fix(Memcache): use different cache key when in maintenance mode

Signed-off-by: Ferdinand Thiessen <[email protected]>

Author: susnux

lib/private/Memcache/Factory.php

@@ -113,12 +113,16 @@ public function __construct(
 	protected function getGlobalPrefix(): string {
 		if ($this->globalPrefix === null) {
 			$config = \OCP\Server::get(SystemConfig::class);
+			$maintenanceMode = $config->getValue('maintenance', false);
 			$versions = [];
-			if ($config->getValue('installed', false)) {
+			if ($config->getValue('installed', false) && !$maintenanceMode) {
 				$appConfig = \OCP\Server::get(IAppConfig::class);
 				// only get the enabled apps to clear the cache in case an app is enabled or disabled (e.g. clear routes)
 				$versions = $appConfig->getAppInstalledVersions(true);
 				ksort($versions);
+			} else {
+				// if not installed or in maintenance mode, we should distinguish between both states.
+				$versions['core:maintenance'] = $maintenanceMode ? '1' : '0';
 			}
 			$versions['core'] = implode('.', $this->serverVersion->getVersion());