From a5cadce60355a8afc49c0bd37375fff78db84d3e Mon Sep 17 00:00:00 2001
From: Charles Haley <>
Date: Sat, 27 Nov 2010 11:30:52 +0000
Subject: [PATCH] Fix #7459: Bug/error when copying and deleting from one
 library to another. Problem arose because field_metadata modified a
 class_level (static) attribute.

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

diff --git a/src/calibre/library/field_metadata.py b/src/calibre/library/field_metadata.py
index dbc871026e..afc63cb692 100644
--- a/src/calibre/library/field_metadata.py
+++ b/src/calibre/library/field_metadata.py
@@ -3,6 +3,7 @@ Created on 25 May 2010
 
 @author: charles
 '''
+import copy
 
 from calibre.utils.ordered_dict import OrderedDict
 from calibre.utils.config import tweaks
@@ -86,7 +87,7 @@ class FieldMetadata(dict):
 
     # Builtin metadata {{{
 
-    _field_metadata = [
+    _field_metadata_prototype = [
             ('authors',   {'table':'authors',
                            'column':'name',
                            'link_column':'author',
@@ -322,6 +323,7 @@ class FieldMetadata(dict):
                     ]
 
     def __init__(self):
+        self._field_metadata = copy.deepcopy(self._field_metadata_prototype)
         self._tb_cats = OrderedDict()
         self._search_term_map = {}
         self.custom_label_to_key_map = {}