dev: add PHPStan level 6 with baseline

.distignore

@@ -29,3 +29,5 @@ cypress.json
 docker-compose.ci.yml
 CONTRIBUTING.md
 artifacts
+phpstan.neon
+phpstan-baseline.neon

.github/workflows/test-php.yml

@@ -51,3 +51,20 @@ jobs:
           composer install --prefer-dist --no-progress  --no-dev
       - name: Run phpunit
         run: phpunit
+
+  phpstan:
+    name: PHPStan
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup PHP version
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "7.4"
+          extensions: simplexml
+      - name: Checkout source code
+        uses: actions/checkout@v4
+      - name: Install composer
+        run: |
+          composer install --prefer-dist --no-progress
+      - name: Run phpstan
+        run: composer run phpstan

composer.json

@@ -32,7 +32,9 @@
   },
   "scripts": {
     "format": "phpcbf --standard=phpcs.xml --report-summary --report-source",
-    "lint": "phpcs --standard=phpcs.xml"
+    "lint": "phpcs --standard=phpcs.xml",
+    "phpstan": "phpstan",
+    "phpstan:generate:baseline": "phpstan --generate-baseline"
   },
   "minimum-stability": "dev",
   "prefer-stable": true,
@@ -48,6 +50,8 @@
   "require-dev": {
     "wp-coding-standards/wpcs": "^2.3",
     "dealerdirect/phpcodesniffer-composer-installer": "^1.0.0",
-    "phpcompatibility/phpcompatibility-wp": "*"
+    "phpcompatibility/phpcompatibility-wp": "*",
+    "phpstan/phpstan": "^2.1",
+    "szepeviktor/phpstan-wordpress": "^2.0"
   }
 }