Raise an exception when Hash::get() receives invalid parameters

I'm not sure on whether this is a problem with my local app but I have
seen it a couple of times in a couple of projects: Warning (2): Invalid
argument supplied for foreach() [CORE/Cake/Utility/Hash.php, line 52]

I think Hash::get should be able to handle this better rather than
throwing an error in a core Util file.

Refs #3754

Author: voycey

lib/Cake/Utility/Hash.php

@@ -38,6 +38,7 @@ class Hash {
  * @param string|array $path The path being searched for. Either a dot
  *   separated string, or an array of path segments.
  * @param mixed $default The return value when the path does not exist
+ * @throws InvalidArgumentException
  * @return mixed The value fetched from the array, or null.
  * @link http://book.cakephp.org/2.0/en/core-utility-libraries/hash.html#Hash::get
  */
@@ -48,15 +49,21 @@ public static function get(array $data, $path, $default = null) {
 		if (is_string($path) || is_numeric($path)) {
 			$parts = explode('.', $path);
 		} else {
-			$parts = $path;
+			if (!is_array($path)) {
+            			 throw new InvalidArgumentException(__d('cake_dev', 'Invalid Parameter %s, should be dot separated path or array.', $path));
+ 			}
+ 			
+ 			$parts = $path;
 		}
+		
 		foreach ($parts as $key) {
 			if (is_array($data) && isset($data[$key])) {
 				$data =& $data[$key];
 			} else {
 				return $default;
 			}
 		}
+
 		return $data;
 	}