only write file caches if minutes is greater than zero.

laravel/cache/drivers/file.php

@@ -67,6 +67,8 @@ protected function retrieve($key)
 	 */
 	public function put($key, $value, $minutes)
 	{
+		if ($minutes <= 0) return;
+
 		$value = $this->expiration($minutes).serialize($value);
 
 		file_put_contents($this->path.$key, $value, LOCK_EX);

laravel/documentation/changes.md

@@ -48,6 +48,7 @@ ## Laravel 3.2
 - Made the `get_timestamp` Eloquent method static.
 - `Request::secure` now takes `application.ssl` configuration option into consideration.
 - Simplified the `paths.php` file.
+- Only write file caches if number of minutes is greater than zero.
 
 <a name="upgrade-3.2"></a>
 ## Upgrading From 3.1