Use split caching to cache deps even if the later build fails

harendra-kumar · harendra-kumar · commit 216c225f281f · 2026-04-08T18:56:17.000+05:30
diff --git a/.github/workflows/haskell.yml b/.github/workflows/haskell.yml
@@ -90,7 +90,7 @@ jobs:
       # If you have not committed packcheck.sh in your repo at PACKCHECK
       # then it is automatically pulled from this URL.
       PACKCHECK_GITHUB_URL: "https://raw.githubusercontent.com/composewell/packcheck"
-      PACKCHECK_GITHUB_COMMIT: "3d3c94bf48f18a99271d509c1f1702d15824b1f0"
+      PACKCHECK_GITHUB_COMMIT: "44902d709e53ea1bbbe00934541e15a9f62ab77f"
 
       # ------------------------------------------------------------------------
       # Final build variables
@@ -106,23 +106,26 @@ jobs:
       fail-fast: false
       matrix:
 
-        # The order of jobs is important to optimize fail-fast.
+        # The order of jobs is important to optimize fail-fast, if
+        # fail-fast is set to true.
 
         # This section is to order the important jobs first especially for
         # "fail-fast" so that these are the ones started first.
         #name:
         #  - ci
 
-        # The name of the CI is built using the name and other info from CI,
-        # therefore, the "name" field can be same for all tests here.
-        #
-        # The reason we have an explicit "name" field here is to force
-        # an additional config instead of adding to an existing config
-        # while adding additional configs.
+        # IMPORTANT NOTE:
+        # If runner, command, ghc version are identical then the name of
+        # CI is used to distinguish the cache key.
+
+        # The reason we have an explicit "name" field in the following
+        # entries is to force an additional config instead of adding to
+        # an existing config while adding additional configs.
         # Look at <https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-syntax-for-github-actions#jobsjob_idstrategymatrix>
         # for more info about adding matrix elements.
         # Adding any element to the list will increase the number of matrix
         # elements proportional to the cross product.
+
         include:
 
           #- name: ci
@@ -219,6 +222,8 @@ jobs:
             runner: windows-latest
             command: cabal
             ghc_version: 9.12.4
+            # WARNING! cannot use # comments inside pack_options.
+            # DISABLE_SDIST_BUILD for shorter paths on Windows
             pack_options: >-
               DISABLE_SDIST_BUILD="y"
 
@@ -246,7 +251,27 @@ jobs:
 # Usually you do need to change anything below, this is generic code for
 # caching and running packcheck on Linux/Mac/Windows.
 #-----------------------------------------------------------------------------
+
     steps:
+
+    - name: Optimize Windows Runner Environment
+      if: runner.os == 'Windows'
+      shell: powershell
+      run: |
+        # Enable long paths.  Sometimes failures occur due to path
+        # length limitation.
+        Set-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Control\FileSystem' -Name 'LongPathsEnabled' -value 1
+
+        # Cache saving is very slow on Windows, it could be due to tar,
+        # or the compression program or the file system. Changing the
+        # compression level of zstd does not help. We are also not able to pick
+        # another tar program by changing the path, tar is picked up by the
+        # cache action itself.
+
+        # This does not seem to make much difference.
+        # Disable Windows Defender to speed up IO/Tar operations
+        Set-MpPreference -DisableRealtimeMonitoring $true
+
     - uses: actions/checkout@v4
 
     # This should happen before cache restore.
@@ -255,34 +280,49 @@ jobs:
       run: |
         rm -f ~/.ghcup
 
-    - name: Cache hackage package index (non-Windows)
-      uses: actions/cache@v4
+    # See the "cabal path" output in the CI logs to tweak the cache
+    # locations.
+
+    # Shared by all tests, all platforms
+    - name: Restore hackage package index (non-Windows)
+      id: restore-hackage
+      uses: actions/cache/restore@v4
       if: runner.os != 'Windows'
       with:
         path: |
             ~/.cache/cabal/packages
-        # Bump the key version to clear the cache
-        key: cache-cabal-packages
-
-    # See the "cabal path" output in the CI logs to tweak the cache locations
-    # ghc is big but cheap to install, if cache size is a concern we can avoid
-    # caching it.
-    - name: Cache ghcup and ghc (non-Windows)
-      uses: actions/cache@v4
+        key: cabal-hackage-index-non-windows
+
+    # GHC is not test/options specific
+    - name: Restore ghcup and ghc (non-Windows)
+      id: restore-ghcup
+      uses: actions/cache/restore@v4
       if: runner.os != 'Windows'
       with:
         path: |
           ~/.ghcup
-        key: ${{ matrix.runner }}-${{ matrix.ghc_version }}.${{ matrix.ghc_salt}}
+        key: ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}
+
+    # GHC is not test/options specific
+    #- name: Restore ghcup and ghc (Windows)
+    #  id: restore-ghcup-win
+    #  uses: actions/cache/restore@v4
+    #  if: runner.os == 'Windows'
+    #  with:
+    #    path: |
+    #      C:/ghcup
+    #    key: ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}
 
