From e5bb1ed4a6a288dd0dea2d5311f8a8fbe26d85db Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 4 May 2014 07:57:56 +0530
Subject: [PATCH] Fix a harmless error message that could occur in rare
 circumstances while editing metadata in the library. Fixes #1315735 [runtime
 error while editing
 metadata](https://bugs.launchpad.net/calibre/+bug/1315735)

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

diff --git a/src/calibre/db/search.py b/src/calibre/db/search.py
index c4f5ed03db..8d018c618b 100644
--- a/src/calibre/db/search.py
+++ b/src/calibre/db/search.py
@@ -814,7 +814,7 @@ class Search(object):
     def _update_caches(self, sqp, book_ids):
         book_ids = sqp.all_book_ids = set(book_ids)
         remove = set()
-        for query, result in self.cache:
+        for query, result in tuple(self.cache):
             try:
                 matches = sqp.parse(query)
             except ParseException: