,6 +911,7 @@ def generate_gitlab_ci_yaml(
     job_log_dir = os.path.join(pipeline_artifacts_dir, "logs")
     job_repro_dir = os.path.join(pipeline_artifacts_dir, "reproduction")
     job_test_dir = os.path.join(pipeline_artifacts_dir, "tests")
+    # TODO: Remove this line in Spack 0.23
     local_mirror_dir = os.path.join(pipeline_artifacts_dir, "mirror")
     user_artifacts_dir = os.path.join(pipeline_artifacts_dir, "user_data")
 
@@ -920,11 +926,11 @@ def generate_gitlab_ci_yaml(
     rel_job_log_dir = os.path.relpath(job_log_dir, ci_project_dir)
     rel_job_repro_dir = os.path.relpath(job_repro_dir, ci_project_dir)
     rel_job_test_dir = os.path.relpath(job_test_dir, ci_project_dir)
+    # TODO: Remove this line in Spack 0.23
     rel_local_mirror_dir = os.path.join(local_mirror_dir, ci_project_dir)
     rel_user_artifacts_dir = os.path.relpath(user_artifacts_dir, ci_project_dir)
 
     # Speed up staging by first fetching binary indices from all mirrors
-    # (including the override mirror we may have just added above).
     try:
         bindist.binary_index.update()
     except bindist.FetchCacheError as e:
@@ -1023,8 +1029,7 @@ def main_script_replacements(cmd):
             if "after_script" in job_object:
                 job_object["after_script"] = _unpack_script(job_object["after_script"])
 
-            osname = str(release_spec.architecture)
-            job_name = get_job_name(release_spec, osname, build_group)
+            job_name = get_job_name(release_spec, build_group)
 
             job_vars = job_object.setdefault("variables", {})
             job_vars["SPACK_JOB_SPEC_DAG_HASH"] = release_spec_dag_hash
@@ -1051,7 +1056,6 @@ def main_script_replacements(cmd):
                 job_object["needs"].extend(
                     _format_job_needs(
                         dep_jobs,
-                        osname,
                         build_group,
                         prune_dag,
                         rebuild_decisions,
@@ -1137,6 +1141,7 @@ def main_script_replacements(cmd):
                 },
             )
 
+            # TODO: Remove this block in Spack 0.23
             if enable_artifacts_buildcache:
                 bc_root = os.path.join(local_mirror_dir, "build_cache")
                 job_object["artifacts"]["paths"].extend(
@@ -1166,10 +1171,12 @@ def main_script_replacements(cmd):
         _print_staging_summary(spec_labels, stages, mirrors_to_check, rebuild_decisions)
 
     # Clean up remote mirror override if enabled
-    if remote_mirror_override:
-        spack.mirror.remove("ci_pr_mirror", cfg.default_modify_scope())
-    if spack_pipeline_type == "spack_pull_request":
-        spack.mirror.remove("ci_shared_pr_mirror", cfg.default_modify_scope())
+    # TODO: Remove this block in Spack 0.23
+    if deprecated_mirror_config:
+        if remote_mirror_override:
+            spack.mirror.remove("ci_pr_mirror", cfg.default_modify_scope())
+        if spack_pipeline_type == "spack_pull_request":
+            spack.mirror.remove("ci_shared_pr_mirror", cfg.default_modify_scope())
 
     tty.debug("{0} build jobs generated in {1} stages".format(job_id, stage_id))
 
@@ -1200,10 +1207,28 @@ def main_script_replacements(cmd):
             sync_job["needs"] = [
                 {"job": generate_job_name, "pipeline": "{0}".format(parent_pipeline_id)}
             ]
+
+        if "variables" not in sync_job:
+            sync_job["variables"] = {}
+
+        sync_job["variables"]["SPACK_COPY_ONLY_DESTINATION"] = (
+            buildcache_destination.fetch_url
+            if buildcache_destination
+            else remote_mirror_override or remote_mirror_url
+        )
+
+        if "buildcache-source" in pipeline_mirrors:
+            buildcache_source = pipeline_mirrors["buildcache-source"].fetch_url
+        else:
+            # TODO: Remove this condition in Spack 0.23
+            buildcache_source = os.environ.get("SPACK_SOURCE_MIRROR", None)
+        sync_job["variables"]["SPACK_BUILDCACHE_SOURCE"] = buildcache_source
+
         output_object["copy"] = sync_job
         job_id += 1
 
     if job_id > 0:
+        # TODO: Remove this block in Spack 0.23
         if temp_storage_url_prefix:
             # There were some rebuild jobs scheduled, so we will need to
             # schedule a job to clean up the temporary storage location
@@ -1237,6 +1262,13 @@ def main_script_replacements(cmd):
             signing_job["when"] = "always"
             signing_job["retry"] = {"max": 2, "when": ["always"]}
             signing_job["interruptible"] = True
+            if "variables" not in signing_job:
+                signing_job["variables"] = {}
+            signing_job["variables"]["SPACK_BUILDCACHE_DESTINATION"] = (
+                buildcache_destination.push_url  # need the s3 url for aws s3 sync
+                if buildcache_destination
+                else remote_mirror_override or remote_mirror_url
+            )
 
             output_object["sign-pkgs"] = signing_job
 
@@ -1245,13 +1277,13 @@ def main_script_replacements(cmd):
             stage_names.append("stage-rebuild-index")
             final_job = spack_ci_ir["jobs"]["reindex"]["attributes"]
 
-            index_target_mirror = mirror_urls[0]
-            if remote_mirror_override:
-                index_target_mirror = remote_mirror_override
             final_job["stage"] = "stage-rebuild-index"
+            target_mirror = remote_mirror_override or remote_mirror_url
+            if buildcache_destination:
+                target_mirror = buildcache_destination.push_url
             final_job["script"] = _unpack_script(
                 final_job["script"],
-                op=lambda cmd: cmd.replace("{index_target_mirror}", index_target_mirror),
+                op=lambda cmd: cmd.replace("{index_target_mirror}", target_mirror),
             )
 
             final_job["when"] = "always"
@@ -1273,20 +1305,24 @@ def main_script_replacements(cmd):
             "SPACK_CONCRETE_ENV_DIR": rel_concrete_env_dir,
             "SPACK_VERSION": spack_version,
             "SPACK_CHECKOUT_VERSION": version_to_clone,
+            # TODO: Remove this line in Spack 0.23
             "SPACK_REMOTE_MIRROR_URL": remote_mirror_url,
             "SPACK_JOB_LOG_DIR": rel_job_log_dir,
             "SPACK_JOB_REPRO_DIR": rel_job_repro_dir,
             "SPACK_JOB_TEST_DIR": rel_job_test_dir,
+            # TODO: Remove this line in Spack 0.23
             "SPACK_LOCAL_MIRROR_DIR": rel_local_mirror_dir,
             "SPACK_PIPELINE_TYPE": str(spack_pipeline_type),
             "SPACK_CI_STACK_NAME": os.environ.get("SPACK_CI_STACK_NAME", "None"),
+            # TODO: Remove this line in Spack 0.23
             "SPACK_CI_SHARED_PR_MIRROR_URL": shared_pr_mirror or "None",
             "SPACK_REBUILD_CHECK_UP_TO_DATE": str(prune_dag),
             "SPACK_REBUILD_EVERYTHING": str(rebuild_everything),
             "SPACK_REQUIRE_SIGNING": os.environ.get("SPACK_REQUIRE_SIGNING", "False"),
         }
 
-        if remote_mirror_override:
+        # TODO: Remove this block in Spack 0.23
+        if deprecated_mirror_config and remote_mirror_override:
             (output_object["variables"]["SPACK_REMOTE_MIRROR_OVERRIDE"]) = remote_mirror_override
 
         spack_stack_name = os.environ.get("SPACK_CI_STACK_NAME", None)
@@ -2026,43 +2062,23 @@ def process_command(name, commands, repro_dir, run=True, exit_on_failure=True):
 
 
 def create_buildcache(
-    input_spec: spack.spec.Spec,
-    *,
-    pipeline_mirror_url: Optional[str] = None,
-    buildcache_mirror_url: Optional[str] = None,
-    sign_binaries: bool = False,
+    input_spec: spack.spec.Spec, *, destination_mirror_urls: List[str], sign_binaries: bool = False
 ) -> List[PushResult]:
     """Create the buildcache at the provided mirror(s).
 
     Arguments:
         input_spec: Installed spec to package and push
-        buildcache_mirror_url: URL for the buildcache mirror
-        pipeline_mirror_url: URL for the pipeline mirror
+        destination_mirror_urls: List of urls to push to
         sign_binaries: Whether or not to sign buildcache entry
 
     Returns: A list of PushResults, indicating success or failure.
     """
     results = []
 
-    # Create buildcache in either the main remote mirror, or in the
-    # per-PR mirror, if this is a PR pipeline
-    if buildcache_mirror_url:
+    for mirror_url in destination_mirror_urls:
         results.append(
             PushResult(
-                success=push_mirror_contents(input_spec, buildcache_mirror_url, sign_binaries),
-                url=buildcache_mirror_url,
-            )
-        )
-
-    # Create another copy of that buildcache in the per-pipeline
-    # temporary storage mirror (this is only done if either
-    # artifacts buildcache is enabled or a temporary storage url
-    # prefix is set)
-    if pipeline_mirror_url:
-        results.append(
-            PushResult(
-                success=push_mirror_contents(input_spec, pipeline_mirror_url, sign_binaries),
-                url=pipeline_mirror_url,
+                success=push_mirror_contents(input_spec, mirror_url, sign_binaries), url=mirror_url
             )
         )
 

lib/spack/spack/cmd/__init__.py

@@ -11,6 +11,7 @@
 from textwrap import dedent
 from typing import List, Match, Tuple
 
+import llnl.string
 import llnl.util.tty as tty
 from llnl.util.filesystem import join_path
 from llnl.util.lang import attr_setdefault, index_by
@@ -29,7 +30,6 @@
 import spack.user_environment as uenv
 import spack.util.spack_json as sjson
 import spack.util.spack_yaml as syaml
-import spack.util.string
 
 # cmd has a submodule called "list" so preserve the python list module
 python_list = list
@@ -516,7 +516,7 @@ def print_how_many_pkgs(specs, pkg_type=""):
             category, e.g. if pkg_type is "installed" then the message
             would be "3 installed packages"
     """
-    tty.msg("%s" % spack.util.string.plural(len(specs), pkg_type + " package"))
+    tty.msg("%s" % llnl.string.plural(len(specs), pkg_type + " package"))
 
 
 def spack_is_git_repo():

lib/spack/spack/cmd/audit.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import llnl.util.tty as tty
+import llnl.util.tty.colify
 import llnl.util.tty.color as cl
 
 import spack.audit
@@ -20,6 +21,15 @@ def setup_parser(subparser):
     # Audit configuration files
     sp.add_parser("configs", help="audit configuration files")
 
+    # Audit package recipes
+    external_parser = sp.add_parser("externals", help="check external detection in packages")
+    external_parser.add_argument(
+        "--list",
+        action="store_true",
+        dest="list_externals",
+        help="if passed, list which packages have detection tests",
+    )
+
     # Https and other linting
     https_parser = sp.add_parser("packages-https", help="check https in packages")
     https_parser.add_argument(
@@ -29,7 +39,7 @@ def setup_parser(subparser):
     # Audit package recipes
     pkg_parser = sp.add_parser("packages", help="audit package recipes")
 
-    for group in [pkg_parser, https_parser]:
+    for group in [pkg_parser, https_parser, external_parser]:
         group.add_argument(
             "name",
             metavar="PKG",
@@ -62,6 +72,18 @@ def packages_https(parser, args):
     _process_reports(reports)
 
 
+def externals(parser, args):
+    if args.list_externals:
+        msg = "@*{The following packages have detection tests:}"
+        tty.msg(cl.colorize(msg))
+        llnl.util.tty.colify.colify(spack.audit.packages_with_detection_tests(), indent=2)
+        return
+
+    pkgs = args.name or spack.repo.PATH.all_package_names()
+    reports = spack.audit.run_group(args.subcommand, pkgs=pkgs)
+    _process_reports(reports)
+
+
 def list(parser, args):
     for subcommand, check_tags in spack.audit.GROUPS.items():
         print(cl.colorize("@*b{" + subcommand + "}:"))
@@ -78,6 +100,7 @@ def list(parser, args):
 def audit(parser, args):
     subcommands = {
         "configs": configs,
+        "externals": externals,
         "packages": packages,
         "packages-https": packages_https,
         "list": list,

lib/spack/spack/cmd/build_env.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import spack.cmd.common.env_utility as env_utility
+from spack.context import Context
 
 description = (
     "run a command in a spec's install environment, or dump its environment to screen or file"
@@ -14,4 +15,4 @@
 
 
 def build_env(parser, args):
-    env_utility.emulate_env_utility("build-env", "build", args)
+    env_utility.emulate_env_utility("build-env", Context.BUILD, args)

lib/spack/spack/cmd/buildcache.py

@@ -13,6 +13,7 @@
 
 import llnl.util.tty as tty
 import llnl.util.tty.color as clr
+from llnl.string import plural
 from llnl.util.lang import elide_list
 
 import spack.binary_distribution as bindist
@@ -32,7 +33,6 @@
 from spack.cmd import display_specs
 from spack.spec import Spec, save_dependency_specfiles
 from spack.stage import Stage
-from spack.util.string import plural
 
 description = "create, download and install binary packages"
 section = "packaging"
@@ -268,7 +268,7 @@ def _matching_specs(specs: List[Spec]) -> List[Spec]:
     return [spack.cmd.disambiguate_spec(s, ev.active_environment(), installed=any) for s in specs]
 
 
-def push_fn(args):
+def push_fn(args: argparse.Namespace):
     """create a binary package and push it to a mirror"""
     if args.spec_file:
         tty.warn(
@@ -414,7 +414,7 @@ def preview_fn(args):
     )
 
 
-def check_fn(args):
+def check_fn(args: argparse.Namespace):
     """check specs against remote binary mirror(s) to see if any need to be rebuilt
 
     this command uses the process exit code to indicate its result, specifically, if the
@@ -429,7 +429,7 @@ def check_fn(args):
     specs = spack.cmd.parse_specs(args.spec or args.spec_file)
 
     if specs:
-        specs = _matching_specs(specs, specs)
+        specs = _matching_specs(specs)
     else:
         specs = spack.cmd.require_active_env("buildcache check").all_specs()
 
@@ -527,7 +527,7 @@ def copy_buildcache_file(src_url, dest_url, local_path=None):
             temp_stage.create()
             temp_stage.fetch()
             web_util.push_to_url(local_path, dest_url, keep_original=True)
-        except web_util.FetchError as e:
+        except spack.error.FetchError as e:
             # Expected, since we have to try all the possible extensions
             tty.debug("no such file: {0}".format(src_url))
             tty.debug(e)

lib/spack/spack/cmd/checksum.py

@@ -7,6 +7,7 @@
 import re
 import sys
 
+import llnl.string
 import llnl.util.lang
 from llnl.util import tty
 
@@ -15,6 +16,7 @@
 import spack.spec
 import spack.stage
 import spack.util.crypto
+import spack.util.web as web_util
 from spack.cmd.common import arguments
 from spack.package_base import PackageBase, deprecated_version, preferred_version
 from spack.util.editor import editor
@@ -66,7 +68,7 @@ def setup_parser(subparser):
     modes_parser.add_argument(
         "--verify", action="store_true", default=False, help="verify known package checksums"
     )
-    arguments.add_common_arguments(subparser, ["package"])
+    arguments.add_common_arguments(subparser, ["package", "jobs"])
     subparser.add_argument(
         "versions", nargs=argparse.REMAINDER, help="versions to generate checksums for"
     )
@@ -96,7 +98,7 @@ def checksum(parser, args):
 
     # Add latest version if requested
     if args.latest:
-        remote_versions = pkg.fetch_remote_versions()
+        remote_versions = pkg.fetch_remote_versions(args.jobs)
         if len(remote_versions) > 0:
             latest_version = sorted(remote_versions.keys(), reverse=True)[0]
             versions.append(latest_version)
@@ -119,27 +121,47 @@ def checksum(parser, args):
         # if we get here, it's because no valid url was provided by the package
         # do expensive fallback to try to recover
         if remote_versions is None:
-            remote_versions = pkg.fetch_remote_versions()
+            remote_versions = pkg.fetch_remote_versions(args.jobs)
         if version in remote_versions:
             url_dict[version] = remote_versions[version]
 
     if len(versions) <= 0:
         if remote_versions is None:
-            remote_versions = pkg.fetch_remote_versions()
+            remote_versions = pkg.fetch_remote_versions(args.jobs)
         url_dict = remote_versions
 
