From a5b37d01c94eb53bffaf14997205840f60692b71 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 16:46:00 -0600
Subject: [PATCH 01/13] added zero subcommand

---
 beetsplug/zero.py | 54 ++++++++++++++++++++++++++++++++++-
 test/test_zero.py | 72 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 1 deletion(-)

diff --git a/beetsplug/zero.py b/beetsplug/zero.py
index 1401b11dea..403def8079 100644
--- a/beetsplug/zero.py
+++ b/beetsplug/zero.py
@@ -21,7 +21,8 @@
 from beets.plugins import BeetsPlugin
 from beets.mediafile import MediaFile
 from beets.importer import action
-from beets.util import confit
+from beets.util import confit, syspath
+from beets.ui import Subcommand, decargs
 import six
 
 __author__ = 'baobab@heresiarch.info'
@@ -41,6 +42,7 @@ def __init__(self):
                                self.import_task_choice_event)
 
         self.config.add({
+            'auto': True,
             'fields': [],
             'keep_fields': [],
             'update_database': False,
@@ -75,6 +77,16 @@ def __init__(self):
                 if key in self.patterns:
                     del self.patterns[key]
 
+    def commands(self):
+        zero_command = Subcommand('zero', help='set fields to null')
+
+        def zero_fields(lib, opts, args):
+            for item in lib.items(decargs(args)):
+                self.process_item(item)
+
+        zero_command.func = zero_fields
+        return [zero_command]
+
     def validate_config(self, mode):
         """Check whether fields in the configuration are valid.
 
@@ -120,10 +132,39 @@ def match_patterns(cls, field, patterns):
                 return True
         return False
 
+    def process_item(self, item):
+        if not self.patterns:
+            self._log.warning(u'no fields, nothing to do')
+            return
+
+        for field, patterns in self.patterns.items():
+            if field in item.keys():
+                if not self.should_update(item, field):
+                    continue
+
+                value = item[field]
+                match = self.match_patterns(item[field], patterns)
+
+            else:
+                value = ''
+                match = patterns is True
+
+            if match:
+                self._log.warning(u'{0}: {1} -> None', field, value)
+                item[field] = None
+                if self.config['update_database']:
+                    item.update({field: None})
+                    item.store()
+
+        item.write()
+
     def write_event(self, item, path, tags):
         """Set values in tags to `None` if the key and value are matched
         by `self.patterns`.
         """
+        if not self.config['auto']:
+            return
+
         if not self.patterns:
             self._log.warning(u'no fields, nothing to do')
             return
@@ -141,3 +182,14 @@ def write_event(self, item, path, tags):
                 tags[field] = None
                 if self.config['update_database']:
                     item[field] = None
+
+    def should_update(self, item, field):
+        media = MediaFile(syspath(item.path))
+        attributes = media.fields()
+        if field in attributes:
+            return True
+
+        if self.config['update_database'] and item[field]:
+            return True
+
+        return False
diff --git a/test/test_zero.py b/test/test_zero.py
index fb28330ee8..ca4a2dd674 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -121,6 +121,78 @@ def test_album_art(self):
         mediafile = MediaFile(syspath(item.path))
         self.assertEqual(0, len(mediafile.images))
 
+    def test_auto_false(self):
+        item = self.add_item_fixture(year=2000)
+        item.write()
+        mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(2000, mediafile.year)
+
+        config['zero'] = {
+            'fields': [u'year'],
+            'update_database': True,
+            'auto': False
+        }
+        self.load_plugins('zero')
+
+        item.write()
+        mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(item['year'], 2000)
+        self.assertEqual(mediafile.year, 2000)
+
+    def test_subcommand(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+        item.write()
+        item_id = item.id
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': True,
+            'auto': False
+        }
+        self.load_plugins('zero')
+        self.run_command('zero')
+
+        mediafile = MediaFile(syspath(item.path))
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mediafile.comments, None)
+        self.assertEqual(item['comments'], u'')
+
+    def test_subcommand_update_database_False(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+        item.write()
+        item_id = item.id
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': False,
+            'auto': False
+        }
+        self.load_plugins('zero')
+
+        z = ZeroPlugin()
+        z.debug = False
+        self.run_command('zero')
+
+        mediafile = MediaFile(syspath(item.path))
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(item['comments'], u'test comment')
+        self.assertEqual(mediafile.comments, None)
+
+
 
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)

