refactor: use natural.Compare directly instead of wrapper

https://claude.ai/code/session_014BYpRBMVc93H3zdHBbRdmW

db/db.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"runtime"
 
+	"github.com/maruel/natural"
 	"github.com/mattn/go-sqlite3"
 	"github.com/navidrome/navidrome/conf"
 	_ "github.com/navidrome/navidrome/db/migrations"
@@ -31,7 +32,10 @@ func Db() *sql.DB {
 	return singleton.GetInstance(func() *sql.DB {
 		sql.Register(Driver, &sqlite3.SQLiteDriver{
 			ConnectHook: func(conn *sqlite3.SQLiteConn) error {
-				return conn.RegisterFunc("SEEDEDRAND", hasher.HashFunc(), false)
+				if err := conn.RegisterFunc("SEEDEDRAND", hasher.HashFunc(), false); err != nil {
+					return err
+				}
+				return conn.RegisterCollation("NATURALSORT", natural.Compare)
 			},
 		})
 		Path = conf.Server.DbPath

db/migrations/20260216200000_add_natural_sort_collation_indexes.sql

@@ -0,0 +1,118 @@
+-- +goose Up
+
+-- Recreate indexes on order_* and sort expression fields to use NATURALSORT collation.
+-- This enables natural number ordering (e.g., "Album 2" before "Album 10").
+
+-- Artist indexes
+drop index if exists artist_order_artist_name;
+create index artist_order_artist_name
+    on artist (order_artist_name collate NATURALSORT);
+
+drop index if exists artist_sort_name;
+create index artist_sort_name
+    on artist (coalesce(nullif(sort_artist_name,''),order_artist_name) collate NATURALSORT);
+
+-- Album indexes
+drop index if exists album_order_album_name;
+create index album_order_album_name
+    on album (order_album_name collate NATURALSORT);
+
+drop index if exists album_order_album_artist_name;
+create index album_order_album_artist_name
+    on album (order_album_artist_name collate NATURALSORT);
+
+drop index if exists album_alphabetical_by_artist;
+create index album_alphabetical_by_artist
+    on album (compilation, order_album_artist_name collate NATURALSORT, order_album_name collate NATURALSORT);
+
+drop index if exists album_sort_name;
+create index album_sort_name
+    on album (coalesce(nullif(sort_album_name,''),order_album_name) collate NATURALSORT);
+
+drop index if exists album_sort_album_artist_name;
+create index album_sort_album_artist_name
+    on album (coalesce(nullif(sort_album_artist_name,''),order_album_artist_name) collate NATURALSORT);
+
+-- Media file indexes
+drop index if exists media_file_order_title;
+create index media_file_order_title
+    on media_file (order_title collate NATURALSORT);
+
+drop index if exists media_file_order_album_name;
+create index media_file_order_album_name
+    on media_file (order_album_name collate NATURALSORT);
+
+drop index if exists media_file_order_artist_name;
+create index media_file_order_artist_name
+    on media_file (order_artist_name collate NATURALSORT);
+
+drop index if exists media_file_sort_title;
+create index media_file_sort_title
+    on media_file (coalesce(nullif(sort_title,''),order_title) collate NATURALSORT);
+
+drop index if exists media_file_sort_artist_name;
+create index media_file_sort_artist_name
+    on media_file (coalesce(nullif(sort_artist_name,''),order_artist_name) collate NATURALSORT);
+
+drop index if exists media_file_sort_album_name;
+create index media_file_sort_album_name
+    on media_file (coalesce(nullif(sort_album_name,''),order_album_name) collate NATURALSORT);
+
+-- +goose Down
+
+-- Restore NOCASE collation indexes
+
+-- Artist indexes
+drop index if exists artist_order_artist_name;
+create index artist_order_artist_name
+    on artist (order_artist_name);
+
+drop index if exists artist_sort_name;
+create index artist_sort_name
+    on artist (coalesce(nullif(sort_artist_name,''),order_artist_name) collate NOCASE);
+
+-- Album indexes
+drop index if exists album_order_album_name;
+create index album_order_album_name
+    on album (order_album_name);
+
+drop index if exists album_order_album_artist_name;
+create index album_order_album_artist_name
+    on album (order_album_artist_name);
+
+drop index if exists album_alphabetical_by_artist;
+create index album_alphabetical_by_artist
+    on album (compilation, order_album_artist_name, order_album_name);
+
+drop index if exists album_sort_name;
+create index album_sort_name
+    on album (coalesce(nullif(sort_album_name,''),order_album_name) collate NOCASE);
+
+drop index if exists album_sort_album_artist_name;
+create index album_sort_album_artist_name
+    on album (coalesce(nullif(sort_album_artist_name,''),order_album_artist_name) collate NOCASE);
+
+-- Media file indexes
+drop index if exists media_file_order_title;
+create index media_file_order_title
+    on media_file (order_title);
+
+drop index if exists media_file_order_album_name;
+create index media_file_order_album_name
+    on media_file (order_album_name);
+
+drop index if exists media_file_order_artist_name;
+create index media_file_order_artist_name
+    on media_file (order_artist_name);
+
+drop index if exists media_file_sort_title;
+create index media_file_sort_title
+    on media_file (coalesce(nullif(sort_title,''),order_title) collate NOCASE);
+
+drop index if exists media_file_sort_artist_name;
+create index media_file_sort_artist_name
+    on media_file (coalesce(nullif(sort_artist_name,''),order_artist_name) collate NOCASE);
+
+drop index if exists media_file_sort_album_name;
+create index media_file_sort_album_name
+    on media_file (coalesce(nullif(sort_album_name,''),order_album_name) collate NOCASE);