+    # A spidered URL can differ from the package.py *computed* URL, pointing to different tarballs.
+    # For example, GitHub release pages sometimes have multiple tarballs with different shasum:
+    # - releases/download/1.0/<pkg>-1.0.tar.gz (uploaded tarball)
+    # - archive/refs/tags/1.0.tar.gz           (generated tarball)
+    # We wanna ensure that `spack checksum` and `spack install` ultimately use the same URL, so
+    # here we check whether the crawled and computed URLs disagree, and if so, prioritize the
+    # former if that URL exists (just sending a HEAD request that is).
+    url_changed_for_version = set()
+    for version, url in url_dict.items():
+        possible_urls = pkg.all_urls_for_version(version)
+        if url not in possible_urls:
+            for possible_url in possible_urls:
+                if web_util.url_exists(possible_url):
+                    url_dict[version] = possible_url
+                    break
+            else:
+                url_changed_for_version.add(version)
+
     if not url_dict:
         tty.die(f"Could not find any remote versions for {pkg.name}")
-
-    # print an empty line to create a new output section block
-    print()
+    elif len(url_dict) > 1 and not args.batch and sys.stdin.isatty():
+        filtered_url_dict = spack.stage.interactive_version_filter(
+            url_dict, pkg.versions, url_changes=url_changed_for_version
+        )
+        if not filtered_url_dict:
+            exit(0)
+        url_dict = filtered_url_dict
+    else:
+        tty.info(f"Found {llnl.string.plural(len(url_dict), 'version')} of {pkg.name}")
 
     version_hashes = spack.stage.get_checksums_for_versions(
-        url_dict,
-        pkg.name,
-        keep_stage=args.keep_stage,
-        batch=(args.batch or len(versions) > 0 or len(url_dict) == 1),
-        fetch_options=pkg.fetch_options,
+        url_dict, pkg.name, keep_stage=args.keep_stage, fetch_options=pkg.fetch_options
     )
 
     if args.verify:
@@ -239,7 +261,7 @@ def add_versions_to_package(pkg: PackageBase, version_lines: str):
                 parsed_version = Version(contents_version.group(1))
 
                 if parsed_version < new_versions[0][0]:
-                    split_contents[i:i] = [new_versions.pop(0)[1], " # FIX ME", "\n"]
+                    split_contents[i:i] = [new_versions.pop(0)[1], " # FIXME", "\n"]
                     num_versions_added += 1
 
                 elif parsed_version == new_versions[0][0]:

lib/spack/spack/cmd/ci.py

@@ -191,6 +191,14 @@ def ci_generate(args):
     """
     env = spack.cmd.require_active_env(cmd_name="ci generate")
 
+    if args.copy_to:
+        tty.warn("The flag --copy-to is deprecated and will be removed in Spack 0.23")
+
+    if args.buildcache_destination:
+        tty.warn(
+            "The flag --buildcache-destination is deprecated and will be removed in Spack 0.23"
+        )
+
     output_file = args.output_file
     copy_yaml_to = args.copy_to
     run_optimizer = args.optimize
@@ -264,12 +272,6 @@ def ci_rebuild(args):
     if not ci_config:
         tty.die("spack ci rebuild requires an env containing ci cfg")
 
-    tty.msg(
-        "SPACK_BUILDCACHE_DESTINATION={0}".format(
-            os.environ.get("SPACK_BUILDCACHE_DESTINATION", None)
-        )
-    )
-
     # Grab the environment variables we need.  These either come from the
     # pipeline generation step ("spack ci generate"), where they were written
     # out as variables, or else provided by GitLab itself.
@@ -277,6 +279,7 @@ def ci_rebuild(args):
     job_log_dir = os.environ.get("SPACK_JOB_LOG_DIR")
     job_test_dir = os.environ.get("SPACK_JOB_TEST_DIR")
     repro_dir = os.environ.get("SPACK_JOB_REPRO_DIR")
+    # TODO: Remove this in Spack 0.23
     local_mirror_dir = os.environ.get("SPACK_LOCAL_MIRROR_DIR")
     concrete_env_dir = os.environ.get("SPACK_CONCRETE_ENV_DIR")
     ci_pipeline_id = os.environ.get("CI_PIPELINE_ID")
@@ -285,9 +288,12 @@ def ci_rebuild(args):
     job_spec_pkg_name = os.environ.get("SPACK_JOB_SPEC_PKG_NAME")
     job_spec_dag_hash = os.environ.get("SPACK_JOB_SPEC_DAG_HASH")
     spack_pipeline_type = os.environ.get("SPACK_PIPELINE_TYPE")
+    # TODO: Remove this in Spack 0.23
     remote_mirror_override = os.environ.get("SPACK_REMOTE_MIRROR_OVERRIDE")
+    # TODO: Remove this in Spack 0.23
     remote_mirror_url = os.environ.get("SPACK_REMOTE_MIRROR_URL")
     spack_ci_stack_name = os.environ.get("SPACK_CI_STACK_NAME")
+    # TODO: Remove this in Spack 0.23
     shared_pr_mirror_url = os.environ.get("SPACK_CI_SHARED_PR_MIRROR_URL")
     rebuild_everything = os.environ.get("SPACK_REBUILD_EVERYTHING")
     require_signing = os.environ.get("SPACK_REQUIRE_SIGNING")
@@ -344,21 +350,36 @@ def ci_rebuild(args):
 
     full_rebuild = True if rebuild_everything and rebuild_everything.lower() == "true" else False
 
+    pipeline_mirrors = spack.mirror.MirrorCollection(binary=True)
+    deprecated_mirror_config = False
+    buildcache_destination = None
+    if "buildcache-destination" in pipeline_mirrors:
+        buildcache_destination = pipeline_mirrors["buildcache-destination"]
+    else:
+        deprecated_mirror_config = True
+        # TODO: This will be an error in Spack 0.23
+
     # If no override url exists, then just push binary package to the
     # normal remote mirror url.
+    # TODO: Remove in Spack 0.23
     buildcache_mirror_url = remote_mirror_override or remote_mirror_url
+    if buildcache_destination:
+        buildcache_mirror_url = buildcache_destination.push_url
 
     # Figure out what is our temporary storage mirror: Is it artifacts
     # buildcache?  Or temporary-storage-url-prefix?  In some cases we need to
     # force something or pipelines might not have a way to propagate build
     # artifacts from upstream to downstream jobs.
+    # TODO: Remove this in Spack 0.23
     pipeline_mirror_url = None
 
+    # TODO: Remove this in Spack 0.23
     temp_storage_url_prefix = None
     if "temporary-storage-url-prefix" in ci_config:
         temp_storage_url_prefix = ci_config["temporary-storage-url-prefix"]
         pipeline_mirror_url = url_util.join(temp_storage_url_prefix, ci_pipeline_id)
 
+    # TODO: Remove this in Spack 0.23
     enable_artifacts_mirror = False
     if "enable-artifacts-buildcache" in ci_config:
         enable_artifacts_mirror = ci_config["enable-artifacts-buildcache"]
@@ -454,12 +475,14 @@ def ci_rebuild(args):
     # If we decided there should be a temporary storage mechanism, add that
     # mirror now so it's used when we check for a hash match already
     # built for this spec.
+    # TODO: Remove this block in Spack 0.23
     if pipeline_mirror_url:
         mirror = spack.mirror.Mirror(pipeline_mirror_url, name=spack_ci.TEMP_STORAGE_MIRROR_NAME)
         spack.mirror.add(mirror, cfg.default_modify_scope())
         pipeline_mirrors.append(pipeline_mirror_url)
 
     # Check configured mirrors for a built spec with a matching hash
+    # TODO: Remove this block in Spack 0.23
     mirrors_to_check = None
     if remote_mirror_override:
         if spack_pipeline_type == "spack_protected_branch":
@@ -477,7 +500,8 @@ def ci_rebuild(args):
             )
         pipeline_mirrors.append(remote_mirror_override)
 
-    if spack_pipeline_type == "spack_pull_request":
+    # TODO: Remove this in Spack 0.23
+    if deprecated_mirror_config and spack_pipeline_type == "spack_pull_request":
         if shared_pr_mirror_url != "None":
             pipeline_mirrors.append(shared_pr_mirror_url)
 
@@ -499,6 +523,7 @@ def ci_rebuild(args):
         tty.msg("No need to rebuild {0}, found hash match at: ".format(job_spec_pkg_name))
         for match in matches:
             tty.msg("    {0}".format(match["mirror_url"]))
+        # TODO: Remove this block in Spack 0.23
         if enable_artifacts_mirror:
             matching_mirror = matches[0]["mirror_url"]
             build_cache_dir = os.path.join(local_mirror_dir, "build_cache")
@@ -513,7 +538,8 @@ def ci_rebuild(args):
     # only want to keep the mirror being used by the current pipeline as it's binary
     # package destination.  This ensures that the when we rebuild everything, we only
     # consume binary dependencies built in this pipeline.
-    if full_rebuild:
+    # TODO: Remove this in Spack 0.23
+    if deprecated_mirror_config and full_rebuild:
         spack_ci.remove_other_mirrors(pipeline_mirrors, cfg.default_modify_scope())
 
     # No hash match anywhere means we need to rebuild spec
@@ -579,7 +605,9 @@ def ci_rebuild(args):
             "SPACK_COLOR=always",
             "SPACK_INSTALL_FLAGS={}".format(args_to_string(deps_install_args)),
             "-j$(nproc)",
-            "install-deps/{}".format(job_spec.format("{name}-{version}-{hash}")),
+            "install-deps/{}".format(
+                ev.depfile.MakefileSpec(job_spec).safe_format("{name}-{version}-{hash}")
+            ),
         ],
         spack_cmd + ["install"] + root_install_args,
     ]
@@ -676,21 +704,25 @@ def ci_rebuild(args):
     # print out some instructions on how to reproduce this build failure
     # outside of the pipeline environment.
     if install_exit_code == 0:
-        if buildcache_mirror_url or pipeline_mirror_url:
-            for result in spack_ci.create_buildcache(
-                input_spec=job_spec,
-                buildcache_mirror_url=buildcache_mirror_url,
-                pipeline_mirror_url=pipeline_mirror_url,
-                sign_binaries=spack_ci.can_sign_binaries(),
-            ):
-                msg = tty.msg if result.success else tty.warn
-                msg(
-                    "{} {} to {}".format(
-                        "Pushed" if result.success else "Failed to push",
-                        job_spec.format("{name}{@version}{/hash:7}", color=clr.get_color_when()),
-                        result.url,
-                    )
+        mirror_urls = [buildcache_mirror_url]
+
+        # TODO: Remove this block in Spack 0.23
+        if pipeline_mirror_url:
+            mirror_urls.append(pipeline_mirror_url)
+
+        for result in spack_ci.create_buildcache(
+            input_spec=job_spec,
+            destination_mirror_urls=mirror_urls,
+            sign_binaries=spack_ci.can_sign_binaries(),
+        ):
+            msg = tty.msg if result.success else tty.warn
+            msg(
+                "{} {} to {}".format(
+                    "Pushed" if result.success else "Failed to push",
+                    job_spec.format("{name}{@version}{/hash:7}", color=clr.get_color_when()),
+                    result.url,
                 )
+            )
 
         # If this is a develop pipeline, check if the spec that we just built is
         # on the broken-specs list. If so, remove it.

lib/spack/spack/cmd/common/env_utility.py

@@ -7,7 +7,6 @@
 
 import llnl.util.tty as tty
 
-import spack.build_environment as build_environment
 import spack.cmd
 import spack.cmd.common.arguments as arguments
 import spack.deptypes as dt
@@ -15,7 +14,8 @@
 import spack.paths
 import spack.spec
 import spack.store
-from spack import traverse
+from spack import build_environment, traverse
+from spack.context import Context
 from spack.util.environment import dump_environment, pickle_environment
 
 
@@ -42,14 +42,14 @@ def setup_parser(subparser):
 
 
 class AreDepsInstalledVisitor:
-    def __init__(self, context="build"):
-        if context not in ("build", "test"):
-            raise ValueError("context can only be build or test")
-
-        if context == "build":
+    def __init__(self, context: Context = Context.BUILD):
+        if context == Context.BUILD:
+            # TODO: run deps shouldn't be required for build env.
             self.direct_deps = dt.BUILD | dt.LINK | dt.RUN
-        else:
+        elif context == Context.TEST:
             self.direct_deps = dt.BUILD | dt.TEST | dt.LINK | dt.RUN
+        else:
+            raise ValueError("context can only be Context.BUILD or Context.TEST")
 
         self.has_uninstalled_deps = False
 
@@ -76,7 +76,7 @@ def neighbors(self, item):
         return item.edge.spec.edges_to_dependencies(depflag=depflag)
 
 
-def emulate_env_utility(cmd_name, context, args):
+def emulate_env_utility(cmd_name, context: Context, args):
     if not args.spec:
         tty.die("spack %s requires a spec." % cmd_name)
 
@@ -120,7 +120,7 @@ def emulate_env_utility(cmd_name, context, args):
                 hashes=True,
                 # This shows more than necessary, but we cannot dynamically change deptypes
                 # in Spec.tree(...).
-                deptypes="all" if context == "build" else ("build", "test", "link", "run"),
+                deptypes="all" if context == Context.BUILD else ("build", "test", "link", "run"),
             ),
         )
 

lib/spack/spack/cmd/create.py

@@ -5,6 +5,7 @@
 
 import os
 import re
+import sys
 import urllib.parse
 
 import llnl.util.tty as tty
@@ -62,6 +63,9 @@ class {class_name}({base_class_name}):
     # notify when the package is updated.
     # maintainers("github_user1", "github_user2")
 
+    # FIXME: Add the SPDX identifier of the project's license below.
+    license("UNKNOWN")
+
 {versions}
 
 {dependencies}
@@ -823,6 +827,11 @@ def get_versions(args, name):
         # Find available versions
         try:
             url_dict = spack.url.find_versions_of_archive(args.url)
+            if len(url_dict) > 1 and not args.batch and sys.stdin.isatty():
+                url_dict_filtered = spack.stage.interactive_version_filter(url_dict)
+                if url_dict_filtered is None:
+                    exit(0)
+                url_dict = url_dict_filtered
         except UndetectableVersionError:
             # Use fake versions
             tty.warn("Couldn't detect version in: {0}".format(args.url))
@@ -834,11 +843,7 @@ def get_versions(args, name):
             url_dict = {version: args.url}
 
         version_hashes = spack.stage.get_checksums_for_versions(
-            url_dict,
-            name,
-            first_stage_function=guesser,
-            keep_stage=args.keep_stage,
-            batch=(args.batch or len(url_dict) == 1),
+            url_dict, name, first_stage_function=guesser, keep_stage=args.keep_stage
         )
 
         versions = get_version_lines(version_hashes, url_dict)

lib/spack/spack/cmd/env.py

@@ -8,7 +8,9 @@
 import shutil
 import sys
 import tempfile
+from typing import Optional
 
+import llnl.string as string
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
 from llnl.util.tty.colify import colify
@@ -28,7 +30,6 @@
 import spack.schema.env
 import spack.spec
 import spack.tengine
-import spack.util.string as string
 from spack.util.environment import EnvironmentModifications
 
 description = "manage virtual environments"
@@ -96,22 +97,16 @@ def env_activate_setup_parser(subparser):
 
     view_options = subparser.add_mutually_exclusive_group()
     view_options.add_argument(
-        "-v",
         "--with-view",
-        action="store_const",
-        dest="with_view",
-        const=True,
-        default=True,
-        help="update PATH, etc., with associated view",
+        "-v",
+        metavar="name",
+        help="set runtime environment variables for specific view",
     )
     view_options.add_argument(
-        "-V",
         "--without-view",
-        action="store_const",
-        dest="with_view",
-        const=False,
-        default=True,
-        help="do not update PATH, etc., with associated view",
+        "-V",
+        action="store_true",
+        help="do not set runtime environment variables for any view",
     )
 
     subparser.add_argument(
@@ -197,10 +192,20 @@ def env_activate(args):
 
     # Activate new environment
     active_env = ev.Environment(env_path)
+
+    # Check if runtime environment variables are requested, and if so, for what view.
+    view: Optional[str] = None
+    if args.with_view:
+        view = args.with_view
+        if not active_env.has_view(view):
+            tty.die(f"The environment does not have a view named '{view}'")
+    elif not args.without_view and active_env.has_view(ev.default_view_name):
+        view = ev.default_view_name
+
     cmds += spack.environment.shell.activate_header(
-        env=active_env, shell=args.shell, prompt=env_prompt if args.prompt else None
+        env=active_env, shell=args.shell, prompt=env_prompt if args.prompt else None, view=view
     )
-    env_mods.extend(spack.environment.shell.activate(env=active_env, add_view=args.with_view))
+    env_mods.extend(spack.environment.shell.activate(env=active_env, view=view))
     cmds += env_mods.shell_modifications(args.shell)
     sys.stdout.write(cmds)
 

lib/spack/spack/cmd/external.py

@@ -5,6 +5,7 @@
 import argparse
 import errno
 import os
+import re
 import sys
 from typing import List, Optional
 
@@ -156,11 +157,20 @@ def packages_to_search_for(
 ):
     result = []
     for current_tag in tags:
-        result.extend(spack.repo.PATH.packages_with_tags(current_tag))
+        result.extend(spack.repo.PATH.packages_with_tags(current_tag, full=True))
+
     if names:
-        result = [x for x in result if x in names]
+        # Match both fully qualified and unqualified
+        parts = [rf"(^{x}$|[.]{x}$)" for x in names]
+        select_re = re.compile("|".join(parts))
+        result = [x for x in result if select_re.search(x)]
+
     if exclude:
-        result = [x for x in result if x not in exclude]
+        # Match both fully qualified and unqualified
+        parts = [rf"(^{x}$|[.]{x}$)" for x in exclude]
+        select_re = re.compile("|".join(parts))
+        result = [x for x in result if not select_re.search(x)]
+
     return result
 
