From 8d46b4647eb0c26b957c7cc21a4d1a414a8cb082 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 5 Jun 2014 09:28:20 +0530
Subject: [PATCH] Check Book: Fix empty (zero byte) XML files causing check
 book to fail. Fixes #1326073 [Private
 bug](https://bugs.launchpad.net/calibre/+bug/1326073)

---
 src/calibre/ebooks/oeb/polish/check/parsing.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/calibre/ebooks/oeb/polish/check/parsing.py b/src/calibre/ebooks/oeb/polish/check/parsing.py
index e27345dc2d..72e5894ebb 100644
--- a/src/calibre/ebooks/oeb/polish/check/parsing.py
+++ b/src/calibre/ebooks/oeb/polish/check/parsing.py
@@ -48,6 +48,7 @@ class XMLParseError(BaseError):
              ' "do the wrong thing".')
 
     def __init__(self, msg, *args, **kwargs):
+        msg = msg or ''
         BaseError.__init__(self, 'Parsing failed: ' + msg, *args, **kwargs)
         m = mismatch_pat.search(msg)
         if m is not None: