support transitive artist aliases (closes #101)

rose/cache.py

@@ -1824,7 +1824,7 @@ def list_releases_delete_this(
         args: list[str | bool] = []
         if artist_filter:
             artists: list[str] = [artist_filter]
-            for alias in c.artist_aliases_map.get(artist_filter, []):
+            for alias in _get_all_artist_aliases(c, artist_filter):
                 artists.append(alias)
             query += f"""
                 AND EXISTS (
@@ -2234,7 +2234,7 @@ def list_artists(c: Config) -> list[str]:
 
 def artist_exists(c: Config, artist: str) -> bool:
     args: list[str] = [artist]
-    for alias in c.artist_aliases_map.get(artist, []):
+    for alias in _get_all_artist_aliases(c, artist):
         args.append(alias)
     with connect(c) as conn:
         cursor = conn.execute(
@@ -2301,18 +2301,39 @@ def _unpack_artists(
     aliases: bool = True,
 ) -> ArtistMapping:
     mapping = ArtistMapping()
+    seen: set[tuple[str, str]] = set()
     for name, role in _unpack(names, roles):
         role_artists: list[Artist] = getattr(mapping, role)
         role_artists.append(Artist(name=name, alias=False))
-        seen: set[str] = {name}
-        if aliases:
-            for alias in c.artist_aliases_parents_map.get(name, []):
-                if alias not in seen:
+        seen.add((name, role))
+        if not aliases:
+            continue
+
+        # Get all immediate and transitive artist aliases.
+        unvisited: set[str] = {name}
+        while unvisited:
+            cur = unvisited.pop()
+            for alias in c.artist_aliases_parents_map.get(cur, []):
+                if (alias, role) not in seen:
                     role_artists.append(Artist(name=alias, alias=True))
-                    seen.add(alias)
+                    seen.add((alias, role))
+                    unvisited.add(alias)
     return mapping
 
 
+def _get_all_artist_aliases(c: Config, x: str) -> list[str]:
+    """Includes transitive aliases."""
+    aliases: set[str] = set()
+    unvisited: set[str] = {x}
+    while unvisited:
+        cur = unvisited.pop()
+        if cur in aliases:
+            continue
+        aliases.add(cur)
+        unvisited.update(c.artist_aliases_map.get(cur, []))
+    return list(aliases)
+
+
 def _get_parent_genres(genres: list[str]) -> list[str]:
     rval: set[str] = set()
     for g in genres:

rose/cache_test.py

@@ -1252,18 +1252,28 @@ def test_get_release_and_associated_tracks(config: Config) -> None:
 def test_get_release_applies_artist_aliases(config: Config) -> None:
     config = dataclasses.replace(
         config,
-        artist_aliases_map={"Hype Boy": ["Bass Man"]},
-        artist_aliases_parents_map={"Bass Man": ["Hype Boy"]},
+        artist_aliases_map={"Hype Boy": ["Bass Man"], "Bubble Gum": ["Hype Boy"]},
+        artist_aliases_parents_map={"Bass Man": ["Hype Boy"], "Hype Boy": ["Bubble Gum"]},
     )
     release = get_release(config, "r1")
     assert release is not None
     assert release.releaseartists == ArtistMapping(
-        main=[Artist("Techno Man"), Artist("Bass Man"), Artist("Hype Boy", True)],
+        main=[
+            Artist("Techno Man"),
+            Artist("Bass Man"),
+            Artist("Hype Boy", True),
+            Artist("Bubble Gum", True),
+        ],
     )
     tracks = get_tracks_associated_with_release(config, release)
     for t in tracks:
         assert t.trackartists == ArtistMapping(
-            main=[Artist("Techno Man"), Artist("Bass Man"), Artist("Hype Boy", True)],
+            main=[
+                Artist("Techno Man"),
+                Artist("Bass Man"),
+                Artist("Hype Boy", True),
+                Artist("Bubble Gum", True),
+            ],
         )
 
 
@@ -1805,6 +1815,16 @@ def test_artist_exists_with_alias(config: Config) -> None:
     assert artist_exists(config, "Hype Boy")
 
 
+@pytest.mark.usefixtures("seeded_cache")
+def test_artist_exists_with_alias_transient(config: Config) -> None:
+    config = dataclasses.replace(
+        config,
+        artist_aliases_map={"Hype Boy": ["Bass Man"], "Bubble Gum": ["Hype Boy"]},
+        artist_aliases_parents_map={"Bass Man": ["Hype Boy"], "Hype Boy": ["Bubble Gum"]},
+    )
+    assert artist_exists(config, "Bubble Gum")
+
+
 @pytest.mark.usefixtures("seeded_cache")
 def test_genre_exists(config: Config) -> None:
     assert genre_exists(config, "Deep House")