revise behavior of Feeds::_cat_of

classes/feeds.php

@@ -1842,13 +1842,14 @@ class Feeds extends Handler_Protected {
 		return $rv;
 	}
 
-	static function _cat_of_feed($feed) {
+	// returns Uncategorized as 0
+	static function _cat_of($feed) : int {
 		$feed = ORM::for_table('ttrss_feeds')->find_one($feed);
 
 		if ($feed) {
-			return $feed->cat_id;
+			return (int)$feed->cat_id;
 		} else {
-			return false;
+			return -1;
 		}
 	}
 

classes/rssutils.php

@@ -1713,7 +1713,7 @@ class RSSUtils {
 		$filters = array();
 
 		$feed_id = (int) $feed_id;
-		$cat_id = (int)Feeds::_cat_of_feed($feed_id);
+		$cat_id = Feeds::_cat_of($feed_id);
 
 		if (!$cat_id)
 			$null_cat_qpart = "cat_id IS NULL OR";