fix some php8 warnings

classes/pref/feeds.php

@@ -690,7 +690,7 @@ class Pref_Feeds extends Handler_Protected {
 		$purge_intl = (int) clean($_POST["purge_interval"] ?? 0);
 		$feed_id = (int) clean($_POST["id"] ?? 0); /* editSave */
 		$feed_ids = explode(",", clean($_POST["ids"] ?? "")); /* batchEditSave */
-		$cat_id = (int) clean($_POST["cat_id"]);
+		$cat_id = (int) clean($_POST["cat_id"] ?? 0);
 		$auth_login = clean($_POST["auth_login"]);
 		$auth_pass = clean($_POST["auth_pass"]);
 		$private = checkbox_to_sql_bool(clean($_POST["private"] ?? ""));

classes/pref/filters.php

@@ -51,8 +51,8 @@ class Pref_Filters extends Handler_Protected {
 		$filter = array();
 
 		$filter["enabled"] = true;
-		$filter["match_any_rule"] = checkbox_to_sql_bool(clean($_REQUEST["match_any_rule"]));
-		$filter["inverse"] = checkbox_to_sql_bool(clean($_REQUEST["inverse"]));
+		$filter["match_any_rule"] = checkbox_to_sql_bool(clean($_REQUEST["match_any_rule"] ?? false));
+		$filter["inverse"] = checkbox_to_sql_bool(clean($_REQUEST["inverse"] ?? false));
 
 		$filter["rules"] = array();
 		$filter["actions"] = array("dummy-action");

classes/rpc.php

@@ -382,10 +382,10 @@ class RPC extends Handler_Protected {
 	}
 
 	function log() {
-		$msg = clean($_REQUEST['msg']);
-		$file = basename(clean($_REQUEST['file']));
-		$line = (int) clean($_REQUEST['line']);
-		$context = clean($_REQUEST['context']);
+		$msg = clean($_REQUEST['msg'] ?? "");
+		$file = basename(clean($_REQUEST['file'] ?? ""));
+		$line = (int) clean($_REQUEST['line'] ?? 0);
+		$context = clean($_REQUEST['context'] ?? "");
 
 		if ($msg) {
 			Logger::log_error(E_USER_WARNING,