build(compat): Improve patch freshness check

Run patch freshness check outside of Testing Chores so as not to block
other checks. Also, improve the logic to only check the patches that
would be affected by the PR changes.

Author: clemyan

.github/workflows/integration-workflow.yml

@@ -48,20 +48,6 @@ jobs:
       env:
         TARGET_BRANCH: ${{github.event.pull_request.base.ref}}
 
-    - name: 'Check that the patch files are consistent with fresh builds'
-      run: |
-        if [[ $(git diff --name-only "$(git merge-base origin/"$TARGET_BRANCH" HEAD)" HEAD -- packages/plugin-compat/sources/patches packages/plugin-compat/extra/ | wc -l) -gt 0 ]]; then
-          for generator in packages/plugin-compat/extra/*/gen-*-patch.ts; do
-            yarn node -r @yarnpkg/monorepo/scripts/setup-ts-execution $generator '*';
-          done
-          [[ $(git diff --name-only packages/plugin-compat/sources/patches "packages/plugin-compat/extra/*/patches/*" | tee /dev/stderr | wc -l) -eq 0 ]]
-        fi
-      shell: bash
-      if: |
-        (success() || failure()) && github.event.pull_request != ''
-      env:
-        TARGET_BRANCH: ${{github.event.pull_request.base.ref}}
-
     - name: 'Check that libzip artifacts are consistent with a fresh build (fix w/ "git merge master && bash packages/yarnpkg-libzip/artifacts/build.sh")'
       run: |
         if [[ $(git diff --name-only "$(git merge-base origin/"$TARGET_BRANCH" HEAD)" HEAD -- 'packages/yarnpkg-libzip/artifacts' 'packages/yarnpkg-libzip/sources/*.js' | wc -l) -gt 0 ]]; then

.github/workflows/plugin-compat-workflow.yml

@@ -24,3 +24,45 @@ jobs:
     - name: 'Run the plugin-compat tests'
       run: |
         node ./scripts/run-yarn.js test:plugin-compat
+
+  check-patches:
+    name: 'Check that the patch files are consistent with fresh builds'
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - run: |
+        git fetch --no-tags --unshallow origin HEAD master
+
+    - uses: ./.github/actions/prepare
+
+    - name: 'Regenerate affected patches'
+      run: |
+        PKGS=$(basename -a packages/plugin-compat/extra/*/)
+        if ! git diff --quiet "$(git merge-base origin/"$TARGET_BRANCH" HEAD)" HEAD -- 'packages/plugin-compat/extra' ':!packages/plugin-compat/extra/*/*'; then
+          # If a file outside of the package-specific folders changed, rebuild all patches
+          for pkg in $PKGS; do
+            echo "::group::Regenerating $pkg patch"
+            yarn "build:patch:$pkg" '*'
+            echo "::endgroup::"
+          done
+        else
+          # Otherwise, only rebuild the patches that have changed
+          for pkg in $PKGS; do
+            if ! git diff --quiet "$(git merge-base origin/"$TARGET_BRANCH" HEAD)" HEAD -- "packages/plugin-compat/sources/patches/$pkg.patch.ts" "packages/plugin-compat/extra/$pkg/"; then
+              echo "::group::Regenerating $pkg patch"
+              yarn "build:patch:$pkg" '*'
+              echo "::endgroup::"
+            fi
+          done
+        fi
+        if ! git diff --quiet -- 'packages/plugin-compat/extra/*/patches/*' 'packages/plugin-compat/sources/patches/'; then
+          echo ''
+          echo "Files would be changed by fresh builds:"
+          git diff --name-only -- 'packages/plugin-compat/extra/*/patches/*' 'packages/plugin-compat/sources/patches/' | sed 's/^/- /'
+          exit 1
+        fi
+      shell: bash
+      if: github.event.pull_request != ''
+      env:
+        TARGET_BRANCH: ${{github.event.pull_request.base.ref}}