[Serializer] Adds FormErrorNormalizer

src/Symfony/Bundle/FrameworkBundle/Resources/config/form.php

@@ -34,6 +34,7 @@ use Symfony\Component\Form\FormRegistry;
 use Symfony\Component\Form\FormRegistryInterface;
 use Symfony\Component\Form\ResolvedFormTypeFactory;
 use Symfony\Component\Form\ResolvedFormTypeFactoryInterface;
+use Symfony\Component\Form\Serializer\FormErrorNormalizer;
 use Symfony\Component\Form\Util\ServerParams;
 
 return static function (ContainerConfigurator $container) {
@@ -140,5 +141,8 @@ return static function (ContainerConfigurator $container) {
                 param('validator.translation_domain'),
             ])
             ->tag('form.type_extension')
+
+        ->set('form.serializer.normalizer.form_error', FormErrorNormalizer::class)
+            ->tag('serializer.normalizer', ['priority' => -915])
     ;
 };

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php

@@ -40,6 +40,7 @@ use Symfony\Component\DependencyInjection\Loader\ClosureLoader;
 use Symfony\Component\DependencyInjection\ParameterBag\EnvPlaceholderParameterBag;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+use Symfony\Component\Form\Serializer\FormErrorNormalizer;
 use Symfony\Component\HttpClient\ScopingHttpClient;
 use Symfony\Component\HttpKernel\DependencyInjection\LoggerPass;
 use Symfony\Component\Messenger\Transport\TransportFactory;
@@ -1150,6 +1151,17 @@ abstract class FrameworkExtensionTest extends TestCase
         $this->assertEquals(-910, $tag[0]['priority']);
     }
 
+    public function testFormErrorNormalizerRegistred()
+    {
+        $container = $this->createContainerFromFile('full');
+
+        $definition = $container->getDefinition('form.serializer.normalizer.form_error');
+        $tag = $definition->getTag('serializer.normalizer');
+
+        $this->assertEquals(FormErrorNormalizer::class, $definition->getClass());
+        $this->assertEquals(-915, $tag[0]['priority']);
+    }
+
     public function testJsonSerializableNormalizerRegistered()
     {
         $container = $this->createContainerFromFile('full');

src/Symfony/Component/Form/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+5.2.0
+-----
+
+* added `FormErrorNormalizer`
+
 5.1.0
 -----
 

src/Symfony/Component/Form/Serializer/FormErrorNormalizer.php

@@ -0,0 +1,94 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Form\Serializer;
+
+use Symfony\Component\Form\FormInterface;
+use Symfony\Component\Serializer\Normalizer\CacheableSupportsMethodInterface;
+use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
+
+/**
+ * Normalizes invalid Form instances.
+ */
+final class FormErrorNormalizer implements NormalizerInterface, CacheableSupportsMethodInterface
+{
+    const TITLE = 'title';
+    const TYPE = 'type';
+    const CODE = 'status_code';
+
+    /**
+     * {@inheritdoc}
+     */
+    public function normalize($object, $format = null, array $context = []): array
+    {
+        $data = [
+            'title' => $context[self::TITLE] ?? 'Validation Failed',
+            'type' => $context[self::TYPE] ?? 'https://symfony.com/errors/form',
+            'code' => $context[self::CODE] ?? null,
+            'errors' => $this->convertFormErrorsToArray($object),
+        ];
+
+        if (0 !== \count($object->all())) {
+            $data['children'] = $this->convertFormChildrenToArray($object);
+        }
+
+        return $data;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsNormalization($data, $format = null): bool
+    {
+        return $data instanceof FormInterface && $data->isSubmitted() && !$data->isValid();
+    }
+
+    private function convertFormErrorsToArray(FormInterface $data): array
+    {
+        $errors = [];
+
+        foreach ($data->getErrors() as $error) {
+            $errors[] = [
+                'message' => $error->getMessage(),
+                'cause' => $error->getCause(),
+            ];
+        }
+
+        return $errors;
+    }
+
+    private function convertFormChildrenToArray(FormInterface $data): array
+    {
+        $children = [];
+
+        foreach ($data->all() as $child) {
+            $childData = [
+                'errors' => $this->convertFormErrorsToArray($child),
+            ];
+
+            if (!empty($child->all())) {
+                $childData['children'] = $this->convertFormChildrenToArray($child);
+            }
+
+            $children[$child->getName()] = $childData;
+        }
+
+        return $children;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function hasCacheableSupportsMethod(): bool
+    {
+        return __CLASS__ === static::class;
+    }
+}

