bug symfony#37103 [Form] switch the context when validating nested forms (xabbuh)

This PR was merged into the 3.4 branch.

Discussion
----------

[Form] switch the context when validating nested forms

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix symfony#37072
| License       | MIT
| Doc PR        |

Commits
-------

38135de switch the context when validating nested forms

Author: fabpot

src/Symfony/Component/Form/Extension/Validator/Constraints/FormValidator.php

@@ -90,6 +90,7 @@ public function validate($form, Constraint $formConstraint)
                             // in different steps without breaking early enough
                             $this->resolvedGroups[$field] = (array) $group;
                             $fieldFormConstraint = new Form();
+                            $this->context->setNode($this->context->getValue(), $field, $this->context->getMetadata(), $this->context->getPropertyPath());
                             $validator->atPath(sprintf('children[%s]', $field->getName()))->validate($field, $fieldFormConstraint);
                         }
                     }
@@ -129,6 +130,7 @@ public function validate($form, Constraint $formConstraint)
                     if ($field->isSubmitted()) {
                         $this->resolvedGroups[$field] = $groups;
                         $fieldFormConstraint = new Form();
+                        $this->context->setNode($this->context->getValue(), $field, $this->context->getMetadata(), $this->context->getPropertyPath());
                         $validator->atPath(sprintf('children[%s]', $field->getName()))->validate($field, $fieldFormConstraint);
                     }
                 }

src/Symfony/Component/Form/Tests/Extension/Validator/Constraints/FormValidatorFunctionalTest.php

@@ -21,6 +21,7 @@
 use Symfony\Component\Form\Test\ForwardCompatTestTrait;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 use Symfony\Component\Validator\Constraints\Collection;
+use Symfony\Component\Validator\Constraints\Expression;
 use Symfony\Component\Validator\Constraints\GroupSequence;
 use Symfony\Component\Validator\Constraints\Length;
 use Symfony\Component\Validator\Constraints\NotBlank;
@@ -283,6 +284,51 @@ public function testCascadeValidationToChildFormsUsingPropertyPathsValidatedInSe
         $this->assertSame('This value should not be blank.', $violations[0]->getMessage());
         $this->assertSame('children[field1].data', $violations[0]->getPropertyPath());
     }
+
+    public function testContextIsPopulatedWithFormBeingValidated()
+    {
+        $form = $this->formFactory->create(FormType::class)
+            ->add('field1', null, [
+                'constraints' => [new Expression([
+                    'expression' => '!this.getParent().get("field2").getData()',
+                ])],
+            ])
+            ->add('field2')
+        ;
+
+        $form->submit([
+            'field1' => '',
+            'field2' => '',
+        ]);
+
+        $violations = $this->validator->validate($form);
+
+        $this->assertCount(0, $violations);
+    }
+
+    public function testContextIsPopulatedWithFormBeingValidatedUsingGroupSequence()
+    {
+        $form = $this->formFactory->create(FormType::class, null, [
+            'validation_groups' => new GroupSequence(['group1']),
+        ])
+            ->add('field1', null, [
+                'constraints' => [new Expression([
+                    'expression' => '!this.getParent().get("field2").getData()',
+                    'groups' => ['group1'],
+                ])],
+            ])
+            ->add('field2')
+        ;
+
+        $form->submit([
+            'field1' => '',
+            'field2' => '',
+        ]);
+
+        $violations = $this->validator->validate($form);
+
+        $this->assertCount(0, $violations);
+    }
 }
 
 class Foo

src/Symfony/Component/Form/composer.json

@@ -26,9 +26,10 @@
     },
     "require-dev": {
         "doctrine/collections": "~1.0",
-        "symfony/validator": "^3.2.5|~4.0",
+        "symfony/validator": "^3.4.3|^4.0.3",
         "symfony/dependency-injection": "~3.3|~4.0",
         "symfony/config": "~2.7|~3.0|~4.0",
+        "symfony/expression-language": "~3.4|~4.0",
         "symfony/http-foundation": "~2.8|~3.0|~4.0",
         "symfony/http-kernel": "^3.3.5|~4.0",
         "symfony/security-csrf": "^2.8.31|^3.3.13|~4.0",