 

lib/spack/spack/cmd/info.py

@@ -72,6 +72,10 @@ def variant(s):
     return spack.spec.ENABLED_VARIANT_COLOR + s + plain_format
 
 
+def license(s):
+    return spack.spec.VERSION_COLOR + s + plain_format
+
+
 class VariantFormatter:
     def __init__(self, variants):
         self.variants = variants
@@ -348,6 +352,22 @@ def print_virtuals(pkg):
         color.cprint("    None")
 
 
+def print_licenses(pkg):
+    """Output the licenses of the project."""
+
+    color.cprint("")
+    color.cprint(section_title("Licenses: "))
+
+    if len(pkg.licenses) == 0:
+        color.cprint("    None")
+    else:
+        pad = padder(pkg.licenses, 4)
+        for when_spec in pkg.licenses:
+            license_identifier = pkg.licenses[when_spec]
+            line = license("    {0}".format(pad(license_identifier))) + color.cescape(when_spec)
+            color.cprint(line)
+
+
 def info(parser, args):
     spec = spack.spec.Spec(args.package)
     pkg_cls = spack.repo.PATH.get_pkg_class(spec.name)
@@ -377,6 +397,7 @@ def info(parser, args):
         (args.all or not args.no_dependencies, print_dependencies),
         (args.all or args.virtuals, print_virtuals),
         (args.all or args.tests, print_tests),
+        (args.all or True, print_licenses),
     ]
     for print_it, func in sections:
         if print_it:

lib/spack/spack/cmd/install.py

@@ -240,8 +240,7 @@ def default_log_file(spec):
     """Computes the default filename for the log file and creates
     the corresponding directory if not present
     """
-    fmt = "test-{x.name}-{x.version}-{hash}.xml"
-    basename = fmt.format(x=spec, hash=spec.dag_hash())
+    basename = spec.format_path("test-{name}-{version}-{hash}.xml")
     dirname = fs.os.path.join(spack.paths.reports_path, "junit")
     fs.mkdirp(dirname)
     return fs.os.path.join(dirname, basename)

lib/spack/spack/cmd/load.py

@@ -5,6 +5,8 @@
 
 import sys
 
+import llnl.util.tty as tty
+
 import spack.cmd
 import spack.cmd.common.arguments as arguments
 import spack.cmd.find
@@ -108,16 +110,14 @@ def load(parser, args):
         )
         return 1
 
-    with spack.store.STORE.db.read_transaction():
-        if "dependencies" in args.things_to_load:
-            include_roots = "package" in args.things_to_load
-            specs = [
-                dep for spec in specs for dep in spec.traverse(root=include_roots, order="post")
-            ]
+    if args.things_to_load != "package,dependencies":
+        tty.warn(
+            "The `--only` flag in spack load is deprecated and will be removed in Spack v0.22"
+        )
 
-        env_mod = spack.util.environment.EnvironmentModifications()
+    with spack.store.STORE.db.read_transaction():
+        env_mod = uenv.environment_modifications_for_specs(*specs)
         for spec in specs:
-            env_mod.extend(uenv.environment_modifications_for_spec(spec))
             env_mod.prepend_path(uenv.spack_loaded_hashes_var, spec.dag_hash())
         cmds = env_mod.shell_modifications(args.shell)
 

lib/spack/spack/cmd/make_installer.py

@@ -6,10 +6,11 @@
 import posixpath
 import sys
 
+from llnl.path import convert_to_posix_path
+
 import spack.paths
 import spack.util.executable
 from spack.spec import Spec
-from spack.util.path import convert_to_posix_path
 
 description = "generate Windows installer"
 section = "admin"

lib/spack/spack/cmd/solve.py

@@ -176,17 +176,29 @@ def solve(parser, args):
     output = sys.stdout if "asp" in show else None
     setup_only = set(show) == {"asp"}
     unify = spack.config.get("concretizer:unify")
+    allow_deprecated = spack.config.get("config:deprecated", False)
     if unify != "when_possible":
         # set up solver parameters
         # Note: reuse and other concretizer prefs are passed as configuration
         result = solver.solve(
-            specs, out=output, timers=args.timers, stats=args.stats, setup_only=setup_only
+            specs,
+            out=output,
+            timers=args.timers,
+            stats=args.stats,
+            setup_only=setup_only,
+            allow_deprecated=allow_deprecated,
         )
         if not setup_only:
             _process_result(result, show, required_format, kwargs)
     else:
         for idx, result in enumerate(
-            solver.solve_in_rounds(specs, out=output, timers=args.timers, stats=args.stats)
+            solver.solve_in_rounds(
+                specs,
+                out=output,
+                timers=args.timers,
+                stats=args.stats,
+                allow_deprecated=allow_deprecated,
+            )
         ):
             if "solutions" in show:
                 tty.msg("ROUND {0}".format(idx))

lib/spack/spack/cmd/tags.py

@@ -5,6 +5,7 @@
 import io
 import sys
 
+import llnl.string
 import llnl.util.tty as tty
 import llnl.util.tty.colify as colify
 
@@ -24,7 +25,7 @@ def report_tags(category, tags):
     if isatty:
         num = len(tags)
         fmt = "{0} package tag".format(category)
-        buffer.write("{0}:\n".format(spack.util.string.plural(num, fmt)))
+        buffer.write("{0}:\n".format(llnl.string.plural(num, fmt)))
 
     if tags:
         colify.colify(tags, output=buffer, tty=isatty, indent=4)

lib/spack/spack/cmd/test_env.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import spack.cmd.common.env_utility as env_utility
+from spack.context import Context
 
 description = (
     "run a command in a spec's test environment, or dump its environment to screen or file"
@@ -14,4 +15,4 @@
 
 
 def test_env(parser, args):
-    env_utility.emulate_env_utility("test-env", "test", args)
+    env_utility.emulate_env_utility("test-env", Context.TEST, args)

lib/spack/spack/cmd/unload.py

@@ -88,9 +88,8 @@ def unload(parser, args):
         )
         return 1
 
-    env_mod = spack.util.environment.EnvironmentModifications()
+    env_mod = uenv.environment_modifications_for_specs(*specs).reversed()
     for spec in specs:
-        env_mod.extend(uenv.environment_modifications_for_spec(spec).reversed())
         env_mod.remove_path(uenv.spack_loaded_hashes_var, spec.dag_hash())
     cmds = env_mod.shell_modifications(args.shell)
 

lib/spack/spack/cmd/versions.py

@@ -37,10 +37,7 @@ def setup_parser(subparser):
         action="store_true",
         help="only list remote versions newer than the latest checksummed version",
     )
-    subparser.add_argument(
-        "-c", "--concurrency", default=32, type=int, help="number of concurrent requests"
-    )
-    arguments.add_common_arguments(subparser, ["package"])
+    arguments.add_common_arguments(subparser, ["package", "jobs"])
 
 
 def versions(parser, args):
@@ -68,7 +65,7 @@ def versions(parser, args):
         if args.safe:
             return
 
-    fetched_versions = pkg.fetch_remote_versions(args.concurrency)
+    fetched_versions = pkg.fetch_remote_versions(args.jobs)
 
     if args.new:
         if sys.stdout.isatty():

lib/spack/spack/compiler.py

@@ -13,6 +13,7 @@
 import tempfile
 from typing import List, Optional, Sequence
 
+import llnl.path
 import llnl.util.lang
 import llnl.util.tty as tty
 from llnl.util.filesystem import path_contains_subdirectory, paths_containing_libs
@@ -24,7 +25,6 @@
 import spack.util.module_cmd
 import spack.version
 from spack.util.environment import filter_system_paths
-from spack.util.path import system_path_filter
 
 __all__ = ["Compiler"]
 
@@ -39,10 +39,17 @@ def _get_compiler_version_output(compiler_path, version_arg, ignore_errors=()):
         version_arg (str): the argument used to extract version information
     """
     compiler = spack.util.executable.Executable(compiler_path)
+    compiler_invocation_args = {
+        "output": str,
+        "error": str,
+        "ignore_errors": ignore_errors,
+        "timeout": 120,
+        "fail_on_error": True,
+    }
     if version_arg:
-        output = compiler(version_arg, output=str, error=str, ignore_errors=ignore_errors)
+        output = compiler(version_arg, **compiler_invocation_args)
     else:
-        output = compiler(output=str, error=str, ignore_errors=ignore_errors)
+        output = compiler(**compiler_invocation_args)
     return output
 
 
@@ -153,7 +160,7 @@ def _parse_link_paths(string):
     return implicit_link_dirs
 
 
-@system_path_filter
+@llnl.path.system_path_filter
 def _parse_non_system_link_dirs(string: str) -> List[str]:
     """Parses link paths out of compiler debug output.
 
@@ -229,6 +236,9 @@ class Compiler:
     # by any compiler
     _all_compiler_rpath_libraries = ["libc", "libc++", "libstdc++"]
 
+    #: Platform matcher for Platform objects supported by compiler
+    is_supported_on_platform = lambda x: True
+
     # Default flags used by a compiler to set an rpath
     @property
     def cc_rpath_arg(self):
@@ -594,8 +604,6 @@ def search_regexps(cls, language):
         compiler_names = getattr(cls, "{0}_names".format(language))
         prefixes = [""] + cls.prefixes
         suffixes = [""]
-        # Windows compilers generally have an extension of some sort
-        # as do most files on Windows, handle that case here
         if sys.platform == "win32":
             ext = r"\.(?:exe|bat)"
             cls_suf = [suf + ext for suf in cls.suffixes]

lib/spack/spack/compilers/__init__.py

@@ -10,7 +10,7 @@
 import itertools
 import multiprocessing.pool
 import os
-from typing import Dict
+from typing import Dict, List
 
 import archspec.cpu
 
@@ -298,7 +298,7 @@ def select_new_compilers(compilers, scope=None):
     return compilers_not_in_config
 
 
-def supported_compilers():
+def supported_compilers() -> List[str]:
     """Return a set of names of compilers supported by Spack.
 
     See available_compilers() to get a list of all the available
@@ -306,10 +306,41 @@ def supported_compilers():
     """
     # Hack to be able to call the compiler `apple-clang` while still
     # using a valid python name for the module
-    return sorted(
-        name if name != "apple_clang" else "apple-clang"
-        for name in llnl.util.lang.list_modules(spack.paths.compilers_path)
-    )
+    return sorted(all_compiler_names())
+
+
+def supported_compilers_for_host_platform() -> List[str]:
+    """Return a set of compiler class objects supported by Spack
+    that are also supported by the current host platform
+    """
+    host_plat = spack.platforms.real_host()
+    return supported_compilers_for_platform(host_plat)
+
+
+def supported_compilers_for_platform(platform: spack.platforms.Platform) -> List[str]:
+    """Return a set of compiler class objects supported by Spack
+    that are also supported by the provided platform
+
+    Args:
+        platform (str): string representation of platform
+            for which compiler compatability should be determined
+    """
+    return [
+        name
+        for name in supported_compilers()
+        if class_for_compiler_name(name).is_supported_on_platform(platform)
+    ]
+
+
+def all_compiler_names() -> List[str]:
+    def replace_apple_clang(name):
+        return name if name != "apple_clang" else "apple-clang"
+
+    return [replace_apple_clang(name) for name in all_compiler_module_names()]
+
+
+def all_compiler_module_names() -> List[str]:
+    return [name for name in llnl.util.lang.list_modules(spack.paths.compilers_path)]
 
 
 @_auto_compiler_spec
@@ -628,7 +659,7 @@ def arguments_to_detect_version_fn(operating_system, paths):
     def _default(search_paths):
         command_arguments = []
         files_to_be_tested = fs.files_in(*search_paths)
-        for compiler_name in spack.compilers.supported_compilers():
+        for compiler_name in spack.compilers.supported_compilers_for_host_platform():
             compiler_cls = class_for_compiler_name(compiler_name)
 
             for language in ("cc", "cxx", "f77", "fc"):
@@ -687,9 +718,11 @@ def _default(fn_args):
                 value = fn_args._replace(id=compiler_id._replace(version=version))
                 return value, None
 
-            error = "Couldn't get version for compiler {0}".format(path)
+            error = f"Couldn't get version for compiler {path}".format(path)
         except spack.util.executable.ProcessError as e:
-            error = "Couldn't get version for compiler {0}\n".format(path) + str(e)
+            error = f"Couldn't get version for compiler {path}\n" + str(e)
+        except spack.util.executable.ProcessTimeoutError as e:
+            error = f"Couldn't get version for compiler {path}\n" + str(e)
         except Exception as e:
             # Catching "Exception" here is fine because it just
             # means something went wrong running a candidate executable.

lib/spack/spack/compilers/aocc.py

@@ -112,6 +112,7 @@ def extract_version_from_output(cls, output):
         match = re.search(r"AOCC_(\d+)[._](\d+)[._](\d+)", output)
         if match:
             return ".".join(match.groups())
+        return "unknown"
 
     @classmethod
     def fc_version(cls, fortran_compiler):

lib/spack/spack/compilers/msvc.py

@@ -7,7 +7,6 @@
 import re
 import subprocess
 import sys
-from distutils.version import StrictVersion
 from typing import Dict, List, Set
 
 import spack.compiler
@@ -115,11 +114,11 @@ def command_str(self):
 
 def get_valid_fortran_pth(comp_ver):
     cl_ver = str(comp_ver)
-    sort_fn = lambda fc_ver: StrictVersion(fc_ver)
+    sort_fn = lambda fc_ver: Version(fc_ver)
     sort_fc_ver = sorted(list(avail_fc_version), key=sort_fn)
     for ver in sort_fc_ver:
         if ver in fortran_mapping:
-            if StrictVersion(cl_ver) <= StrictVersion(fortran_mapping[ver]):
+            if Version(cl_ver) <= Version(fortran_mapping[ver]):
                 return fc_path[ver]
     return None
 
@@ -154,9 +153,12 @@ class Msvc(Compiler):
 
     #: Regex used to extract version from compiler's output
     version_regex = r"([1-9][0-9]*\.[0-9]*\.[0-9]*)"
+    # The MSVC compiler class overrides this to prevent instances
+    # of erroneous matching on executable names that cannot be msvc
+    # compilers
+    suffixes = []
 
-    # Initialize, deferring to base class but then adding the vcvarsallfile
-    # file based on compiler executable path.
+    is_supported_on_platform = lambda x: isinstance(x, spack.platforms.Windows)
 
     def __init__(self, *args, **kwargs):
         # This positional argument "paths" is later parsed and process by the base class
@@ -167,6 +169,8 @@ def __init__(self, *args, **kwargs):
         cspec = args[0]
         new_pth = [pth if pth else get_valid_fortran_pth(cspec.version) for pth in paths]
         paths[:] = new_pth
+        # Initialize, deferring to base class but then adding the vcvarsallfile
+        # file based on compiler executable path.
         super().__init__(*args, **kwargs)
         # To use the MSVC compilers, VCVARS must be invoked
         # VCVARS is located at a fixed location, referencable

lib/spack/spack/concretize.py

@@ -155,7 +155,7 @@ def _valid_virtuals_and_externals(self, spec):
             ),
         )
 
-    def choose_virtual_or_external(self, spec):
+    def choose_virtual_or_external(self, spec: spack.spec.Spec):
         """Given a list of candidate virtual and external packages, try to
         find one that is most ABI compatible.
         """
@@ -744,8 +744,11 @@ def concretize_specs_together(*abstract_specs, **kwargs):
 def _concretize_specs_together_new(*abstract_specs, **kwargs):
     import spack.solver.asp
 
+    allow_deprecated = spack.config.get("config:deprecated", False)
     solver = spack.solver.asp.Solver()
-    result = solver.solve(abstract_specs, tests=kwargs.get("tests", False))
+    result = solver.solve(
+        abstract_specs, tests=kwargs.get("tests", False), allow_deprecated=allow_deprecated
+    )
     result.raise_if_unsat()
     return [s.copy() for s in result.specs]
 

lib/spack/spack/container/writers/__init__.py

@@ -272,13 +272,6 @@ def _os_pkg_manager(self):
             raise spack.error.SpackError(msg)
         return os_pkg_manager
 
-    @tengine.context_property
-    def extra_instructions(self):
-        Extras = namedtuple("Extra", ["build", "final"])
-        extras = self.container_config.get("extra_instructions", {})
-        build, final = extras.get("build", None), extras.get("final", None)
-        return Extras(build=build, final=final)
-
     @tengine.context_property
     def labels(self):
         return self.container_config.get("labels", {})

lib/spack/spack/context.py

@@ -0,0 +1,29 @@
+# Copyright 2013-2023 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 module provides classes used in user and build environment"""
+
+from enum import Enum
+
+
+class Context(Enum):
+    """Enum used to indicate the context in which an environment has to be setup: build,
+    run or test."""
+
+    BUILD = 1
+    RUN = 2
+    TEST = 3
+
+    def __str__(self):
+        return ("build", "run", "test")[self.value - 1]
+
+    @classmethod
+    def from_string(cls, s: str):
+        if s == "build":
+            return Context.BUILD
+        elif s == "run":
+            return Context.RUN
+        elif s == "test":
+            return Context.TEST
+        raise ValueError(f"context should be one of 'build', 'run', 'test', got {s}")

lib/spack/spack/cray_manifest.py

@@ -4,6 +4,9 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
 import json
+import os
+import traceback
+import warnings
 
 import jsonschema
 import jsonschema.exceptions
@@ -46,9 +49,29 @@ def translated_compiler_name(manifest_compiler_name):
         )
 