     # XXX If we want to invalidate the cache on resolver change we
     # should use a separate cache for stack as it should be keyed on
     # resolver as well. But that requires resolver as a matrix element
     # and then copied to pack_options from there, needs some work. It
     # should be fine as resolver minor version change can only increase
     # the cache size.
-    - name: Cache build dependencies (non-Windows)
-      uses: actions/cache@v4
+    # Deps are test/options specific
+    - name: Restore build dependencies (non-Windows)
+      id: restore-deps-nonwin
+      uses: actions/cache/restore@v4
       if: runner.os != 'Windows'
       with:
         # cabal: ~/.local/bin, ~/.local/state/cabal
@@ -292,18 +332,17 @@ jobs:
           ~/.local/bin
           ~/.local/state/cabal
           ~/.stack
-        # Bump the key version to clear the cache
-        key: ${{ matrix.runner }}-${{ matrix.command }}-${{ matrix.ghc_version }}-${{ matrix.name }}-v1
+        key: ${{ matrix.command }}-deps-ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}-${{ matrix.name }}
 
-    - name: Cache common directories (Windows)
-      uses: actions/cache@v4
+    # Deps are test/options specific
+    - name: Restore build dependencies, hackage index, local/bin (Windows)
+      id: restore-deps-win
+      uses: actions/cache/restore@v4
       if: runner.os == 'Windows'
       with:
         path: |
-          ${{ env.APPDATA }}/local
-          C:/ghcup
           C:/cabal
-        key: ${{ matrix.runner }}-${{ matrix.command }}-${{ matrix.ghc_version }}-${{ matrix.name }}-v1
+        key: ${{ matrix.command }}-deps-ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}-${{ matrix.name }}
 
     - name: Download packcheck
       # on windows-latest GitHub Actions defaults to PowerShell
@@ -323,7 +362,8 @@ jobs:
             chmod +x $PACKCHECK
         fi
 
