From 2532de27fb50695e9b52b72683703a1b169b6c65 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 4 Nov 2011 22:49:09 +0530
Subject: [PATCH] Do not error out if there is an invalid regex for title sort
 set in tweaks

---
 src/calibre/ebooks/metadata/__init__.py | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index decba3b780..a6b3c1ad21 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -116,10 +116,14 @@ def title_sort(title, order=None):
         title = title[1:]
     match = _title_pat.search(title)
     if match:
-        prep = match.group(1)
-        title = title[len(prep):] + ', ' + prep
-        if title[0] in _ignore_starts:
-            title = title[1:]
+        try:
+            prep = match.group(1)
+        except IndexError:
+            pass
+        else:
+            title = title[len(prep):] + ', ' + prep
+            if title[0] in _ignore_starts:
+                title = title[1:]
     return title.strip()
 
 coding = zip(