get_album (and evalute_template) with non-DB items

Alternative fix for #403.

beets/library.py

@@ -475,9 +475,11 @@ class Item(LibModel):
 
     def get_album(self):
         """Get the Album object that this item belongs to, if any, or
-        None if the item is a singleton.
+        None if the item is a singleton or is not associated with a
+        library.
         """
-        self._check_db()
+        if not self._lib:
+            return None
         return self._lib.get_album(self)
 
 

beetsplug/missing.py

@@ -153,8 +153,6 @@ class MissingPlugin(BeetsPlugin):
 
                 else:
                     for item in _missing(album):
-                        item._lib = lib
-                        item.id = '-1'
                         print_obj(item, lib, fmt=fmt)
 
         self._command.func = _miss