zero: Only changes media file tags not database

Uses the new API from the previous commit and fixes #963.

There is a possible issue with backwards compatibility: Changes to the
item in the 'write' event do not propagate to the tags anymore. But I'm
not aware of other plugins that use the API in that way.

Author: Thomas Scholtes

beetsplug/zero.py

@@ -78,18 +78,18 @@ def match_patterns(cls, field, patterns):
                 return True
         return False
 
-    def write_event(self, item):
+    def write_event(self, item, path, tags):
         """Listen for write event."""
         if not self.patterns:
             log.warn(u'[zero] no fields, nothing to do')
             return
 
         for field, patterns in self.patterns.items():
-            if field not in item.keys():
+            if field not in tags:
                 log.error(u'[zero] no such field: {0}'.format(field))
                 continue
 
-            value = item[field]
+            value = tags[field]
             if self.match_patterns(value, patterns):
                 log.debug(u'[zero] {0}: {1} -> None'.format(field, value))
-                item[field] = None
+                tags[field] = None

docs/changelog.rst

@@ -70,6 +70,8 @@ Fixes:
   automatically.
 * The ``write`` event allows plugins to change the tags that are
   written to a media file.
+* :doc:`/plugins/zero`: Do not delete database values, only media file
+  tags.
 
 .. _discogs_client: https://github.com/discogs/discogs_client
 

test/test_zero.py

@@ -18,37 +18,38 @@ def tearDown(self):
         self.unload_plugins()
 
     def test_no_patterns(self):
-        i = Item(
-            comments='test comment',
-            day=13,
-            month=3,
-            year=2012,
-        )
+        tags = {
+            'comments': 'test comment',
+            'day': 13,
+            'month': 3,
+            'year': 2012,
+        }
         z = ZeroPlugin()
         z.debug = False
         z.fields = ['comments', 'month', 'day']
         z.patterns = {'comments': ['.'],
                       'month': ['.'],
                       'day': ['.']}
-        z.write_event(i)
-        self.assertEqual(i.comments, '')
-        self.assertEqual(i.day, 0)
-        self.assertEqual(i.month, 0)
-        self.assertEqual(i.year, 2012)
+        z.write_event(None, None, tags)
+        self.assertEqual(tags['comments'], None)
+        self.assertEqual(tags['day'], None)
+        self.assertEqual(tags['month'], None)
+        self.assertEqual(tags['year'], 2012)
 
     def test_patterns(self):
-        i = Item(
-            comments='from lame collection, ripped by eac',
-            year=2012,
-        )
         z = ZeroPlugin()
         z.debug = False
         z.fields = ['comments', 'year']
         z.patterns = {'comments': 'eac lame'.split(),
                       'year': '2098 2099'.split()}
-        z.write_event(i)
-        self.assertEqual(i.comments, '')
-        self.assertEqual(i.year, 2012)
+
+        tags = {
+            'comments': 'from lame collection, ripped by eac',
+            'year': 2012,
+        }
+        z.write_event(None, None, tags)
+        self.assertEqual(tags['comments'], None)
+        self.assertEqual(tags['year'], 2012)
 
     def test_delete_replaygain_tag(self):
         path = self.create_mediafile_fixture()
@@ -70,6 +71,17 @@ def test_delete_replaygain_tag(self):
         self.assertIsNone(mediafile.rg_track_peak)
         self.assertIsNone(mediafile.rg_track_gain)
 
+    def test_do_not_change_database(self):
+        item = self.add_item_fixture(year=2000)
+        mediafile = MediaFile(item.path)
+
+        config['zero'] = {'fields': ['year']}
+        self.load_plugins('zero')
+
+        item.write()
+        self.assertEqual(item['year'], 2000)
+        self.assertIsNone(mediafile.year)
+
 
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)