Array Merge recursive distinct function

src/system/helpers/Arrays.php

@@ -27,10 +27,52 @@ public static function arrayWalkWithRoute(
             if (is_array($val)) {
                 self::arrayWalkWithRoute($val, $callback, $_route, $separator);
             } else {
-                call_user_func_array($callback,[$key,&$val,$_route]);
+                call_user_func_array($callback, [$key, &$val, $_route]);
+            }
+        }
+    }
+
+    /**
+     * array_merge_recursive does indeed merge arrays,
+     * but it converts values with duplicate
+     * keys to arrays rather than overwriting the value
+     * in the first array with the duplicate
+     * value in the second array,
+     * as array_merge does. I.e., with array_merge_recursive,
+     * this happens (documented behavior):
+     *
+     * array_merge_recursive(array('key' => 'org value'), array('key' => 'new value'));
+     *     => array('key' => array('org value', 'new value'));
+     *
+     * array_merge_recursive_distinct does not change the datatypes of the values in the arrays.
+     * Matching keys' values in the second array overwrite those in the first array, as is the
+     * case with array_merge, i.e.:
+     *
+     * array_merge_recursive_distinct(array('key' => 'org value'), array('key' => 'new value'));
+     *     => array('key' => array('new value'));
+     *
+     * Parameters are passed by reference, though only for performance reasons. They're not
+     * altered by this function.
+     *
+     * @param array $array1
+     * @param array $array2
+     * @return array
+     *
+     * @author Daniel <daniel (at) danielsmedegaardbuus (dot) dk>
+     * @author Gabriel Sobrinho <gabriel (dot) sobrinho (at) gmail (dot) com>
+     */
+    public static function arrayMergeRecursiveDistinct(array &$array1, array &$array2)
+    {
+        $merged = $array1;
 
-//                $callback($key, $val, $_route);
+        foreach ($array2 as $key => &$value) {
+            if (is_array($value) && isset ($merged [$key]) && is_array($merged [$key])) {
+                $merged [$key] = array_merge_recursive_distinct($merged [$key], $value);
+            } else {
+                $merged [$key] = $value;
             }
         }
+
+        return $merged;
     }
 }