Merge pull request #49386 from nextcloud/bugfix/47658/dont-fail-preco…

…ndition-if-unset

fix(userconfig): Don't fail the precondition if the value is not set at all

lib/private/AllConfig.php

@@ -246,7 +246,7 @@ public function setUserValue($userId, $appName, $key, $value, $preCondition = nu
 		$userPreferences = \OCP\Server::get(IUserConfig::class);
 		if ($preCondition !== null) {
 			try {
-				if ($userPreferences->getValueMixed($userId, $appName, $key) !== (string)$preCondition) {
+				if ($userPreferences->hasKey($userId, $appName, $key) && $userPreferences->getValueMixed($userId, $appName, $key) !== (string)$preCondition) {
 					throw new PreConditionNotMetException();
 				}
 			} catch (TypeConflictException) {