minor #43611 UniqueEntityValidator: Retrieve at max two entities to check uniqueness. (AndreasA)

fabpot · fabpot · commit ed3660af7324 · 2021-10-26T10:21:32.000+02:00
This PR was merged into the 5.4 branch. Discussion ---------- UniqueEntityValidator: Retrieve at max two entities to check uniqueness. | Q | A | ------------- | --- | Branch? | 5.4 | Bug fix? | no | New feature? | no | Deprecations? | no | Tickets | Fix #43254 | License | MIT | Doc PR | symfony/symfony-docs#15965 It is enough to retrieve two entities to check for uniqueness. - No entity returned, it is definitely unique. - Two or more entities returned and it cannot be unique. - One entity returned, it depends on the entity if it is unique or not. By providing a limit it avoids potential performance and memory issues in case the entity uniqueness check is not done on a unique field. Commits ------- f55efc3 UniqueEntityValidator: Retrieve at max two entities for unique entity check.
diff --git a/src/Symfony/Bridge/Doctrine/CHANGELOG.md b/src/Symfony/Bridge/Doctrine/CHANGELOG.md
@@ -6,6 +6,7 @@ CHANGELOG
 
  * Add `DoctrineOpenTransactionLoggerMiddleware` to log when a transaction has been left open
  * Deprecate `PdoCacheAdapterDoctrineSchemaSubscriber` and add `DoctrineDbalCacheAdapterSchemaSubscriber` instead
+ * `UniqueEntity` constraint retrieves a maximum of two entities if the default repository method is used.
 
 5.3
 ---
diff --git a/src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php b/src/Symfony/Bridge/Doctrine/Validator/Constraints/UniqueEntityValidator.php
@@ -134,7 +134,18 @@ public function validate($entity, Constraint $constraint)
             $repository = $em->getRepository(\get_class($entity));
         }
 
-        $result = $repository->{$constraint->repositoryMethod}($criteria);
+        $arguments = [$criteria];
+
+        /* If the default repository method is used, it is always enough to retrieve at most two entities because:
+         * - No entity returned, the current entity is definitely unique.
+         * - More than one entity returned, the current entity cannot be unique.
+         * - One entity returned the uniqueness depends on the current entity.
+         */
+        if ('findBy' === $constraint->repositoryMethod) {
+            $arguments = [$criteria, null, 2];
+        }
+
+        $result = $repository->{$constraint->repositoryMethod}(...$arguments);
 
         if ($result instanceof \IteratorAggregate) {
             $result = $result->getIterator();
