GH Action/cs: use the threshold/branch report

... instead of a full scan.

As there are some YoastCS 3.0 issues which still need to be solved by the teams, this changes the CS workflow to use the threshold report instead of expecting a 100% clean code base.

.github/workflows/cs.yml

@@ -38,6 +38,22 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Determine the base branch for the file diff
+        id: base_branch
+        env:
+          BASE_REF: ${{ github.base_ref }}
+        run: |
+          if [ "${{ github.event_name }}" == "pull_request" ]; then
+            echo "NAME=$BASE_REF" >> $GITHUB_OUTPUT
+            echo "REF=origin/$BASE_REF" >> $GITHUB_OUTPUT
+          else
+            echo 'NAME=develop' >> $GITHUB_OUTPUT
+            echo "REF=origin/develop" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Fetch base branch
+        run: git fetch --no-tags --depth=1 origin ${{ steps.base_branch.outputs.NAME }}
+
       - name: Install PHP
         uses: shivammathur/setup-php@v2
         with:
@@ -58,12 +74,18 @@ jobs:
           # Bust the cache at least once a month - output format: YYYY-MM.
           custom-cache-suffix: $(date -u "+%Y-%m")
 
-      # Check the codestyle of the files.
-      # The results of the CS check will be shown inline in the PR via the CS2PR tool.
+      # Check the codestyle of the files against a threshold of expected errors and warnings.
+      - name: Check PHP code style against the thresholds
+        run: composer check-cs-thresholds
+
+      # Check the codestyle only of the files which were changed in the current branch.
+      # This step will only be executed if the threshold check exited with a failure status.
+      # The results of this CS check will be shown inline in the PR via the CS2PR tool.
       # @link https://github.com/staabm/annotate-pull-request-from-checkstyle/
-      - name: Check PHP code style
+      - name: Check PHP code style for the changes made in the branch only
+        if: ${{ failure() }}
         id: phpcs
-        run: composer check-cs-warnings -- --no-cache --report-full --report-checkstyle=./phpcs-report.xml
+        run: composer check-branch-cs -- ${{ steps.base_branch.outputs.REF }}
 
       - name: Show PHPCS results in PR
         if: ${{ always() && steps.phpcs.outcome == 'failure' }}

composer.json

@@ -85,7 +85,7 @@
 			"Yoast\\WP\\ACF\\Config\\Composer\\Actions::check_coding_standards"
 		],
 		"check-cs-thresholds": [
-			"@putenv YOASTCS_THRESHOLD_ERRORS=0",
+			"@putenv YOASTCS_THRESHOLD_ERRORS=11",
 			"@putenv YOASTCS_THRESHOLD_WARNINGS=0",
 			"Yoast\\WP\\ACF\\Config\\Composer\\Actions::check_cs_thresholds"
 		],