[Form] Added capability to process "." rules in "error_mapping"

src/Symfony/Component/Form/CHANGELOG.md

@@ -73,6 +73,8 @@ CHANGELOG
  * added option "mapped" which should be used instead of setting "property_path" to false
  * "data_class" now *must* be set if a form maps to an object and should be left empty otherwise
  * improved error mapping on forms
+   * dot (".") rules are now allowed to map errors assigned to a form to
+     one of its children
  * errors are not mapped to unsynchronized forms anymore
  * changed Form constructor to accept a single `FormConfigInterface` object
  * changed argument order in the FormBuilder constructor

src/Symfony/Component/Form/Extension/Validator/ViolationMapper/MappingRule.php

@@ -90,7 +90,7 @@ public function isPrefix($propertyPath)
      *
      * @throws ErrorMappingException
      */
-    private function getTarget()
+    public function getTarget()
     {
         $childNames = explode('.', $this->targetPath);
         $target = $this->origin;

src/Symfony/Component/Form/Extension/Validator/ViolationMapper/ViolationMapper.php

@@ -91,6 +91,15 @@ public function mapViolation(ConstraintViolation $violation, FormInterface $form
             }
         }
 
+        // Follow dot rules until we have the final target
+        $mapping = $this->scope->getAttribute('error_mapping');
+
+        while (isset($mapping['.'])) {
+            $dotRule = new MappingRule($this->scope, '.', $mapping['.']);
+            $this->scope = $dotRule->getTarget();
+            $mapping = $this->scope->getAttribute('error_mapping');
+        }
+
         // Only add the error if the form is synchronized
         // If the form is not synchronized, it already contains an
         // error about being invalid. Further errors could be a result
@@ -260,7 +269,10 @@ private function setScope(FormInterface $form)
             new VirtualFormAwareIterator($form->getChildren())
         );
         foreach ($form->getAttribute('error_mapping') as $propertyPath => $targetPath) {
-            $this->rules[] = new MappingRule($form, $propertyPath, $targetPath);
+            // Dot rules are considered at the very end
+            if ('.' !== $propertyPath) {
+                $this->rules[] = new MappingRule($form, $propertyPath, $targetPath);
+            }
         }
     }
 }

src/Symfony/Component/Form/Tests/Extension/Validator/ViolationMapper/ViolationMapperTest.php

@@ -1354,4 +1354,30 @@ public function testDontMapToUnsynchronizedForms()
         $this->assertFalse($parent->hasErrors(), $parent->getName() . ' should not have an error, but has one');
         $this->assertFalse($child->hasErrors(), $child->getName() . ' should not have an error, but has one');
     }
+
+    public function testFollowDotRules()
+    {
+        $violation = $this->getConstraintViolation('data.foo');
+        $parent = $this->getForm('parent', null, null, array(
+            'foo' => 'address',
+        ));
+        $child = $this->getForm('address', null, null, array(
+            '.' => 'street',
+        ));
+        $grandChild = $this->getForm('street', null, null, array(
+            '.' => 'name',
+        ));
+        $grandGrandChild = $this->getForm('name');
+
+        $parent->add($child);
+        $child->add($grandChild);
+        $grandChild->add($grandGrandChild);
+
+        $this->mapper->mapViolation($violation, $parent);
+
+        $this->assertFalse($parent->hasErrors(), $parent->getName() . ' should not have an error, but has one');
+        $this->assertFalse($child->hasErrors(), $child->getName() . ' should not have an error, but has one');
+        $this->assertFalse($grandChild->hasErrors(), $grandChild->getName() . ' should not have an error, but has one');
+        $this->assertEquals(array($this->getFormError()), $grandGrandChild->getErrors(), $grandGrandChild->getName() . ' should have an error, but has none');
+    }
 }