bug symfony#13346 [PropertyAccessor] Allow null value for a array (2.3) (boekkooi)

This PR was merged into the 2.3 branch.

Discussion
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[PropertyAccessor] Allow null value for a array (2.3)

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#12482
| License       | MIT
| Doc PR        | -

Original PR is symfony#12511
A rebase on 2.3 was requested by @fabpot

Commits
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9706b09 [PropertyAccessor] Added test to allow null value for a array

Author: fabpot

src/Symfony/Component/PropertyAccess/PropertyAccessor.php

@@ -117,10 +117,15 @@ private function &readPropertiesUntil(&$objectOrArray, PropertyPathInterface $pr
 
             $property = $propertyPath->getElement($i);
             $isIndex = $propertyPath->isIndex($i);
-            $isArrayAccess = is_array($objectOrArray) || $objectOrArray instanceof \ArrayAccess;
 
             // Create missing nested arrays on demand
-            if ($isIndex && $isArrayAccess && !isset($objectOrArray[$property])) {
+            if (
+                $isIndex &&
+                (
+                    ($objectOrArray instanceof \ArrayAccess && !isset($objectOrArray[$property])) ||
+                    (is_array($objectOrArray) && !array_key_exists($property, $objectOrArray))
+                )
+            ) {
                 $objectOrArray[$property] = $i + 1 < $propertyPath->getLength() ? array() : null;
             }
 

src/Symfony/Component/PropertyAccess/Tests/PropertyAccessorTest.php

@@ -221,6 +221,12 @@ public function testGetValueThrowsExceptionIfEmpty()
         $this->propertyAccessor->getValue('', 'foobar');
     }
 
+    public function testGetValueWhenArrayValueIsNull()
+    {
+        $this->propertyAccessor = new PropertyAccessor(false, true);
+        $this->assertNull($this->propertyAccessor->getValue(array('index' => array('nullable' => null)), '[index][nullable]'));
+    }
+
     public function testSetValueUpdatesArrays()
     {
         $array = array();