missing plugin, modify "missing" attribute by modifying album_types,

making it of type INTEGER. also changelog for above.

beetsplug/missing.py

@@ -22,7 +22,7 @@ from beets.library import Item
 from beets.plugins import BeetsPlugin
 from beets.ui import decargs, print_, Subcommand
 from beets import config
-
+from beets.dbcore import types
 
 def _missing_count(album):
     """Return number of missing items in `album`.
@@ -81,6 +81,11 @@ def _item(track_info, album_info, album_id):
 class MissingPlugin(BeetsPlugin):
     """List missing tracks
     """
+
+    album_types = {
+       'missing':  types.INTEGER,
+    }
+
     def __init__(self):
         super(MissingPlugin, self).__init__()
 

docs/changelog.rst

@@ -84,6 +84,8 @@ And there are a few bug fixes too:
   single track, two-sided mediums are treated as single discs, and tracks
   have ``media``, ``medium_total`` and ``medium`` set correctly. :bug:`2222`
   :bug:`2228`.
+* :doc:`/plugins/missing`: ``missing`` is now treated as an integer, allowing
+  the use of (for example) ranges in queries.
 
 The last release, 1.3.19, also erroneously reported its version as "1.3.18"
 when you typed ``beet version``. This has been corrected.