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 +1,151 @@
+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: ''
+  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: Work around XDG directories existence (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.validate.project
+
+    - name: Add manually supplied constraints
+      if: inputs.constraints != ''
+      shell: ${{ inputs.shell }}
+      run: |
+        echo "constraints: ${{ inputs.constraints }}" >> cabal.validate.project
+
+    - name: Enable statically linked executables
+      if: inputs.static == 'true'
+      shell: ${{ inputs.shell }}
+      run: |
+        echo 'executable-static: true' >> cabal.validate.project
+
+    # must happen before the main setup so the correct ghc is default
+    # hm, but what if setup-haskell needs to install ghcup?
+    - name: Install extra ghc for tests
+      if: inputs.extra_ghc != ''
+      shell: ${{ inputs.shell }}
+      run: |
+        ghcup install ghc ${{ inputs.extra_ghc }}
+
+    - uses: haskell-actions/setup@v2
+      id: setup-haskell
+      with:
+        ghc-version: ${{ inputs.ghc }}
+        cabal-version: 3.12.1.0 # see https://github.com/haskell/cabal/pull/10251
+        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 }}-
+
+    # 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
+
+    # 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: ${{ inputs.shell }}
+      run: |
+        FLAGS="${{ env.GHC_COMMON_FLAGS }}"
+        if [[ "${{ inputs.ghc }}" == "$GHC_FOR_SOLVER_BENCHMARKS" ]]; then
+          FLAGS="$FLAGS --solver-benchmarks"
+        fi
+        if [[ "${{ matrix.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/validate-full/action.yml

@@ -0,0 +1,124 @@
+name: Validate full
+description: Run 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 }}
+
+    - name: Validate build
+      id: build
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Build
+        sh validate.sh $FLAGS -s build
+
+    - name: Tar cabal head executable
+      if: matrix.ghc == env.GHC_FOR_RELEASE
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Tar
+        CABAL_EXEC=$(cabal list-bin --builddir=dist-newstyle-validate-ghc-${{ matrix.ghc }} --project-file=cabal.validate.project cabal-install:exe:cabal)
+        # We have to tar the executable to preserve executable permissions
+        # see https://github.com/actions/upload-artifact/issues/38
+        if [[ "${{ 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 }}-$CABAL_ARCH.tar.gz"
+        tar -czvf "$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
+    - name: Upload cabal-install executable to workflow artifacts
+      if: inputs.ghc == env.GHC_FOR_RELEASE
+      uses: actions/upload-artifact@v4
+      with:
+        name: cabal-${{ runner.os }}-${{ env.CABAL_ARCH }}
+        path: ${{ env.CABAL_EXEC_TAR }}
+
+    - name: Validate lib-tests
+      env:
+        # `rawSystemStdInOut reports text decoding errors`
+        # test does not find ghc without the full path in windows
+        GHCPATH: ${{ steps.setup-haskell.outputs.ghc-exe }}
+      if: "(success() || failure()) && steps.build.outcome == 'success'"
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Validate lib-tests
+        sh validate.sh $FLAGS -s lib-tests
+
+    - name: Validate lib-suite
+      if: "(success() || failure()) && steps.build.outcome == 'success'"
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Validate lib-suite
+        sh validate.sh $FLAGS -s lib-suite
+
+    - name: Validate cli-tests
+      if: "(success() || failure()) && steps.build.outcome == 'success'"
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Validate cli-tests
+        sh validate.sh $FLAGS -s cli-tests
+
+    - name: Validate cli-suite
+      if: "(success() || failure()) && steps.build.outcome == 'success'"
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Validate cli-suite
+        sh validate.sh $FLAGS -s cli-suite
+
+    - name: Validate solver-benchmarks-tests
+      if: "(success() || failure()) && steps.build.outcome == 'success' && matrix.ghc == env.GHC_FOR_SOLVER_BENCHMARKS"
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Validate solver-benchmarks-tests
+        sh validate.sh $FLAGS -s solver-benchmarks-tests
+
+    - name: Validate solver-benchmarks-run
+      if: "(success() || failure()) && steps.build.outcome == 'success' && matrix.ghc == env.GHC_FOR_SOLVER_BENCHMARKS"
+      shell: ${{ inputs.shell }}
+      run: |
+        echo ::group::Validate solver-benchmarks-run
+        sh validate.sh $FLAGS -s solver-benchmarks-run

.github/config.yml

@@ -0,0 +1,16 @@
+# all of these will get "GHC_" prepended
+# the single quotes will be consumed by the JSON parser
+# note: FOR_RELEASE must be an element of both FOR_VALIDATE and FOR_BOOTSTRAP!
+FOR_RELEASE: '9.4.8'
+FOR_SOLVER_BENCHMARKS: '${GHC_FOR_RELEASE}'
+FOR_COMPLETE_HACKAGE_TESTS: '${GHC_FOR_RELEASE}'
+# these will be decoded with fromJSON
+# If you remove something from here, then add it to the old-ghcs job.
+# Also a removed GHC from here means that we are actually dropping
+# support, so the PR *must* have a changelog entry.
+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.
+FOR_VALIDATE_OLD: '["8.4.4", "8.2.2", "8.0.2"]'
+FOR_BOOTSTRAP: '["9.8.2", "9.6.6", "9.4.8", "9.2.8", "9.0.2"]'
+COMMON_FLAGS: '-j 2 -v'