Issue #2770065 by joseph.olstad, joelpittet, dawehner, catch, willzyx:...

Issue #2770065 by joseph.olstad, joelpittet, dawehner, catch, willzyx: array_key_exists() micro-optimization

core/lib/Drupal/Component/Utility/NestedArray.php

@@ -69,7 +69,7 @@ class NestedArray {
   public static function &getValue(array &$array, array $parents, &$key_exists = NULL) {
     $ref = &$array;
     foreach ($parents as $parent) {
-      if (is_array($ref) && array_key_exists($parent, $ref)) {
+      if (is_array($ref) && (isset($ref[$parent]) || array_key_exists($parent, $ref))) {
         $ref = &$ref[$parent];
       }
       else {
@@ -219,7 +219,7 @@ public static function setValue(array &$array, array $parents, $value, $force =
   public static function unsetValue(array &$array, array $parents, &$key_existed = NULL) {
     $unset_key = array_pop($parents);
     $ref = &self::getValue($array, $parents, $key_existed);
-    if ($key_existed && is_array($ref) && array_key_exists($unset_key, $ref)) {
+    if ($key_existed && is_array($ref) && (isset($ref[$unset_key]) || array_key_exists($unset_key, $ref))) {
       $key_existed = TRUE;
       unset($ref[$unset_key]);
     }

core/lib/Drupal/Core/Utility/ThemeRegistry.php

@@ -96,7 +96,7 @@ public function has($key) {
     // are not registered, just check the existence of the key in the registry.
     // Use array_key_exists() here since a NULL value indicates that the theme
     // hook exists but has not yet been requested.
-    return array_key_exists($key, $this->storage);
+    return isset($this->storage[$key]) || array_key_exists($key, $this->storage);
   }
 
   /**