[PIWOO-714] Fix PHPStan warnings at level 5

.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

@@ -63,6 +63,7 @@
     "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"
   },

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 '';
         }
     }
 

lib/payment-gateway/src/PaymentGatewayModule.php

@@ -48,7 +48,7 @@ public function services(): array
                  * prevent potential namespace conflicts when multiple plugins use this payment gateway library.
                  */
                 'payment_gateways.plugin_slug' => static function (ContainerInterface $container): string {
-                    /** @var PluginProperties $properties */
+                    /** @var PluginProperties $pluginProperties */
                     $pluginProperties = $container->get(Package::PROPERTIES);
 
                     return $pluginProperties->baseName();

phpstan.neon.dist

@@ -1,12 +1,29 @@
 parameters:
   level: 5
+  dynamicConstantNames:
+    - M4W_PLUGIN_DIR
+    - M4W_FILE
+    - M4W_PLUGIN_URL
   paths:
     - mollie-payments-for-woocommerce.php
     - lib/
     - inc/
     - src/
+  excludePaths:
+    - '*/node_modules/*'
   bootstrapFiles:
     - vendor/php-stubs/woocommerce-stubs/woocommerce-stubs.php
     - vendor/php-stubs/woocommerce-stubs/woocommerce-packages-stubs.php
     - vendor/php-stubs/woocommerce-subscriptions-stubs/woocommerce-subscriptions-stubs.php
+  ignoreErrors:
+    # apply_filters is variadic in WordPress but the stubs only declare 2 required params
+    - '#^Function apply_filters invoked with [0-9]+ parameters, [0-9]+ required\.$#'
+    # CustomOrdersTableController is an internal WooCommerce class not in stubs
+    - '#^(Class Automattic\\WooCommerce\\Internal\\DataStores\\Orders\\CustomOrdersTableController not found|Call to method custom_orders_table_usage_is_enabled\(\) on an unknown class)#'
+    # Vendored PSR container uses a namespaced path
+    - '#(unknown class|Call to method .+ on an unknown class|has unknown class) Mollie\\WooCommerce\\Vendor\\Psr\\Container\\ContainerInterface#'
+    # WC()->cart and WC()->customer are typed as non-nullable in stubs but can be null at runtime
+    - '#^(Property WooCommerce::\$cart \(WC_Cart\) in isset\(\) is not nullable|Left side of && is always true)\.$#'
+    # M4W_PLUGIN_DIR constant is defined at runtime in the main plugin file
+    - '#^Constant M4W_PLUGIN_DIR not found\.$#'
 

src/Assets/AssetsModule.php

@@ -484,7 +484,7 @@ function () use ($container, $pluginUrl, $pluginPath) {
         );
         add_action(
             'admin_init',
-            function () use ($container, $pluginVersion, $pluginUrl) {
+            function () use ($pluginVersion, $pluginUrl) {
                 if (is_admin()) {
                     global $current_section;
                     wp_register_script(