Disable Union support by default. Add option to enable it optionally

doc/reference/annotations.rst

@@ -17,6 +17,39 @@ please use the alternative syntax ``#[Groups(groups: ['value' => 'any value here
 - Some support for unions exists.  For unions of primitive types, the system will try to resolve them automatically.  For
 classes that contain union attributes, the ``#[UnionDiscriminator]`` attribute must be used to specify the type of the union.
 
+Enum support
+~~~~~~~~~~~~~~
+
+Enum support is disabled by default, to enable it run:
+
+.. code-block :: php
+
+    $builder = SerializerBuilder::create();
+    $builder->enableEnumSupport();
+
+    $serializer = $builder->build();
+
+
+With the enum support enabled, enums are automatically detected using typed properties typehints.
+When typed properties are no available (virtual properties as example), it is necessary to explicitly typehint
+the underlying type using the ``#[Type]`` attribute.
+
+- If the enum is a ``BackedEnum``, the case value will be used for serialization and deserialization by default;
+- If the enum is not a ``BackedEnum``, the case name will be used for serialization and deserialization by default;
+
+Union support
+~~~~~~~~~~~~~~
+
+Union support is disabled by default, to enable it run:
+
+.. code-block :: php
+
+    $builder = SerializerBuilder::create();
+    $builder->enableUnionSupport();
+
+    $serializer = $builder->build();
+
+
 Converting your annotations to attributes
 -----------------------------------------
 
@@ -958,22 +991,3 @@ Resulting XML:
     </blog>
 
 
-Enum support
-~~~~~~~~~~~~~~
-
-Enum support is disabled by default, to enable it run:
-
-.. code-block :: php
-
-    $builder = SerializerBuilder::create();
-    $builder->enableEnumSupport();
-
-    $serializer = $builder->build();
-
-
-With the enum support enabled, enums are automatically detected using typed properties typehints.
-When typed properties are no available (virtual properties as example), it is necessary to explicitly typehint
-the underlying type using the ``#[Type]`` attribute.
-
-- If the enum is a ``BackedEnum``, the case value will be used for serialization and deserialization by default;
-- If the enum is not a ``BackedEnum``, the case name will be used for serialization and deserialization by default;

src/Builder/DefaultDriverFactory.php

@@ -24,25 +24,15 @@
 
 final class DefaultDriverFactory implements DriverFactoryInterface
 {
-    /**
-     * @var ParserInterface
-     */
-    private $typeParser;
-
-    /**
-     * @var bool
-     */
-    private $enableEnumSupport = false;
-
-    /**
-     * @var PropertyNamingStrategyInterface
-     */
-    private $propertyNamingStrategy;
-
-    /**
-     * @var CompilableExpressionEvaluatorInterface
-     */
-    private $expressionEvaluator;
+    private ParserInterface $typeParser;
+
+    private bool $enableEnumSupport = false;
+
+    private bool $enableUnionSupport = false;
+
+    private PropertyNamingStrategyInterface $propertyNamingStrategy;
+
+    private ?CompilableExpressionEvaluatorInterface $expressionEvaluator;
 
     public function __construct(PropertyNamingStrategyInterface $propertyNamingStrategy, ?ParserInterface $typeParser = null, ?CompilableExpressionEvaluatorInterface $expressionEvaluator = null)
     {
@@ -56,6 +46,11 @@ public function enableEnumSupport(bool $enableEnumSupport = true): void
         $this->enableEnumSupport = $enableEnumSupport;
     }
 
+    public function enableUnionSupport(bool $enableUnionSupport = true): void
+    {
+        $this->enableUnionSupport = $enableUnionSupport;
+    }
+
     public function createDriver(array $metadataDirs, ?Reader $annotationReader = null): DriverInterface
     {
         if (PHP_VERSION_ID < 80000 && empty($metadataDirs) && !interface_exists(Reader::class)) {
@@ -93,7 +88,7 @@ public function createDriver(array $metadataDirs, ?Reader $annotationReader = nu
             $driver = new EnumPropertiesDriver($driver);
         }
 
-        $driver = new TypedPropertiesDriver($driver, $this->typeParser);
+        $driver = new TypedPropertiesDriver($driver, $this->typeParser, [], $this->enableUnionSupport);
 
         if (PHP_VERSION_ID >= 80000) {
             $driver = new DefaultValuePropertyDriver($driver);

src/Metadata/Driver/TypedPropertiesDriver.php

@@ -22,29 +22,24 @@
 
 class TypedPropertiesDriver implements DriverInterface
 {
-    /**
-     * @var DriverInterface
-     */
-    protected $delegate;
-
-    /**
-     * @var ParserInterface
-     */
-    protected $typeParser;
+    protected DriverInterface $delegate;
+    protected ParserInterface $typeParser;
 
     /**
      * @var string[]
      */
-    private $allowList;
+    private array $allowList;
+    private bool $allowUnionProperties;
 
     /**
      * @param string[] $allowList
      */
-    public function __construct(DriverInterface $delegate, ?ParserInterface $typeParser = null, array $allowList = [])
+    public function __construct(DriverInterface $delegate, ?ParserInterface $typeParser = null, array $allowList = [], bool $allowUnionProperties = false)
     {
         $this->delegate = $delegate;
         $this->typeParser = $typeParser ?: new Parser();
         $this->allowList = array_merge($allowList, $this->getDefaultWhiteList());
+        $this->allowUnionProperties = $allowUnionProperties;
     }
 
     /**
@@ -176,6 +171,10 @@ private function shouldTypeHint(?ReflectionType $reflectionType): bool
      */
     private function shouldTypeHintUnion(?ReflectionType $reflectionType)
     {
+        if (!$this->allowUnionProperties) {
+            return false;
+        }
+
         if (!$reflectionType instanceof \ReflectionUnionType) {
             return false;
         }

src/SerializerBuilder.php

@@ -91,6 +91,11 @@ final class SerializerBuilder
      */
     private $enableEnumSupport = false;
 
+    /**
+     * @var bool
+     */
+    private $enableUnionSupport = false;
+
     /**
      * @var bool
      */
@@ -284,7 +289,7 @@ public function addDefaultHandlers(): self
             $this->handlerRegistry->registerSubscribingHandler(new EnumHandler());
         }
 
-        if (PHP_VERSION_ID >= 80000) {
+        if ($this->enableUnionSupport) {
             $this->handlerRegistry->registerSubscribingHandler(new UnionHandler());
         }
 
@@ -540,6 +545,17 @@ public function enableEnumSupport(bool $enableEnumSupport = true): self
         return $this;
     }
 
+    public function enableUnionSupport(bool $enableUnionSupport = true): self
+    {
+        if ($enableUnionSupport && PHP_VERSION_ID < 80000) {
+            throw new InvalidArgumentException('Enum support can be enabled only on PHP 8.1 or higher.');
+        }
+
+        $this->enableUnionSupport = $enableUnionSupport;
+
+        return $this;
+    }
+
     public function setMetadataCache(CacheInterface $cache): self
     {
         $this->metadataCache = $cache;
@@ -569,6 +585,7 @@ public function build(): Serializer
                 $this->expressionEvaluator instanceof CompilableExpressionEvaluatorInterface ? $this->expressionEvaluator : null,
             );
             $this->driverFactory->enableEnumSupport($this->enableEnumSupport);
+            $this->driverFactory->enableUnionSupport($this->enableUnionSupport);
         }
 
         if ($this->docBlockTyperResolver) {

tests/Metadata/Driver/DefaultDriverFactoryTest.php

@@ -31,7 +31,7 @@ public function testDefaultDriverFactoryLoadsTypedPropertiesDriver()
         ];
 
         foreach ($expectedPropertyTypes as $property => $type) {
-            self::assertEquals(['name' => $type, 'params' => []], $m->propertyMetadata[$property]->type);
+            self::assertEquals(['name' => $type, 'params' => []], $m->propertyMetadata[$property]->type, 'for ' . $property);
         }
     }
 }

tests/Metadata/Driver/TypedPropertiesDriverTest.php

@@ -9,6 +9,7 @@
 use JMS\Serializer\Metadata\Driver\AnnotationDriver;
 use JMS\Serializer\Metadata\Driver\TypedPropertiesDriver;
 use JMS\Serializer\Naming\IdenticalPropertyNamingStrategy;
+use JMS\Serializer\Tests\Fixtures\TypedProperties\UnionTypedProperties;
 use JMS\Serializer\Tests\Fixtures\TypedProperties\User;
 use PHPUnit\Framework\TestCase;
 use ReflectionClass;
@@ -33,6 +34,13 @@ public function testInferPropertiesFromTypes()
         }
     }
 
+    public function testInferUnionTypesShouldResultInManyTypes()
+    {
+        $m = $this->resolve(UnionTypedProperties::class);
+
+        self::assertNull($m->propertyMetadata['data']->type);
+    }
+
     private function resolve(string $classToResolve): ClassMetadata
     {
         $baseDriver = new AnnotationDriver(new AnnotationReader(), new IdenticalPropertyNamingStrategy());

tests/Metadata/Driver/UnionTypedPropertiesDriverTest.php

@@ -95,7 +95,7 @@ private function resolve(string $classToResolve): ClassMetadata
             new NullDriver($namingStrategy),
         ]);
 
-        $driver = new TypedPropertiesDriver($driver);
+        $driver = new TypedPropertiesDriver($driver, null, [], true);
 
         $m = $driver->loadMetadataForClass(new ReflectionClass($classToResolve));
         self::assertNotNull($m);

tests/Serializer/BaseSerializationTestCase.php

@@ -2162,6 +2162,10 @@ static function (DeserializationVisitorInterface $visitor, $data, $type, Context
             $builder->enableEnumSupport();
         }
 
+        if (PHP_VERSION_ID >= 80000) {
+            $builder->enableUnionSupport();
+        }
+
         $this->extendBuilder($builder);
         $this->serializer = $builder->build();
     }