Merge pull request #638 from brilnius/ui_del_attr2

Modify command: ability to delete/reset an attribute (beet modify field!)

beets/ui/commands.py

@@ -1082,7 +1082,7 @@ default_commands.append(version_cmd)
 
 # modify: Declaratively change metadata.
 
-def modify_items(lib, mods, query, write, move, album, confirm):
+def modify_items(lib, mods, dels, query, write, move, album, confirm):
     """Modifies matching items according to key=value assignments."""
     # Parse key=value specifications into a dictionary.
     model_cls = library.Album if album else library.Item
@@ -1102,6 +1102,8 @@ def modify_items(lib, mods, query, write, move, album, confirm):
     for obj in objs:
         for field, value in fsets.iteritems():
             obj[field] = value
+        for field in dels:
+            del obj[field]
         if ui.show_model_changes(obj):
             changed.add(obj)
 
@@ -1155,13 +1157,22 @@ modify_cmd.parser.add_option('-f', '--format', action='store',
     help='print with custom format', default=None)
 def modify_func(lib, opts, args):
     args = decargs(args)
-    mods = [a for a in args if '=' in a]
-    query = [a for a in args if '=' not in a]
-    if not mods:
+    mods = []
+    dels = []
+    query = []
+    for arg in args:
+        if arg.endswith('!') and '=' not in arg and ':' not in arg:
+            dels.append(arg[:-1])
+        elif '=' in arg:
+            mods.append(arg)
+        else:
+            query.append(arg)
+    if not mods and not dels:
         raise ui.UserError('no modifications specified')
     write = opts.write if opts.write is not None else \
         config['import']['write'].get(bool)
-    modify_items(lib, mods, query, write, opts.move, opts.album, not opts.yes)
+    modify_items(lib, mods, dels, query, write, opts.move, opts.album,
+                 not opts.yes)
 modify_cmd.func = modify_func
 default_commands.append(modify_cmd)
 

docs/changelog.rst

@@ -32,8 +32,10 @@ New stuff:
 * We now only use "primary" aliases for artist names from MusicBrainz. This
   eliminates some strange naming that could occur when the `languages` config
   option was set. Thanks to Filipe Fortes.
-
-
+* The :ref:`modify-cmd` command now allows removing flexible attribute. For
+  example: ``beet modify artist:beatles oldies!`` deletes the ``oldies``
+  flexible attribute from the database, for the matching items. Thanks to
+  brilnius.
 
 Fixes:
 

docs/guides/advanced.rst

@@ -111,9 +111,9 @@ Store any data you like
 
 The beets database keeps track of a long list of :ref:`built-in fields
 <itemfields>`, but you're not limited to just that list. Say, for example,
-that you like to like to categorize your music by the setting where it should
-be played. You can invent a new ``context`` attribute store this. Set the
-field using the :ref:`modify-cmd` command::
+that you like to categorize your music by the setting where it should be
+played. You can invent a new ``context`` attribute store this. Set the field
+using the :ref:`modify-cmd` command::
 
     beet modify context=party artist:'beastie boys'
 
@@ -125,6 +125,10 @@ other field::
 You can even use these fields in your filenames (see
 :ref:`path-format-config`).
 
+And, unlike :ref:`built-in fields <itemfields>`, such fields can be removed::
+
+    beet modify context! artist:'beastie boys'
+
 Read more than you ever wanted to know about the *flexible attributes*
 feature `on the beets blog`_.
 

docs/reference/cli.rst

@@ -201,20 +201,21 @@ modify
 ``````
 ::
 
-    beet modify [-MWay] QUERY FIELD=VALUE...
+    beet modify [-MWay] QUERY [FIELD=VALUE...] [FIELD!...]
 
 Change the metadata for items or albums in the database.
 
 Supply a :doc:`query <query>` matching the things you want to change and a
 series of ``field=value`` pairs. For example, ``beet modify genius of love
 artist="Tom Tom Club"`` will change the artist for the track "Genius of Love."
-The ``-a`` switch operates on albums instead of individual tracks. Items will
-automatically be moved around when necessary if they're in your library
-directory, but you can disable that with ``-M``. Tags will be written to the
-files according to the settings you have for imports, but these can be
-overridden with ``-w`` (write tags, the default) and ``-W`` (don't write tags).
-Finally, this command politely asks for your permission before making any
-changes, but you can skip that prompt with the ``-y`` switch.
+For removing fields (only possible with flexible attributes), specify one or
+more ``field!`` argument(s). The ``-a`` switch operates on albums instead of
+individual tracks. Items will automatically be moved around when necessary if
+they're in your library directory, but you can disable that with ``-M``. Tags
+will be written to the files according to the settings you have for imports,
+but these can be overridden with ``-w`` (write tags, the default) and ``-W``
+(don't write tags).  Finally, this command politely asks for your permission
+before making any changes, but you can skip that prompt with the ``-y`` switch.
 
 .. _move-cmd:
 

test/test_ui.py

@@ -157,9 +157,10 @@ class ModifyTest(_common.TestCase):
         self.i.move(True)
         self.album = self.lib.add_album([self.i])
 
-    def _modify(self, mods, query=(), write=False, move=False, album=False):
+    def _modify(self, mods, dels=(), query=(), write=False, move=False,
+                album=False):
         self.io.addinput('y')
-        commands.modify_items(self.lib, mods, query,
+        commands.modify_items(self.lib, mods, dels, query,
                               write, move, album, True)
 
     def test_modify_item_dbdata(self):