Remove documentation tests from GitHub Actions (#26981)

We moved documentation tests to readthedocs since a while,
so remove the one on GitHub.

.github/workflows/unit_tests.yaml

@@ -48,26 +48,6 @@ jobs:
     - name: Run style tests
       run: |
           share/spack/qa/run-style-tests
-  # Build the documentation
-  documentation:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-python@v2
-      with:
-        python-version: 3.9
-    - name: Install System packages
-      run: |
-        sudo apt-get -y update
-        sudo apt-get install -y coreutils ninja-build graphviz
-    - name: Install Python packages
-      run: |
-        pip install --upgrade pip six setuptools
-        pip install --upgrade -r lib/spack/docs/requirements.txt
-    - name: Build documentation
-      run: |
-          share/spack/qa/run-doc-tests
-
   # Check which files have been updated by the PR
   changes:
     runs-on: ubuntu-latest
@@ -112,7 +92,7 @@ jobs:
 
   # Run unit tests with different configurations on linux
   unittests:
-    needs: [ validate, style, documentation, changes ]
+    needs: [ validate, style, changes ]
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -177,7 +157,7 @@ jobs:
         flags: unittests,linux,${{ matrix.concretizer }}
   # Test shell integration
   shell:
-    needs: [ validate, style, documentation, changes ]
+    needs: [ validate, style, changes ]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -215,7 +195,7 @@ jobs:
         flags: shelltests,linux
   # Test for Python2.6 run on Centos 6
   centos6:
-    needs: [ validate, style, documentation, changes ]
+    needs: [ validate, style, changes ]
     runs-on: ubuntu-latest
     container: spack/github-actions:centos6
     steps:
@@ -248,7 +228,7 @@ jobs:
   # Test RHEL8 UBI with platform Python. This job is run
   # only on PRs modifying core Spack
   rhel8-platform-python:
-    needs: [ validate, style, documentation, changes ]
+    needs: [ validate, style, changes ]
     runs-on: ubuntu-latest
     if: ${{ needs.changes.outputs.with_coverage == 'true' }}
     container: registry.access.redhat.com/ubi8/ubi
@@ -274,7 +254,7 @@ jobs:
           spack unit-test -k 'not cvs and not svn and not hg' -x --verbose
   # Test for the clingo based solver (using clingo-cffi)
   clingo-cffi:
-    needs: [ validate, style, documentation, changes ]
+    needs: [ validate, style, changes ]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -320,7 +300,7 @@ jobs:
         flags: unittests,linux,clingo
   # Run unit tests on MacOS
   build:
-    needs: [ validate, style, documentation, changes ]
+    needs: [ validate, style, changes ]
     runs-on: macos-latest
     strategy:
       matrix:

lib/spack/docs/contribution_guide.rst

@@ -338,15 +338,6 @@ Once all of the dependencies are installed, you can try building the documentati
 If you see any warning or error messages, you will have to correct those before
 your PR is accepted.
 
-.. note::
-
-   There is also a ``run-doc-tests`` script in ``share/spack/qa``. The only
-   difference between running this script and running ``make`` by hand is that
-   the script will exit immediately if it encounters an error or warning. This
-   is necessary for CI. If you made a lot of documentation changes, it is
-   much quicker to run ``make`` by hand so that you can see all of the warnings
-   at once.
-
 If you are editing the documentation, you should obviously be running the
 documentation tests. But even if you are simply adding a new package, your
 changes could cause the documentation tests to fail:

share/spack/qa/run-doc-tests

@@ -1,26 +0,0 @@
-#!/bin/bash -e
-#
-# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
-# Spack Project Developers. See the top-level COPYRIGHT file for details.
-#
-# SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
-#
-# Description:
-#     Builds Spack documentation and checks for
-#     possible syntax errors. Treats warnings as
-#     fatal errors.
-#
-# Usage:
-#     run-doc-tests
-#
-. "$(dirname $0)/setup.sh"
-check_dependencies sphinx-apidoc sphinx-build dot git hg svn
-
-# Move to documentation directory
-# Allows script to be run from anywhere
-cd "$SPACK_ROOT/lib/spack/docs"
-
-# Treat warnings as fatal errors
-make clean --silent
-make SPHINXOPTS=-W