src/Symfony/Component/Form/Tests/Serializer/FormErrorNormalizerTest.php

@@ -0,0 +1,163 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Form\Tests\Serializer;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Form\FormError;
+use Symfony\Component\Form\FormErrorIterator;
+use Symfony\Component\Form\FormInterface;
+use Symfony\Component\Form\Serializer\FormErrorNormalizer;
+
+class FormErrorNormalizerTest extends TestCase
+{
+    /**
+     * @var FormErrorNormalizer
+     */
+    private $normalizer;
+
+    /**
+     * @var FormInterface
+     */
+    private $form;
+
+    protected function setUp(): void
+    {
+        $this->normalizer = new FormErrorNormalizer();
+
+        $this->form = $this->createMock(FormInterface::class);
+        $this->form->method('isSubmitted')->willReturn(true);
+        $this->form->method('all')->willReturn([]);
+
+        $this->form->method('getErrors')
+            ->willReturn(new FormErrorIterator($this->form, [
+                new FormError('a', 'b', ['c', 'd'], 5, 'f'),
+                new FormError(1, 2, [3, 4], 5, 6),
+            ])
+        );
+    }
+
+    public function testSupportsNormalizationWithWrongClass()
+    {
+        $this->assertFalse($this->normalizer->supportsNormalization(new \stdClass()));
+    }
+
+    public function testSupportsNormalizationWithNotSubmittedForm()
+    {
+        $form = $this->createMock(FormInterface::class);
+        $this->assertFalse($this->normalizer->supportsNormalization($form));
+    }
+
+    public function testSupportsNormalizationWithValidForm()
+    {
+        $this->assertTrue($this->normalizer->supportsNormalization($this->form));
+    }
+
+    public function testNormalize()
+    {
+        $expected = [
+            'code' => null,
+            'title' => 'Validation Failed',
+            'type' => 'https://symfony.com/errors/form',
+            'errors' => [
+                [
+                    'message' => 'a',
+                    'cause' => 'f',
+                ],
+                [
+                    'message' => '1',
+                    'cause' => 6,
+                ],
+            ],
+        ];
+
+        $this->assertEquals($expected, $this->normalizer->normalize($this->form));
+    }
+
+    public function testNormalizeWithChildren()
+    {
+        $exptected = [
+            'code' => null,
+            'title' => 'Validation Failed',
+            'type' => 'https://symfony.com/errors/form',
+            'errors' => [
+                [
+                    'message' => 'a',
+                    'cause' => null,
+                ],
+            ],
+            'children' => [
+                'form1' => [
+                    'errors' => [
+                        [
+                            'message' => 'b',
+                            'cause' => null,
+                        ],
+                    ],
+                ],
+                'form2' => [
+                    'errors' => [
+                        [
+                            'message' => 'c',
+                            'cause' => null,
+                        ],
+                    ],
+                    'children' => [
+                        'form3' => [
+                            'errors' => [
+                                [
+                                    'message' => 'd',
+                                    'cause' => null,
+                                ],
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ];
+
+        $form = clone $form1 = clone $form2 = clone $form3 = $this->createMock(FormInterface::class);
+
+        $form1->method('getErrors')
+            ->willReturn(new FormErrorIterator($form1, [
+                new FormError('b'),
+            ])
+        );
+        $form1->method('getName')->willReturn('form1');
+
+        $form2->method('getErrors')
+            ->willReturn(new FormErrorIterator($form1, [
+                new FormError('c'),
+            ])
+        );
+        $form2->method('getName')->willReturn('form2');
+
+        $form3->method('getErrors')
+            ->willReturn(new FormErrorIterator($form1, [
+                new FormError('d'),
+            ])
+        );
+        $form3->method('getName')->willReturn('form3');
+
+        $form2->method('all')->willReturn([$form3]);
+
+        $form = $this->createMock(FormInterface::class);
+        $form->method('isSubmitted')->willReturn(true);
+        $form->method('all')->willReturn([$form1, $form2]);
+        $form->method('getErrors')
+            ->willReturn(new FormErrorIterator($form, [
+                new FormError('a'),
+            ])
+        );
+
+        $this->assertEquals($exptected, $this->normalizer->normalize($form));
+    }
+}

src/Symfony/Component/Form/composer.json

@@ -37,6 +37,7 @@
         "symfony/http-foundation": "^4.4|^5.0",
         "symfony/http-kernel": "^4.4|^5.0",
         "symfony/security-csrf": "^4.4|^5.0",
+        "symfony/serializer": "^4.4|^5.0",
         "symfony/translation": "^4.4|^5.0",
         "symfony/var-dumper": "^4.4|^5.0"
     },