From fec7e30fe18a441c4d5b18b640e122f92790f908 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 17:17:55 -0600
Subject: [PATCH 02/13] added documentation for zero subcommand

---
 docs/plugins/zero.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/plugins/zero.rst b/docs/plugins/zero.rst
index ecaa60a3d1..282bb4fc8f 100644
--- a/docs/plugins/zero.rst
+++ b/docs/plugins/zero.rst
@@ -18,6 +18,7 @@ Configuration
 Make a ``zero:`` section in your configuration file. You can specify the
 fields to nullify and the conditions for nullifying them:
 
+* Set ``auto`` to ``yes`` to null fields automatically on import. Default ``yes``
 * Set ``fields`` to a whitespace-separated list of fields to change. You can
   get the list of all available fields by running ``beet fields``. In
   addition, the ``images`` field allows you to remove any images
@@ -42,3 +43,9 @@ If a custom pattern is not defined for a given field, the field will be nulled
 unconditionally.
 
 Note that the plugin currently does not zero fields when importing "as-is".
+
+Manually Triggering Zero
+------------------------
+
+The ``zero`` command will invoke the zero plugin on items matching a query. Use the
+command ``beet zero [QUERY]``

From 148354c5c499bed665813a4631c5fd6f3e4e788a Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 17:30:07 -0600
Subject: [PATCH 03/13] additional zero tests

---
 test/test_zero.py | 54 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 49 insertions(+), 5 deletions(-)

diff --git a/test/test_zero.py b/test/test_zero.py
index ca4a2dd674..38fdb3726a 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -139,7 +139,7 @@ def test_auto_false(self):
         self.assertEqual(item['year'], 2000)
         self.assertEqual(mediafile.year, 2000)
 
-    def test_subcommand(self):
+    def test_subcommand_update_database_true(self):
         item = self.add_item_fixture(
             year=2016,
             day=13,
@@ -164,7 +164,7 @@ def test_subcommand(self):
         self.assertEqual(mediafile.comments, None)
         self.assertEqual(item['comments'], u'')
 
-    def test_subcommand_update_database_False(self):
+    def test_subcommand_update_database_false(self):
         item = self.add_item_fixture(
             year=2016,
             day=13,
@@ -179,9 +179,6 @@ def test_subcommand_update_database_False(self):
             'auto': False
         }
         self.load_plugins('zero')
-
-        z = ZeroPlugin()
-        z.debug = False
         self.run_command('zero')
 
         mediafile = MediaFile(syspath(item.path))
@@ -192,6 +189,53 @@ def test_subcommand_update_database_False(self):
         self.assertEqual(item['comments'], u'test comment')
         self.assertEqual(mediafile.comments, None)
 
+    def test_subcommand_query_include(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+
+        item.write()
+
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': False,
+            'auto': False
+        }
+
+        self.load_plugins('zero')
+        self.run_command('zero', 'year: 2016')
+
+        mediafile = MediaFile(syspath(item.path))
+
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mediafile.comments, None)
+
+    def test_subcommand_query_exclude(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+
+        item.write()
+
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': False,
+            'auto': False
+        }
+
+        self.load_plugins('zero')
+        self.run_command('zero', 'year: 0000')
+
+        mediafile = MediaFile(syspath(item.path))
+
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mediafile.comments, u'test comment')
 
 
 def suite():

From c40a587e68d6dd6cb579183c4728d06a95090945 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 17:49:45 -0600
Subject: [PATCH 04/13] update changelog

---
 docs/changelog.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 40b044941b..b5ea8a62b6 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -6,6 +6,10 @@ Changelog
 
 Changelog goes here!
 
+Features:
+
+* :doc:`/plugins/zero`: Added ``zero`` command to manually trigger the zero
+  plugin.
 
