[PIWOO-714] Introduce phpstan

.github/workflows/ci.yml

@@ -36,8 +36,8 @@ jobs:
       - name: Run PHPUnit
         run: ./vendor/bin/phpunit
 
-      - name: Run Psalm
-        run: ./vendor/bin/psalm --show-info=false --threads=2
+      - name: Run PHPStan
+        run: ./vendor/bin/phpstan analyze --error-format=github
 
       - name: Run PhpCS
         run: ./vendor/bin/phpcs -n --parallel=2 --runtime-set ignore_warnings_on_exit 1

composer.json

@@ -35,9 +35,12 @@
     "inpsyde/php-coding-standards": "^1.0.0",
     "inpsyde/composer-assets-compiler": "^2.5",
     "php-stubs/wordpress-stubs": "^5.0@stable",
-    "php-stubs/woocommerce-stubs": "7.9.0",
+    "php-stubs/woocommerce-stubs": "^10.6",
     "vimeo/psalm": "^4.8 || ^5.13.0",
-    "vlucas/phpdotenv": "^5.6"
+    "vlucas/phpdotenv": "^5.6",
+    "szepeviktor/phpstan-wordpress": "^1.3",
+    "phpstan/extension-installer": "^1.4",
+    "php-stubs/woocommerce-subscriptions-stubs": "^8.4"
   },
   "autoload": {
     "psr-4": {
@@ -59,6 +62,8 @@
     "fix-coding-standards": "vendor/bin/phpcbf",
     "tests": "@php ./vendor/phpunit/phpunit/phpunit --coverage-text",
     "tests:no-cov": "@php ./vendor/phpunit/phpunit/phpunit --no-coverage",
+    "phpstan": "vendor/bin/phpstan analyse",
+    "phpstan:raw": "vendor/bin/phpstan analyse --no-progress --error-format=raw",
     "check-psalm": "vendor/bin/psalm",
     "check-psalm:no-cache": "vendor/bin/psalm --no-cache"
   },
@@ -98,7 +103,8 @@
       "composer/package-versions-deprecated": true,
       "automattic/jetpack-autoloader": false,
       "composer/installers": true,
-      "inpsyde/composer-assets-compiler": true
+      "inpsyde/composer-assets-compiler": true,
+      "phpstan/extension-installer": true
     }
   }
 }

inc/woocommerce.php

@@ -30,11 +30,11 @@ function is_order_received_page()
 
 if (!function_exists('untrailingslashit')) {
     /**
-     * @since WooCommerce 2.2.0
-     * @param string $string
+     * @param string|null $string
      * @return string
+     * @since WooCommerce 2.2.0
      */
-    function untrailingslashit($string)
+    function untrailingslashit(?string $string): string
     {
         if ($string === null) {
             return '';

lib/payment-gateway/src/PaymentGateway.php

@@ -67,6 +67,8 @@ public function __construct(
         unset($this->form_fields);
         unset($this->enabled);
 
+        // phpstan:ignore [wc-stub] process_admin_options is inherited from WC_Payment_Gateway but absent from stubs
+        // @phpstan-ignore-next-line
         add_action(
             'woocommerce_update_options_payment_gateways_' . $this->id,
             [$this, 'process_admin_options']
@@ -420,7 +422,7 @@ public function get_field_value($key, $field, $postData = [])
                 sprintf('Field "%1$s" is invalid: %2$s', $key, $exception->getMessage())
             );
 
-            return null;
+            return '';
         }
     }