Make the annotation/attribute reader optional in the extension metadata factory

Author: mbabker

rector.php

@@ -26,6 +26,7 @@
 
     $rectorConfig->skip([
         TypedPropertyFromAssignsRector::class => [
+            __DIR__.'/src/Mapping/MappedEventSubscriber.php', // Rector is trying to set a type on the $annotationReader property which requires a union type, not supported on PHP 7.4
             __DIR__.'/tests/Gedmo/Wrapper/Fixture/Entity/CompositeRelation.php', // @todo: remove this when https://github.com/doctrine/orm/issues/8255 is solved
         ],
     ]);

src/Mapping/ExtensionMetadataFactory.php

@@ -61,20 +61,20 @@ class ExtensionMetadataFactory
     protected $extensionNamespace;
 
     /**
-     * Custom annotation reader
+     * Metadata annotation reader
      *
-     * @var Reader|AttributeReader|object
+     * @var Reader|AttributeReader|object|null
      */
     protected $annotationReader;
 
     private ?CacheItemPoolInterface $cacheItemPool = null;
 
     /**
-     * @param Reader|AttributeReader|object $annotationReader
+     * @param Reader|AttributeReader|object|null $annotationReader
      */
-    public function __construct(ObjectManager $objectManager, string $extensionNamespace, object $annotationReader, ?CacheItemPoolInterface $cacheItemPool = null)
+    public function __construct(ObjectManager $objectManager, string $extensionNamespace, ?object $annotationReader = null, ?CacheItemPoolInterface $cacheItemPool = null)
     {
-        if (!$annotationReader instanceof Reader && !$annotationReader instanceof AttributeReader) {
+        if (null !== $annotationReader && !$annotationReader instanceof Reader && !$annotationReader instanceof AttributeReader) {
             trigger_deprecation(
                 'gedmo/doctrine-extensions',
                 '3.11',
@@ -98,7 +98,7 @@ public function __construct(ObjectManager $objectManager, string $extensionNames
      *
      * @param ClassMetadata&(DocumentClassMetadata|EntityClassMetadata|LegacyEntityClassMetadata) $meta
      *
-     * @return array<string, mixed> the metatada configuration
+     * @return array<string, mixed> the metadata configuration
      */
     public function getExtensionMetadata($meta)
     {
@@ -209,8 +209,20 @@ protected function getDriver($omDriver)
             // create driver instance
             $driverClassName = $this->extensionNamespace.'\Mapping\Driver\\'.$driverName;
             if (!class_exists($driverClassName)) {
-                $driverClassName = $this->extensionNamespace.'\Mapping\Driver\Annotation';
+                $originalDriverClassName = $driverClassName;
+
+                // try to fall back to either an annotation or attribute driver depending on the available dependencies
+                if (interface_exists(Reader::class)) {
+                    $driverClassName = $this->extensionNamespace.'\Mapping\Driver\Annotation';
+                } elseif (\PHP_VERSION_ID >= 80000) {
+                    $driverClassName = $this->extensionNamespace.'\Mapping\Driver\Attribute';
+                }
+
                 if (!class_exists($driverClassName)) {
+                    if ($originalDriverClassName !== $driverClassName) {
+                        throw new RuntimeException("Failed to create mapping driver: ({$originalDriverClassName}), the extension driver nor a fallback annotation or attribute driver could be found.");
+                    }
+
                     throw new RuntimeException("Failed to fallback to annotation driver: ({$driverClassName}), extension driver was not found.");
                 }
             }
@@ -227,14 +239,20 @@ protected function getDriver($omDriver)
                 }
             }
 
