From 1831407a2d1a516ed4b1d5528606fd92a61cad81 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 7 Apr 2023 08:26:36 +0530
Subject: [PATCH] ...

---
 src/calibre/gui2/tag_mapper.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/calibre/gui2/tag_mapper.py b/src/calibre/gui2/tag_mapper.py
index d3e990b2e1..001aa2324f 100644
--- a/src/calibre/gui2/tag_mapper.py
+++ b/src/calibre/gui2/tag_mapper.py
@@ -392,7 +392,7 @@ class Rules(QWidget):
     @rules.setter
     def rules(self, rules):
         self.rule_list.clear()
-        for rule in rules:
+        for rule in (rules or ()):
             if self.ACTION_KEY in rule and 'match_type' in rule and 'query' in rule:
                 self.RuleItemClass(rule, self.rule_list)