From 7239c3af0134a9f1ea8150f0a8493e9a65acfe8d Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 29 Jan 2011 09:49:34 -0700
Subject: [PATCH] Fix #8656 (Attempting to merge two books, getting ValueError)

---
 src/calibre/library/database2.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 3c6d4016f2..3fc16e99b4 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -1549,7 +1549,9 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         elif mi.cover is not None:
             if os.access(mi.cover, os.R_OK):
                 with lopen(mi.cover, 'rb') as f:
-                    doit(self.set_cover, id, f, commit=False)
+                    raw = f.read()
+                if raw:
+                    doit(self.set_cover, id, raw, commit=False)
         if mi.tags:
             doit(self.set_tags, id, mi.tags, notify=False, commit=False)
         if mi.comments: