[Serializer] Fix denormalizing union types

Fixes symfony#45818

Author: T-bond

Normalizer/AbstractObjectNormalizer.php

@@ -404,6 +404,7 @@ private function validateAndDenormalize(string $currentClass, string $attribute,
         }
 
         $expectedTypes = [];
+        $isUnionType = \count($types) > 1;
         foreach ($types as $type) {
             if (null === $data && $type->isNullable()) {
                 return null;
@@ -455,29 +456,40 @@ private function validateAndDenormalize(string $currentClass, string $attribute,
 
             $expectedTypes[Type::BUILTIN_TYPE_OBJECT === $builtinType && $class ? $class : $builtinType] = true;
 
-            if (Type::BUILTIN_TYPE_OBJECT === $builtinType) {
-                if (!$this->serializer instanceof DenormalizerInterface) {
-                    throw new LogicException(sprintf('Cannot denormalize attribute "%s" for class "%s" because injected serializer is not a denormalizer.', $attribute, $class));
+            // This try-catch should cover all NotNormalizableValueException (and all return branches after the first
+            // exception) so we could try denormalizing all types of an union type. If the target type is not an union
+            // type, we will just re-throw the catched exception.
+            // In the case of no denormalization succeeds with an union type, it will fall back to the default exception
+            // with the acceptable types list.
+            try {
+                if (Type::BUILTIN_TYPE_OBJECT === $builtinType) {
+                    if (!$this->serializer instanceof DenormalizerInterface) {
+                        throw new LogicException(sprintf('Cannot denormalize attribute "%s" for class "%s" because injected serializer is not a denormalizer.', $attribute, $class));
+                    }
+
+                    $childContext = $this->createChildContext($context, $attribute, $format);
+                    if ($this->serializer->supportsDenormalization($data, $class, $format, $childContext)) {
+                        return $this->serializer->denormalize($data, $class, $format, $childContext);
+                    }
                 }
 
-                $childContext = $this->createChildContext($context, $attribute, $format);
-                if ($this->serializer->supportsDenormalization($data, $class, $format, $childContext)) {
-                    return $this->serializer->denormalize($data, $class, $format, $childContext);
+                // JSON only has a Number type corresponding to both int and float PHP types.
+                // PHP's json_encode, JavaScript's JSON.stringify, Go's json.Marshal as well as most other JSON encoders convert
+                // floating-point numbers like 12.0 to 12 (the decimal part is dropped when possible).
+                // PHP's json_decode automatically converts Numbers without a decimal part to integers.
+                // To circumvent this behavior, integers are converted to floats when denormalizing JSON based formats and when
+                // a float is expected.
+                if (Type::BUILTIN_TYPE_FLOAT === $builtinType && \is_int($data) && null !== $format && str_contains($format, JsonEncoder::FORMAT)) {
+                    return (float) $data;
                 }
-            }
-
-            // JSON only has a Number type corresponding to both int and float PHP types.
-            // PHP's json_encode, JavaScript's JSON.stringify, Go's json.Marshal as well as most other JSON encoders convert
-            // floating-point numbers like 12.0 to 12 (the decimal part is dropped when possible).
-            // PHP's json_decode automatically converts Numbers without a decimal part to integers.
-            // To circumvent this behavior, integers are converted to floats when denormalizing JSON based formats and when
-            // a float is expected.
-            if (Type::BUILTIN_TYPE_FLOAT === $builtinType && \is_int($data) && null !== $format && str_contains($format, JsonEncoder::FORMAT)) {
-                return (float) $data;
-            }
 
-            if (('is_'.$builtinType)($data)) {
-                return $data;
+                if (('is_'.$builtinType)($data)) {
+                    return $data;
+                }
+            } catch (NotNormalizableValueException $e) {
+                if (!$isUnionType) {
+                    throw $e;
+                }
             }
         }
 
@@ -639,7 +651,7 @@ private function getCacheKey(?string $format, array $context)
                 'ignored' => $this->ignoredAttributes,
                 'camelized' => $this->camelizedAttributes,
             ]));
-        } catch (\Exception $exception) {
+        } catch (\Exception $e) {
             // The context cannot be serialized, skip the cache
             return false;
         }

Tests/SerializerTest.php

@@ -15,6 +15,7 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\PropertyInfo\Extractor\PhpDocExtractor;
 use Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor;
+use Symfony\Component\PropertyInfo\PropertyInfoExtractor;
 use Symfony\Component\Serializer\Encoder\DecoderInterface;
 use Symfony\Component\Serializer\Encoder\EncoderInterface;
 use Symfony\Component\Serializer\Encoder\JsonEncoder;
@@ -33,6 +34,7 @@
 use Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer;
 use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
 use Symfony\Component\Serializer\Normalizer\CustomNormalizer;
+use Symfony\Component\Serializer\Normalizer\DateTimeNormalizer;
 use Symfony\Component\Serializer\Normalizer\DenormalizerAwareInterface;
 use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
 use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
@@ -538,6 +540,38 @@ public function testNormalizePreserveEmptyArrayObject()
         $this->assertEquals('{"foo":{},"bar":["notempty"],"baz":{"nested":{}}}', $serializer->serialize($object, 'json', [AbstractObjectNormalizer::PRESERVE_EMPTY_OBJECTS => true]));
     }
 
+    public function testUnionTypeDeserializable()
+    {
+        $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
+        $extractor = new PropertyInfoExtractor([], [new PhpDocExtractor(), new ReflectionExtractor()]);
+        $serializer = new Serializer(
+            [
+                new DateTimeNormalizer(),
+                new ObjectNormalizer($classMetadataFactory, null, null, $extractor, new ClassDiscriminatorFromClassMetadata($classMetadataFactory)),
+            ],
+            ['json' => new JsonEncoder()]
+        );
+
+        $actual = $serializer->deserialize('{ "changed": null }', DummyUnionType::class, 'json', [
+            DateTimeNormalizer::FORMAT_KEY => \DateTime::ISO8601,
+        ]);
+
+        $this->assertEquals((new DummyUnionType())->setChanged(null), $actual, 'Union type denormalization first case failed.');
+
+        $actual = $serializer->deserialize('{ "changed": "2022-03-22T16:15:05+0000" }', DummyUnionType::class, 'json', [
+            DateTimeNormalizer::FORMAT_KEY => \DateTime::ISO8601,
+        ]);
+
+        $expectedDateTime = \DateTime::createFromFormat(\DateTime::ISO8601, '2022-03-22T16:15:05+0000');
+        $this->assertEquals((new DummyUnionType())->setChanged($expectedDateTime), $actual, 'Union type denormalization second case failed.');
+
+        $actual = $serializer->deserialize('{ "changed": false }', DummyUnionType::class, 'json', [
+            DateTimeNormalizer::FORMAT_KEY => \DateTime::ISO8601,
+        ]);
+
+        $this->assertEquals(new DummyUnionType(), $actual, 'Union type denormalization third case failed.');
+    }
+
     private function serializerWithClassDiscriminator()
     {
         $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
@@ -610,6 +644,26 @@ public function __construct($value)
     }
 }
 
+class DummyUnionType
+{
+    /**
+     * @var \DateTime|bool|null
+     */
+    public $changed = false;
+
+    /**
+     * @param \DateTime|bool|null
+     *
+     * @return $this
+     */
+    public function setChanged($changed): self
+    {
+        $this->changed = $changed;
+
+        return $this;
+    }
+}
+
 interface NormalizerAwareNormalizer extends NormalizerInterface, NormalizerAwareInterface
 {
 }