Disallow disabling of files app

core/command/app/disable.php

@@ -28,8 +28,12 @@ class Disable extends Command {
 	protected function execute(InputInterface $input, OutputInterface $output) {
 		$appId = $input->getArgument('app-id');
 		if (\OC_App::isEnabled($appId)) {
-			\OC_App::disable($appId);
-			$output->writeln($appId . ' disabled');
+			try {
+				\OC_App::disable($appId);
+				$output->writeln($appId . ' disabled');
+			} catch(\Exception $e) {
+				$output->writeln($e->getMessage());
+			}
 		} else {
 			$output->writeln('No such app enabled: ' . $appId);
 		}

lib/private/app.php

@@ -321,6 +321,9 @@ class OC_App {
 	 * @param string $app app
 	 */
 	public static function disable($app) {
+		if($app === 'files') {
+			throw new \Exception("App 'files' can't be disabled.");
+		}
 		self::$enabledAppsCache = array(); // flush
 		// check if app is a shipped app or not. if not delete
 		\OC_Hook::emit('OC_App', 'pre_disable', array('app' => $app));

lib/private/app/appmanager.php

@@ -131,8 +131,12 @@ class AppManager implements IAppManager {
 	 * Disable an app for every user
 	 *
 	 * @param string $appId
+	 * @throws \Exception if app can't be disabled
 	 */
 	public function disableApp($appId) {
+		if($appId === 'files') {
+			throw new \Exception("App 'files' can't be disabled.");
+		}
 		$this->appConfig->setValue($appId, 'enabled', 'no');
 	}
 }