From 8fbf09a641d5d568424825484e83698c74b61c5f Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 14 May 2022 17:29:09 +0530
Subject: [PATCH] Fix #1973400 [Private
 bug](https://bugs.launchpad.net/calibre/+bug/1973400)

---
 src/calibre/gui2/viewer/toc.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/calibre/gui2/viewer/toc.py b/src/calibre/gui2/viewer/toc.py
index 6c22d5d108..cb1f7ee80a 100644
--- a/src/calibre/gui2/viewer/toc.py
+++ b/src/calibre/gui2/viewer/toc.py
@@ -264,7 +264,10 @@ class TOC(QStandardItemModel):
     def find_items(self, query):
         for item in self.all_items:
             text = item.text()
-            if not query or (text and primary_contains(query, text)):
+            if query and isinstance(query, str):
+                if text and isinstance(text, str) and primary_contains(query, text):
+                    yield item
+            else:
                 yield item
 
     def items_at_depth(self, depth):