 1.4.2 (December 16, 2016)
 -------------------------

From 510fe6f146f1be757d321fae639fadb769f41986 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sun, 18 Dec 2016 14:27:42 -0600
Subject: [PATCH 05/13] refactor changes to zero plugin

---
 beetsplug/zero.py | 55 +++++++++++++++--------------------------------
 1 file changed, 17 insertions(+), 38 deletions(-)

diff --git a/beetsplug/zero.py b/beetsplug/zero.py
index 403def8079..73961134a3 100644
--- a/beetsplug/zero.py
+++ b/beetsplug/zero.py
@@ -21,7 +21,7 @@
 from beets.plugins import BeetsPlugin
 from beets.mediafile import MediaFile
 from beets.importer import action
-from beets.util import confit, syspath
+from beets.util import confit
 from beets.ui import Subcommand, decargs
 import six
 
@@ -94,13 +94,13 @@ def validate_config(self, mode):
         the section of the configuration to validate.
         """
         for field in self.config[mode].as_str_seq():
-            if field not in MediaFile.fields():
-                self._log.error(u'invalid field: {0}', field)
-                continue
             if mode == 'fields' and field in ('id', 'path', 'album_id'):
                 self._log.warning(u'field \'{0}\' ignored, zeroing '
                                   u'it would be dangerous', field)
                 continue
+            if field not in MediaFile.fields():
+                self._log.error(u'invalid field: {0}', field)
+                continue
 
     def set_pattern(self, field):
         """Set a field in `self.patterns` to a string list corresponding to
@@ -133,30 +133,12 @@ def match_patterns(cls, field, patterns):
         return False
 
     def process_item(self, item):
-        if not self.patterns:
-            self._log.warning(u'no fields, nothing to do')
-            return
-
-        for field, patterns in self.patterns.items():
-            if field in item.keys():
-                if not self.should_update(item, field):
-                    continue
-
-                value = item[field]
-                match = self.match_patterns(item[field], patterns)
-
-            else:
-                value = ''
-                match = patterns is True
+        tags = dict(item)
 
-            if match:
-                self._log.warning(u'{0}: {1} -> None', field, value)
-                item[field] = None
-                if self.config['update_database']:
-                    item.update({field: None})
-                    item.store()
-
-        item.write()
+        if self.set_fields(item, tags):
+            item.write(tags=tags)
+            if self.config['update_database']:
+                item.store(fields=tags)
 
     def write_event(self, item, path, tags):
         """Set values in tags to `None` if the key and value are matched
@@ -165,9 +147,14 @@ def write_event(self, item, path, tags):
         if not self.config['auto']:
             return
 
+        self.set_fields(item, tags)
+
+    def set_fields(self, item, tags):
+        fields_set = False
+
         if not self.patterns:
             self._log.warning(u'no fields, nothing to do')
-            return
+            return False
 
         for field, patterns in self.patterns.items():
             if field in tags:
@@ -178,18 +165,10 @@ def write_event(self, item, path, tags):
                 match = patterns is True
 
             if match:
+                fields_set = True
                 self._log.debug(u'{0}: {1} -> None', field, value)
                 tags[field] = None
                 if self.config['update_database']:
                     item[field] = None
 
-    def should_update(self, item, field):
-        media = MediaFile(syspath(item.path))
-        attributes = media.fields()
-        if field in attributes:
-            return True
-
-        if self.config['update_database'] and item[field]:
-            return True
-
-        return False
+        return fields_set

From 69a58ca842e9741a1125e5622e3d1c1c5b613ef9 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sun, 18 Dec 2016 14:28:55 -0600
Subject: [PATCH 06/13] additional test coverage for zero plugin

---
 test/test_zero.py | 71 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/test/test_zero.py b/test/test_zero.py
index 38fdb3726a..e7af5fee86 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -19,6 +19,7 @@ def setUp(self):
         self.setup_beets()
 
     def tearDown(self):
+        self.remove_mediafile_fixtures()
         self.teardown_beets()
         self.unload_plugins()
 
@@ -237,6 +238,76 @@ def test_subcommand_query_exclude(self):
         self.assertEqual(mediafile.year, 2016)
         self.assertEqual(mediafile.comments, u'test comment')
 
+    def test_no_fields(self):
+        item = self.add_item_fixture(year=2016)
+        item.write()
+        mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(mediafile.year, 2016)
+
+        item_id = item.id
+        config['zero'] = {}
+        self.load_plugins('zero')
+        self.run_command('zero')
+
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mediafile.year, 2016)
+
+    def test_whitelist_and_blacklist(self):
+        item = self.add_item_fixture(year=2016)
+        item.write()
+        mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(mediafile.year, 2016)
+
+        item_id = item.id
+        config['zero'] = {'fields': [u'year'],
+                          'keep_fields': [u'comments']}
+
+        self.load_plugins('zero')
+        self.run_command('zero')
+
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mediafile.year, 2016)
+
+    def test_keep_fields(self):
+        item = self.add_item_fixture(year=2016, comments=u'test comment')
+        config['zero'] = {'keep_fields': [u'year'],
+                          'fields': None,
+                          'update_database': True,
+                          'auto': True}
+
+        tags = {
+            'comments': u'test comment',
+            'year': 2016,
+        }
+        self.load_plugins('zero')
+        z = ZeroPlugin()
+        z.write_event(item, item.path, tags)
+        self.assertEqual(tags['comments'], None)
+        self.assertEqual(tags['year'], 2016)
+
+    def test_keep_fields_removes_preserved_tags(self):
+        config['zero'] = {'keep_fields': [u'year id'],
+                          'fields': None,
+                          'update_database': True,
+                          'auto': True}
+
+        z = ZeroPlugin()
+
+        self.assertNotIn('id', z.patterns)
+
+    def test_field_preserved_tags(self):
+        config['zero'] = {'fields': [u'year id'],
+                          'update_database': True,
+                          'auto': True}
+
+        z = ZeroPlugin()
+
+        self.assertNotIn('id', z.patterns)
+
 
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)

From 4cc4fe1290a018486becff8a023cabad10214061 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 16:46:00 -0600
Subject: [PATCH 07/13] added zero subcommand

---
 test/test_zero.py | 72 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/test/test_zero.py b/test/test_zero.py
index 1223e5c9ed..e7eb95413c 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -108,6 +108,78 @@ def test_album_art(self):
         mediafile = MediaFile(syspath(path))
         self.assertEqual(0, len(mediafile.images))
 
+    def test_auto_false(self):
+        item = self.add_item_fixture(year=2000)
+        item.write()
+        mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(2000, mediafile.year)
+
+        config['zero'] = {
+            'fields': [u'year'],
+            'update_database': True,
+            'auto': False
+        }
+        self.load_plugins('zero')
+
+        item.write()
+        mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(item['year'], 2000)
+        self.assertEqual(mediafile.year, 2000)
+
+    def test_subcommand(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+        item.write()
+        item_id = item.id
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': True,
+            'auto': False
+        }
+        self.load_plugins('zero')
+        self.run_command('zero')
+
+        mediafile = MediaFile(syspath(item.path))
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mediafile.comments, None)
+        self.assertEqual(item['comments'], u'')
+
+    def test_subcommand_update_database_False(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+        item.write()
+        item_id = item.id
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': False,
+            'auto': False
+        }
+        self.load_plugins('zero')
+
+        z = ZeroPlugin()
+        z.debug = False
+        self.run_command('zero')
+
+        mediafile = MediaFile(syspath(item.path))
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(item['comments'], u'test comment')
+        self.assertEqual(mediafile.comments, None)
+
+
 
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)

From 5b8b61f0c0d3f10250f3e3622b7f08c2a4f6d219 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 17:17:55 -0600
Subject: [PATCH 08/13] added documentation for zero subcommand

---
 docs/plugins/zero.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/plugins/zero.rst b/docs/plugins/zero.rst
index ecaa60a3d1..282bb4fc8f 100644
--- a/docs/plugins/zero.rst
+++ b/docs/plugins/zero.rst
@@ -18,6 +18,7 @@ Configuration
 Make a ``zero:`` section in your configuration file. You can specify the
 fields to nullify and the conditions for nullifying them:
 
+* Set ``auto`` to ``yes`` to null fields automatically on import. Default ``yes``
 * Set ``fields`` to a whitespace-separated list of fields to change. You can
   get the list of all available fields by running ``beet fields``. In
   addition, the ``images`` field allows you to remove any images
@@ -42,3 +43,9 @@ If a custom pattern is not defined for a given field, the field will be nulled
 unconditionally.
 
 Note that the plugin currently does not zero fields when importing "as-is".
+
+Manually Triggering Zero
+------------------------
+
+The ``zero`` command will invoke the zero plugin on items matching a query. Use the
+command ``beet zero [QUERY]``

From ef802293502aa07398bae723e9347d2b295874b2 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 17:30:07 -0600
Subject: [PATCH 09/13] additional zero tests

---
 test/test_zero.py | 54 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 49 insertions(+), 5 deletions(-)

diff --git a/test/test_zero.py b/test/test_zero.py
index e7eb95413c..4baacba905 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -126,7 +126,7 @@ def test_auto_false(self):
         self.assertEqual(item['year'], 2000)
         self.assertEqual(mediafile.year, 2000)
 
