Throw exception instead of logging in debug mode.

lib/Cake/View/Helper/CacheHelper.php

@@ -109,6 +109,7 @@ class CacheHelper extends AppHelper {
  * @param string $out output to cache
  * @return string view output
  * @link http://book.cakephp.org/2.0/en/core-libraries/helpers/cache.html
+ * @throws Exception If debug mode is enabled and writing to cache file fails.
  */
 	public function cache($file, $out) {
 		$cacheTime = 0;
@@ -153,6 +154,10 @@ class CacheHelper extends AppHelper {
 			try {
 				$this->_writeFile($cached, $cacheTime, $useCallbacks);
 			} catch (Exception $e) {
+				if (Configure::read('debug')) {
+					throw $e;
+				}
+
 				$message = __d(
 					'cake_dev',
 					'Unable to write view cache file: "%s" for "%s"',