Throw exception if memcache misconfigured or missing

Instead of falling back to null memcache, throw exceptions.
Also throw file locking specific exceptions in case the class is not
available.

2 files changed, 19 insertions, 2 deletions

diff --git a/lib/private/memcache/factory.php b/lib/private/memcache/factory.php
index 5e3d857006c..320657a71ad 100644
--- a/lib/private/memcache/factory.php
+++ b/lib/private/memcache/factory.php
@@ -62,12 +62,25 @@ class Factory implements ICacheFactory {
 	{
 		$this->globalPrefix = $globalPrefix;
 
-		if (!($localCacheClass && $localCacheClass::isAvailable())) {
+		if (!$localCacheClass) {
 			$localCacheClass = self::NULL_CACHE;
 		}
-		if (!($distributedCacheClass && $distributedCacheClass::isAvailable())) {
+		if (!$distributedCacheClass) {
 			$distributedCacheClass = $localCacheClass;
 		}
+
+		if (!$localCacheClass::isAvailable()) {
+			throw new \OC\HintException(
+				'Missing memcache class ' . $localCacheClass . ' for local cache',
+				'Is the matching PHP module installed and enabled ?'
+			);
+		}
+		if (!$distributedCacheClass::isAvailable()) {
+			throw new \OC\HintException(
+				'Missing memcache class ' . $distributedCacheClass . ' for distributed cache',
+				'Is the matching PHP module installed and enabled ?'
+			);
+		}
 		if (!($lockingCacheClass && $lockingCacheClass::isAvailable())) {
 			// dont fallback since the fallback might not be suitable for storing lock
 			$lockingCacheClass = '\OC\Memcache\NullCache';
diff --git a/lib/private/server.php b/lib/private/server.php
index 5ed9d78f41b..ef033eb389d 100644
--- a/lib/private/server.php
+++ b/lib/private/server.php
@@ -431,6 +431,10 @@ class Server extends SimpleContainer implements IServerContainer {
 				if (!($memcache instanceof \OC\Memcache\NullCache)) {
 					return new MemcacheLockingProvider($memcache);
 				}
+				throw new HintException(
+					'File locking is enabled but the locking cache class was not found',
+					'Please check the "memcache.locking" setting and make sure the matching PHP module is installed and enabled'
+				);
 			}
 			return new NoopLockingProvider();
 		});