-    def test_subcommand(self):
+    def test_subcommand_update_database_true(self):
         item = self.add_item_fixture(
             year=2016,
             day=13,
@@ -151,7 +151,7 @@ def test_subcommand(self):
         self.assertEqual(mediafile.comments, None)
         self.assertEqual(item['comments'], u'')
 
-    def test_subcommand_update_database_False(self):
+    def test_subcommand_update_database_false(self):
         item = self.add_item_fixture(
             year=2016,
             day=13,
@@ -166,9 +166,6 @@ def test_subcommand_update_database_False(self):
             'auto': False
         }
         self.load_plugins('zero')
-
-        z = ZeroPlugin()
-        z.debug = False
         self.run_command('zero')
 
         mediafile = MediaFile(syspath(item.path))
@@ -179,6 +176,53 @@ def test_subcommand_update_database_False(self):
         self.assertEqual(item['comments'], u'test comment')
         self.assertEqual(mediafile.comments, None)
 
+    def test_subcommand_query_include(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+
+        item.write()
+
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': False,
+            'auto': False
+        }
+
+        self.load_plugins('zero')
+        self.run_command('zero', 'year: 2016')
+
+        mediafile = MediaFile(syspath(item.path))
+
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mediafile.comments, None)
+
+    def test_subcommand_query_exclude(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+
+        item.write()
+
+        config['zero'] = {
+            'fields': [u'comments'],
+            'update_database': False,
+            'auto': False
+        }
+
+        self.load_plugins('zero')
+        self.run_command('zero', 'year: 0000')
+
+        mediafile = MediaFile(syspath(item.path))
+
+        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mediafile.comments, u'test comment')
 
 
 def suite():

From 30ae211e66c101aaeb3917253033b528d29a7bc5 Mon Sep 17 00:00:00 2001
From: Josh Brown <Josh@SJoshBrown.com>
Date: Sat, 17 Dec 2016 17:49:45 -0600
Subject: [PATCH 10/13] update changelog

---
 docs/changelog.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 2720ffe193..9cdf298c0f 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -15,6 +15,10 @@ Fixes:
 
 * :doc:`/plugins/bpd`: Fix a crash on non-ASCII MPD commands. :bug:`2332`
 
+Features:
+
+* :doc:`/plugins/zero`: Added ``zero`` command to manually trigger the zero
+  plugin.
 
 1.4.2 (December 16, 2016)
 -------------------------

From 2903925e2f18f7e9cf3db59b9ad05a7182ffaeb7 Mon Sep 17 00:00:00 2001
From: Josh Brown <S.Josh.Brown@gmail.com>
Date: Mon, 26 Dec 2016 13:34:34 -0600
Subject: [PATCH 11/13] Rewrite zero plugin manual mode

---
 beetsplug/zero.py |  33 ++++++++++-
 test/test_zero.py | 141 ++++++++++++++++++++++++++++++++--------------
 2 files changed, 130 insertions(+), 44 deletions(-)

diff --git a/beetsplug/zero.py b/beetsplug/zero.py
index 5659207fe2..975a9944ff 100644
--- a/beetsplug/zero.py
+++ b/beetsplug/zero.py
@@ -23,6 +23,7 @@
 from beets.plugins import BeetsPlugin
 from beets.mediafile import MediaFile
 from beets.importer import action
+from beets.ui import Subcommand, decargs
 from beets.util import confit
 
 __author__ = 'baobab@heresiarch.info'
@@ -39,6 +40,7 @@ def __init__(self):
                                self.import_task_choice_event)
 
         self.config.add({
+            'auto': True,
             'fields': [],
             'keep_fields': [],
             'update_database': False,
@@ -63,6 +65,16 @@ def __init__(self):
                         field not in ('id', 'path', 'album_id')):
                     self._set_pattern(field)
 
