trying to run phpcs only on changed files

.github/workflows/php-standards-scrutinizer.yml

@@ -40,11 +40,22 @@ jobs:
         coverage: none
         tools: composer:v2
 
+    - name: Get changed files
+      id: changed-files
+      uses: tj-actions/changed-files@v41
+      with:
+          files: |
+            **/*.php
+
     - name: Install dependencies
       run: composer install
 
     - name: Check WordPress Coding Standards
-      run: ./vendor/bin/phpcs --standard=.phpcs.xml
+      if: ${{ steps.changed-files.outputs.any_changed == 'true' }}
+      run: |
+        HEAD_REF=$(git rev-parse HEAD)
+        git checkout $HEAD_REF
+      run: ./vendor/bin/phpcs-changed --standard=.phpcs.xml -s --git --git-base origin/${{ github.base_ref }} ${{ steps.changed-files.outputs.all_changed_files }}
 
     - name: Check PHP Compatibility
       run: ./vendor/bin/phpcs --standard=.phpcompat.xml

composer.json

@@ -22,7 +22,8 @@
 		"phpunit/phpunit": "*@stable",
 		"brianium/paratest": "6.x-dev",
 		"10up/wp_mock": "dev-trunk",
-		"10up/phpcs-composer": "dev-master"
+		"10up/phpcs-composer": "dev-master",
+		"sirbrillig/phpcs-changed": "^2.11.1"
 	},
 	"config": {
 		"allow-plugins": {