attempt to use local actions

Extremely experimental, and with all the limitations and
restrictions I keep finding in GitHub Actions it'll probably fail
in the messiest way it can.

At present this is incomplete but sufficient to see if this has
any chance of working to begin with. If it somehow does, I'll
look into abstracting out the other sub-jobs, then making an
overnight validate for Tier 2 platforms and probably a prerelease
job (which would fix the recently revealed problem where if there
is no need to rebase on merge, no prerelease is made).

.github/actions/cabal-setup/action.yml

@@ -0,0 +1,155 @@
+name: Cabal setup
+description: Set up a workflow for Cabal
+
+inputs:
+  ghc:
+    description: ghc version to use
+    required: true
+  extra-ghc:
+    description: additional ghc for tests
+    required: false
+    default: ''
+  project:
+    description: which cabal.project to use
+    required: false
+    default: 'validate'
+  allow-newer:
+    description: allow-newer line
+    required: false
+    default: ''
+  constraints:
+    description: constraints line
+    required: false
+    default: ''
+  static:
+    description: whether to build statically
+    required: false
+    default: 'false'
+  shell:
+    description: shell to use
+    required: false
+    default: 'bash'
+  with_cache:
+    description: whether to instantiate cache
+    required: false
+    default: 'true'
+
+outputs:
+  ghc-exe:
+    description: Path to ghc installed by setup-haskell
+    value: ${{ steps.setup-haskell.outputs.ghc-exe }}
+
+runs:
+  using: composite
+  steps:
+    - name: Make sure ghc is specified
+      if: inputs.ghc == ''
+      shell: ${{ inputs.shell }}
+      run: exit 1
+
+    - name: Work around existence of XDG directories (haskell-actions/setup#62)
+      if: runner.os == 'macOS'
+      shell: ${{ inputs.shell }}
+      run: |
+        rm -rf ~/.config/cabal
+        rm -rf ~/.cache/cabal
+
+    - name: "WIN: Setup TMP environment variable"
+      if: runner.os == 'Windows'
+      shell: ${{ inputs.shell }}
+      run: |
+        echo "TMP=${{ runner.temp }}" >> "$GITHUB_ENV"
+
+    # See https://github.com/haskell/cabal/blob/master/CONTRIBUTING.md#hackage-revisions
+    - name: Add manually supplied allow-newer
+      if: inputs.allow-newer != ''
+      shell: ${{ inputs.shell }}
+      run: |
+        echo "allow-newer: ${{ inputs.allow-newer }}" >> cabal.${{ inputs.project }}.project
+
+    - name: Add manually supplied constraints
+      if: inputs.constraints != ''
+      shell: ${{ inputs.shell }}
+      run: |
+        echo "constraints: ${{ inputs.constraints }}" >> cabal.${{ inputs.project }}.project
+
+    - name: Enable statically linked executables
+      if: inputs.static == 'true'
+      shell: ${{ inputs.shell }}
+      run: |
+        echo 'executable-static: true' >> cabal.${{ inputs.project }}.project
+
+    # must happen before the main setup so the correct ghc is default
+    - name: Install extra ghc for tests
+      if: inputs.extra-ghc != ''
+      uses: haskell-actions/setup@v2
+      with:
+        ghc-version: ${{ inputs.extra-ghc }}
+        cabal-version: '3.12.1.0' # see https://github.com/haskell/cabal/pull/10251
+
+    - uses: haskell-actions/setup@v2
+      id: setup-haskell
+      with:
+        ghc-version: ${{ inputs.ghc }}
+        cabal-version: '3.12.1.0'
+        # do we use this?
+        ghcup-release-channel: https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-prereleases-0.0.8.yaml
+
+    # See the following link for a breakdown of the following step
+    # https://github.com/haskell/actions/issues/7#issuecomment-745697160
+    - uses: actions/cache@v4
+      if: inputs.with_cache != 'false'
+      with:
+        # validate.sh uses a special build dir
+        path: |
+          ${{ steps.setup-haskell.outputs.cabal-store }}
+          dist-*
+        key: ${{ runner.os }}-${{ inputs.ghc }}-${{ github.sha }}
+        restore-keys: ${{ runner.os }}-${{ inputs.ghc }}-
+
+    # Needed by cabal-testsuite/PackageTests/Configure/setup.test.hs
+    - name: "MAC: Install Autotools"
+      if: runner.os == 'macOS'
+      shell: ${{ inputs.shell }}
+      run: |
+        brew install automake
+
+    # Needed by cabal-testsuite/PackageTests/Configure/setup.test.hs
+    - name: "WIN: Install Autotools"
+      if: runner.os == 'Windows'
+      shell: ${{ inputs.shell }}
+      run: |
+        /usr/bin/pacman --noconfirm -S autotools
+
+    - name: Set validate inputs
+      shell: ${{ inputs.shell }}
+      run: |
+        FLAGS="$COMMON_FLAGS"
+        if [[ "${{ inputs.ghc }}" == "$GHC_FOR_SOLVER_BENCHMARKS" ]]; then
+          FLAGS="$FLAGS --solver-benchmarks"
+        fi
+        if [[ "${{ inputs.ghc }}" == "$GHC_FOR_COMPLETE_HACKAGE_TESTS" ]]; then
+          FLAGS="$FLAGS --complete-hackage-tests"
+        fi
+        echo "FLAGS=$FLAGS" >> "$GITHUB_ENV"
+
+    - name: Validate print-config
+      shell: ${{ inputs.shell }}
+      run: |
+        sh validate.sh $FLAGS -s print-config
+
+    - name: Validate print-tool-versions
+      shell: ${{ inputs.shell }}
+      run: |
+        sh validate.sh $FLAGS -s print-tool-versions
+
+    - name: Canonicalize architecture
+      shell: ${{ inputs.shell }}
+      run: |
+        case ${{ runner.arch }} in
+          X86) arch=i386 ;;
+          X64) arch=x86_64 ;;
+          ARM64) arch=aarch64 ;;
+          *) echo "Unsupported architecture, please fix validate.yaml" 2>/dev/null; exit 1 ;;
+        esac
+        echo "CABAL_ARCH=$arch" >> "$GITHUB_ENV"

