Simplify the code / check number of parameters in mergeConditions

src/Database/DBA.php

@@ -669,6 +669,10 @@ class DBA
 	 */
 	public static function mergeConditions(array ...$conditions)
 	{
+		if (count($conditions) == 1) {
+			return current($conditions);
+		}
+
 		$conditionStrings = [];
 		$result = [];
 

src/Model/Item.php

@@ -201,11 +201,7 @@ class Item
 			return [];
 		}
 
-		if (!empty($condition)) {
-			$condition = DBA::mergeConditions(['iid' => $pinned], $condition);
-		} else {
-			$condition = ['iid' => $pinned];
-		}
+		$condition = DBA::mergeConditions(['iid' => $pinned], $condition);
 
 		return self::selectThreadForUser($uid, $selected, $condition, $params);
 	}