<?php

public function testBacktrackIfSeveralSubFormsWithSamePropertyPath()
{
    $violation = $this->getConstraintViolation('data.address.street');
    $parent = $this->getForm('parent');
    $child1 = $this->getForm('subform1', 'address');
    $child2 = $this->getForm('subform2', 'address');
    $grandChild = $this->getForm('street');

    $parent->add($child1);
    $parent->add($child2);
    $child2->add($grandChild);

    $this->mapper->mapViolation($violation, $parent);

    // The error occurred on the child of the second form with the same path
    $this->assertCount(0, $parent->getErrors(), $parent->getName() . ' should not have an error, but has one');
    $this->assertCount(0, $child1->getErrors(), $child1->getName() . ' should not have an error, but has one');
    $this->assertCount(0, $child2->getErrors(), $child2->getName() . ' should not have an error, but has one');
    $this->assertEquals(array($this->getFormError()), $grandChild->getErrors(), $grandChild->getName() . ' should have an error, but has none');
}

<?php

// Test children unless we already found one
if (null === $foundChild) {
    foreach ($childIterator as $child) {
        /* @var FormInterface $child */
        $childPath = (string) $child->getPropertyPath();

        // Child found, mark as return value
        if ($chunk === $childPath) {
            $foundChild = $child;
            $foundAtIndex = $it->key();
        }
    }
}