music_kraken/objects/collection.py

@@ -162,6 +162,25 @@ class Collection(Generic[T]):
 
         object_trace(f"Appending {other.option_string} to {self}")
 
+        for attribute, a in self.sync_on_append.items():
+            # syncing two collections by reference
+            b = other.__getattribute__(attribute)
+            if a is b:
+                continue
+
+            object_trace(f"Syncing [{a}] = [{b}]")
+
+            b_data = b.data.copy()
+            b_collection_for = b._collection_for.copy()
+
+            del b
+
+            for synced_with, key in b_collection_for.items():
+                synced_with.__setattr__(key, a)
+                a._collection_for[synced_with] = key
+
+            a.extend(b_data, **kwargs)
+
         # switching collection in the case of push to
         for c in self.push_to:
             r = c._find_object(other)

music_kraken/objects/song.py

@@ -148,7 +148,7 @@ class Song(Base):
         self.feature_artist_collection.push_to = [self.artist_collection]
         self.artist_collection.pull_from = [self.feature_artist_collection]
 
-        self.album_collection.extend_object_to_attribute = {
+        self.album_collection.sync_on_append = {
             "artist_collection": self.artist_collection,
         }
 
@@ -310,7 +310,7 @@ class Album(Base):
         self.song_collection.append_object_to_attribute = {
             "album_collection": self
         }
-        self.song_collection.extend_object_to_attribute = {
+        self.song_collection.sync_on_append = {
             "artist_collection": self.artist_collection
         }