 
-def compiler_from_entry(entry):
+def compiler_from_entry(entry: dict, manifest_path: str):
+    # Note that manifest_path is only passed here to compose a
+    # useful warning message when paths appear to be missing.
     compiler_name = translated_compiler_name(entry["name"])
-    paths = entry["executables"]
+
+    if "prefix" in entry:
+        prefix = entry["prefix"]
+        paths = dict(
+            (lang, os.path.join(prefix, relpath))
+            for (lang, relpath) in entry["executables"].items()
+        )
+    else:
+        paths = entry["executables"]
+
+    # Do a check for missing paths. Note that this isn't possible for
+    # all compiler entries, since their "paths" might actually be
+    # exe names like "cc" that depend on modules being loaded. Cray
+    # manifest entries are always paths though.
+    missing_paths = []
+    for path in paths.values():
+        if not os.path.exists(path):
+            missing_paths.append(path)
+
     # to instantiate a compiler class we may need a concrete version:
     version = "={}".format(entry["version"])
     arch = entry["arch"]
@@ -57,8 +80,18 @@ def compiler_from_entry(entry):
 
     compiler_cls = spack.compilers.class_for_compiler_name(compiler_name)
     spec = spack.spec.CompilerSpec(compiler_cls.name, version)
-    paths = [paths.get(x, None) for x in ("cc", "cxx", "f77", "fc")]
-    return compiler_cls(spec, operating_system, target, paths)
+    path_list = [paths.get(x, None) for x in ("cc", "cxx", "f77", "fc")]
+
+    if missing_paths:
+        warnings.warn(
+            "Manifest entry refers to nonexistent paths:\n\t"
+            + "\n\t".join(missing_paths)
+            + f"\nfor {str(spec)}"
+            + f"\nin {manifest_path}"
+            + "\nPlease report this issue"
+        )
+
+    return compiler_cls(spec, operating_system, target, path_list)
 
 
 def spec_from_entry(entry):
@@ -187,12 +220,21 @@ def read(path, apply_updates):
     tty.debug("{0}: {1} specs read from manifest".format(path, str(len(specs))))
     compilers = list()
     if "compilers" in json_data:
-        compilers.extend(compiler_from_entry(x) for x in json_data["compilers"])
+        compilers.extend(compiler_from_entry(x, path) for x in json_data["compilers"])
     tty.debug("{0}: {1} compilers read from manifest".format(path, str(len(compilers))))
     # Filter out the compilers that already appear in the configuration
     compilers = spack.compilers.select_new_compilers(compilers)
     if apply_updates and compilers:
-        spack.compilers.add_compilers_to_config(compilers, init_config=False)
+        for compiler in compilers:
+            try:
+                spack.compilers.add_compilers_to_config([compiler], init_config=False)
+            except Exception:
+                warnings.warn(
+                    f"Could not add compiler {str(compiler.spec)}: "
+                    f"\n\tfrom manifest: {path}"
+                    "\nPlease reexecute with 'spack -d' and include the stack trace"
+                )
+                tty.debug(f"Include this\n{traceback.format_exc()}")
     if apply_updates:
         for spec in specs.values():
             spack.store.STORE.db.add(spec, directory_layout=None)

lib/spack/spack/detection/__init__.py

@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 from .common import DetectedPackage, executable_prefix, update_configuration
 from .path import by_path, executables_in_path
+from .test import detection_tests
 
 __all__ = [
     "DetectedPackage",
@@ -11,4 +12,5 @@
     "executables_in_path",
     "executable_prefix",
     "update_configuration",
+    "detection_tests",
 ]

lib/spack/spack/detection/common.py

@@ -299,36 +299,36 @@ def find_windows_compiler_bundled_packages() -> List[str]:
 
 
 class WindowsKitExternalPaths:
-    plat_major_ver = None
-    if sys.platform == "win32":
-        plat_major_ver = str(winOs.windows_version()[0])
-
     @staticmethod
-    def find_windows_kit_roots() -> Optional[str]:
+    def find_windows_kit_roots() -> List[str]:
         """Return Windows kit root, typically %programfiles%\\Windows Kits\\10|11\\"""
         if sys.platform != "win32":
-            return None
+            return []
         program_files = os.environ["PROGRAMFILES(x86)"]
-        kit_base = os.path.join(
-            program_files, "Windows Kits", WindowsKitExternalPaths.plat_major_ver
-        )
-        return kit_base
+        kit_base = os.path.join(program_files, "Windows Kits", "**")
+        return glob.glob(kit_base)
 
     @staticmethod
     def find_windows_kit_bin_paths(kit_base: Optional[str] = None) -> List[str]:
         """Returns Windows kit bin directory per version"""
         kit_base = WindowsKitExternalPaths.find_windows_kit_roots() if not kit_base else kit_base
-        assert kit_base is not None, "unexpected value for kit_base"
-        kit_bin = os.path.join(kit_base, "bin")
-        return glob.glob(os.path.join(kit_bin, "[0-9]*", "*\\"))
+        assert kit_base, "Unexpectedly empty value for Windows kit base path"
+        kit_paths = []
+        for kit in kit_base:
+            kit_bin = os.path.join(kit, "bin")
+            kit_paths.extend(glob.glob(os.path.join(kit_bin, "[0-9]*", "*\\")))
+        return kit_paths
 
     @staticmethod
     def find_windows_kit_lib_paths(kit_base: Optional[str] = None) -> List[str]:
         """Returns Windows kit lib directory per version"""
         kit_base = WindowsKitExternalPaths.find_windows_kit_roots() if not kit_base else kit_base
-        assert kit_base is not None, "unexpected value for kit_base"
-        kit_lib = os.path.join(kit_base, "Lib")
-        return glob.glob(os.path.join(kit_lib, "[0-9]*", "*", "*\\"))
+        assert kit_base, "Unexpectedly empty value for Windows kit base path"
+        kit_paths = []
+        for kit in kit_base:
+            kit_lib = os.path.join(kit, "Lib")
+            kit_paths.extend(glob.glob(os.path.join(kit_lib, "[0-9]*", "*", "*\\")))
+        return kit_paths
 
     @staticmethod
     def find_windows_driver_development_kit_paths() -> List[str]:
@@ -347,23 +347,30 @@ def find_windows_kit_reg_installed_roots_paths() -> List[str]:
         if not reg:
             # couldn't find key, return empty list
             return []
-        return WindowsKitExternalPaths.find_windows_kit_lib_paths(
-            reg.get_value("KitsRoot%s" % WindowsKitExternalPaths.plat_major_ver).value
-        )
+        kit_root_reg = re.compile(r"KitsRoot[0-9]+")
+        root_paths = []
+        for kit_root in filter(kit_root_reg.match, reg.get_values().keys()):
+            root_paths.extend(
+                WindowsKitExternalPaths.find_windows_kit_lib_paths(reg.get_value(kit_root).value)
+            )
+        return root_paths
 
     @staticmethod
     def find_windows_kit_reg_sdk_paths() -> List[str]:
-        reg = spack.util.windows_registry.WindowsRegistryView(
-            "SOFTWARE\\WOW6432Node\\Microsoft\\Microsoft SDKs\\Windows\\v%s.0"
-            % WindowsKitExternalPaths.plat_major_ver,
+        sdk_paths = []
+        sdk_regex = re.compile(r"v[0-9]+.[0-9]+")
+        windows_reg = spack.util.windows_registry.WindowsRegistryView(
+            "SOFTWARE\\WOW6432Node\\Microsoft\\Microsoft SDKs\\Windows",
             root_key=spack.util.windows_registry.HKEY.HKEY_LOCAL_MACHINE,
         )
-        if not reg:
-            # couldn't find key, return empty list
-            return []
-        return WindowsKitExternalPaths.find_windows_kit_lib_paths(
-            reg.get_value("InstallationFolder").value
-        )
+        for key in filter(sdk_regex.match, [x.name for x in windows_reg.get_subkeys()]):
+            reg = windows_reg.get_subkey(key)
+            sdk_paths.extend(
+                WindowsKitExternalPaths.find_windows_kit_lib_paths(
+                    reg.get_value("InstallationFolder").value
+                )
+            )
+        return sdk_paths
 
 
 def find_win32_additional_install_paths() -> List[str]:

lib/spack/spack/detection/path.py

@@ -2,7 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
-"""Detection of software installed in the system based on paths inspections
+"""Detection of software installed in the system, based on paths inspections
 and running executables.
 """
 import collections
@@ -322,12 +322,14 @@ def by_path(
     path_hints: Optional[List[str]] = None,
     max_workers: Optional[int] = None,
 ) -> Dict[str, List[DetectedPackage]]:
-    """Return the list of packages that have been detected on the system,
-    searching by path.
+    """Return the list of packages that have been detected on the system, keyed by
+    unqualified package name.
 
     Args:
-        packages_to_search: list of package classes to be detected
+        packages_to_search: list of packages to be detected. Each package can be either unqualified
+            of fully qualified
         path_hints: initial list of paths to be searched
+        max_workers: maximum number of workers to search for packages in parallel
     """
     # TODO: Packages should be able to define both .libraries and .executables in the future
     # TODO: determine_spec_details should get all relevant libraries and executables in one call
@@ -355,7 +357,8 @@ def by_path(
                 try:
                     detected = future.result(timeout=DETECTION_TIMEOUT)
                     if detected:
-                        result[pkg_name].extend(detected)
+                        _, unqualified_name = spack.repo.partition_package_name(pkg_name)
+                        result[unqualified_name].extend(detected)
                 except Exception:
                     llnl.util.tty.debug(
                         f"[EXTERNAL DETECTION] Skipping {pkg_name}: timeout reached"

lib/spack/spack/detection/test.py

@@ -0,0 +1,187 @@
+# Copyright 2013-2023 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)
+"""Create and run mock e2e tests for package detection."""
+import collections
+import contextlib
+import pathlib
+import tempfile
+from typing import Any, Deque, Dict, Generator, List, NamedTuple, Tuple
+
+import jinja2
+
+from llnl.util import filesystem
+
+import spack.repo
+import spack.spec
+from spack.util import spack_yaml
+
+from .path import by_path
+
+
+class MockExecutables(NamedTuple):
+    """Mock executables to be used in detection tests"""
+
+    #: Relative paths for mock executables to be created
+    executables: List[str]
+    #: Shell script for the mock executable
+    script: str
+
+
+class ExpectedTestResult(NamedTuple):
+    """Data structure to model assertions on detection tests"""
+
+    #: Spec to be detected
+    spec: str
+
+
+class DetectionTest(NamedTuple):
+    """Data structure to construct detection tests by PATH inspection.
+
+    Packages may have a YAML file containing the description of one or more detection tests
+    to be performed. Each test creates a few mock executable scripts in a temporary folder,
+    and checks that detection by PATH gives the expected results.
+    """
+
+    pkg_name: str
+    layout: List[MockExecutables]
+    results: List[ExpectedTestResult]
+
+
+class Runner:
+    """Runs an external detection test"""
+
+    def __init__(self, *, test: DetectionTest, repository: spack.repo.RepoPath) -> None:
+        self.test = test
+        self.repository = repository
+        self.tmpdir = tempfile.TemporaryDirectory()
+
+    def execute(self) -> List[spack.spec.Spec]:
+        """Executes a test and returns the specs that have been detected.
+
+        This function sets-up a test in a temporary directory, according to the prescriptions
+        in the test layout, then performs a detection by executables and returns the specs that
+        have been detected.
+        """
+        with self._mock_layout() as path_hints:
+            entries = by_path([self.test.pkg_name], path_hints=path_hints)
+            _, unqualified_name = spack.repo.partition_package_name(self.test.pkg_name)
+            specs = set(x.spec for x in entries[unqualified_name])
+        return list(specs)
+
+    @contextlib.contextmanager
+    def _mock_layout(self) -> Generator[List[str], None, None]:
+        hints = set()
+        try:
+            for entry in self.test.layout:
+                exes = self._create_executable_scripts(entry)
+
+                for mock_executable in exes:
+                    hints.add(str(mock_executable.parent))
+
+            yield list(hints)
+        finally:
+            self.tmpdir.cleanup()
+
+    def _create_executable_scripts(self, mock_executables: MockExecutables) -> List[pathlib.Path]:
+        relative_paths = mock_executables.executables
+        script = mock_executables.script
+        script_template = jinja2.Template("#!/bin/bash\n{{ script }}\n")
+        result = []
+        for mock_exe_path in relative_paths:
+            rel_path = pathlib.Path(mock_exe_path)
+            abs_path = pathlib.Path(self.tmpdir.name) / rel_path
+            abs_path.parent.mkdir(parents=True, exist_ok=True)
+            abs_path.write_text(script_template.render(script=script))
+            filesystem.set_executable(abs_path)
+            result.append(abs_path)
+        return result
+
+    @property
+    def expected_specs(self) -> List[spack.spec.Spec]:
+        return [spack.spec.Spec(r.spec) for r in self.test.results]
+
+
+def detection_tests(pkg_name: str, repository: spack.repo.RepoPath) -> List[Runner]:
+    """Returns a list of test runners for a given package.
+
+    Currently, detection tests are specified in a YAML file, called ``detection_test.yaml``,
+    alongside the ``package.py`` file.
+
+    This function reads that file to create a bunch of ``Runner`` objects.
+
+    Args:
+        pkg_name: name of the package to test
+        repository: repository where the package lives
+    """
+    result = []
+    detection_tests_content = read_detection_tests(pkg_name, repository)
+
+    tests_by_path = detection_tests_content.get("paths", [])
+    for single_test_data in tests_by_path:
+        mock_executables = []
+        for layout in single_test_data["layout"]:
+            mock_executables.append(
+                MockExecutables(executables=layout["executables"], script=layout["script"])
+            )
+        expected_results = []
+        for assertion in single_test_data["results"]:
+            expected_results.append(ExpectedTestResult(spec=assertion["spec"]))
+
+        current_test = DetectionTest(
+            pkg_name=pkg_name, layout=mock_executables, results=expected_results
+        )
+        result.append(Runner(test=current_test, repository=repository))
+
+    return result
+
+
+def read_detection_tests(pkg_name: str, repository: spack.repo.RepoPath) -> Dict[str, Any]:
+    """Returns the normalized content of the detection_tests.yaml associated with the package
+    passed in input.
+
+    The content is merged with that of any package that is transitively included using the
+    "includes" attribute.
+
+    Args:
+        pkg_name: name of the package to test
+        repository: repository in which to search for packages
+    """
+    content_stack, seen = [], set()
+    included_packages: Deque[str] = collections.deque()
+
+    root_detection_yaml, result = _detection_tests_yaml(pkg_name, repository)
+    included_packages.extend(result.get("includes", []))
+    seen |= set(result.get("includes", []))
+
+    while included_packages:
+        current_package = included_packages.popleft()
+        try:
+            current_detection_yaml, content = _detection_tests_yaml(current_package, repository)
+        except FileNotFoundError as e:
+            msg = (
+                f"cannot read the detection tests from the '{current_package}' package, "
+                f"included by {root_detection_yaml}"
+            )
+            raise FileNotFoundError(msg + f"\n\n\t{e}\n")
+
+        content_stack.append((current_package, content))
+        included_packages.extend(x for x in content.get("includes", []) if x not in seen)
+        seen |= set(content.get("includes", []))
+
+    result.setdefault("paths", [])
+    for pkg_name, content in content_stack:
+        result["paths"].extend(content.get("paths", []))
+
+    return result
+
+
+def _detection_tests_yaml(
+    pkg_name: str, repository: spack.repo.RepoPath
+) -> Tuple[pathlib.Path, Dict[str, Any]]:
+    pkg_dir = pathlib.Path(repository.filename_for_package_name(pkg_name)).parent
+    detection_tests_yaml = pkg_dir / "detection_test.yaml"
+    with open(str(detection_tests_yaml)) as f:
+        content = spack_yaml.load(f)
+    return detection_tests_yaml, content

lib/spack/spack/directives.py

@@ -64,6 +64,7 @@ class OpenMpi(Package):
     "depends_on",
     "extends",
     "maintainers",
+    "license",
     "provides",
     "patch",
     "variant",
@@ -862,6 +863,44 @@ def _execute_maintainer(pkg):
     return _execute_maintainer
 
