[Validator] Change preg_match condition on ContainsAlphanumericValidator

Author: valmonzo

validation/custom_constraint.rst

@@ -117,12 +117,14 @@ The validator class only has one required method ``validate()``::
  // ...
  }
 
- if (!preg_match('/^[a-zA-Z0-9]+$/', $value, $matches)) {
- // the argument must be a string or an object implementing __toString()
- $this->context->buildViolation($constraint->message)
- ->setParameter('{{ string }}', $value)
- ->addViolation();
+ if (preg_match('/^[a-zA-Z0-9]+$/', $value, $matches)) {
+ return;
  }
+
+ // the argument must be a string or an object implementing __toString()
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ string }}', $value)
+ ->addViolation();
  }
  }
 
@@ -664,3 +666,4 @@ class to simplify writing unit tests for your custom constraints::
  // ...
  }
  }
+