PICARD-2174: Provide settings to File.format_specific_metadata

Allows for optimizations without having to read the settings from config on each invocation.

picard/file.py

@@ -4,7 +4,7 @@
 #
 # Copyright (C) 2004 Robert Kaye
 # Copyright (C) 2006-2009, 2011-2013, 2017 Lukáš Lalinský
-# Copyright (C) 2007-2011, 2015, 2018-2020 Philipp Wolfer
+# Copyright (C) 2007-2011, 2015, 2018-2021 Philipp Wolfer
 # Copyright (C) 2008 Gary van der Merwe
 # Copyright (C) 2008-2009 Nikolai Prokoschenko
 # Copyright (C) 2009 Carlin Mangar
@@ -157,7 +157,20 @@ class File(QtCore.QObject, Item):
         return '<%s %r>' % (type(self).__name__, self.base_filename)
 
     # pylint: disable=no-self-use
-    def format_specific_metadata(self, metadata, tag):
+    def format_specific_metadata(self, metadata, tag, settings=None):
+        """Can be overridden to customize how a tag is displayed in the UI.
+        This is useful if a tag saved to the underlying format will differ from
+        the internal representation in a way that would cause data loss. This is e.g.
+        the case for some ID3v2.3 tags.
+
+        Args:
+            metadata: The metadata object to read the tag from
+            tag: Name of the tag
+            settings: Dictionary of settings. If not set, config.setting should be used
+
+        Returns:
+            An array of values for the tag
+        """
         return metadata.getall(tag)
 
     def load(self, callback):

picard/formats/id3.py

@@ -3,7 +3,7 @@
 # Picard, the next-generation MusicBrainz tagger
 #
 # Copyright (C) 2006-2009, 2011-2012 Lukáš Lalinský
-# Copyright (C) 2008-2011, 2014, 2018-2020 Philipp Wolfer
+# Copyright (C) 2008-2011, 2014, 2018-2021 Philipp Wolfer
 # Copyright (C) 2009 Carlin Mangar
 # Copyright (C) 2011-2012 Johannes Weißl
 # Copyright (C) 2011-2014 Michael Wiencek
@@ -650,12 +650,16 @@ class ID3File(File):
             tags.update_to_v24()
             tags.save(filename, v2_version=4, v1=v1)
 
-    def format_specific_metadata(self, metadata, tag):
-        config = get_config()
-        if not config.setting["write_id3v23"]:
-            return super().format_specific_metadata(metadata, tag)
+    def format_specific_metadata(self, metadata, tag, settings=None):
+        if not settings:
+            config = get_config()
+            settings = {
+                "write_id3v23": config.setting["write_id3v23"],
+                "id3v23_join_with": config.setting["id3v23_join_with"],
+            }
 
-        join_with = config.setting["id3v23_join_with"]
+        if not settings["write_id3v23"]:
+            return super().format_specific_metadata(metadata, tag, settings)
 
         values = metadata.getall(tag)
         if not values:
@@ -670,6 +674,7 @@ class ID3File(File):
         # unless it's TIPL or TMCL which can still be multi-valued.
         if (len(values) > 1 and tag not in ID3File._rtipl_roles
                 and not tag.startswith("performer:")):
+            join_with = settings["id3v23_join_with"]
             values = [join_with.join(values)]
 
         return values

picard/ui/metadatabox.py

@@ -585,14 +585,19 @@ class MetadataBox(QtWidgets.QTableWidget):
         top_tags = config.setting['metadatabox_top_tags']
         top_tags_set = set(top_tags)
 
+        format_settings = {
+            "write_id3v23": config.setting["write_id3v23"],
+            "id3v23_join_with": config.setting["id3v23_join_with"],
+        }
+
         for file in files:
             new_metadata = file.metadata
             orig_metadata = file.orig_metadata
             tags = set(list(new_metadata.keys()) + list(orig_metadata.keys()))
 
             for name in filter(lambda x: not x.startswith("~") and file.supports_tag(x), tags):
-                new_values = file.format_specific_metadata(new_metadata, name)
-                orig_values = file.format_specific_metadata(orig_metadata, name)
+                new_values = file.format_specific_metadata(new_metadata, name, format_settings)
+                orig_values = file.format_specific_metadata(orig_metadata, name, format_settings)
 
                 if not clear_existing_tags and not new_values:
                     new_values = list(orig_values or [""])

test/formats/test_id3.py

@@ -668,3 +668,11 @@ class ID3FileTest(PicardTestCase):
         metadata = self.file.metadata
         metadata['date'] = '2021-04'
         self.assertEqual(['2021'], self.file.format_specific_metadata(metadata, 'date'))
+
+    def test_format_specific_metadata_override_settings(self):
+        settings = {
+            'write_id3v23': True,
+            'id3v23_join_with': '; ',
+        }
+        metadata = self.file.metadata
+        self.assertEqual(['foo; bar'], self.file.format_specific_metadata(metadata, 'artist', settings))