 
+def _execute_license(pkg, license_identifier: str, when):
+    # If when is not specified the license always holds
+    when_spec = make_when_spec(when)
+    if not when_spec:
+        return
+
+    for other_when_spec in pkg.licenses:
+        if when_spec.intersects(other_when_spec):
+            when_message = ""
+            if when_spec != make_when_spec(None):
+                when_message = f"when {when_spec}"
+            other_when_message = ""
+            if other_when_spec != make_when_spec(None):
+                other_when_message = f"when {other_when_spec}"
+            err_msg = (
+                f"{pkg.name} is specified as being licensed as {license_identifier} "
+                f"{when_message}, but it is also specified as being licensed under "
+                f"{pkg.licenses[other_when_spec]} {other_when_message}, which conflict."
+            )
+            raise OverlappingLicenseError(err_msg)
+
+    pkg.licenses[when_spec] = license_identifier
+
+
+@directive("licenses")
+def license(license_identifier: str, when=None):
+    """Add a new license directive, to specify the SPDX identifier the software is
+    distributed under.
+
+    Args:
+        license_identifiers: A list of SPDX identifiers specifying the licenses
+            the software is distributed under.
+        when: A spec specifying when the license applies.
+    """
+
+    return lambda pkg: _execute_license(pkg, license_identifier, when)
+
+
 @directive("requirements")
 def requires(*requirement_specs, policy="one_of", when=None, msg=None):
     """Allows a package to request a configuration to be present in all valid solutions.
@@ -920,3 +959,7 @@ class DependencyPatchError(DirectiveError):
 
 class UnsupportedPackageDirective(DirectiveError):
     """Raised when an invalid or unsupported package directive is specified."""
+
+
+class OverlappingLicenseError(DirectiveError):
+    """Raised when two licenses are declared that apply on overlapping specs."""

lib/spack/spack/directory_layout.py

@@ -104,7 +104,7 @@ def relative_path_for_spec(self, spec):
         _check_concrete(spec)
 
         projection = spack.projections.get_projection(self.projections, spec)
-        path = spec.format(projection)
+        path = spec.format_path(projection)
         return str(Path(path))
 
     def write_spec(self, spec, path):
@@ -120,10 +120,8 @@ def write_host_environment(self, spec):
         versioning. We use it in the case that an analysis later needs to
         easily access this information.
         """
-        from spack.util.environment import get_host_environment_metadata
-
         env_file = self.env_metadata_path(spec)
-        environ = get_host_environment_metadata()
+        environ = spack.spec.get_host_environment_metadata()
         with open(env_file, "w") as fd:
             sjson.dump(environ, fd)
 

lib/spack/spack/environment/__init__.py

@@ -365,6 +365,7 @@
     read,
     root,
     spack_env_var,
+    spack_env_view_var,
     update_yaml,
 )
 
@@ -397,5 +398,6 @@
     "read",
     "root",
     "spack_env_var",
+    "spack_env_view_var",
     "update_yaml",
 ]

lib/spack/spack/environment/environment.py

@@ -64,6 +64,8 @@
 #: environment variable used to indicate the active environment
 spack_env_var = "SPACK_ENV"
 
+#: environment variable used to indicate the active environment view
+spack_env_view_var = "SPACK_ENV_VIEW"
 
 #: currently activated environment
 _active_environment: Optional["Environment"] = None
@@ -404,7 +406,7 @@ def _write_yaml(data, str_or_file):
 
 def _eval_conditional(string):
     """Evaluate conditional definitions using restricted variable scope."""
-    valid_variables = spack.util.environment.get_host_environment()
+    valid_variables = spack.spec.get_host_environment()
     valid_variables.update({"re": re, "env": os.environ})
     return eval(string, valid_variables)
 
@@ -1396,7 +1398,10 @@ def _concretize_together_where_possible(
 
         result_by_user_spec = {}
         solver = spack.solver.asp.Solver()
-        for result in solver.solve_in_rounds(specs_to_concretize, tests=tests):
+        allow_deprecated = spack.config.get("config:deprecated", False)
+        for result in solver.solve_in_rounds(
+            specs_to_concretize, tests=tests, allow_deprecated=allow_deprecated
+        ):
             result_by_user_spec.update(result.specs_by_input)
 
         result = []
@@ -1475,11 +1480,12 @@ def _concretize_separately(self, tests=False):
                 self._add_concrete_spec(s, concrete, new=False)
 
         # Concretize any new user specs that we haven't concretized yet
-        arguments, root_specs = [], []
+        args, root_specs, i = [], [], 0
         for uspec, uspec_constraints in zip(self.user_specs, self.user_specs.specs_as_constraints):
             if uspec not in old_concretized_user_specs:
                 root_specs.append(uspec)
-                arguments.append((uspec_constraints, tests))
+                args.append((i, uspec_constraints, tests))
+                i += 1
 
         # Ensure we don't try to bootstrap clingo in parallel
         if spack.config.get("config:concretizer", "clingo") == "clingo":
@@ -1498,34 +1504,39 @@ def _concretize_separately(self, tests=False):
         _ = spack.compilers.get_compiler_config()
 
         # Early return if there is nothing to do
-        if len(arguments) == 0:
+        if len(args) == 0:
             return []
 
         # Solve the environment in parallel on Linux
         start = time.time()
-        max_processes = min(
-            len(arguments),  # Number of specs
-            spack.util.cpus.determine_number_of_jobs(parallel=True),
-        )
+        num_procs = min(len(args), spack.util.cpus.determine_number_of_jobs(parallel=True))
 
-        # TODO: revisit this print as soon as darwin is parallel too
+        # TODO: support parallel concretization on macOS and Windows
         msg = "Starting concretization"
-        if sys.platform != "darwin":
-            pool_size = spack.util.parallel.num_processes(max_processes=max_processes)
-            if pool_size > 1:
-                msg = msg + " pool with {0} processes".format(pool_size)
+        if sys.platform not in ("darwin", "win32") and num_procs > 1:
+            msg += f" pool with {num_procs} processes"
         tty.msg(msg)
 
-        concretized_root_specs = spack.util.parallel.parallel_map(
-            _concretize_task, arguments, max_processes=max_processes, debug=tty.is_debug()
-        )
+        batch = []
+        for j, (i, concrete, duration) in enumerate(
+            spack.util.parallel.imap_unordered(
+                _concretize_task, args, processes=num_procs, debug=tty.is_debug()
+            )
+        ):
+            batch.append((i, concrete))
+            percentage = (j + 1) / len(args) * 100
+            tty.verbose(f"{duration:6.1f}s [{percentage:3.0f}%] {root_specs[i]}")
+            sys.stdout.flush()
+
+        # Add specs in original order
+        batch.sort(key=lambda x: x[0])
+        by_hash = {}  # for attaching information on test dependencies
+        for root, (_, concrete) in zip(root_specs, batch):
+            self._add_concrete_spec(root, concrete)
+            by_hash[concrete.dag_hash()] = concrete
 
         finish = time.time()
-        tty.msg("Environment concretized in %.2f seconds." % (finish - start))
-        by_hash = {}
-        for abstract, concrete in zip(root_specs, concretized_root_specs):
-            self._add_concrete_spec(abstract, concrete)
-            by_hash[concrete.dag_hash()] = concrete
+        tty.msg(f"Environment concretized in {finish - start:.2f} seconds")
 
         # Unify the specs objects, so we get correct references to all parents
         self._read_lockfile_dict(self._to_lockfile_dict())
@@ -1592,16 +1603,14 @@ def concretize_and_add(self, user_spec, concrete_spec=None, tests=False):
 
     @property
     def default_view(self):
-        if not self.views:
-            raise SpackEnvironmentError("{0} does not have a view enabled".format(self.name))
-
-        if default_view_name not in self.views:
-            raise SpackEnvironmentError(
-                "{0} does not have a default view enabled".format(self.name)
-            )
+        if not self.has_view(default_view_name):
+            raise SpackEnvironmentError(f"{self.name} does not have a default view enabled")
 
         return self.views[default_view_name]
 
+    def has_view(self, view_name: str) -> bool:
+        return view_name in self.views
+
     def update_default_view(self, path_or_bool: Union[str, bool]) -> None:
         """Updates the path of the default view.
 
@@ -1687,62 +1696,34 @@ def check_views(self):
                 "Loading the environment view will require reconcretization." % self.name
             )
 
-    def _env_modifications_for_default_view(self, reverse=False):
-        all_mods = spack.util.environment.EnvironmentModifications()
+    def _env_modifications_for_view(
+        self, view: ViewDescriptor, reverse: bool = False
+    ) -> spack.util.environment.EnvironmentModifications:
+        try:
+            mods = uenv.environment_modifications_for_specs(*self.concrete_roots(), view=view)
+        except Exception as e:
+            # Failing to setup spec-specific changes shouldn't be a hard error.
+            tty.warn(
+                "couldn't load runtime environment due to {}: {}".format(e.__class__.__name__, e)
+            )
+            return spack.util.environment.EnvironmentModifications()
+        return mods.reversed() if reverse else mods
 
-        visited = set()
-
-        errors = []
-        for root_spec in self.concrete_roots():
-            if root_spec in self.default_view and root_spec.installed and root_spec.package:
-                for spec in root_spec.traverse(deptype="run", root=True):
-                    if spec.name in visited:
-                        # It is expected that only one instance of the package
-                        # can be added to the environment - do not attempt to
-                        # add multiple.
-                        tty.debug(
-                            "Not adding {0} to shell modifications: "
-                            "this package has already been added".format(
-                                spec.format("{name}/{hash:7}")
-                            )
-                        )
-                        continue
-                    else:
-                        visited.add(spec.name)
-
-                    try:
-                        mods = uenv.environment_modifications_for_spec(spec, self.default_view)
-                    except Exception as e:
-                        msg = "couldn't get environment settings for %s" % spec.format(
-                            "{name}@{version} /{hash:7}"
-                        )
-                        errors.append((msg, str(e)))
-                        continue
-
-                    all_mods.extend(mods.reversed() if reverse else mods)
-
-        return all_mods, errors
-
-    def add_default_view_to_env(self, env_mod):
-        """
-        Collect the environment modifications to activate an environment using the
-        default view. Removes duplicate paths.
+    def add_view_to_env(
+        self, env_mod: spack.util.environment.EnvironmentModifications, view: str
+    ) -> spack.util.environment.EnvironmentModifications:
+        """Collect the environment modifications to activate an environment using the provided
+        view. Removes duplicate paths.
 
         Args:
-            env_mod (spack.util.environment.EnvironmentModifications): the environment
-                modifications object that is modified.
-        """
-        if default_view_name not in self.views:
-            # No default view to add to shell
+            env_mod: the environment modifications object that is modified.
+            view: the name of the view to activate."""
+        descriptor = self.views.get(view)
+        if not descriptor:
             return env_mod
 
-        env_mod.extend(uenv.unconditional_environment_modifications(self.default_view))
-
-        mods, errors = self._env_modifications_for_default_view()
-        env_mod.extend(mods)
-        if errors:
-            for err in errors:
-                tty.warn(*err)
+        env_mod.extend(uenv.unconditional_environment_modifications(descriptor))
+        env_mod.extend(self._env_modifications_for_view(descriptor))
 
         # deduplicate paths from specs mapped to the same location
         for env_var in env_mod.group_by_name():
@@ -1750,23 +1731,21 @@ def add_default_view_to_env(self, env_mod):
 
         return env_mod
 
-    def rm_default_view_from_env(self, env_mod):
-        """
-        Collect the environment modifications to deactivate an environment using the
-        default view. Reverses the action of ``add_default_view_to_env``.
+    def rm_view_from_env(
+        self, env_mod: spack.util.environment.EnvironmentModifications, view: str
+    ) -> spack.util.environment.EnvironmentModifications:
+        """Collect the environment modifications to deactivate an environment using the provided
+        view. Reverses the action of ``add_view_to_env``.
 
         Args:
-            env_mod (spack.util.environment.EnvironmentModifications): the environment
-                modifications object that is modified.
-        """
-        if default_view_name not in self.views:
-            # No default view to add to shell
+            env_mod: the environment modifications object that is modified.
+            view: the name of the view to deactivate."""
+        descriptor = self.views.get(view)
+        if not descriptor:
             return env_mod
 
-        env_mod.extend(uenv.unconditional_environment_modifications(self.default_view).reversed())
-
-        mods, _ = self._env_modifications_for_default_view(reverse=True)
-        env_mod.extend(mods)
+        env_mod.extend(uenv.unconditional_environment_modifications(descriptor).reversed())
+        env_mod.extend(self._env_modifications_for_view(descriptor, reverse=True))
 
         return env_mod
 
@@ -2419,10 +2398,12 @@ def _concretize_from_constraints(spec_constraints, tests=False):
             invalid_constraints.extend(inv_variant_constraints)
 
 
-def _concretize_task(packed_arguments):
-    spec_constraints, tests = packed_arguments
+def _concretize_task(packed_arguments) -> Tuple[int, Spec, float]:
+    index, spec_constraints, tests = packed_arguments
     with tty.SuppressOutput(msg_enabled=False):
-        return _concretize_from_constraints(spec_constraints, tests)
+        start = time.time()
+        spec = _concretize_from_constraints(spec_constraints, tests)
+        return index, spec, time.time() - start
 
 
 def make_repo_path(root):

lib/spack/spack/environment/shell.py

@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 import os
+from typing import Optional
 
 import llnl.util.tty as tty
 from llnl.util.tty.color import colorize
@@ -13,12 +14,14 @@
 from spack.util.environment import EnvironmentModifications
 
 
-def activate_header(env, shell, prompt=None):
+def activate_header(env, shell, prompt=None, view: Optional[str] = None):
     # Construct the commands to run
     cmds = ""
     if shell == "csh":
         # TODO: figure out how to make color work for csh
         cmds += "setenv SPACK_ENV %s;\n" % env.path
+        if view:
+            cmds += "setenv SPACK_ENV_VIEW %s;\n" % view
         cmds += 'alias despacktivate "spack env deactivate";\n'
         if prompt:
             cmds += "if (! $?SPACK_OLD_PROMPT ) "
@@ -29,6 +32,8 @@ def activate_header(env, shell, prompt=None):
             prompt = colorize("@G{%s} " % prompt, color=True)
 
         cmds += "set -gx SPACK_ENV %s;\n" % env.path
+        if view:
+            cmds += "set -gx SPACK_ENV_VIEW %s;\n" % view
         cmds += "function despacktivate;\n"
         cmds += "   spack env deactivate;\n"
         cmds += "end;\n"
@@ -40,15 +45,21 @@ def activate_header(env, shell, prompt=None):
     elif shell == "bat":
         # TODO: Color
         cmds += 'set "SPACK_ENV=%s"\n' % env.path
+        if view:
+            cmds += 'set "SPACK_ENV_VIEW=%s"\n' % view
         # TODO: despacktivate
         # TODO: prompt
     elif shell == "pwsh":
         cmds += "$Env:SPACK_ENV='%s'\n" % env.path
+        if view:
+            cmds += "$Env:SPACK_ENV_VIEW='%s'\n" % view
     else:
         if "color" in os.getenv("TERM", "") and prompt:
             prompt = colorize("@G{%s}" % prompt, color=True, enclose=True)
 
         cmds += "export SPACK_ENV=%s;\n" % env.path
+        if view:
+            cmds += "export SPACK_ENV_VIEW=%s;\n" % view
         cmds += "alias despacktivate='spack env deactivate';\n"
         if prompt:
             cmds += "if [ -z ${SPACK_OLD_PS1+x} ]; then\n"
@@ -66,12 +77,14 @@ def deactivate_header(shell):
     cmds = ""
     if shell == "csh":
         cmds += "unsetenv SPACK_ENV;\n"
+        cmds += "unsetenv SPACK_ENV_VIEW;\n"
         cmds += "if ( $?SPACK_OLD_PROMPT ) "
         cmds += '    eval \'set prompt="$SPACK_OLD_PROMPT" &&'
         cmds += "          unsetenv SPACK_OLD_PROMPT';\n"
         cmds += "unalias despacktivate;\n"
     elif shell == "fish":
         cmds += "set -e SPACK_ENV;\n"
+        cmds += "set -e SPACK_ENV_VIEW;\n"
         cmds += "functions -e despacktivate;\n"
         #
         # NOTE: Not changing fish_prompt (above) => no need to restore it here.
@@ -79,14 +92,19 @@ def deactivate_header(shell):
     elif shell == "bat":
         # TODO: Color
         cmds += 'set "SPACK_ENV="\n'
+        cmds += 'set "SPACK_ENV_VIEW="\n'
         # TODO: despacktivate
         # TODO: prompt
     elif shell == "pwsh":
         cmds += "Set-Item -Path Env:SPACK_ENV\n"
+        cmds += "Set-Item -Path Env:SPACK_ENV_VIEW\n"
     else:
         cmds += "if [ ! -z ${SPACK_ENV+x} ]; then\n"
         cmds += "unset SPACK_ENV; export SPACK_ENV;\n"
         cmds += "fi;\n"
+        cmds += "if [ ! -z ${SPACK_ENV_VIEW+x} ]; then\n"
+        cmds += "unset SPACK_ENV_VIEW; export SPACK_ENV_VIEW;\n"
+        cmds += "fi;\n"
         cmds += "alias despacktivate > /dev/null 2>&1 && unalias despacktivate;\n"
         cmds += "if [ ! -z ${SPACK_OLD_PS1+x} ]; then\n"
         cmds += "    if [ \"$SPACK_OLD_PS1\" = '$$$$' ]; then\n"
@@ -100,24 +118,23 @@ def deactivate_header(shell):
     return cmds
 
 
-def activate(env, use_env_repo=False, add_view=True):
-    """
-    Activate an environment and append environment modifications
+def activate(
+    env: ev.Environment, use_env_repo=False, view: Optional[str] = "default"
+) -> EnvironmentModifications:
+    """Activate an environment and append environment modifications
 
     To activate an environment, we add its configuration scope to the
     existing Spack configuration, and we set active to the current
     environment.
 
