Symfony: detect callback constraints

src/Provider/SymfonyUsageProvider.php

@@ -326,6 +326,10 @@ protected function shouldMarkAsUsed(ReflectionMethod $method): ?string
             return 'Route method via #[Route] attribute';
         }
 
+        if ($this->isMethodWithCallbackConstraintAttribute($method)) {
+            return 'Callback constraint method via #[Assert\Callback] attribute';
+        }
+
         if ($this->isProbablySymfonyListener($method)) {
             return 'Probable listener method';
         }
@@ -461,6 +465,23 @@ protected function isMethodWithRouteAttribute(ReflectionMethod $method): bool
             || $this->hasAttribute($method, 'Symfony\Component\Routing\Annotation\Route', $isInstanceOf);
     }
 
+    protected function isMethodWithCallbackConstraintAttribute(ReflectionMethod $method): bool
+    {
+        $attributes = $method->getDeclaringClass()->getAttributes('Symfony\Component\Validator\Constraints\Callback');
+
+        foreach ($attributes as $attribute) {
+            $arguments = $attribute->getArguments();
+
+            $callback = $arguments['callback'] ?? $arguments[0] ?? null;
+
+            if ($callback === $method->getName()) {
+                return true;
+            }
+        }
+
+        return $this->hasAttribute($method, 'Symfony\Component\Validator\Constraints\Callback');
+    }
+
     /**
      * Ideally, we would need to parse DIC xml to know this for sure just like phpstan-symfony does.
      */
@@ -502,6 +523,7 @@ private function isSymfonyInstalled(): bool
             || InstalledVersions::isInstalled('symfony/contracts')
             || InstalledVersions::isInstalled('symfony/console')
             || InstalledVersions::isInstalled('symfony/http-kernel')
+            || InstalledVersions::isInstalled('symfony/validator')
             || InstalledVersions::isInstalled('symfony/dependency-injection');
     }
 

tests/Rule/data/providers/symfony.php

@@ -16,6 +16,7 @@
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
 use Symfony\Component\Routing\Attribute\Route;
 use Symfony\Contracts\Service\Attribute\Required;
+use Symfony\Component\Validator\Constraints as Assert;
 
 class SomeController {
 
@@ -115,3 +116,21 @@ public function create(): self {
 class Sftp {
     const RETRY_LIMIT = 3; // used in yaml via !php/const
 }
+
+class ModelValidator
+{
+    public static function validate(): void {}
+}
+
+#[Assert\Callback([ModelValidator::class, 'validate'])]
+#[Assert\Callback('validateBar')]
+#[Assert\Callback(callback: 'validateBaz')]
+class ValidatedModel
+{
+    #[Assert\Callback]
+    public function validateFoo(): void {}
+
+    public function validateBar(): void {}
+
+    public function validateBaz(): void {}
+}