[RFC] add HydrationFactory as extension point for tracking hydrations

src/Configuration.php

@@ -9,6 +9,8 @@
 use Doctrine\ORM\Cache\CacheConfiguration;
 use Doctrine\ORM\Exception\InvalidEntityRepository;
 use Doctrine\ORM\Internal\Hydration\AbstractHydrator;
+use Doctrine\ORM\Internal\Hydration\DefaultHydratorFactory;
+use Doctrine\ORM\Internal\Hydration\HydratorFactory;
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Doctrine\ORM\Mapping\ClassMetadataFactory;
 use Doctrine\ORM\Mapping\DefaultEntityListenerResolver;
@@ -47,6 +49,16 @@
     /** @phpstan-var array<class-string<AbstractPlatform>, ClassMetadata::GENERATOR_TYPE_*> */
     private $identityGenerationPreferences = [];
 
+    public function setHydratorFactory(HydratorFactory $factory): void
+    {
+        $this->attributes['hydratorFactory'] = $factory;
+    }
+
+    public function getHydratorFactory(): HydratorFactory
+    {
+        return $this->attributes['hydratorFactory'] ?? new DefaultHydratorFactory();
+    }
+
     /** @phpstan-param array<class-string<AbstractPlatform>, ClassMetadata::GENERATOR_TYPE_*> $value */
     public function setIdentityGenerationPreferences(array $value): void
     {

src/EntityManager.php

@@ -10,12 +10,12 @@
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\LockMode;
 use Doctrine\ORM\Exception\EntityManagerClosed;
-use Doctrine\ORM\Exception\InvalidHydrationMode;
 use Doctrine\ORM\Exception\MissingIdentifierField;
 use Doctrine\ORM\Exception\MissingMappingDriverImplementation;
 use Doctrine\ORM\Exception\ORMException;
 use Doctrine\ORM\Exception\UnrecognizedIdentifierFields;
 use Doctrine\ORM\Internal\Hydration\AbstractHydrator;
+use Doctrine\ORM\Internal\Hydration\HydratorFactory;
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Doctrine\ORM\Mapping\ClassMetadataFactory;
 use Doctrine\ORM\Proxy\DefaultProxyClassNameResolver;
@@ -104,6 +104,11 @@ class EntityManager implements EntityManagerInterface
      */
     private Cache|null $cache = null;
 
+    /**
+     * The hydrator factory to use.
+     */
+    private HydratorFactory $hydratorFactory;
+
     /**
      * Creates a new EntityManager that operates on the given database connection
      * and uses the given Configuration and EventManager implementations.
@@ -150,6 +155,8 @@ public function __construct(
             $cacheFactory = $cacheConfig->getCacheFactory();
             $this->cache  = $cacheFactory->createCache($this);
         }
+
+        $this->hydratorFactory = $this->config->getHydratorFactory();
     }
 
     public function getConnection(): Connection
@@ -545,15 +552,7 @@ public function getUnitOfWork(): UnitOfWork
 
     public function newHydrator(string|int $hydrationMode): AbstractHydrator
     {
-        return match ($hydrationMode) {
-            Query::HYDRATE_OBJECT => new Internal\Hydration\ObjectHydrator($this),
-            Query::HYDRATE_ARRAY => new Internal\Hydration\ArrayHydrator($this),
-            Query::HYDRATE_SCALAR => new Internal\Hydration\ScalarHydrator($this),
-            Query::HYDRATE_SINGLE_SCALAR => new Internal\Hydration\SingleScalarHydrator($this),
-            Query::HYDRATE_SIMPLEOBJECT => new Internal\Hydration\SimpleObjectHydrator($this),
-            Query::HYDRATE_SCALAR_COLUMN => new Internal\Hydration\ScalarColumnHydrator($this),
-            default => $this->createCustomHydrator((string) $hydrationMode),
-        };
+        return $this->hydratorFactory->create($this, $this->config, $hydrationMode);
     }
 
     public function getProxyFactory(): ProxyFactory
@@ -621,15 +620,4 @@ private function configureMetadataCache(): void
 
         $this->metadataFactory->setCache($metadataCache);
     }
-
-    private function createCustomHydrator(string $hydrationMode): AbstractHydrator
-    {
-        $class = $this->config->getCustomHydrationMode($hydrationMode);
-
-        if ($class !== null) {
-            return new $class($this);
-        }
-
-        throw InvalidHydrationMode::fromMode($hydrationMode);
-    }
 }

src/Internal/Hydration/DefaultHydratorFactory.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\ORM\Internal\Hydration;
+
+use Doctrine\ORM\Configuration;
+use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\Exception\InvalidHydrationMode;
+use Doctrine\ORM\Query;
+
+final class DefaultHydratorFactory implements HydratorFactory
+{
+    public function create(EntityManagerInterface $em, Configuration $config, string|int $hydrationMode): AbstractHydrator
+    {
+        return match ($hydrationMode) {
+            Query::HYDRATE_OBJECT => new ObjectHydrator($em),
+            Query::HYDRATE_ARRAY => new ArrayHydrator($em),
+            Query::HYDRATE_SCALAR => new ScalarHydrator($em),
+            Query::HYDRATE_SINGLE_SCALAR => new SingleScalarHydrator($em),
+            Query::HYDRATE_SIMPLEOBJECT => new SimpleObjectHydrator($em),
+            Query::HYDRATE_SCALAR_COLUMN => new ScalarColumnHydrator($em),
+            default => $this->createCustomHydrator((string) $hydrationMode, $em, $config),
+        };
+    }
+
+    private function createCustomHydrator(string $hydrationMode, EntityManagerInterface $em, Configuration $config): AbstractHydrator
+    {
+        $class = $config->getCustomHydrationMode($hydrationMode);
+
+        if ($class !== null) {
+            return new $class($em);
+        }
+
+        throw InvalidHydrationMode::fromMode($hydrationMode);
+    }
+}

src/Internal/Hydration/HydratorFactory.php

@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\ORM\Internal\Hydration;
+
+use Doctrine\ORM\AbstractQuery;
+use Doctrine\ORM\Configuration;
+use Doctrine\ORM\EntityManagerInterface;
+
+interface HydratorFactory
+{
+    /**
+     * Create a new instance for the given hydration mode.
+     *
+     * @psalm-param string|AbstractQuery::HYDRATE_* $hydrationMode
+     */
+    public function create(EntityManagerInterface $em, Configuration $config, string|int $hydrationMode): AbstractHydrator;
+}