     Arguments:
-        env (spack.environment.Environment): the environment to activate
-        use_env_repo (bool): use the packages exactly as they appear in the
-            environment's repository
-        add_view (bool): generate commands to add view to path variables
+        env: the environment to activate
+        use_env_repo: use the packages exactly as they appear in the environment's repository
+        view: generate commands to add runtime environment variables for named view
 
     Returns:
         spack.util.environment.EnvironmentModifications: Environment variables
-        modifications to activate environment.
-    """
+        modifications to activate environment."""
     ev.activate(env, use_env_repo=use_env_repo)
 
     env_mods = EnvironmentModifications()
@@ -129,9 +146,9 @@ def activate(env, use_env_repo=False, add_view=True):
     # become PATH variables.
     #
     try:
-        if add_view and ev.default_view_name in env.views:
+        if view and env.has_view(view):
             with spack.store.STORE.db.read_transaction():
-                env.add_default_view_to_env(env_mods)
+                env.add_view_to_env(env_mods, view)
     except (spack.repo.UnknownPackageError, spack.repo.UnknownNamespaceError) as e:
         tty.error(e)
         tty.die(
@@ -145,17 +162,15 @@ def activate(env, use_env_repo=False, add_view=True):
     return env_mods
 
 
-def deactivate():
-    """
-    Deactivate an environment and collect corresponding environment modifications.
+def deactivate() -> EnvironmentModifications:
+    """Deactivate an environment and collect corresponding environment modifications.
 
     Note: unloads the environment in its current state, not in the state it was
         loaded in, meaning that specs that were removed from the spack environment
         after activation are not unloaded.
 
     Returns:
-        spack.util.environment.EnvironmentModifications: Environment variables
-        modifications to activate environment.
+        Environment variables modifications to activate environment.
     """
     env_mods = EnvironmentModifications()
     active = ev.active_environment()
@@ -163,10 +178,12 @@ def deactivate():
     if active is None:
         return env_mods
 
-    if ev.default_view_name in active.views:
+    active_view = os.getenv(ev.spack_env_view_var)
+
+    if active_view and active.has_view(active_view):
         try:
             with spack.store.STORE.db.read_transaction():
-                active.rm_default_view_from_env(env_mods)
+                active.rm_view_from_env(env_mods, active_view)
         except (spack.repo.UnknownPackageError, spack.repo.UnknownNamespaceError) as e:
             tty.warn(e)
             tty.warn(

lib/spack/spack/error.py

@@ -128,3 +128,7 @@ def __init__(self, provided, required, constraint_type):
         self.provided = provided
         self.required = required
         self.constraint_type = constraint_type
+
+
+class FetchError(SpackError):
+    """Superclass for fetch-related errors."""

lib/spack/spack/fetch_strategy.py

@@ -35,6 +35,7 @@
 import llnl.util
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
+from llnl.string import comma_and, quote
 from llnl.util.filesystem import get_single_file, mkdirp, temp_cwd, temp_rename, working_dir
 from llnl.util.symlink import symlink
 
@@ -49,7 +50,6 @@
 import spack.version.git_ref_lookup
 from spack.util.compression import decompressor_for
 from spack.util.executable import CommandNotFoundError, which
-from spack.util.string import comma_and, quote
 
 #: List of all fetch strategies, created by FetchStrategy metaclass.
 all_strategies = []
@@ -401,7 +401,7 @@ def _fetch_curl(self, url):
 
             try:
                 web_util.check_curl_code(curl.returncode)
-            except web_util.FetchError as err:
+            except spack.error.FetchError as err:
                 raise spack.fetch_strategy.FailedDownloadError(url, str(err))
 
         self._check_headers(headers)
@@ -734,7 +734,11 @@ def version_from_git(git_exe):
     @property
     def git(self):
         if not self._git:
-            self._git = spack.util.git.git()
+            try:
+                self._git = spack.util.git.git(required=True)
+            except CommandNotFoundError as exc:
+                tty.error(str(exc))
+                raise
 
             # Disable advice for a quieter fetch
             # https://github.com/git/git/blob/master/Documentation/RelNotes/1.7.2.txt
@@ -1290,7 +1294,7 @@ def fetch(self):
 
         parsed_url = urllib.parse.urlparse(self.url)
         if parsed_url.scheme != "s3":
-            raise web_util.FetchError("S3FetchStrategy can only fetch from s3:// urls.")
+            raise spack.error.FetchError("S3FetchStrategy can only fetch from s3:// urls.")
 
         tty.debug("Fetching {0}".format(self.url))
 
@@ -1337,7 +1341,7 @@ def fetch(self):
 
         parsed_url = urllib.parse.urlparse(self.url)
         if parsed_url.scheme != "gs":
-            raise web_util.FetchError("GCSFetchStrategy can only fetch from gs:// urls.")
+            raise spack.error.FetchError("GCSFetchStrategy can only fetch from gs:// urls.")
 
         tty.debug("Fetching {0}".format(self.url))
 
@@ -1431,7 +1435,7 @@ def from_kwargs(**kwargs):
             on attribute names (e.g., ``git``, ``hg``, etc.)
 
     Raises:
-        spack.util.web.FetchError: If no ``fetch_strategy`` matches the args.
+        spack.error.FetchError: If no ``fetch_strategy`` matches the args.
     """
     for fetcher in all_strategies:
         if fetcher.matches(kwargs):
@@ -1538,7 +1542,7 @@ def for_package_version(pkg, version=None):
     # if it's a commit, we must use a GitFetchStrategy
     if isinstance(version, spack.version.GitVersion):
         if not hasattr(pkg, "git"):
-            raise web_util.FetchError(
+            raise spack.error.FetchError(
                 f"Cannot fetch git version for {pkg.name}. Package has no 'git' attribute"
             )
         # Populate the version with comparisons to other commits
@@ -1688,11 +1692,11 @@ def destroy(self):
         shutil.rmtree(self.root, ignore_errors=True)
 
 
-class NoCacheError(web_util.FetchError):
+class NoCacheError(spack.error.FetchError):
     """Raised when there is no cached archive for a package."""
 
 
-class FailedDownloadError(web_util.FetchError):
+class FailedDownloadError(spack.error.FetchError):
     """Raised when a download fails."""
 
     def __init__(self, url, msg=""):
@@ -1700,23 +1704,23 @@ def __init__(self, url, msg=""):
         self.url = url
 
 
-class NoArchiveFileError(web_util.FetchError):
+class NoArchiveFileError(spack.error.FetchError):
     """Raised when an archive file is expected but none exists."""
 
 
-class NoDigestError(web_util.FetchError):
+class NoDigestError(spack.error.FetchError):
     """Raised after attempt to checksum when URL has no digest."""
 
 
-class ExtrapolationError(web_util.FetchError):
+class ExtrapolationError(spack.error.FetchError):
     """Raised when we can't extrapolate a version for a package."""
 
 
-class FetcherConflict(web_util.FetchError):
+class FetcherConflict(spack.error.FetchError):
     """Raised for packages with invalid fetch attributes."""
 
 
-class InvalidArgsError(web_util.FetchError):
+class InvalidArgsError(spack.error.FetchError):
     """Raised when a version can't be deduced from a set of arguments."""
 
     def __init__(self, pkg=None, version=None, **args):
@@ -1729,11 +1733,11 @@ def __init__(self, pkg=None, version=None, **args):
         super().__init__(msg, long_msg)
 
 
-class ChecksumError(web_util.FetchError):
+class ChecksumError(spack.error.FetchError):
     """Raised when archive fails to checksum."""
 
 
-class NoStageError(web_util.FetchError):
+class NoStageError(spack.error.FetchError):
     """Raised when fetch operations are called before set_stage()."""
 
     def __init__(self, method):

lib/spack/spack/filesystem_view.py

@@ -500,7 +500,7 @@ def get_projection_for_spec(self, spec):
 
         proj = spack.projections.get_projection(self.projections, locator_spec)
         if proj:
-            return os.path.join(self._root, locator_spec.format(proj))
+            return os.path.join(self._root, locator_spec.format_path(proj))
         return self._root
 
     def get_all_specs(self):
@@ -776,7 +776,7 @@ def get_relative_projection_for_spec(self, spec):
             spec = spec.package.extendee_spec
 
         p = spack.projections.get_projection(self.projections, spec)
-        return spec.format(p) if p else ""
+        return spec.format_path(p) if p else ""
 
     def get_projection_for_spec(self, spec):
         """
@@ -791,7 +791,7 @@ def get_projection_for_spec(self, spec):
 
         proj = spack.projections.get_projection(self.projections, spec)
         if proj:
-            return os.path.join(self._root, spec.format(proj))
+            return os.path.join(self._root, spec.format_path(proj))
         return self._root
 
 

lib/spack/spack/graph.py

@@ -531,7 +531,7 @@ def edge_entry(self, edge):
         return (
             edge.parent.dag_hash(),
             edge.spec.dag_hash(),
-            f"[color=\"{':'.join(colormap[x] for x in edge.deptypes)}\"]",
+            f"[color=\"{':'.join(colormap[x] for x in dt.flag_to_tuple(edge.depflag))}\"]",
         )
 
 

lib/spack/spack/hooks/drop_redundant_rpaths.py

@@ -79,8 +79,7 @@ class ElfFilesWithRPathVisitor(BaseDirectoryVisitor):
     """Visitor that collects all elf files that have an rpath"""
 
     def __init__(self):
-        # Map from (ino, dev) -> path. We need 1 path per file, if there are hardlinks,
-        # we don't need to store the path multiple times.
+        # Keep track of what hardlinked files we've already visited.
         self.visited = set()
 
     def visit_file(self, root, rel_path, depth):
@@ -89,10 +88,10 @@ def visit_file(self, root, rel_path, depth):
         identifier = (s.st_ino, s.st_dev)
 
         # We're hitting a hardlink or symlink of an excluded lib, no need to parse.
-        if identifier in self.visited:
-            return
-
-        self.visited.add(identifier)
+        if s.st_nlink > 1:
+            if identifier in self.visited:
+                return
+            self.visited.add(identifier)
 
         result = drop_redundant_rpaths(filepath)
 

lib/spack/spack/hooks/module_file_generation.py

@@ -11,7 +11,6 @@
 
 def _for_each_enabled(spec, method_name, explicit=None):
     """Calls a method for each enabled module"""
-    spack.modules.ensure_modules_are_enabled_or_warn()
     set_names = set(spack.config.get("modules", {}).keys())
     for name in set_names:
         enabled = spack.config.get("modules:%s:enable" % name)

lib/spack/spack/install_test.py

@@ -17,6 +17,7 @@
 
 import llnl.util.filesystem as fs
 import llnl.util.tty as tty
+from llnl.string import plural
 from llnl.util.lang import nullcontext
 from llnl.util.tty.color import colorize
 
@@ -26,7 +27,6 @@
 from spack.installer import InstallError
 from spack.spec import Spec
 from spack.util.prefix import Prefix
-from spack.util.string import plural
 
 #: Stand-alone test failure info type
 TestFailureType = Tuple[BaseException, str]
@@ -1039,7 +1039,7 @@ def test_pkg_id(cls, spec):
         Returns:
             str: the install test package identifier
         """
-        return spec.format("{name}-{version}-{hash:7}")
+        return spec.format_path("{name}-{version}-{hash:7}")
 
     @classmethod
     def test_log_name(cls, spec):

lib/spack/spack/installer.py

@@ -131,12 +131,12 @@ def set_term_title(self, text: str):
         if not sys.stdout.isatty():
             return
 
-        status = "{0} {1}".format(text, self.get_progress())
-        sys.stdout.write("\033]0;Spack: {0}\007".format(status))
+        status = f"{text} {self.get_progress()}"
+        sys.stdout.write(f"\x1b]0;Spack: {status}\x07")
         sys.stdout.flush()
 
     def get_progress(self) -> str:
-        return "[{0}/{1}]".format(self.pkg_num, self.pkg_count)
+        return f"[{self.pkg_num}/{self.pkg_count}]"
 
 
 class TermStatusLine:
@@ -175,7 +175,7 @@ def clear(self):
 
         # Move the cursor to the beginning of the first "Waiting for" message and clear
         # everything after it.
-        sys.stdout.write("\x1b[%sF\x1b[J" % lines)
+        sys.stdout.write(f"\x1b[{lines}F\x1b[J")
         sys.stdout.flush()
 
 
@@ -220,14 +220,13 @@ def _handle_external_and_upstream(pkg: "spack.package_base.PackageBase", explici
     # consists in module file generation and registration in the DB.
     if pkg.spec.external:
         _process_external_package(pkg, explicit)
-        _print_installed_pkg("{0} (external {1})".format(pkg.prefix, package_id(pkg)))
+        _print_installed_pkg(f"{pkg.prefix} (external {package_id(pkg)})")
         return True
 
     if pkg.spec.installed_upstream:
         tty.verbose(
-            "{0} is installed in an upstream Spack instance at {1}".format(
-                package_id(pkg), pkg.spec.prefix
-            )
+            f"{package_id(pkg)} is installed in an upstream Spack instance at "
+            f"{pkg.spec.prefix}"
         )
         _print_installed_pkg(pkg.prefix)
 
@@ -296,7 +295,7 @@ def _packages_needed_to_bootstrap_compiler(
             package is the bootstrap compiler (``True``) or one of its dependencies
             (``False``).  The list will be empty if there are no compilers.
     """
-    tty.debug("Bootstrapping {0} compiler".format(compiler))
+    tty.debug(f"Bootstrapping {compiler} compiler")
     compilers = spack.compilers.compilers_for_spec(compiler, arch_spec=architecture)
     if compilers:
         return []
@@ -305,9 +304,9 @@ def _packages_needed_to_bootstrap_compiler(
 
     # Set the architecture for the compiler package in a way that allows the
     # concretizer to back off if needed for the older bootstrapping compiler
-    dep.constrain("platform=%s" % str(architecture.platform))
-    dep.constrain("os=%s" % str(architecture.os))
-    dep.constrain("target=%s:" % architecture.target.microarchitecture.family.name)
+    dep.constrain(f"platform={str(architecture.platform)}")
+    dep.constrain(f"os={str(architecture.os)}")
+    dep.constrain(f"target={architecture.target.microarchitecture.family.name}:")
     # concrete CompilerSpec has less info than concrete Spec
     # concretize as Spec to add that information
     dep.concretize()
@@ -340,15 +339,15 @@ def _hms(seconds: int) -> str:
     if m:
         parts.append("%dm" % m)
     if s:
-        parts.append("%.2fs" % s)
+        parts.append(f"{s:.2f}s")
     return " ".join(parts)
 
 
 def _log_prefix(pkg_name) -> str:
     """Prefix of the form "[pid]: [pkg name]: ..." when printing a status update during
     the build."""
-    pid = "{0}: ".format(os.getpid()) if tty.show_pid() else ""
-    return "{0}{1}:".format(pid, pkg_name)
+    pid = f"{os.getpid()}: " if tty.show_pid() else ""
+    return f"{pid}{pkg_name}:"
 
 
 def _print_installed_pkg(message: str) -> None:
@@ -375,9 +374,9 @@ def print_install_test_log(pkg: "spack.package_base.PackageBase") -> None:
 
 
 def _print_timer(pre: str, pkg_id: str, timer: timer.BaseTimer) -> None:
-    phases = ["{}: {}.".format(p.capitalize(), _hms(timer.duration(p))) for p in timer.phases]
-    phases.append("Total: {}".format(_hms(timer.duration())))
-    tty.msg("{0} Successfully installed {1}".format(pre, pkg_id), "  ".join(phases))
+    phases = [f"{p.capitalize()}: {_hms(timer.duration(p))}." for p in timer.phases]
+    phases.append(f"Total: {_hms(timer.duration())}")
+    tty.msg(f"{pre} Successfully installed {pkg_id}", "  ".join(phases))
 
 
 def _install_from_cache(
@@ -402,14 +401,14 @@ def _install_from_cache(
     )
     pkg_id = package_id(pkg)
     if not installed_from_cache:
-        pre = "No binary for {0} found".format(pkg_id)
+        pre = f"No binary for {pkg_id} found"
         if cache_only:
-            tty.die("{0} when cache-only specified".format(pre))
+            tty.die(f"{pre} when cache-only specified")
 
-        tty.msg("{0}: installing from source".format(pre))
+        tty.msg(f"{pre}: installing from source")
         return False
     t.stop()
-    tty.debug("Successfully extracted {0} from binary cache".format(pkg_id))
+    tty.debug(f"Successfully extracted {pkg_id} from binary cache")
 
     _write_timer_json(pkg, t, True)
     _print_timer(pre=_log_prefix(pkg.name), pkg_id=pkg_id, timer=t)
@@ -430,19 +429,19 @@ def _process_external_package(pkg: "spack.package_base.PackageBase", explicit: b
     """
     assert pkg.spec.external, "Expected to post-install/register an external package."
 