.github/actions/dogfooding/action.yml

@@ -0,0 +1,50 @@
+name: Dogfooding cabal-install on a ghc/platform
+description: Run a cabal-install uncached validate from a previously built binary
+inputs:
+  ghc:
+    description: ghc version to use
+    required: true
+  shell:
+    description: shell to use
+    required: false
+    default: 'bash'
+  allow-newer:
+    description: allow-newer line
+    required: false
+  constraints:
+    description: constraints line
+    required: false
+
+runs:
+  using: composite
+  steps:
+    - uses: ./.github/actions/cabal-setup
+      with:
+        ghc: ${{ inputs.ghc }}
+        shell: ${{ inputs.shell }}
+        allow-newer: ${{ inputs.allow_newer }}
+        constraints: ${{ inputs.constraints }}
+        # We don't use cache to force a build with a fresh store dir and build dir
+        # This way we check cabal can build all its dependencies
+        with_cache: 'false'
+
+    - name: Download cabal executable from workflow artifacts
+      uses: actions/download-artifact@v4
+      with:
+        name: cabal-${{ runner.os }}-${{ env.CABAL_ARCH }}
+        path: cabal-head
+
+    - name: Untar the cabal executable
+      shell: ${{ inputs.shell }}
+      run: |
+        tar -xzf "./cabal-head/cabal-head-${{ runner.os }}-$CABAL_ARCH.tar.gz" -C cabal-head
+
+    - name: print-config using cabal HEAD
+      shell: ${{ inputs.shell }}
+      run: |
+        sh validate.sh $COMMON_FLAGS --with-cabal ./cabal-head/cabal -s print-config
+
+    - name: Build using cabal HEAD
+      shell: ${{ inputs.shell }}
+      run: |
+        sh validate.sh $COMMON_FLAGS --with-cabal ./cabal-head/cabal -s build