+    def commands(self):
+        zero_command = Subcommand('zero', help='set fields to null')
+
+        def zero_fields(lib, opts, args):
+            for item in lib.items(decargs(args)):
+                self.process_item(item)
+
+        zero_command.func = zero_fields
+        return [zero_command]
+
     def _set_pattern(self, field):
         """Set a field in `self.patterns` to a string list corresponding to
         the configuration, or `True` if the field has no specific
@@ -93,24 +105,41 @@ def write_event(self, item, path, tags):
         """Set values in tags to `None` if the key and value are matched
         by `self.patterns`.
         """
+        if self.config['auto']:
+            self.set_fields(item, tags)
+
+    def set_fields(self, item, tags):
+        fields_set = False
+
         if not self.fields_to_progs:
             self._log.warning(u'no fields, nothing to do')
-            return
+            return False
 
         for field, progs in self.fields_to_progs.items():
             if field in tags:
                 value = tags[field]
-                match = _match_progs(value, progs, self._log)
+                match = _match_progs(tags[field], progs, self._log)
             else:
                 value = ''
                 match = not progs
 
             if match:
+                fields_set = True
                 self._log.debug(u'{0}: {1} -> None', field, value)
                 tags[field] = None
                 if self.config['update_database']:
                     item[field] = None
 
+        return fields_set
+
+    def process_item(self, item):
+        tags = dict(item)
+
+        if self.set_fields(item, tags):
+            item.write(tags=tags)
+            if self.config['update_database']:
+                item.store(fields=tags)
+
 
 def _match_progs(value, progs, log):
     """Check if field (as string) is matching any of the patterns in
diff --git a/test/test_zero.py b/test/test_zero.py
index 4baacba905..87e31c5394 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -105,26 +105,21 @@ def test_album_art(self):
         self.load_plugins('zero')
         item.write()
 
-        mediafile = MediaFile(syspath(path))
-        self.assertEqual(0, len(mediafile.images))
+        mf = MediaFile(syspath(path))
+        self.assertEqual(0, len(mf.images))
 
     def test_auto_false(self):
+        self.config['zero']['fields'] = ['year']
+        self.config['zero']['update_database'] = True
+        self.config['zero']['auto'] = False
+
         item = self.add_item_fixture(year=2000)
         item.write()
-        mediafile = MediaFile(syspath(item.path))
-        self.assertEqual(2000, mediafile.year)
 
-        config['zero'] = {
-            'fields': [u'year'],
-            'update_database': True,
-            'auto': False
-        }
         self.load_plugins('zero')
-
         item.write()
-        mediafile = MediaFile(syspath(item.path))
+
         self.assertEqual(item['year'], 2000)
-        self.assertEqual(mediafile.year, 2000)
 
     def test_subcommand_update_database_true(self):
         item = self.add_item_fixture(
@@ -135,20 +130,19 @@ def test_subcommand_update_database_true(self):
         )
         item.write()
         item_id = item.id
-        config['zero'] = {
-            'fields': [u'comments'],
-            'update_database': True,
-            'auto': False
-        }
+        self.config['zero']['fields'] = ['comments']
+        self.config['zero']['update_database'] = True
+        self.config['zero']['auto'] = False
+
         self.load_plugins('zero')
         self.run_command('zero')
 
-        mediafile = MediaFile(syspath(item.path))
+        mf = MediaFile(syspath(item.path))
         item = self.lib.get_item(item_id)
 
         self.assertEqual(item['year'], 2016)
-        self.assertEqual(mediafile.year, 2016)
-        self.assertEqual(mediafile.comments, None)
+        self.assertEqual(mf.year, 2016)
+        self.assertEqual(mf.comments, None)
         self.assertEqual(item['comments'], u'')
 
     def test_subcommand_update_database_false(self):
@@ -160,21 +154,21 @@ def test_subcommand_update_database_false(self):
         )
         item.write()
         item_id = item.id
-        config['zero'] = {
-            'fields': [u'comments'],
-            'update_database': False,
-            'auto': False
-        }
+
+        self.config['zero']['fields'] = ['comments']
+        self.config['zero']['update_database'] = False
+        self.config['zero']['auto'] = False
+
         self.load_plugins('zero')
         self.run_command('zero')
 
-        mediafile = MediaFile(syspath(item.path))
+        mf = MediaFile(syspath(item.path))
         item = self.lib.get_item(item_id)
 
         self.assertEqual(item['year'], 2016)
-        self.assertEqual(mediafile.year, 2016)
+        self.assertEqual(mf.year, 2016)
         self.assertEqual(item['comments'], u'test comment')
-        self.assertEqual(mediafile.comments, None)
+        self.assertEqual(mf.comments, None)
 
     def test_subcommand_query_include(self):
         item = self.add_item_fixture(
@@ -186,19 +180,17 @@ def test_subcommand_query_include(self):
 
         item.write()
 