-    pre = "{s.name}@{s.version} :".format(s=pkg.spec)
+    pre = f"{pkg.spec.name}@{pkg.spec.version} :"
     spec = pkg.spec
 
     if spec.external_modules:
-        tty.msg("{0} has external module in {1}".format(pre, spec.external_modules))
-        tty.debug("{0} is actually installed in {1}".format(pre, spec.external_path))
+        tty.msg(f"{pre} has external module in {spec.external_modules}")
+        tty.debug(f"{pre} is actually installed in {spec.external_path}")
     else:
-        tty.debug("{0} externally installed in {1}".format(pre, spec.external_path))
+        tty.debug(f"{pre} externally installed in {spec.external_path}")
 
     try:
         # Check if the package was already registered in the DB.
         # If this is the case, then only make explicit if required.
-        tty.debug("{0} already registered in DB".format(pre))
+        tty.debug(f"{pre} already registered in DB")
         record = spack.store.STORE.db.get_record(spec)
         if explicit and not record.explicit:
             spack.store.STORE.db.update_explicit(spec, explicit)
@@ -451,11 +450,11 @@ def _process_external_package(pkg: "spack.package_base.PackageBase", explicit: b
         # If not, register it and generate the module file.
         # For external packages we just need to run
         # post-install hooks to generate module files.
-        tty.debug("{0} generating module file".format(pre))
+        tty.debug(f"{pre} generating module file")
         spack.hooks.post_install(spec, explicit)
 
         # Add to the DB
-        tty.debug("{0} registering into DB".format(pre))
+        tty.debug(f"{pre} registering into DB")
         spack.store.STORE.db.add(spec, None, explicit=explicit)
 
 
@@ -490,7 +489,7 @@ def _process_binary_cache_tarball(
         if download_result is None:
             return False
 
-    tty.msg("Extracting {0} from binary cache".format(package_id(pkg)))
+    tty.msg(f"Extracting {package_id(pkg)} from binary cache")
 
     with timer.measure("install"), spack.util.path.filter_padding():
         binary_distribution.extract_tarball(
@@ -522,7 +521,7 @@ def _try_install_from_binary_cache(
     if not spack.mirror.MirrorCollection(binary=True):
         return False
 
-    tty.debug("Searching for binary cache of {0}".format(package_id(pkg)))
+    tty.debug(f"Searching for binary cache of {package_id(pkg)}")
 
     with timer.measure("search"):
         matches = binary_distribution.get_mirrors_for_spec(pkg.spec, index_only=True)
@@ -590,9 +589,9 @@ def dump_packages(spec: "spack.spec.Spec", path: str) -> None:
                 source_repo = spack.repo.Repo(source_repo_root)
                 source_pkg_dir = source_repo.dirname_for_package_name(node.name)
             except spack.repo.RepoError as err:
-                tty.debug("Failed to create source repo for {0}: {1}".format(node.name, str(err)))
+                tty.debug(f"Failed to create source repo for {node.name}: {str(err)}")
                 source_pkg_dir = None
-                tty.warn("Warning: Couldn't copy in provenance for {0}".format(node.name))
+                tty.warn(f"Warning: Couldn't copy in provenance for {node.name}")
 
         # Create a destination repository
         dest_repo_root = os.path.join(path, node.namespace)
@@ -632,7 +631,7 @@ def install_msg(name: str, pid: int, install_status: InstallStatus) -> str:
 
     Return: Colorized installing message
     """
-    pre = "{0}: ".format(pid) if tty.show_pid() else ""
+    pre = f"{pid}: " if tty.show_pid() else ""
     post = (
         " @*{%s}" % install_status.get_progress()
         if install_status and spack.config.get("config:install_status", True)
@@ -698,7 +697,7 @@ def log(pkg: "spack.package_base.PackageBase") -> None:
             # in the stage tree (not arbitrary files)
             abs_expr = os.path.realpath(glob_expr)
             if os.path.realpath(pkg.stage.path) not in abs_expr:
-                errors.write("[OUTSIDE SOURCE PATH]: {0}\n".format(glob_expr))
+                errors.write(f"[OUTSIDE SOURCE PATH]: {glob_expr}\n")
                 continue
             # Now that we are sure that the path is within the correct
             # folder, make it relative and check for matches
@@ -718,14 +717,14 @@ def log(pkg: "spack.package_base.PackageBase") -> None:
                     # Here try to be conservative, and avoid discarding
                     # the whole install procedure because of copying a
                     # single file failed
-                    errors.write("[FAILED TO ARCHIVE]: {0}".format(f))
+                    errors.write(f"[FAILED TO ARCHIVE]: {f}")
 
         if errors.getvalue():
             error_file = os.path.join(target_dir, "errors.txt")
             fs.mkdirp(target_dir)
             with open(error_file, "w") as err:
                 err.write(errors.getvalue())
-            tty.warn("Errors occurred when archiving files.\n\t" "See: {0}".format(error_file))
+            tty.warn(f"Errors occurred when archiving files.\n\tSee: {error_file}")
 
     dump_packages(pkg.spec, packages_dir)
 
@@ -761,11 +760,11 @@ def __init__(self, pkg: "spack.package_base.PackageBase", install_args: dict):
         """
         # Ensure dealing with a package that has a concrete spec
         if not isinstance(pkg, spack.package_base.PackageBase):
-            raise ValueError("{0} must be a package".format(str(pkg)))
+            raise ValueError(f"{str(pkg)} must be a package")
 
         self.pkg = pkg
         if not self.pkg.spec.concrete:
-            raise ValueError("{0} must have a concrete spec".format(self.pkg.name))
+            raise ValueError(f"{self.pkg.name} must have a concrete spec")
 
         # Cache the package phase options with the explicit package,
         # popping the options to ensure installation of associated
@@ -797,14 +796,14 @@ def __init__(self, pkg: "spack.package_base.PackageBase", install_args: dict):
 
     def __repr__(self) -> str:
         """Returns a formal representation of the build request."""
-        rep = "{0}(".format(self.__class__.__name__)
+        rep = f"{self.__class__.__name__}("
         for attr, value in self.__dict__.items():
-            rep += "{0}={1}, ".format(attr, value.__repr__())
-        return "{0})".format(rep.strip(", "))
+            rep += f"{attr}={value.__repr__()}, "
+        return f"{rep.strip(', ')})"
 
     def __str__(self) -> str:
         """Returns a printable version of the build request."""
-        return "package={0}, install_args={1}".format(self.pkg.name, self.install_args)
+        return f"package={self.pkg.name}, install_args={self.install_args}"
 
     def _add_default_args(self) -> None:
         """Ensure standard install options are set to at least the default."""
@@ -847,10 +846,11 @@ def get_depflags(self, pkg: "spack.package_base.PackageBase") -> int:
         else:
             cache_only = self.install_args.get("dependencies_cache_only")
 
-        # Include build dependencies if pkg is not installed and cache_only
-        # is False, or if build depdencies are explicitly called for
-        # by include_build_deps.
-        if include_build_deps or not (cache_only or pkg.spec.installed):
+        # Include build dependencies if pkg is going to be built from sources, or
+        # if build deps are explicitly requested.
+        if include_build_deps or not (
+            cache_only or pkg.spec.installed and not pkg.spec.dag_hash() in self.overwrite
+        ):
             depflag |= dt.BUILD
         if self.run_tests(pkg):
             depflag |= dt.TEST
@@ -929,18 +929,18 @@ def __init__(
 
         # Ensure dealing with a package that has a concrete spec
         if not isinstance(pkg, spack.package_base.PackageBase):
-            raise ValueError("{0} must be a package".format(str(pkg)))
+            raise ValueError(f"{str(pkg)} must be a package")
 
         self.pkg = pkg
         if not self.pkg.spec.concrete:
-            raise ValueError("{0} must have a concrete spec".format(self.pkg.name))
+            raise ValueError(f"{self.pkg.name} must have a concrete spec")
 
         # The "unique" identifier for the task's package
         self.pkg_id = package_id(self.pkg)
 
         # The explicit build request associated with the package
         if not isinstance(request, BuildRequest):
-            raise ValueError("{0} must have a build request".format(str(pkg)))
+            raise ValueError(f"{str(pkg)} must have a build request")
 
         self.request = request
 
@@ -948,8 +948,9 @@ def __init__(
         # ensure priority queue invariants when tasks are "removed" from the
         # queue.
         if status == STATUS_REMOVED:
-            msg = "Cannot create a build task for {0} with status '{1}'"
-            raise InstallError(msg.format(self.pkg_id, status), pkg=pkg)
+            raise InstallError(
+                f"Cannot create a build task for {self.pkg_id} with status '{status}'", pkg=pkg
+            )
 
         self.status = status
 
@@ -963,9 +964,9 @@ def __init__(
         # to support tracking of parallel, multi-spec, environment installs.
         self.dependents = set(get_dependent_ids(self.pkg.spec))
 
-        tty.debug("Pkg id {0} has the following dependents:".format(self.pkg_id))
+        tty.debug(f"Pkg id {self.pkg_id} has the following dependents:")
         for dep_id in self.dependents:
-            tty.debug("- {0}".format(dep_id))
+            tty.debug(f"- {dep_id}")
 
         # Set of dependencies
         #
@@ -987,9 +988,9 @@ def __init__(
         if not spack.compilers.compilers_for_spec(compiler_spec, arch_spec=arch_spec):
             # The compiler is in the queue, identify it as dependency
             dep = spack.compilers.pkg_spec_for_compiler(compiler_spec)
-            dep.constrain("platform=%s" % str(arch_spec.platform))
-            dep.constrain("os=%s" % str(arch_spec.os))
-            dep.constrain("target=%s:" % arch_spec.target.microarchitecture.family.name)
+            dep.constrain(f"platform={str(arch_spec.platform)}")
+            dep.constrain(f"os={str(arch_spec.os)}")
+            dep.constrain(f"target={arch_spec.target.microarchitecture.family.name}:")
             dep.concretize()
             dep_id = package_id(dep.package)
             self.dependencies.add(dep_id)
@@ -1025,14 +1026,14 @@ def __ne__(self, other):
 
     def __repr__(self) -> str:
         """Returns a formal representation of the build task."""
-        rep = "{0}(".format(self.__class__.__name__)
+        rep = f"{self.__class__.__name__}("
         for attr, value in self.__dict__.items():
-            rep += "{0}={1}, ".format(attr, value.__repr__())
-        return "{0})".format(rep.strip(", "))
+            rep += f"{attr}={value.__repr__()}, "
+        return f"{rep.strip(', ')})"
 
     def __str__(self) -> str:
         """Returns a printable version of the build task."""
-        dependencies = "#dependencies={0}".format(len(self.dependencies))
+        dependencies = f"#dependencies={len(self.dependencies)}"
         return "priority={0}, status={1}, start={2}, {3}".format(
             self.priority, self.status, self.start, dependencies
         )
@@ -1055,7 +1056,7 @@ def add_dependent(self, pkg_id: str) -> None:
             pkg_id:  package identifier of the dependent package
         """
         if pkg_id != self.pkg_id and pkg_id not in self.dependents:
-            tty.debug("Adding {0} as a dependent of {1}".format(pkg_id, self.pkg_id))
+            tty.debug(f"Adding {pkg_id} as a dependent of {self.pkg_id}")
             self.dependents.add(pkg_id)
 
     def flag_installed(self, installed: List[str]) -> None:
@@ -1069,9 +1070,8 @@ def flag_installed(self, installed: List[str]) -> None:
         for pkg_id in now_installed:
             self.uninstalled_deps.remove(pkg_id)
             tty.debug(
-                "{0}: Removed {1} from uninstalled deps list: {2}".format(
-                    self.pkg_id, pkg_id, self.uninstalled_deps
-                ),
+                f"{self.pkg_id}: Removed {pkg_id} from uninstalled deps list: "
+                f"{self.uninstalled_deps}",
                 level=2,
             )
 
@@ -1169,18 +1169,18 @@ def __init__(self, installs: List[Tuple["spack.package_base.PackageBase", dict]]
 
     def __repr__(self) -> str:
         """Returns a formal representation of the package installer."""
-        rep = "{0}(".format(self.__class__.__name__)
+        rep = f"{self.__class__.__name__}("
         for attr, value in self.__dict__.items():
-            rep += "{0}={1}, ".format(attr, value.__repr__())
-        return "{0})".format(rep.strip(", "))
+            rep += f"{attr}={value.__repr__()}, "
+        return f"{rep.strip(', ')})"
 
     def __str__(self) -> str:
         """Returns a printable version of the package installer."""
-        requests = "#requests={0}".format(len(self.build_requests))
-        tasks = "#tasks={0}".format(len(self.build_tasks))
-        failed = "failed ({0}) = {1}".format(len(self.failed), self.failed)
-        installed = "installed ({0}) = {1}".format(len(self.installed), self.installed)
-        return "{0}: {1}; {2}; {3}; {4}".format(self.pid, requests, tasks, installed, failed)
+        requests = f"#requests={len(self.build_requests)}"
+        tasks = f"#tasks={len(self.build_tasks)}"
+        failed = f"failed ({len(self.failed)}) = {self.failed}"
+        installed = f"installed ({len(self.installed)}) = {self.installed}"
+        return f"{self.pid}: {requests}; {tasks}; {installed}; {failed}"
 
     def _add_bootstrap_compilers(
         self,
@@ -1225,9 +1225,7 @@ def _modify_existing_task(self, pkgid: str, attr, value) -> None:
         for i, tup in enumerate(self.build_pq):
             key, task = tup
             if task.pkg_id == pkgid:
-                tty.debug(
-                    "Modifying task for {0} to treat it as a compiler".format(pkgid), level=2
-                )
+                tty.debug(f"Modifying task for {pkgid} to treat it as a compiler", level=2)
                 setattr(task, attr, value)
                 self.build_pq[i] = (key, task)
 
@@ -1292,7 +1290,7 @@ def _check_deps_status(self, request: BuildRequest) -> None:
             # Check for failure since a prefix lock is not required
             if spack.store.STORE.failure_tracker.has_failed(dep):
                 action = "'spack install' the dependency"
-                msg = "{0} is marked as an install failure: {1}".format(dep_id, action)
+                msg = f"{dep_id} is marked as an install failure: {action}"
                 raise InstallError(err.format(request.pkg_id, msg), pkg=dep_pkg)
 
             # Attempt to get a read lock to ensure another process does not
@@ -1300,7 +1298,7 @@ def _check_deps_status(self, request: BuildRequest) -> None:
             # installed
             ltype, lock = self._ensure_locked("read", dep_pkg)
             if lock is None:
-                msg = "{0} is write locked by another process".format(dep_id)
+                msg = f"{dep_id} is write locked by another process"
                 raise InstallError(err.format(request.pkg_id, msg), pkg=request.pkg)
 
             # Flag external and upstream packages as being installed
@@ -1319,7 +1317,7 @@ def _check_deps_status(self, request: BuildRequest) -> None:
                     or rec.installation_time > request.overwrite_time
                 )
             ):
-                tty.debug("Flagging {0} as installed per the database".format(dep_id))
+                tty.debug(f"Flagging {dep_id} as installed per the database")
                 self._flag_installed(dep_pkg)
             else:
                 lock.release_read()
@@ -1355,9 +1353,9 @@ def _prepare_for_install(self, task: BuildTask) -> None:
             # Ensure there is no other installed spec with the same prefix dir
             if spack.store.STORE.db.is_occupied_install_prefix(task.pkg.spec.prefix):
                 raise InstallError(
-                    "Install prefix collision for {0}".format(task.pkg_id),
-                    long_msg="Prefix directory {0} already used by another "
-                    "installed spec.".format(task.pkg.spec.prefix),
+                    f"Install prefix collision for {task.pkg_id}",
+                    long_msg=f"Prefix directory {task.pkg.spec.prefix} already "
+                    "used by another installed spec.",
                     pkg=task.pkg,
                 )
 
@@ -1367,7 +1365,7 @@ def _prepare_for_install(self, task: BuildTask) -> None:
                 if not keep_prefix:
                     task.pkg.remove_prefix()
                 else:
-                    tty.debug("{0} is partially installed".format(task.pkg_id))
+                    tty.debug(f"{task.pkg_id} is partially installed")
 
             # Destroy the stage for a locally installed, non-DIYStage, package
             if restage and task.pkg.stage.managed_by_spack:
@@ -1412,9 +1410,8 @@ def _cleanup_failed(self, pkg_id: str) -> None:
         lock = self.failed.get(pkg_id, None)
         if lock is not None:
             err = "{0} exception when removing failure tracking for {1}: {2}"
-            msg = "Removing failure mark on {0}"
             try:
-                tty.verbose(msg.format(pkg_id))
+                tty.verbose(f"Removing failure mark on {pkg_id}")
                 lock.release_write()
             except Exception as exc:
                 tty.warn(err.format(exc.__class__.__name__, pkg_id, str(exc)))
@@ -1441,19 +1438,19 @@ def _ensure_install_ready(self, pkg: "spack.package_base.PackageBase") -> None:
             pkg: the package being locally installed
         """
         pkg_id = package_id(pkg)
-        pre = "{0} cannot be installed locally:".format(pkg_id)
+        pre = f"{pkg_id} cannot be installed locally:"
 
         # External packages cannot be installed locally.
         if pkg.spec.external:
-            raise ExternalPackageError("{0} {1}".format(pre, "is external"))
+            raise ExternalPackageError(f"{pre} is external")
 
         # Upstream packages cannot be installed locally.
         if pkg.spec.installed_upstream:
-            raise UpstreamPackageError("{0} {1}".format(pre, "is upstream"))
+            raise UpstreamPackageError(f"{pre} is upstream")
 
