fix: a file tagged with no release group joins the same-named album its folder holds

Under e45561e2 a file with no group tag took the oldest same-named album row,
which left three of Weezer's 1994 bonus tracks on the 2016 album. The lookup
now ranks same-named rows by how many tracks they hold from the file's
folder; tagReadVersion 8 re-places the existing ones.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/dbq/albums.sql.go

@@ -72,11 +72,14 @@ func (q *Queries) DeleteAlbumIfEmpty(ctx context.Context, id pgtype.UUID) (Delet
 }
 
 const getAlbumByArtistAndTitle = `-- name: GetAlbumByArtistAndTitle :one
-SELECT id, title, sort_title, artist_id, release_date, mbid, cover_art_path, created_at, updated_at, cover_art_source, cover_art_sources_version, release_group_mbid FROM albums
- WHERE artist_id = $1 AND title = $2
-   AND ($3::text IS NULL OR release_group_mbid IS NULL
-        OR release_group_mbid = $3)
- ORDER BY (release_group_mbid IS NOT DISTINCT FROM $3) DESC, id
+SELECT albums.id, albums.title, albums.sort_title, albums.artist_id, albums.release_date, albums.mbid, albums.cover_art_path, albums.created_at, albums.updated_at, albums.cover_art_source, albums.cover_art_sources_version, albums.release_group_mbid FROM albums
+ WHERE albums.artist_id = $1 AND albums.title = $2
+   AND ($3::text IS NULL OR albums.release_group_mbid IS NULL
+        OR albums.release_group_mbid = $3)
+ ORDER BY (albums.release_group_mbid IS NOT DISTINCT FROM $3) DESC,
+          (SELECT count(*) FROM tracks t
+            WHERE t.album_id = albums.id AND starts_with(t.file_path, $4::text || '/')) DESC,
+          albums.id
  LIMIT 1
 `
 
@@ -84,15 +87,24 @@ type GetAlbumByArtistAndTitleParams struct {
 	ArtistID         pgtype.UUID
 	Title            string
 	ReleaseGroupMbid *string
+	Dir              string
 }
 
 // Scanner uses this for the no-mbid dedupe path: resolve-or-create. An album
 // of the same name in another release group is a different album (Weezer's
 // six self-titled albums shared one row until 2026-10-20), so a row whose
 // group is known and differs is not returned. A row of the file's own group
-// comes first, then one with no group yet.
+// comes first, then one with no group yet, then the one holding the most
+// tracks from the file's folder: a file tagged with no group (a live bonus
+// track beside Weezer's 1994 album) belongs with its folder, not the oldest
+// row, and a few strays already misfiled do not outvote the folder.
 func (q *Queries) GetAlbumByArtistAndTitle(ctx context.Context, arg GetAlbumByArtistAndTitleParams) (Album, error) {
-	row := q.db.QueryRow(ctx, getAlbumByArtistAndTitle, arg.ArtistID, arg.Title, arg.ReleaseGroupMbid)
+	row := q.db.QueryRow(ctx, getAlbumByArtistAndTitle,
+		arg.ArtistID,
+		arg.Title,
+		arg.ReleaseGroupMbid,
+		arg.Dir,
+	)
 	var i Album
 	err := row.Scan(
 		&i.ID,

internal/db/queries/albums.sql

@@ -40,12 +40,18 @@ ORDER BY release_date NULLS LAST, sort_title;
 -- of the same name in another release group is a different album (Weezer's
 -- six self-titled albums shared one row until 2026-10-20), so a row whose
 -- group is known and differs is not returned. A row of the file's own group
--- comes first, then one with no group yet.
-SELECT * FROM albums
- WHERE artist_id = sqlc.arg(artist_id) AND title = sqlc.arg(title)
-   AND (sqlc.narg(release_group_mbid)::text IS NULL OR release_group_mbid IS NULL
-        OR release_group_mbid = sqlc.narg(release_group_mbid))
- ORDER BY (release_group_mbid IS NOT DISTINCT FROM sqlc.narg(release_group_mbid)) DESC, id
+-- comes first, then one with no group yet, then the one holding the most
+-- tracks from the file's folder: a file tagged with no group (a live bonus
+-- track beside Weezer's 1994 album) belongs with its folder, not the oldest
+-- row, and a few strays already misfiled do not outvote the folder.
+SELECT albums.* FROM albums
+ WHERE albums.artist_id = sqlc.arg(artist_id) AND albums.title = sqlc.arg(title)
+   AND (sqlc.narg(release_group_mbid)::text IS NULL OR albums.release_group_mbid IS NULL
+        OR albums.release_group_mbid = sqlc.narg(release_group_mbid))
+ ORDER BY (albums.release_group_mbid IS NOT DISTINCT FROM sqlc.narg(release_group_mbid)) DESC,
+          (SELECT count(*) FROM tracks t
+            WHERE t.album_id = albums.id AND starts_with(t.file_path, sqlc.arg(dir)::text || '/')) DESC,
+          albums.id
  LIMIT 1;
 