-        config['zero'] = {
-            'fields': [u'comments'],
-            'update_database': False,
-            'auto': False
-        }
+        self.config['zero']['fields'] = ['comments']
+        self.config['zero']['update_database'] = False
+        self.config['zero']['auto'] = False
 
         self.load_plugins('zero')
         self.run_command('zero', 'year: 2016')
 
-        mediafile = MediaFile(syspath(item.path))
+        mf = MediaFile(syspath(item.path))
 
-        self.assertEqual(mediafile.year, 2016)
-        self.assertEqual(mediafile.comments, None)
+        self.assertEqual(mf.year, 2016)
+        self.assertEqual(mf.comments, None)
 
     def test_subcommand_query_exclude(self):
         item = self.add_item_fixture(
@@ -210,19 +202,84 @@ def test_subcommand_query_exclude(self):
 
         item.write()
 
-        config['zero'] = {
-            'fields': [u'comments'],
-            'update_database': False,
-            'auto': False
-        }
+        self.config['zero']['fields'] = ['comments']
+        self.config['zero']['update_database'] = False
+        self.config['zero']['auto'] = False
 
         self.load_plugins('zero')
         self.run_command('zero', 'year: 0000')
 
+        mf = MediaFile(syspath(item.path))
+
+        self.assertEqual(mf.year, 2016)
+        self.assertEqual(mf.comments, u'test comment')
+
+    def test_no_fields(self):
+        item = self.add_item_fixture(year=2016)
+        item.write()
         mediafile = MediaFile(syspath(item.path))
+        self.assertEqual(mediafile.year, 2016)
+
+        item_id = item.id
+
+        self.load_plugins('zero')
+        self.run_command('zero')
+
+        item = self.lib.get_item(item_id)
 
+        self.assertEqual(item['year'], 2016)
         self.assertEqual(mediafile.year, 2016)
-        self.assertEqual(mediafile.comments, u'test comment')
+
+    def test_whitelist_and_blacklist(self):
+        item = self.add_item_fixture(year=2016)
+        item.write()
+        mf = MediaFile(syspath(item.path))
+        self.assertEqual(mf.year, 2016)
+
+        item_id = item.id
+        self.config['zero']['fields'] = [u'year']
+        self.config['zero']['keep_fields'] = [u'comments']
+
+        self.load_plugins('zero')
+        self.run_command('zero')
+
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mf.year, 2016)
+
+    def test_keep_fields(self):
+        item = self.add_item_fixture(year=2016, comments=u'test comment')
+        self.config['zero']['keep_fields'] = [u'year']
+        self.config['zero']['fields'] = None
+        self.config['zero']['update_database'] = True
+
+        tags = {
+            'comments': u'test comment',
+            'year': 2016,
+        }
+        self.load_plugins('zero')
+        z = ZeroPlugin()
+        z.write_event(item, item.path, tags)
+        self.assertEqual(tags['comments'], None)
+        self.assertEqual(tags['year'], 2016)
+
+    def test_keep_fields_removes_preserved_tags(self):
+        self.config['zero']['keep_fields'] = [u'year']
+        self.config['zero']['fields'] = None
+        self.config['zero']['update_database'] = True
+
+        z = ZeroPlugin()
+
+        self.assertNotIn('id', z.fields_to_progs)
+
+    def test_fields_removes_preserved_tags(self):
+        self.config['zero']['fields'] = [u'year id']
+        self.config['zero']['update_database'] = True
+
+        z = ZeroPlugin()
+
+        self.assertNotIn('id', z.fields_to_progs)
 
 
 def suite():

From 7833469261c9e15e922691beb8c698ec543c362e Mon Sep 17 00:00:00 2001
From: Josh Brown <S.Josh.Brown@gmail.com>
Date: Mon, 26 Dec 2016 14:13:01 -0600
Subject: [PATCH 12/13] add confirmation for empty query

---
 beetsplug/zero.py |  4 +++-
 test/test_zero.py | 40 +++++++++++++++++++++++++++++++++++-----
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/beetsplug/zero.py b/beetsplug/zero.py
index 975a9944ff..d3c3a697fe 100644
--- a/beetsplug/zero.py
+++ b/beetsplug/zero.py
@@ -23,7 +23,7 @@
 from beets.plugins import BeetsPlugin
 from beets.mediafile import MediaFile
 from beets.importer import action
-from beets.ui import Subcommand, decargs
+from beets.ui import Subcommand, decargs, input_yn
 from beets.util import confit
 
