do not hide exception when ldap server has a hiccup

apps/user_ldap/lib/connection.php

@@ -167,7 +167,8 @@ class Connection extends LDAPUtility {
 			$this->establishConnection();
 		}
 		if(is_null($this->ldapConnectionRes)) {
-			\OCP\Util::writeLog('user_ldap', 'Connection could not be established', \OCP\Util::ERROR);
+			\OCP\Util::writeLog('user_ldap', 'No LDAP Connection to server ' . $this->connection->ldapHost, \OCP\Util::ERROR);
+			throw new \Exception('Connection to LDAP server could not be established');
 		}
 		return $this->ldapConnectionRes;
 	}

apps/user_ldap/lib/user/manager.php

@@ -165,6 +165,7 @@ class Manager {
 	 * @brief returns a User object by it's DN or ownCloud username
 	 * @param string the DN or username of the user
 	 * @return \OCA\user_ldap\lib\user\User|\OCA\user_ldap\lib\user\OfflineUser|null
+	 * @throws \Exception when connection could not be established
 	 */
 	public function get($id) {
 		$this->checkAccess();
@@ -181,12 +182,7 @@ class Manager {
 			}
 		}
 
-		try {
-			$user = $this->createInstancyByUserName($id);
-			return $user;
-		} catch (\Exception $e) {
-			return null;
-		}
+		return $this->createInstancyByUserName($id);
 	}
 
 }

apps/user_ldap/user_ldap.php

@@ -190,6 +190,7 @@ class USER_LDAP extends BackendUtility implements \OCP\IUserBackend, \OCP\UserIn
 	 * check if a user exists
 	 * @param string $uid the username
 	 * @return boolean
+	 * @throws \Exception when connection could not be established
 	 */
 	public function userExists($uid) {
 		if($this->access->connection->isCached('userExists'.$uid)) {
@@ -208,17 +209,12 @@ class USER_LDAP extends BackendUtility implements \OCP\IUserBackend, \OCP\UserIn
 			return true;
 		}
 
-		try {
-			$result = $this->userExistsOnLDAP($user);
-			$this->access->connection->writeToCache('userExists'.$uid, $result);
-			if($result === true) {
-				$user->update();
-			}
-			return $result;
-		} catch (\Exception $e) {
-			\OCP\Util::writeLog('user_ldap', $e->getMessage(), \OCP\Util::WARN);
-			return false;
+		$result = $this->userExistsOnLDAP($user);
+		$this->access->connection->writeToCache('userExists'.$uid, $result);
+		if($result === true) {
+			$user->update();
 		}
+		return $result;
 	}
 
 	/**