 -- name: ListAlbumsByArtist :many

internal/library/scanner.go

@@ -78,7 +78,10 @@ var audioExtensions = map[string]bool{
 //	   (resolveAlbum). Weezer's six self-titled albums were one 118-track row,
 //	   so their merges, wants and upgrades all counted as one album; a re-read
 //	   files each existing track under its own album.
-const tagReadVersion int16 = 7
+//	8: a file tagged with no release group joins the same-named album that
+//	   already holds a track from its folder. Under 7 it took the oldest row,
+//	   which left three of Weezer's 1994 bonus tracks on the 2016 album.
+const tagReadVersion int16 = 8
 
 type Stats struct {
 	Scanned int `json:"scanned"`
@@ -319,7 +322,7 @@ func (s *Scanner) scanFile(
 	if err != nil {
 		return pgtype.UUID{}, false, fmt.Errorf("artist: %w", err)
 	}
-	album, err := s.resolveAlbum(ctx, q, artist.ID, albumTitle, meta.Year(), albumMBID, releaseGroupMBID)
+	album, err := s.resolveAlbum(ctx, q, artist.ID, albumTitle, meta.Year(), albumMBID, releaseGroupMBID, filepath.Dir(path))
 	if err != nil {
 		return pgtype.UUID{}, false, fmt.Errorf("album: %w", err)
 	}
@@ -565,8 +568,8 @@ func (s *Scanner) resolveArtist(ctx context.Context, q *dbq.Queries, name, mbid
 	return artist, nil
 }
 
-func (s *Scanner) resolveAlbum(ctx context.Context, q *dbq.Queries, artistID pgtype.UUID, title string, year int, mbid, releaseGroupMBID string) (dbq.Album, error) {
-	lookup := dbq.GetAlbumByArtistAndTitleParams{ArtistID: artistID, Title: title}
+func (s *Scanner) resolveAlbum(ctx context.Context, q *dbq.Queries, artistID pgtype.UUID, title string, year int, mbid, releaseGroupMBID, dir string) (dbq.Album, error) {
+	lookup := dbq.GetAlbumByArtistAndTitleParams{ArtistID: artistID, Title: title, Dir: dir}
 	if releaseGroupMBID != "" {
 		rg := releaseGroupMBID
 		lookup.ReleaseGroupMbid = &rg

internal/library/scanner_test.go

@@ -459,20 +459,29 @@ func TestScanner_SameTitledAlbumsOfTwoGroupsAreTwoAlbums_Integration(t *testing.
 		t.Fatalf("albums by group = %v, want blue with 2 tracks and green with 1", got)
 	}
 
+	// A bonus track tagged with no release group joins the album its folder
+	// holds, whichever row is older.
+	writeTestMP3(t, filepath.Join(root, "Weezer (2001)/02.mp3"), map[string]string{
+		"TIT2": "Photograph (live)", "TPE1": "Weezer", "TALB": "Weezer",
+	})
+	if _, err := scanner.Scan(ctx, nil); err != nil {
+		t.Fatalf("scan the bonus track: %v", err)
+	}
+	if got := albumsByGroup(); len(got) != 2 || got[blue] != 2 || got[green] != 2 {
+		t.Fatalf("albums by group = %v, want the ungrouped 2001 bonus track on green", got)
+	}
+
 	// The green track as the old lookup left it: on the blue album's row,
-	// under an older tag-read version, its own album row gone.
+	// under an older tag-read version.
 	if _, err := pool.Exec(ctx, `
 		WITH b AS (SELECT id FROM albums WHERE release_group_mbid = $1)
 		UPDATE tracks SET album_id = (SELECT id FROM b), tag_read_version = 6 WHERE file_path = $2`, blue, greenPath); err != nil {
 		t.Fatal(err)
 	}
-	if _, err := pool.Exec(ctx, `DELETE FROM albums WHERE release_group_mbid = $1`, green); err != nil {
-		t.Fatal(err)
-	}
 	if _, err := scanner.Scan(ctx, nil); err != nil {
 		t.Fatalf("rescan: %v", err)
 	}
-	if got := albumsByGroup(); len(got) != 2 || got[blue] != 2 || got[green] != 1 {
+	if got := albumsByGroup(); len(got) != 2 || got[blue] != 2 || got[green] != 2 {
 		t.Errorf("after the re-read, albums by group = %v, want the green track on its own album", got)
 	}
 }