Drop Flyweight pattern

There is a growing need for types with parameters, and that pattern was
probably used out of concerns that are no longer relevant anyway.

UPGRADE.md

@@ -6,6 +6,13 @@ awareness about deprecated code.
 - Use of our low-overhead runtime deprecation API, details:
   https://github.com/doctrine/deprecations/
 
+# Upgrade to 3.3
+
+## Deprecated `TypeRegistry::lookupName()`.
+
+Since `Type` instances are no longer flyweight, and might therefore be
+registered more than once, it makes no sense to lookup the name of a given type.
+
 # Upgrade to 3.2
 
 ## Deprecated `SQLLogger` and its implementations.

docs/en/reference/types.rst

@@ -909,3 +909,57 @@ hook it into the database platform:
 This would allow using a money type in the ORM for example and
 have Doctrine automatically convert it back and forth to the
 database.
+
+It is also possible to register type instances directly, in case you
+need to pass parameters to your instance::
+
+    <?php
+    namespace My\Project\Types;
+
+    use Doctrine\DBAL\Types\Type;
+    use Doctrine\DBAL\Platforms\AbstractPlatform;
+
+    final class EncryptedType extends StringType
+    {
+        const MONEY = 'money'; // modify to match your type name
+
+        public function __construct(
+            private string $cipher,
+            private string $secretName,
+            private SecretStore $secretStore
+        ) {
+        }
+
+        public function convertToPHPValue($value, AbstractPlatform $platform): string
+        {
+            return openssl_decrypt(
+                $value,
+                $this->cipher,
+                $this->secretStore->fetch($this->secretName)
+            );
+        }
+
+        public function convertToDatabaseValue($value, AbstractPlatform $platform): string
+        {
+            return openssl_encrypt(
+                $value,
+                $this->cipher,
+                $this->secretStore->fetch($this->secretName)
+            );
+        }
+
+        public function getName(): string
+        {
+            return 'encrypted';
+        }
+    }
+
+To do that, you can obtain the ``TypeRegistry`` singleton from ``Type``
+and register your type in it::
+
+    <?php
+    Type::getTypeRegistry()->addType('encrypted', new EncryptedType(
+        'aes-256-cbc-hmac-sha256',
+        '/path/to/secret',
+        $secretStore
+    ));

src/Exception.php

@@ -137,11 +137,4 @@ public static function typeNotRegistered(Type $type): self
             sprintf('Type of the class %s@%s is not registered.', get_class($type), spl_object_hash($type))
         );
     }
-
-    public static function typeAlreadyRegistered(Type $type): self
-    {
-        return new self(
-            sprintf('Type of the class %s@%s is already registered.', get_class($type), spl_object_hash($type))
-        );
-    }
 }

src/Types/Type.php

@@ -130,7 +130,6 @@ private static function createTypeRegistry(): TypeRegistry
 
     /**
      * Factory method to create type instances.
-     * Type instances are implemented as flyweights.
      *
      * @param string $name The name of the type (as returned by getName()).
      *

src/Types/TypeRegistry.php

@@ -6,16 +6,15 @@
 
 use Doctrine\DBAL\Exception;
 
+use Doctrine\Deprecations\Deprecation;
 use function array_search;
-use function in_array;
 
 /**
  * The type registry is responsible for holding a map of all known DBAL types.
- * The types are stored using the flyweight pattern so that one type only exists as exactly one instance.
  */
 final class TypeRegistry
 {
-    /** @var array<string, Type> Map of type names and their corresponding flyweight objects. */
+    /** @var array<string, Type> Map of type names and their corresponding objects. */
     private $instances;
 
     /**
@@ -43,13 +42,20 @@ public function get(string $name): Type
     /**
      * Finds a name for the given type.
      *
+     * @deprecated this method will be removed in 4.0.0
+     *
      * @throws Exception
      */
     public function lookupName(Type $type): string
     {
-        $name = $this->findTypeName($type);
+        Deprecation::trigger(
+            'doctrine/dbal',
+            'https://github.com/doctrine/dbal/pulls/5036',
+            'This method will be removed in 4.0.0, since the same type can be registered twice.',
+        );
+        $name = array_search($type, $this->instances, true);
 
-        if ($name === null) {
+        if ($name === false) {
             throw Exception::typeNotRegistered($type);
         }
 
@@ -75,10 +81,6 @@ public function register(string $name, Type $type): void
             throw Exception::typeExists($name);
         }
 
-        if ($this->findTypeName($type) !== null) {
-            throw Exception::typeAlreadyRegistered($type);
-        }
-
         $this->instances[$name] = $type;
     }
 
@@ -93,10 +95,6 @@ public function override(string $name, Type $type): void
             throw Exception::typeNotFound($name);
         }
 
-        if (! in_array($this->findTypeName($type), [$name, null], true)) {
-            throw Exception::typeAlreadyRegistered($type);
-        }
-
         $this->instances[$name] = $type;
     }
 
@@ -111,15 +109,4 @@ public function getMap(): array
     {
         return $this->instances;
     }
-
-    private function findTypeName(Type $type): ?string
-    {
-        $name = array_search($type, $this->instances, true);
-
-        if ($name === false) {
-            return null;
-        }
-
-        return $name;
-    }
 }

tests/Types/TypeRegistryTest.php

@@ -86,7 +86,7 @@ public function testRegister(): void
         self::assertSame($newType, $this->registry->get('some'));
     }
 
-    public function testRegisterWithAlradyRegisteredName(): void
+    public function testRegisterWithAlreadyRegisteredName(): void
     {
         $this->registry->register('some', new TextType());
 
@@ -99,9 +99,11 @@ public function testRegisterWithAlreadyRegisteredInstance(): void
         $newType = new TextType();
 
         $this->registry->register('some', $newType);
-
-        $this->expectException(Exception::class);
-        $this->registry->register('other', $newType);
+        $this->registry->register('sameButDifferent', $newType);
+        self::assertSame(
+            $this->registry->get('some'),
+            $this->registry->get('sameButDifferent')
+        );
     }
 
     public function testOverride(): void
@@ -125,17 +127,6 @@ public function testOverrideAllowsExistingInstance(): void
         self::assertSame($type, $this->registry->get('some'));
     }
 
-    public function testOverrideWithAlreadyRegisteredInstance(): void
-    {
-        $newType = new TextType();
-
-        $this->registry->register('first', $newType);
-        $this->registry->register('second', new StringType());
-
-        $this->expectException(Exception::class);
-        $this->registry->override('second', $newType);
-    }
-
     public function testOverrideWithUnknownType(): void
     {
         $this->expectException(Exception::class);