WIP get some form of code coverage input in PRs

Author: MaximilianAlgehed

.github/workflows/haskell-ci.yml

@@ -21,10 +21,9 @@ jobs:
     strategy:
       matrix:
         ghc-version: [latest, 9.12, "9.10", 9.8, 9.6]
-        os: [ubuntu-24.04]
       fail-fast: false
 
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v4
@@ -33,13 +32,67 @@ jobs:
           ghc-version: ${{matrix.ghc-version}}
       - uses: actions/cache/restore@v4
         with:
-          key: ${{ matrix.os }}-${{ matrix.ghc-version }}-${{ github.sha }}
+          key: ${{ matrix.ghc-version }}-${{ github.sha }}
           path: ~/.cabal/store
-          restore-keys: ${{ matrix.os }}-${{ matrix.ghc-version }}-
+          restore-keys: ${{ matrix.ghc-version }}-
       - run: cabal build all
-      - run: cabal test all
+      - run: cabal test all --ghc-options=-fhpc
+      - run: mv constrained.tix constrained-${{matrix.ghc-version}}.tix
       - run: cabal haddock all
       - uses: actions/cache/save@v4
         with:
-          key: ${{ matrix.os }}-${{ matrix.ghc-version }}-${{ github.sha }}
+          key: ${{ matrix.ghc-version }}-${{ github.sha }}
           path: ~/.cabal/store
+
+      - name: Upload coverage report
+        uses: actions/upload-artifact@v4
+        with:
+          name: constrained-${{matrix.ghc-version}}-coverage
+          path: constrained-${{ matrix.ghc-version }}.tix
+          if-no-files-found: error
+          compression-level: 0
+          retention-days: 1
+
+  coverage:
+    name: Generate coverage badge
+
+    runs-on: ubuntu-latest
+
+    needs: linux
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: haskell-actions/setup@v2
+        with:
+          ghc-version: latest
+
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: '*-coverage'
+          merge-multiple: true
+
+      - run: cabal install hpc
+
+      - run: hpc sum constrained.tix constrained-*.tix
+
+      - run: hpc report constrained.tix > report.md
+
+      - name: Find Comment
+        if: github.event.pull_request
+        uses: peter-evans/find-comment@v3
+        id: fc
+        with:
+          issue-number: ${{ github.event.pull_request.number }}
+          comment-author: 'github-actions[bot]'
+          body-includes: "expressions used"
+
+      - name: Create or update comment
+        if: github.event.pull_request
+        uses: peter-evans/create-or-update-comment@v4
+        if: steps.difference.outputs.changed == 1
+        with:
+          comment-id: ${{ steps.fc.outputs.comment-id }}
+          issue-number: ${{ github.event.pull_request.number }}
+          body: report.md
+          edit-mode: replace

.gitignore

@@ -22,3 +22,4 @@ cabal.project.local~
 .HTF/
 .ghc.environment.*
 *.*.sw*
+*.tix