.github/actions/validate-build/action.yml

@@ -0,0 +1,89 @@
+name: Validate build
+description: Build for a full validate on a ghc version
+inputs:
+  ghc:
+    description: ghc version to use
+    required: true
+  allow-newer:
+    description: allow-newer line
+    required: false
+  constraints:
+    description: constraints line
+    required: false
+  static:
+    description: whether to build statically
+    required: false
+    default: 'false'
+  shell:
+    description: shell to use
+    required: false
+    default: 'bash'
+  with_cache:
+    description: whether to instantiate cache
+    required: false
+    default: 'true'
+
+runs:
+  using: composite
+  steps:
+    - uses: ./.github/actions/cabal-setup
+      id: cabal-setup
+      with:
+        shell: ${{ inputs.shell }}
+        ghc: ${{ inputs.ghc }}
+        allow-newer: ${{ inputs.allow-newer }}
+        constraints: ${{ inputs.constraints }}
+        static: ${{ inputs.static }}
+        with_cache: ${{ inputs.with_cache }}
+
+    # The tool is not essential to the rest of the test suite. If
+    # hackage-repo-tool is not present, any test that requires it will
+    # be skipped.
+    # We want to keep this in the loop but we don't want to fail if
+    # hackage-repo-tool breaks or fails to support a newer GHC version.
+    - name: Install hackage-repo-tool
+      continue-on-error: true
+      shell: ${{ inputs.shell }}
+      run: |
+        cabal install --ignore-project hackage-repo-tool
+
+    - name: Validate build
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Build
+        sh validate.sh $FLAGS -s build
+
+    - name: Tar cabal head executable
+      if: inputs.ghc == env.GHC_FOR_RELEASE
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Tar
+        CABAL_EXEC=$(cabal list-bin --builddir=dist-newstyle-validate-ghc-${{ inputs.ghc }} --project-file=cabal.validate.project cabal-install:exe:cabal)
+        # We have to tar the executable to preserve executable permissions
+        # see https://github.com/actions/upload-artifact/issues/38
+        if [[ "${{ runner.os }}" == "Windows" ]]; then
+          # `cabal list-bin` gives us a windows path but tar needs the posix one
+          CABAL_EXEC=$(cygpath "$CABAL_EXEC")
+        fi
+        if [[ "${{ runner.os }}" == "macOS" ]]; then
+            # Workaround to avoid bsdtar corrupting the executable
+            # such that executing it after untar throws `cannot execute binary file`
+            # see https://github.com/actions/virtual-environments/issues/2619#issuecomment-788397841
+            sudo /usr/sbin/purge
+        fi
+        DIR=$(dirname "$CABAL_EXEC")
+        FILE=$(basename "$CABAL_EXEC")
+        CABAL_EXEC_TAR="cabal-head-${{ runner.os }}${{ inputs.static == 'true' && '-static' || '' }}-$CABAL_ARCH.tar.gz"
+        tar -czvf "$CABAL_EXEC_TAR" -C "$DIR" "$FILE"
+        echo "CABAL_EXEC_TAR=$CABAL_EXEC_TAR" >> "$GITHUB_ENV"
+
+    # We upload the cabal executable built with the ghc used in the release for:
+    # - Reuse it in the dogfooding job (although we could use the cached build dir)
+    # - Make it available in the workflow to make easier testing it locally
+    # (Using the cache in dogfooding would defeat its purpose, though.)
+    - name: Upload cabal-install executable to workflow artifacts
+      if: inputs.ghc == env.GHC_FOR_RELEASE
+      uses: actions/upload-artifact@v4
+      with:
+        name: cabal-${{ runner.os }}${{ inputs.static == 'true' && '-static' || '' }}-${{ env.CABAL_ARCH }}
+        path: ${{ env.CABAL_EXEC_TAR }}

.github/actions/validate-old/action.yml

@@ -0,0 +1,43 @@
+name: Validate old ghcs
+description: Run a Cabal-only validate on an older ghc version
+inputs:
+  ghc:
+    description: ghc version to use
+    required: true
+  extra-ghc:
+    description: old ghc version to test
+    required: true
+  shell:
+    description: shell to use
+    required: false
+    default: 'bash'
+
+runs:
+  using: composite
+  steps:
+    - name: Install prerequisites for old GHCs
+      shell: ${{ inputs.shell }}
+      run: |
+        sudo apt-get update
+        sudo apt-get install libncurses5 libtinfo5
+
+    - uses: ./.github/actions/cabal-setup
+      with:
+        ghc: ${{ inputs.ghc }}
+        extra-ghc: ${{ inputs.extra-ghc }}
+
+    - name: GHC versions
+      shell: ${{ inputs.shell }}
+      run: |
+        ghc --version
+        "ghc-${{ inputs.extra-ghc }}" --version
+
+    - name: Validate build
+      shell: ${{ inputs.shell }}
+      run: |
+        sh validate.sh $COMMON_FLAGS -s build
+
+    - name: "Validate lib-suite-extras --extra-hc ghc-${{ inputs.extra-ghc }}"
+      shell: ${{ inputs.shell }}
+      run: |
+        sh validate.sh $COMMON_FLAGS --lib-only -s lib-suite-extras --extra-hc "ghc-${{ inputs.extra-ghc }}"

.github/config.yml

@@ -0,0 +1,15 @@
+# note: GHC_FOR_RELEASE must be an element of GHC_FOR_VALIDATE!
+GHC_FOR_RELEASE: "9.4.8"
+GHC_FOR_SOLVER_BENCHMARKS: $(GHC_FOR_RELEASE)
+GHC_FOR_COMPLETE_HACKAGE_TESTS: $(GHC_FOR_RELEASE)
+# these will be decoded with fromJSON, and must be quoted to keep YAML from making objects
+# If you remove something from here, then add it to GHC_FOR_VALIDATE_OLD.
+# Also a removed GHC from here means that we are actually dropping
+# support, so the PR *must* have a changelog entry.
+GHC_FOR_VALIDATE: '["9.10.1", "9.8.2", "9.6.6", "9.4.8", "9.2.8", "9.0.2", "8.10.7", "8.8.4"]'
+## GHC 7.10.3 does not install on ubuntu-22.04 with ghcup.
+## Older GHCs are not supported by ghcup in the first place.
+GHC_FOR_VALIDATE_OLD: '["8.4.4", "8.2.2", "8.0.2"]'
+#
+COMMON_FLAGS: -j 2 -v
+LTS_BRANCH: '3.12'

.github/workflows/bootstrap.yml

@@ -61,6 +61,7 @@ jobs:
           restore-keys: bootstrap-${{ runner.os }}-${{ matrix.ghc }}-20221115-
 
       - uses: actions/checkout@v4
+
       - uses: haskell-actions/setup@v2
         with:
           ghc-version: ${{ matrix.ghc }}