fix: address code review findings

internal/musicbrainz/sync.go

@@ -57,7 +57,7 @@ func SyncArtistDiscography(
 		if err != nil {
 			return nil, fmt.Errorf("sync artist discography: read artist filter options: %w", err)
 		}
-		filtered := cachedReleases[:0]
+		filtered := make([]database.ExternalRelease, 0, len(cachedReleases))
 		for _, r := range cachedReleases {
 			if opts.IgnoreSingles && r.Type == "Single" {
 				continue

internal/normalize/normalize.go

@@ -18,10 +18,11 @@ var (
 	parenRe   = regexp.MustCompile(`\([^)]*\)`)
 	yearRe    = regexp.MustCompile(`\b(1[0-9]{3}|2[0-9]{3})\b`)
 	spaceRe   = regexp.MustCompile(`\s+`)
-	// wordRe matches any alphabetic character. Used to decide whether a title
-	// that collapses entirely to a year actually had other words worth keeping
-	// (e.g. "1989 (Deluxe)") versus being a bare year title (e.g. "1989").
-	wordRe = regexp.MustCompile(`[a-z]`)
+	// bareYearRe matches a title that is *only* a single year (with optional
+	// surrounding whitespace), e.g. "1989" or "2112". Used to decide whether a
+	// title that collapses entirely to a year should keep it (so it matches
+	// itself) or be treated as a distinct reissue that must collapse to empty.
+	bareYearRe = regexp.MustCompile(`^\s*(1[0-9]{3}|2[0-9]{3})\s*$`)
 )
 
 // NormalizeString normalizes a string for fuzzy matching by:
@@ -46,20 +47,22 @@ func NormalizeString(s string) string {
 	s = parenRe.ReplaceAllString(s, "")
 
 	// Remove years (4-digit numbers between 1000-2999). If stripping the year
-	// would empty the entire string, we must decide what to keep:
+	// empties the entire string, decide what to keep:
 	//   - A bare year title (e.g. "1989", "2112") has no other words, so keep
 	//     the year so it can still match itself (the user owns that album).
 	//   - A title that had OTHER words alongside the year (e.g. "1989 (Deluxe)")
 	//     collapses to empty on purpose: it is a distinct release group that
 	//     must NOT be considered already-present just because the user owns the
 	//     standard "1989". Collapsing to empty makes it score 0.0 against a
-	//     plain "1989", correctly reporting the reissue as missing.
+	//     plain "1989", correctly reporting the reissue as missing. The check
+	//     is against the original (brackets intact) so a title like "1989
+	//     [2020]" is correctly NOT treated as a bare year.
 	stripped := yearRe.ReplaceAllString(s, "")
 	if strings.TrimSpace(stripped) == "" {
-		if wordRe.MatchString(strings.ToLower(original)) {
-			s = ""
-		} else {
+		if bareYearRe.MatchString(strings.TrimSpace(original)) {
 			s = strings.TrimSpace(s)
+		} else {
+			s = ""
 		}
 	} else {
 		s = stripped

internal/normalize/normalize_test.go

@@ -44,6 +44,12 @@ func TestNormalizeString_Basic(t *testing.T) {
 		{"1989 (Deluxe)", ""},
 		{"1989 [Deluxe Edition]", ""},
 		{"2112 (Remastered)", ""},
+		// Regression: a year with a bracketed/suffixed year must NOT collapse to
+		// the bare year (it falsely matched "1989" before). It collapses to empty.
+		{"1989 [2020]", ""},
+		{"1989 2020", ""},
+		{"3000 2000", "3000"},
+		{"1989 RMX", "rmx"},
 	}
 
 	for _, tt := range tests {

internal/scanner/scan.go

@@ -28,7 +28,7 @@ func ScanArtist(ctx context.Context, db *database.DB, artistID string, threshold
 		return nil, err
 	}
 
-	missing := FindMissingReleases(local, external, resolveThreshold(threshold))
+	missing := FindMissingReleases(local, external, threshold)
 	return missing, nil
 }
 
@@ -46,8 +46,6 @@ func ScanAll(ctx context.Context, db *database.DB, threshold float64) ([]Missing
 		return nil, err
 	}
 
-	resolved := resolveThreshold(threshold)
-
 	var all []MissingRelease
 	for _, s := range settings {
 		if err := ctx.Err(); err != nil {
@@ -58,7 +56,7 @@ func ScanAll(ctx context.Context, db *database.DB, threshold float64) ([]Missing
 		}
 		// A transient error for one artist must not abort the whole scan and
 		// take down the daemon; log it and continue with the remaining artists.
-		missing, err := ScanArtist(ctx, db, s.ID, resolved)
+		missing, err := ScanArtist(ctx, db, s.ID, threshold)
 		if err != nil {
 			log.Printf("scan artist %s failed: %v", s.ID, err)
 			continue