From cf97f6228a0833ae871ea15506d0a70e454a27d9 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 8 May 2012 19:15:09 +0530
Subject: [PATCH] Fix #996439 ('NoneType' object has no attribute 'partition'
 (Error Code: 1) when converitng to AWZ3)

---
 src/calibre/ebooks/mobi/writer8/main.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/calibre/ebooks/mobi/writer8/main.py b/src/calibre/ebooks/mobi/writer8/main.py
index 4e6719bb90..acba9be454 100644
--- a/src/calibre/ebooks/mobi/writer8/main.py
+++ b/src/calibre/ebooks/mobi/writer8/main.py
@@ -316,7 +316,7 @@ class KF8Writer(object):
         # Flatten the ToC into a depth first list
         fl = toc.iter() if is_periodical else toc.iterdescendants()
         for i, item in enumerate(fl):
-            entry = {'id': id(item), 'index': i, 'href':item.href,
+            entry = {'id': id(item), 'index': i, 'href':item.href or '',
                     'label':(item.title or _('Unknown')),
                     'children':[]}
             entry['depth'] = getattr(item, 'ncx_hlvl', 0)