bug #19388 [Validator][GroupSequence] fixed GroupSequence validation ignores PropetyMetadata of parent classes (Sandro Hopf)

This PR was submitted for the 2.8 branch but it was merged into the 2.7 branch instead (closes #19388).

Discussion
----------

[Validator][GroupSequence] fixed GroupSequence validation ignores PropetyMetadata of parent classes

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #19387
| License       | MIT
| Doc PR        | N/A

Commits
-------

54a7eff [Validator][GroupSequence] fixed GroupSequence validation ignores PropertyMetadata of parent classes

Author: fabpot

src/Symfony/Component/Validator/Mapping/ClassMetadata.php

@@ -350,6 +350,7 @@ public function mergeConstraints(ClassMetadata $source)
                 $member = clone $member;
 
                 foreach ($member->getConstraints() as $constraint) {
+                    $member->constraintsByGroup[$this->getDefaultGroup()][] = $constraint;
                     $constraint->addImplicitGroupName($this->getDefaultGroup());
                 }
 

src/Symfony/Component/Validator/Tests/Mapping/ClassMetadataTest.php

@@ -138,23 +138,41 @@ public function testMergeConstraintsMergesMemberConstraints()
         $this->metadata->mergeConstraints($parent);
         $this->metadata->addPropertyConstraint('firstName', new ConstraintA());
 
+        $constraintA1 = new ConstraintA(array('groups' => array(
+            'Default',
+            'EntityParent',
+            'Entity',
+        )));
+        $constraintA2 = new ConstraintA(array('groups' => array(
+            'Default',
+            'Entity',
+        )));
+
         $constraints = array(
-            new ConstraintA(array('groups' => array(
-                'Default',
-                'EntityParent',
-                'Entity',
-            ))),
-            new ConstraintA(array('groups' => array(
-                'Default',
-                'Entity',
-            ))),
+            $constraintA1,
+            $constraintA2,
+        );
+
+        $constraintsByGroup = array(
+            'Default' => array(
+                $constraintA1,
+                $constraintA2,
+            ),
+            'EntityParent' => array(
+                $constraintA1,
+            ),
+            'Entity' => array(
+                $constraintA1,
+                $constraintA2,
+            ),
         );
 
         $members = $this->metadata->getPropertyMetadata('firstName');
 
         $this->assertCount(1, $members);
         $this->assertEquals(self::PARENTCLASS, $members[0]->getClassName());
         $this->assertEquals($constraints, $members[0]->getConstraints());
+        $this->assertEquals($constraintsByGroup, $members[0]->constraintsByGroup);
     }
 
     public function testMemberMetadatas()