-            if ($driver instanceof AttributeDriverInterface) {
-                if ($this->annotationReader instanceof AttributeReader) {
-                    $driver->setAnnotationReader($this->annotationReader);
+            if ($driver instanceof AnnotationDriverInterface) {
+                if (null === $this->annotationReader) {
+                    throw new RuntimeException("Cannot use metadata driver ({$driverClassName}), an annotation or attribute reader was not provided.");
+                }
+
+                if ($driver instanceof AttributeDriverInterface) {
+                    if ($this->annotationReader instanceof AttributeReader) {
+                        $driver->setAnnotationReader($this->annotationReader);
+                    } else {
+                        $driver->setAnnotationReader(new AttributeAnnotationReader(new AttributeReader(), $this->annotationReader));
+                    }
                 } else {
-                    $driver->setAnnotationReader(new AttributeAnnotationReader(new AttributeReader(), $this->annotationReader));
+                    $driver->setAnnotationReader($this->annotationReader);
                 }
-            } elseif ($driver instanceof AnnotationDriverInterface) {
-                $driver->setAnnotationReader($this->annotationReader);
             }
         }
 

src/Mapping/MappedEventSubscriber.php

@@ -23,7 +23,6 @@
 use Doctrine\Persistence\Mapping\ClassMetadata;
 use Doctrine\Persistence\ObjectManager;
 use Gedmo\Exception\InvalidArgumentException;
-use Gedmo\Exception\RuntimeException;
 use Gedmo\Mapping\Driver\AttributeReader;
 use Gedmo\Mapping\Event\AdapterInterface;
 use Gedmo\ReferenceIntegrity\Mapping\Validator as ReferenceIntegrityValidator;
@@ -81,14 +80,14 @@ abstract class MappedEventSubscriber implements EventSubscriber
     /**
      * Custom annotation reader
      *
-     * @var Reader|AttributeReader|object|null
+     * @var Reader|AttributeReader|object|false|null
      */
-    private $annotationReader;
+    private $annotationReader = false;
 
     /**
-     * @var Reader|AttributeReader|null
+     * @var Reader|AttributeReader|false|null
      */
-    private static $defaultAnnotationReader;
+    private static $defaultAnnotationReader = false;
 
     /**
      * @var CacheItemPoolInterface|null
@@ -171,8 +170,8 @@ public function getExtensionMetadataFactory(ObjectManager $objectManager)
     {
         $oid = spl_object_id($objectManager);
         if (!isset($this->extensionMetadataFactory[$oid])) {
-            if (null === $this->annotationReader) {
-                // create default annotation reader for extensions
+            if (false === $this->annotationReader) {
+                // create default annotation/attribute reader for extensions
                 $this->annotationReader = $this->getDefaultAnnotationReader();
             }
             $this->extensionMetadataFactory[$oid] = new ExtensionMetadataFactory(
@@ -307,19 +306,22 @@ protected function setFieldValue(AdapterInterface $adapter, $object, $field, $ol
     }
 
     /**
-     * Create default annotation reader for extensions
+     * Get the default annotation or attribute reader for extensions, creating it if necessary.
      *
-     * @return Reader|AttributeReader
+     * If a reader cannot be created due to missing requirements, no default will be set as the reader is only required for annotation or attribute metadata,
+     * and the {@see ExtensionMetadataFactory} can handle raising an error if it tries to create a mapping driver that requires this reader.
+     *
+     * @return Reader|AttributeReader|null
      */
     private function getDefaultAnnotationReader()
     {
-        if (null === self::$defaultAnnotationReader) {
+        if (false === self::$defaultAnnotationReader) {
             if (class_exists(PsrCachedReader::class)) {
                 self::$defaultAnnotationReader = new PsrCachedReader(new AnnotationReader(), new ArrayAdapter());
             } elseif (\PHP_VERSION_ID >= 80000) {
                 self::$defaultAnnotationReader = new AttributeReader();
             } else {
-                throw new RuntimeException(sprintf('Cannot create a default annotation reader in "%1$s". Ensure you are running PHP 8 to use attributes, have installed the "doctrine/annotations" package, or call "%1$s::setAnnotationReader()" with a configured reader.', self::class));
+                self::$defaultAnnotationReader = null;
             }
         }