chore: fix Pyink GitHub Action to check on all changed .py files

Three fixes:
1. used "fetch-depth: 2" to ensure that files in all commits in the PR are checked
2. triggered by all changed ".py" files in the repo
3. merged the "check modified files" and "run Pyink" steps because $GITHUB_ENV cannot handle multi-line env vars without special treatment

PiperOrigin-RevId: 766793736

.github/workflows/pyink.yml

@@ -17,8 +17,7 @@ name: Check Pyink Formatting
 on:
   pull_request:
     paths:
-      - 'src/**/*.py'
-      - 'tests/**/*.py'
+      - '**.py'
       - 'pyproject.toml'
 
 jobs:
@@ -28,6 +27,8 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
 
       - name: Set up Python
         uses: actions/setup-python@v5
@@ -38,36 +39,31 @@ jobs:
         run: |
           pip install pyink
 
-      - name: Detect changed Python files
-        id: detect_changes
+      - name: Run pyink on changed files
+        id: run_pyink
         run: |
           git fetch origin ${{ github.base_ref }}
           CHANGED_FILES=$(git diff --diff-filter=ACMR --name-only origin/${{ github.base_ref }}...HEAD | grep -E '\.py$' || true)
-          echo "CHANGED_FILES=${CHANGED_FILES}" >> $GITHUB_ENV
-
-      - name: Run pyink on changed files
-        if: env.CHANGED_FILES != ''
-        run: |
+          if [ -n "$CHANGED_FILES" ]; then
             echo "Changed Python files:"
             echo "$CHANGED_FILES"
+            echo ""
+            FORMATTED_FILES=$(echo "$CHANGED_FILES" | tr '\n' ' ')
 
             # Run pyink --check
             set +e
-          pyink --check --config pyproject.toml $CHANGED_FILES
+            pyink --check --diff --config pyproject.toml $CHANGED_FILES
             RESULT=$?
             set -e
-
             if [ $RESULT -ne 0 ]; then
               echo ""
               echo "❌ Pyink formatting check failed!"
               echo "👉 To fix formatting, run locally:"
               echo ""
-            echo "    pyink --config pyproject.toml $CHANGED_FILES"
+              echo "    pyink --config pyproject.toml $FORMATTED_FILES"
               echo ""
               exit $RESULT
             fi
-
-      - name: No changed Python files detected
-        if: env.CHANGED_FILES == ''
-        run: |
+          else
             echo "No Python files changed. Skipping pyink check."
+          fi