persistence/collation_test.go

@@ -41,18 +41,18 @@ var _ = Describe("Collation", func() {
 		func(table, column string) {
 			Expect(checkIndexUsage(conn, table, column)).To(Succeed())
 		},
-		Entry("artist.order_artist_name", "artist", "order_artist_name collate nocase"),
-		Entry("artist.sort_artist_name", "artist", "coalesce(nullif(sort_artist_name,''),order_artist_name) collate nocase"),
-		Entry("album.order_album_name", "album", "order_album_name collate nocase"),
-		Entry("album.order_album_artist_name", "album", "order_album_artist_name collate nocase"),
-		Entry("album.sort_album_name", "album", "coalesce(nullif(sort_album_name,''),order_album_name) collate nocase"),
-		Entry("album.sort_album_artist_name", "album", "coalesce(nullif(sort_album_artist_name,''),order_album_artist_name) collate nocase"),
-		Entry("media_file.order_title", "media_file", "order_title collate nocase"),
-		Entry("media_file.order_album_name", "media_file", "order_album_name collate nocase"),
-		Entry("media_file.order_artist_name", "media_file", "order_artist_name collate nocase"),
-		Entry("media_file.sort_title", "media_file", "coalesce(nullif(sort_title,''),order_title) collate nocase"),
-		Entry("media_file.sort_album_name", "media_file", "coalesce(nullif(sort_album_name,''),order_album_name) collate nocase"),
-		Entry("media_file.sort_artist_name", "media_file", "coalesce(nullif(sort_artist_name,''),order_artist_name) collate nocase"),
+		Entry("artist.order_artist_name", "artist", "order_artist_name collate NATURALSORT"),
+		Entry("artist.sort_artist_name", "artist", "coalesce(nullif(sort_artist_name,''),order_artist_name) collate NATURALSORT"),
+		Entry("album.order_album_name", "album", "order_album_name collate NATURALSORT"),
+		Entry("album.order_album_artist_name", "album", "order_album_artist_name collate NATURALSORT"),
+		Entry("album.sort_album_name", "album", "coalesce(nullif(sort_album_name,''),order_album_name) collate NATURALSORT"),
+		Entry("album.sort_album_artist_name", "album", "coalesce(nullif(sort_album_artist_name,''),order_album_artist_name) collate NATURALSORT"),
+		Entry("media_file.order_title", "media_file", "order_title collate NATURALSORT"),
+		Entry("media_file.order_album_name", "media_file", "order_album_name collate NATURALSORT"),
+		Entry("media_file.order_artist_name", "media_file", "order_artist_name collate NATURALSORT"),
+		Entry("media_file.sort_title", "media_file", "coalesce(nullif(sort_title,''),order_title) collate NATURALSORT"),
+		Entry("media_file.sort_album_name", "media_file", "coalesce(nullif(sort_album_name,''),order_album_name) collate NATURALSORT"),
+		Entry("media_file.sort_artist_name", "media_file", "coalesce(nullif(sort_artist_name,''),order_artist_name) collate NATURALSORT"),
 		Entry("media_file.path", "media_file", "path collate nocase"),
 		Entry("playlist.name", "playlist", "name collate nocase"),
 		Entry("radio.name", "radio", "name collate nocase"),

persistence/helpers.go

@@ -82,11 +82,19 @@ func (e existsCond) ToSql() (string, []any, error) {
 
 var sortOrderRegex = regexp.MustCompile(`order_([a-z_]+)`)
 
