Change in beets so it only writes tags that have values. This should

prevent things like disc reading as "0" instead of null. To reiterate:
the tag isn't blank - it's not written at all. I'm not sure what
implications that has.

lib/beets/autotag/__init__.py

@@ -378,8 +378,8 @@ def apply_metadata(items, info):
         
         # Compilation flag.
         item.comp = info['va']
-	item.comments = 'tagged by headphones/beets'
-
+        item.comments = 'tagged by headphones/beets'
+        
 def match_by_id(items):
     """If the items are tagged with a MusicBrainz album ID, returns an
     info dict for the corresponding album. Otherwise, returns None.

lib/beets/library.py

@@ -204,7 +204,8 @@ class Item(object):
         """
         f = MediaFile(syspath(self.path))
         for key in ITEM_KEYS_WRITABLE:
-            setattr(f, key, getattr(self, key))
+            if getattr(self, key):  #make sure it has a value before we set it and create blank tags with wrong types
+                setattr(f, key, getattr(self, key))
         f.save()