From 447afcdd08f1c40b7def917f50f3c8c57a314d6f Mon Sep 17 00:00:00 2001
From: Charles Haley <>
Date: Thu, 15 Jul 2010 21:28:52 +0100
Subject: [PATCH] Fix cache problem where merging metadata did not values
 explicitly set to None, such as erasing series.

---
 src/calibre/devices/usbms/books.py      |  2 +-
 src/calibre/ebooks/metadata/__init__.py | 14 +++++++++-----
 src/calibre/gui2/device.py              | 15 ++++++++++-----
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/calibre/devices/usbms/books.py b/src/calibre/devices/usbms/books.py
index 6394626a9f..5ad4ef4723 100644
--- a/src/calibre/devices/usbms/books.py
+++ b/src/calibre/devices/usbms/books.py
@@ -78,7 +78,7 @@ class Book(MetaInformation):
         in C{other} takes precedence, unless the information in C{other} is NULL.
         '''
 
-        MetaInformation.smart_update(self, other, replace_tags=True)
+        MetaInformation.smart_update(self, other, replace_metadata=True)
 
         for attr in self.BOOK_ATTRS:
             if hasattr(other, attr):
diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index 0dbffd5f7f..d5e7aafb32 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -268,10 +268,12 @@ class MetaInformation(object):
                   ):
             prints(x, getattr(self, x, 'None'))
 
-    def smart_update(self, mi, replace_tags=False):
+    def smart_update(self, mi, replace_metadata=False):
         '''
-        Merge the information in C{mi} into self. In case of conflicts, the information
-        in C{mi} takes precedence, unless the information in mi is NULL.
+        Merge the information in C{mi} into self. In case of conflicts, the
+        information in C{mi} takes precedence, unless the information in mi is
+        NULL. If replace_metadata is True, then the information in mi always
+        takes precedence.
         '''
         if mi.title and mi.title != _('Unknown'):
             self.title = mi.title
@@ -285,13 +287,15 @@ class MetaInformation(object):
                      'cover', 'guide', 'book_producer',
                      'timestamp', 'lccn', 'lcc', 'ddc', 'pubdate', 'rights',
                      'publication_type', 'uuid'):
-            if hasattr(mi, attr):
+            if replace_metadata:
+                setattr(self, attr, getattr(mi, attr, None))
+            elif hasattr(mi, attr):
                 val = getattr(mi, attr)
                 if val is not None:
                     setattr(self, attr, val)
 
         if mi.tags:
-            if replace_tags:
+            if replace_metadata:
                 self.tags = mi.tags
             else:
                 self.tags += mi.tags
diff --git a/src/calibre/gui2/device.py b/src/calibre/gui2/device.py
index d81918c307..bc8ba7c381 100644
--- a/src/calibre/gui2/device.py
+++ b/src/calibre/gui2/device.py
@@ -1439,7 +1439,8 @@ class DeviceMixin(object): # {{{
             for book in booklist:
                 if getattr(book, 'uuid', None) in self.db_book_uuid_cache:
                     if update_metadata:
-                        book.smart_update(self.db_book_uuid_cache[book.uuid])
+                        book.smart_update(self.db_book_uuid_cache[book.uuid],
+                                          replace_metadata=True)
                     book.in_library = True
                     # ensure that the correct application_id is set
                     book.application_id = \
@@ -1454,12 +1455,14 @@ class DeviceMixin(object): # {{{
                     if getattr(book, 'application_id', None) in d['db_ids']:
                         book.in_library = True
                         if update_metadata:
-                            book.smart_update(d['db_ids'][book.application_id])
+                            book.smart_update(d['db_ids'][book.application_id],
+                                              replace_metadata=True)
                         continue
                     if book.db_id in d['db_ids']:
                         book.in_library = True
                         if update_metadata:
-                            book.smart_update(d['db_ids'][book.db_id])
+                            book.smart_update(d['db_ids'][book.db_id],
+                                              replace_metadata=True)
                         continue
                     if book.authors:
                         # Compare against both author and author sort, because
@@ -1469,11 +1472,13 @@ class DeviceMixin(object): # {{{
                         if book_authors in d['authors']:
                             book.in_library = True
                             if update_metadata:
-                                book.smart_update(d['authors'][book_authors])
+                                book.smart_update(d['authors'][book_authors],
+                                                  replace_metadata=True)
                         elif book_authors in d['author_sort']:
                             book.in_library = True
                             if update_metadata:
-                                book.smart_update(d['author_sort'][book_authors])
+                                book.smart_update(d['author_sort'][book_authors],
+                                                  replace_metadata=True)
                 # Set author_sort if it isn't already
                 asort = getattr(book, 'author_sort', None)
                 if not asort and book.authors: