catch a few tagging failure modes

beets/autotag/__init__.py

@@ -31,6 +31,8 @@ from beets import library, mediafile
 LENGTH_TOLERANCE = 30
 
 class AutotagError(Exception): pass
+class InsufficientMetadataError(AutotagError): pass
+class UnknownAlbumError(AutotagError): pass
 class UnorderedTracksError(AutotagError): pass
 
 def albums_in_dir(path, lib=None):
@@ -244,13 +246,18 @@ def tag_album(items):
         - The current metadata: an (artist, album) tuple.
         - The inferred metadata dictionary.
         - The distance between the current and new metadata.
-    May raise an UnorderedTracksError if existing metadata is
-    insufficient.
+    May raise an AutotagError if existing metadata is insufficient.
     """
     # Get current and candidate metadata.
     cur_artist, cur_album = current_metadata(items)
+    if not cur_artist or not cur_album:
+        raise InsufficientMetadataError()
     info = mb.match_album(cur_artist, cur_album, len(items))
     
+    # Make sure the album has the correct number of tracks.
+    if len(items) != len(info['tracks']):
+        raise UnknownAlbumError()
+    
     # Put items in order.
     #fixme need to try ordering tracks for every candidate album
     items = order_items(items, info['tracks'])

bts

@@ -59,8 +59,8 @@ def tag_album(items, lib):
     # Infer tags.
     try:
         items, (cur_artist, cur_album), info, dist = autotag.tag_album(items)
-    except autotag.UnorderedTracksError:
-        print "Tracks could not be ordered."
+    except autotag.AutotagError:
+        print "Untaggable album:", os.path.dirname(items[0].path)
         return
     
     # Show what we're about to do.