bug #15069 [Form] Fixed: Data mappers always receive forms indexed by their names (webmozart)

This PR was merged into the 2.3 branch.

Discussion
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[Form] Fixed: Data mappers always receive forms indexed by their names

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

This PR facilitates writing domain-specific data mappers, since it guarantees that you can access forms by name in the data mapper methods. Currently, `Form::add()` does not set the index of the array passed to the data mapper to the form's name.

Commits
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86b7fe5 [Form] Fixed: Data mappers always receive forms indexed by their names

src/Symfony/Component/Form/Form.php

@@ -895,7 +895,7 @@ class Form implements \IteratorAggregate, FormInterface
         $child->setParent($this);
 
         if (!$this->lockSetData && $this->defaultDataSet && !$this->config->getInheritData()) {
-            $iterator = new InheritDataAwareIterator(new \ArrayIterator(array($child)));
+            $iterator = new InheritDataAwareIterator(new \ArrayIterator(array($child->getName() => $child)));
             $iterator = new \RecursiveIteratorIterator($iterator);
             $this->config->getDataMapper()->mapDataToForms($viewData, $iterator);
         }

src/Symfony/Component/Form/Tests/CompoundFormTest.php

@@ -352,7 +352,7 @@ class CompoundFormTest extends AbstractFormTest
             ->with('bar', $this->isInstanceOf('\RecursiveIteratorIterator'))
             ->will($this->returnCallback(function ($data, \RecursiveIteratorIterator $iterator) use ($child, $test) {
                 $test->assertInstanceOf('Symfony\Component\Form\Util\InheritDataAwareIterator', $iterator->getInnerIterator());
-                $test->assertSame(array($child), iterator_to_array($iterator));
+                $test->assertSame(array($child->getName() => $child), iterator_to_array($iterator));
             }));
 
         $form->initialize();