-    - name: Run packcheck
+    - name: Run packcheck (dependencies only)
+      id: deps-only
       # on windows-latest GitHub Actions defaults to PowerShell
       shell: bash
       run: |
@@ -344,6 +384,8 @@ jobs:
             export GHCUP_INSTALL_BASE_PREFIX=$HOME
             ;;
           CYGWIN*|MINGW*|MSYS*)
+            # To keep the paths shorter on Windows
+            # XXX Will docspec work with this?
             export CABAL_BUILDDIR="C:\b"
             PATH_VAR="$PATH_VAR:/c/Program Files/7-Zip:/mingw64/bin"
             ;;
@@ -352,20 +394,99 @@ jobs:
         # arguments in PACKCHECK_COMMAND e.g. DOCSPEC_OPTIONS="--timeout 60".
         # Direct invocation would word-split on spaces inside quoted values.
         echo "$PACKCHECK $PACKCHECK_COMMAND PATH=\"$PATH_VAR\""
-        bash -c "$PACKCHECK $PACKCHECK_COMMAND PATH=\"$PATH_VAR\""
+        bash -c "$PACKCHECK $PACKCHECK_COMMAND BUILD_ONLY_DEPS=y PATH=\"$PATH_VAR\""
+
+    - name: Save hackage package index (non-Windows)
+      uses: actions/cache/save@v4
+      if: always() && steps.deps-only.outcome == 'success' && runner.os != 'Windows' && steps.restore-hackage.outputs.cache-hit != 'true'
+      with:
+        path: ~/.cache/cabal/packages
+        key: cabal-hackage-index-non-windows
+
+    - name: Save ghcup and ghc (non-Windows)
+      uses: actions/cache/save@v4
+      if: always() && steps.deps-only.outcome == 'success' && runner.os != 'Windows' && steps.restore-ghcup.outputs.cache-hit != 'true'
+      with:
+        path: ~/.ghcup
+        key: ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}
+
+    # On Windows, ghc restore step takes 2-3 minutes whereas installing
+    # GHC takes less than 2 minutes. On top of this saving the ghc cache
+    # takes 7 minutes. So this does not make sense.
+    #- name: Save ghcup and ghc (Windows)
+    #  uses: actions/cache/save@v4
+    #  if: always() && steps.deps-only.outcome == 'success' && runner.os == 'Windows' && steps.restore-ghcup-win.outputs.cache-hit != 'true'
+    #  with:
+    #    path: |
+    #      C:/ghcup
+    #    key: ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}
+
+    # Deps are test/options specific, hence, matrix.name in the key
+    - name: Save build dependencies (non-Windows)
+      uses: actions/cache/save@v4
+      if: always() && steps.deps-only.outcome == 'success' && runner.os != 'Windows' && steps.restore-deps-nonwin.outputs.cache-hit != 'true'
+      with:
+        path: |
+          ~/.local/bin
+          ~/.local/state/cabal
+          ~/.stack
+        key: ${{ matrix.command }}-deps-ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}-${{ matrix.name }}
+
+    # hackage package index is part of C:/cabal
+    # Deps are test/options specific, hence, matrix.name in the key
+    - name: Save build dependencies (Windows)
+      uses: actions/cache/save@v4
+      if: always() && steps.deps-only.outcome == 'success' && runner.os == 'Windows' && steps.restore-deps-win.outputs.cache-hit != 'true'
+      with:
+        path: |
+          ${{ env.APPDATA }}/local
+          C:/cabal
+        key: ${{ matrix.command }}-deps-ghc-${{ matrix.ghc_version }}-v${{ matrix.ghc_salt }}-${{ matrix.runner }}-${{ matrix.name }}
+
+    - name: Run packcheck (final build)
+      # on windows-latest GitHub Actions defaults to PowerShell
+      shell: bash
+      run: |
+        if test -n "$SUBDIR"
+        then
+          cd "$SUBDIR"
+        fi
+        # Commands like mount, sysctl for info require sbin
+        PATH_VAR=/bin:/usr/bin:/sbin:/usr/sbin
+        case "$(uname)" in
+          Linux)
+            # On Linux it defaults to /usr/local, during cache restore
+            # tar is unable to change permissions and restore fails.
+            export GHCUP_INSTALL_BASE_PREFIX=$HOME
+            ;;
+          CYGWIN*|MINGW*|MSYS*)
+            PATH_VAR="$PATH_VAR:/c/Program Files/7-Zip:/mingw64/bin"
+            ;;
+        esac
+        echo "$PACKCHECK $PACKCHECK_COMMAND PATH=\"$PATH_VAR\""
+        bash -c "$PACKCHECK $PACKCHECK_COMMAND BUILD_POST_DEPS=y PATH=\"$PATH_VAR\""
 
     - name: Check cache locations
-      if: runner.os != 'Windows'
+      shell: bash
       run: |
-        # We want to see if it is a symlink; e.g. on github ~/.ghcup is a
-        # pre-existing symlink to /usr/local.
-        list="$HOME/.local/bin $HOME/.local/state/cabal $HOME/.ghcup $HOME/.stack"
+        # We want to see if any cache paths are symlinks; e.g. on github
+        # ~/.ghcup is a pre-existing symlink to /usr/local.
+        if [ "$RUNNER_OS" == "Windows" ]; then
+          # Convert Windows paths to Unix-style for Bash
+          APPDATA_UNIX=$(cygpath "$APPDATA")
+          list="$APPDATA_UNIX/local C:/ghcup C:/cabal"
+        else
+          list="$HOME/.local/bin $HOME/.local/state/cabal $HOME/.ghcup $HOME/.stack"
+        fi
+
         for dir in $list; do
           # macOS does not have --no-dereference option
           if [ -L "$dir" ]; then
             echo "$dir is a symlink -> $(readlink $dir)"
+          elif [ -d "$dir" ]; then
+            du -sh "$dir" 2>/dev/null || echo "$dir permission denied"
           else
-            du -sh "$dir" 2>/dev/null || echo "$dir missing"
+            echo "$dir missing or not a dir"
           fi
         done
         echo