         # The package must have a prefix lock at this stage.
         if pkg_id not in self.locks:
-            raise InstallLockError("{0} {1}".format(pre, "not locked"))
+            raise InstallLockError(f"{pre} not locked")
 
     def _ensure_locked(
         self, lock_type: str, pkg: "spack.package_base.PackageBase"
@@ -1480,14 +1477,14 @@ def _ensure_locked(
         assert lock_type in [
             "read",
             "write",
-        ], '"{0}" is not a supported package management lock type'.format(lock_type)
+        ], f'"{lock_type}" is not a supported package management lock type'
 
         pkg_id = package_id(pkg)
         ltype, lock = self.locks.get(pkg_id, (lock_type, None))
         if lock and ltype == lock_type:
             return ltype, lock
 
-        desc = "{0} lock".format(lock_type)
+        desc = f"{lock_type} lock"
         msg = "{0} a {1} on {2} with timeout {3}"
         err = "Failed to {0} a {1} for {2} due to {3}: {4}"
 
@@ -1506,11 +1503,7 @@ def _ensure_locked(
                 op = "acquire"
                 lock = spack.store.STORE.prefix_locker.lock(pkg.spec, timeout)
                 if timeout != lock.default_timeout:
-                    tty.warn(
-                        "Expected prefix lock timeout {0}, not {1}".format(
-                            timeout, lock.default_timeout
-                        )
-                    )
+                    tty.warn(f"Expected prefix lock timeout {timeout}, not {lock.default_timeout}")
                 if lock_type == "read":
                     lock.acquire_read()
                 else:
@@ -1535,7 +1528,7 @@ def _ensure_locked(
                 tty.debug(msg.format("Upgrading to", desc, pkg_id, pretty_seconds(timeout or 0)))
                 op = "upgrade to"
                 lock.upgrade_read_to_write(timeout)
-            tty.debug("{0} is now {1} locked".format(pkg_id, lock_type))
+            tty.debug(f"{pkg_id} is now {lock_type} locked")
 
         except (lk.LockDowngradeError, lk.LockTimeoutError) as exc:
             tty.debug(err.format(op, desc, pkg_id, exc.__class__.__name__, str(exc)))
@@ -1560,14 +1553,14 @@ def _add_tasks(self, request: BuildRequest, all_deps):
             all_deps (defaultdict(set)): dictionary of all dependencies and
                 associated dependents
         """
-        tty.debug("Initializing the build queue for {0}".format(request.pkg.name))
+        tty.debug(f"Initializing the build queue for {request.pkg.name}")
 
         # Ensure not attempting to perform an installation when user didn't
         # want to go that far for the requested package.
         try:
             _check_last_phase(request.pkg)
         except BadInstallPhase as err:
-            tty.warn("Installation request refused: {0}".format(str(err)))
+            tty.warn(f"Installation request refused: {str(err)}")
             return
 
         # Skip out early if the spec is not being installed locally (i.e., if
@@ -1718,9 +1711,9 @@ def _install_task(self, task: BuildTask, install_status: InstallStatus) -> None:
             # A StopPhase exception means that do_install was asked to
             # stop early from clients, and is not an error at this point
             spack.hooks.on_install_failure(task.request.pkg.spec)
-            pid = "{0}: ".format(self.pid) if tty.show_pid() else ""
-            tty.debug("{0}{1}".format(pid, str(e)))
-            tty.debug("Package stage directory: {0}".format(pkg.stage.source_path))
+            pid = f"{self.pid}: " if tty.show_pid() else ""
+            tty.debug(f"{pid}{str(e)}")
+            tty.debug(f"Package stage directory: {pkg.stage.source_path}")
 
     def _next_is_pri0(self) -> bool:
         """
@@ -1815,7 +1808,7 @@ def _remove_task(self, pkg_id: str) -> Optional[BuildTask]:
             pkg_id: identifier for the package to be removed
         """
         if pkg_id in self.build_tasks:
-            tty.debug("Removing build task for {0} from list".format(pkg_id))
+            tty.debug(f"Removing build task for {pkg_id} from list")
             task = self.build_tasks.pop(pkg_id)
             task.status = STATUS_REMOVED
             return task
@@ -1831,10 +1824,8 @@ def _requeue_task(self, task: BuildTask, install_status: InstallStatus) -> None:
         """
         if task.status not in [STATUS_INSTALLED, STATUS_INSTALLING]:
             tty.debug(
-                "{0} {1}".format(
-                    install_msg(task.pkg_id, self.pid, install_status),
-                    "in progress by another process",
-                )
+                f"{install_msg(task.pkg_id, self.pid, install_status)} "
+                "in progress by another process"
             )
 
         new_task = task.next_attempt(self.installed)
@@ -1851,7 +1842,7 @@ def _setup_install_dir(self, pkg: "spack.package_base.PackageBase") -> None:
         """
         if not os.path.exists(pkg.spec.prefix):
             path = spack.util.path.debug_padded_filter(pkg.spec.prefix)
-            tty.debug("Creating the installation directory {0}".format(path))
+            tty.debug(f"Creating the installation directory {path}")
             spack.store.STORE.layout.create_install_directory(pkg.spec)
         else:
             # Set the proper group for the prefix
@@ -1887,8 +1878,8 @@ def _update_failed(
             exc: optional exception if associated with the failure
         """
         pkg_id = task.pkg_id
-        err = "" if exc is None else ": {0}".format(str(exc))
-        tty.debug("Flagging {0} as failed{1}".format(pkg_id, err))
+        err = "" if exc is None else f": {str(exc)}"
+        tty.debug(f"Flagging {pkg_id} as failed{err}")
         if mark:
             self.failed[pkg_id] = spack.store.STORE.failure_tracker.mark(task.pkg.spec)
         else:
@@ -1897,14 +1888,14 @@ def _update_failed(
 
         for dep_id in task.dependents:
             if dep_id in self.build_tasks:
-                tty.warn("Skipping build of {0} since {1} failed".format(dep_id, pkg_id))
+                tty.warn(f"Skipping build of {dep_id} since {pkg_id} failed")
                 # Ensure the dependent's uninstalled dependents are
                 # up-to-date and their build tasks removed.
                 dep_task = self.build_tasks[dep_id]
                 self._update_failed(dep_task, mark)
                 self._remove_task(dep_id)
             else:
-                tty.debug("No build task for {0} to skip since {1} failed".format(dep_id, pkg_id))
+                tty.debug(f"No build task for {dep_id} to skip since {pkg_id} failed")
 
     def _update_installed(self, task: BuildTask) -> None:
         """
@@ -1934,23 +1925,21 @@ def _flag_installed(
             # Already determined the package has been installed
             return
 
-        tty.debug("Flagging {0} as installed".format(pkg_id))
+        tty.debug(f"Flagging {pkg_id} as installed")
 
         self.installed.add(pkg_id)
 
         # Update affected dependents
         dependent_ids = dependent_ids or get_dependent_ids(pkg.spec)
         for dep_id in set(dependent_ids):
-            tty.debug("Removing {0} from {1}'s uninstalled dependencies.".format(pkg_id, dep_id))
+            tty.debug(f"Removing {pkg_id} from {dep_id}'s uninstalled dependencies.")
             if dep_id in self.build_tasks:
                 # Ensure the dependent's uninstalled dependencies are
                 # up-to-date.  This will require requeueing the task.
                 dep_task = self.build_tasks[dep_id]
                 self._push_task(dep_task.next_attempt(self.installed))
             else:
-                tty.debug(
-                    "{0} has no build task to update for {1}'s success".format(dep_id, pkg_id)
-                )
+                tty.debug(f"{dep_id} has no build task to update for {pkg_id}'s success")
 
     def _init_queue(self) -> None:
         """Initialize the build queue from the list of build requests."""
@@ -2031,8 +2020,8 @@ def install(self) -> None:
 
             pkg, pkg_id, spec = task.pkg, task.pkg_id, task.pkg.spec
             install_status.next_pkg(pkg)
-            install_status.set_term_title("Processing {0}".format(pkg.name))
-            tty.debug("Processing {0}: task={1}".format(pkg_id, task))
+            install_status.set_term_title(f"Processing {pkg.name}")
+            tty.debug(f"Processing {pkg_id}: task={task}")
             # Ensure that the current spec has NO uninstalled dependencies,
             # which is assumed to be reflected directly in its priority.
             #
@@ -2044,24 +2033,19 @@ def install(self) -> None:
             if task.priority != 0:
                 term_status.clear()
                 tty.error(
-                    "Detected uninstalled dependencies for {0}: {1}".format(
-                        pkg_id, task.uninstalled_deps
-                    )
+                    f"Detected uninstalled dependencies for {pkg_id}: " f"{task.uninstalled_deps}"
                 )
                 left = [dep_id for dep_id in task.uninstalled_deps if dep_id not in self.installed]
                 if not left:
-                    tty.warn(
-                        "{0} does NOT actually have any uninstalled deps" " left".format(pkg_id)
-                    )
+                    tty.warn(f"{pkg_id} does NOT actually have any uninstalled deps left")
                 dep_str = "dependencies" if task.priority > 1 else "dependency"
 
                 # Hook to indicate task failure, but without an exception
                 spack.hooks.on_install_failure(task.request.pkg.spec)
 
                 raise InstallError(
-                    "Cannot proceed with {0}: {1} uninstalled {2}: {3}".format(
-                        pkg_id, task.priority, dep_str, ",".join(task.uninstalled_deps)
-                    ),
+                    f"Cannot proceed with {pkg_id}: {task.priority} uninstalled "
+                    f"{dep_str}: {','.join(task.uninstalled_deps)}",
                     pkg=pkg,
                 )
 
@@ -2078,7 +2062,7 @@ def install(self) -> None:
             # assume using a separate (failed) prefix lock file.
             if pkg_id in self.failed or spack.store.STORE.failure_tracker.has_failed(spec):
                 term_status.clear()
-                tty.warn("{0} failed to install".format(pkg_id))
+                tty.warn(f"{pkg_id} failed to install")
                 self._update_failed(task)
 
                 # Mark that the package failed
@@ -2095,7 +2079,7 @@ def install(self) -> None:
             # another process is likely (un)installing the spec or has
             # determined the spec has already been installed (though the
             # other process may be hung).
-            install_status.set_term_title("Acquiring lock for {0}".format(pkg.name))
+            install_status.set_term_title(f"Acquiring lock for {pkg.name}")
             term_status.add(pkg_id)
             ltype, lock = self._ensure_locked("write", pkg)
             if lock is None:
@@ -2118,7 +2102,7 @@ def install(self) -> None:
                 task.request.overwrite_time = time.time()
 
             # Determine state of installation artifacts and adjust accordingly.
-            install_status.set_term_title("Preparing {0}".format(pkg.name))
+            install_status.set_term_title(f"Preparing {pkg.name}")
             self._prepare_for_install(task)
 
             # Flag an already installed package
@@ -2164,7 +2148,7 @@ def install(self) -> None:
 
             # Proceed with the installation since we have an exclusive write
             # lock on the package.
-            install_status.set_term_title("Installing {0}".format(pkg.name))
+            install_status.set_term_title(f"Installing {pkg.name}")
             try:
                 action = self._install_action(task)
 
@@ -2185,8 +2169,9 @@ def install(self) -> None:
             except KeyboardInterrupt as exc:
                 # The build has been terminated with a Ctrl-C so terminate
                 # regardless of the number of remaining specs.
-                err = "Failed to install {0} due to {1}: {2}"
-                tty.error(err.format(pkg.name, exc.__class__.__name__, str(exc)))
+                tty.error(
+                    f"Failed to install {pkg.name} due to " f"{exc.__class__.__name__}: {str(exc)}"
+                )
                 spack.hooks.on_install_cancel(task.request.pkg.spec)
                 raise
 
@@ -2195,9 +2180,10 @@ def install(self) -> None:
                     raise
 
                 # Checking hash on downloaded binary failed.
-                err = "Failed to install {0} from binary cache due to {1}:"
-                err += " Requeueing to install from source."
-                tty.error(err.format(pkg.name, str(exc)))
+                tty.error(
+                    f"Failed to install {pkg.name} from binary cache due "
+                    f"to {str(exc)}: Requeueing to install from source."
+                )
                 # this overrides a full method, which is ugly.
                 task.use_cache = False  # type: ignore[misc]
                 self._requeue_task(task, install_status)
@@ -2215,13 +2201,12 @@ def install(self) -> None:
                     # lower levels -- skip printing if already printed.
                     # TODO: sort out this and SpackError.print_context()
                     tty.error(
-                        "Failed to install {0} due to {1}: {2}".format(
-                            pkg.name, exc.__class__.__name__, str(exc)
-                        )
+                        f"Failed to install {pkg.name} due to "
+                        f"{exc.__class__.__name__}: {str(exc)}"
                     )
                 # Terminate if requested to do so on the first failure.
                 if self.fail_fast:
-                    raise InstallError("{0}: {1}".format(fail_fast_err, str(exc)), pkg=pkg)
+                    raise InstallError(f"{fail_fast_err}: {str(exc)}", pkg=pkg)
 
                 # Terminate at this point if the single explicit spec has
                 # failed to install.
@@ -2260,17 +2245,17 @@ def install(self) -> None:
 
         if failed_explicits or missing:
             for _, pkg_id, err in failed_explicits:
-                tty.error("{0}: {1}".format(pkg_id, err))
+                tty.error(f"{pkg_id}: {err}")
 
             for _, pkg_id in missing:
-                tty.error("{0}: Package was not installed".format(pkg_id))
+                tty.error(f"{pkg_id}: Package was not installed")
 
             if len(failed_explicits) > 0:
                 pkg = failed_explicits[0][0]
                 ids = [pkg_id for _, pkg_id, _ in failed_explicits]
                 tty.debug(
                     "Associating installation failure with first failed "
-                    "explicit package ({0}) from {1}".format(ids[0], ", ".join(ids))
+                    f"explicit package ({ids[0]}) from {', '.join(ids)}"
                 )
 
             elif len(missing) > 0:
@@ -2278,7 +2263,7 @@ def install(self) -> None:
                 ids = [pkg_id for _, pkg_id in missing]
                 tty.debug(
                     "Associating installation failure with first "
-                    "missing package ({0}) from {1}".format(ids[0], ", ".join(ids))
+                    f"missing package ({ids[0]}) from {', '.join(ids)}"
                 )
 
             raise InstallError(
@@ -2356,7 +2341,7 @@ def run(self) -> bool:
             self.timer.stop("stage")
 
             tty.debug(
-                "{0} Building {1} [{2}]".format(self.pre, self.pkg_id, self.pkg.build_system_class)  # type: ignore[attr-defined] # noqa: E501
+                f"{self.pre} Building {self.pkg_id} [{self.pkg.build_system_class}]"  # type: ignore[attr-defined] # noqa: E501
             )
 
             # get verbosity from do_install() parameter or saved value
@@ -2401,7 +2386,7 @@ def _install_source(self) -> None:
             return
 
         src_target = os.path.join(pkg.spec.prefix, "share", pkg.name, "src")
-        tty.debug("{0} Copying source to {1}".format(self.pre, src_target))
+        tty.debug(f"{self.pre} Copying source to {src_target}")
 
         fs.install_tree(
             pkg.stage.source_path, src_target, allow_broken_symlinks=(sys.platform != "win32")
@@ -2463,8 +2448,7 @@ def _real_install(self) -> None:
                         with logger.force_echo():
                             inner_debug_level = tty.debug_level()
                             tty.set_debug(debug_level)
-                            msg = "{0} Executing phase: '{1}'"
-                            tty.msg(msg.format(self.pre, phase_fn.name))
+                            tty.msg(f"{self.pre} Executing phase: '{phase_fn.name}'")
                             tty.set_debug(inner_debug_level)
 
                         # Catch any errors to report to logging
@@ -2538,12 +2522,9 @@ def install(self):
         except fs.CouldNotRestoreDirectoryBackup as e:
             self.database.remove(self.task.pkg.spec)
             tty.error(
-                "Recovery of install dir of {0} failed due to "
-                "{1}: {2}. The spec is now uninstalled.".format(
-                    self.task.pkg.name,
-                    e.outer_exception.__class__.__name__,
-                    str(e.outer_exception),
-                )
+                f"Recovery of install dir of {self.task.pkg.name} failed due to "
+                f"{e.outer_exception.__class__.__name__}: {str(e.outer_exception)}. "
+                "The spec is now uninstalled."
             )
 
             # Unwrap the actual installation exception.
@@ -2566,7 +2547,7 @@ class BadInstallPhase(InstallError):
     """Raised for an install phase option is not allowed for a package."""
 
     def __init__(self, pkg_name, phase):
-        super().__init__("'{0}' is not a valid phase for package {1}".format(phase, pkg_name))
+        super().__init__(f"'{phase}' is not a valid phase for package {pkg_name}")
 
 
 class ExternalPackageError(InstallError):

lib/spack/spack/main.py

@@ -774,7 +774,7 @@ def _profile_wrapper(command, parser, args, unknown_args):
         pr.disable()
 
         # print out profile stats.
-        stats = pstats.Stats(pr)
+        stats = pstats.Stats(pr, stream=sys.stderr)
         stats.sort_stats(*sortby)
         stats.print_stats(nlines)