 __author__ = 'baobab@heresiarch.info'
@@ -69,6 +69,8 @@ def commands(self):
         zero_command = Subcommand('zero', help='set fields to null')
 
         def zero_fields(lib, opts, args):
+            if not decargs(args) and not input_yn(u"Remove fields for all items? (Y/n)", True):
+                return
             for item in lib.items(decargs(args)):
                 self.process_item(item)
 
diff --git a/test/test_zero.py b/test/test_zero.py
index 87e31c5394..025eaa5407 100644
--- a/test/test_zero.py
+++ b/test/test_zero.py
@@ -5,7 +5,7 @@
 from __future__ import division, absolute_import, print_function
 
 import unittest
-from test.helper import TestHelper
+from test.helper import TestHelper, control_stdin
 
 from beets.library import Item
 from beetsplug.zero import ZeroPlugin
@@ -135,7 +135,8 @@ def test_subcommand_update_database_true(self):
         self.config['zero']['auto'] = False
 
         self.load_plugins('zero')
-        self.run_command('zero')
+        with control_stdin('y'):
+            self.run_command('zero')
 
         mf = MediaFile(syspath(item.path))
         item = self.lib.get_item(item_id)
@@ -160,7 +161,8 @@ def test_subcommand_update_database_false(self):
         self.config['zero']['auto'] = False
 
         self.load_plugins('zero')
-        self.run_command('zero')
+        with control_stdin('y'):
+            self.run_command('zero')
 
         mf = MediaFile(syspath(item.path))
         item = self.lib.get_item(item_id)
@@ -223,7 +225,8 @@ def test_no_fields(self):
         item_id = item.id
 
         self.load_plugins('zero')
-        self.run_command('zero')
+        with control_stdin('y'):
+            self.run_command('zero')
 
         item = self.lib.get_item(item_id)
 
@@ -241,7 +244,8 @@ def test_whitelist_and_blacklist(self):
         self.config['zero']['keep_fields'] = [u'comments']
 
         self.load_plugins('zero')
-        self.run_command('zero')
+        with control_stdin('y'):
+            self.run_command('zero')
 
         item = self.lib.get_item(item_id)
 
@@ -259,6 +263,7 @@ def test_keep_fields(self):
             'year': 2016,
         }
         self.load_plugins('zero')
+
         z = ZeroPlugin()
         z.write_event(item, item.path, tags)
         self.assertEqual(tags['comments'], None)
@@ -281,6 +286,31 @@ def test_fields_removes_preserved_tags(self):
 
         self.assertNotIn('id', z.fields_to_progs)
 
+    def test_empty_query_n_response_no_changes(self):
+        item = self.add_item_fixture(
+            year=2016,
+            day=13,
+            month=3,
+            comments=u'test comment'
+        )
+        item.write()
+        item_id = item.id
+        self.config['zero']['fields'] = ['comments']
+        self.config['zero']['update_database'] = True
+        self.config['zero']['auto'] = False
+
+        self.load_plugins('zero')
+        with control_stdin('n'):
+            self.run_command('zero')
+
+        mf = MediaFile(syspath(item.path))
+        item = self.lib.get_item(item_id)
+
+        self.assertEqual(item['year'], 2016)
+        self.assertEqual(mf.year, 2016)
+        self.assertEqual(mf.comments, u'test comment')
+        self.assertEqual(item['comments'], u'test comment')
+
 
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)

From b6577b42267ab4c4fc0112ef6720cbbe4cda470d Mon Sep 17 00:00:00 2001
From: Josh Brown <S.Josh.Brown@gmail.com>
Date: Mon, 26 Dec 2016 14:42:10 -0600
Subject: [PATCH 13/13] refactor long line for PEP8

---
 beetsplug/zero.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/beetsplug/zero.py b/beetsplug/zero.py
index d3c3a697fe..6a3013069a 100644
--- a/beetsplug/zero.py
+++ b/beetsplug/zero.py
@@ -69,7 +69,9 @@ def commands(self):
         zero_command = Subcommand('zero', help='set fields to null')
 
         def zero_fields(lib, opts, args):
-            if not decargs(args) and not input_yn(u"Remove fields for all items? (Y/n)", True):
+            if not decargs(args) and not input_yn(
+                    u"Remove fields for all items? (Y/n)",
+                    True):
                 return
             for item in lib.items(decargs(args)):
                 self.process_item(item)