-// Convert the order_* columns to an expression using sort_* columns. Example:
-// sort_album_name -> (coalesce(nullif(sort_album_name,”),order_album_name) collate nocase)
+// mapSortOrder converts order_* columns to an expression using sort_* columns with NATURALSORT collation. Example:
+// order_album_name -> (coalesce(nullif(sort_album_name,''),order_album_name) collate NATURALSORT)
 // It finds order column names anywhere in the substring
 func mapSortOrder(tableName, order string) string {
 	order = strings.ToLower(order)
-	repl := fmt.Sprintf("(coalesce(nullif(%[1]s.sort_$1,''),%[1]s.order_$1) collate nocase)", tableName)
+	repl := fmt.Sprintf("(coalesce(nullif(%[1]s.sort_$1,''),%[1]s.order_$1) collate NATURALSORT)", tableName)
 	return sortOrderRegex.ReplaceAllString(order, repl)
 }
+
+// mapNaturalSortCollation wraps bare order_* column references with NATURALSORT collation. Example:
+// order_album_name -> (order_album_name collate NATURALSORT)
+// It finds order column names anywhere in the substring
+func mapNaturalSortCollation(order string) string {
+	order = strings.ToLower(order)
+	return sortOrderRegex.ReplaceAllString(order, "(order_$1 collate NATURALSORT)")
+}

persistence/helpers_test.go

@@ -94,13 +94,23 @@ var _ = Describe("Helpers", func() {
 			sort := "ORDER_ALBUM_NAME asc"
 			mapped := mapSortOrder("album", sort)
 			Expect(mapped).To(Equal(`(coalesce(nullif(album.sort_album_name,''),album.order_album_name)` +
-				` collate nocase) asc`))
+				` collate NATURALSORT) asc`))
 		})
 		It("changes multiple order columns to sort expressions", func() {
 			sort := "compilation, order_title asc, order_album_artist_name desc, year desc"
 			mapped := mapSortOrder("album", sort)
-			Expect(mapped).To(Equal(`compilation, (coalesce(nullif(album.sort_title,''),album.order_title) collate nocase) asc,` +
-				` (coalesce(nullif(album.sort_album_artist_name,''),album.order_album_artist_name) collate nocase) desc, year desc`))
+			Expect(mapped).To(Equal(`compilation, (coalesce(nullif(album.sort_title,''),album.order_title) collate NATURALSORT) asc,` +
+				` (coalesce(nullif(album.sort_album_artist_name,''),album.order_album_artist_name) collate NATURALSORT) desc, year desc`))
+		})
+		It("wraps bare order columns with NATURALSORT collation", func() {
+			sort := "order_album_name, order_album_artist_name"
+			mapped := mapNaturalSortCollation(sort)
+			Expect(mapped).To(Equal(`(order_album_name collate NATURALSORT), (order_album_artist_name collate NATURALSORT)`))
+		})
+		It("does not change non-order columns in mapNaturalSortCollation", func() {
+			sort := "compilation, year desc"
+			mapped := mapNaturalSortCollation(sort)
+			Expect(mapped).To(Equal(sort))
 		})
 	})
 })

persistence/sql_base_repository.go

@@ -71,9 +71,12 @@ func (r *sqlRepository) registerModel(instance any, filters map[string]filterFun
 //
 // If PreferSortTags is enabled, it will map the order fields to the corresponding sort expression,
 // which gives precedence to sort tags.
-// Ex: order_title => (coalesce(nullif(sort_title,”),order_title) collate nocase)
+// Ex: order_title => (coalesce(nullif(sort_title,"),order_title) collate NATURALSORT)
 // To avoid performance issues, indexes should be created for these sort expressions
 //
+// All order_* fields are wrapped with NATURALSORT collation to enable natural number ordering
+// (e.g., "Album 2" sorts before "Album 10").
+//
 // NOTE: if an individual item has spaces, it should be wrapped in parentheses. For example,
 // you should write "(lyrics != '[]')". This prevents the item being split unexpectedly.
 // Without parentheses, "lyrics != '[]'" would be mapped as simply "lyrics"
@@ -82,11 +85,13 @@ func (r *sqlRepository) setSortMappings(mappings map[string]string, tableName ..
 	if len(tableName) > 0 {
 		tn = tableName[0]
 	}
-	if conf.Server.PreferSortTags {
-		for k, v := range mappings {
+	for k, v := range mappings {
+		if conf.Server.PreferSortTags {
 			v = mapSortOrder(tn, v)
-			mappings[k] = v
+		} else {
+			v = mapNaturalSortCollation(v)
 		}
+		mappings[k] = v
 	}
 	r.sortMappings = mappings
 }