Omit missing years from upload destination paths

services/api/internal/library/meta/template_test.go

@@ -7,6 +7,41 @@ import (
 
 const docTemplate = "{albumartist}/{year} - {album}/{disc:1-}{track:02} - {title}.{ext}"
 
+func TestRenderWithoutMissingYear(t *testing.T) {
+	for _, pattern := range []string{
+		"{artist}/{album} ({year})/{track:02} - {title}.{ext}",
+		"{artist}/{year} - {album}/{track:02} - {title}.{ext}",
+		"{artist}/{album} - {year}/{track:02} - {title}.{ext}",
+		"{artist}/{year}/{album}/{track:02} - {title}.{ext}",
+		"{artist}/[{year} - ]{album}/{track:02} - {title}.{ext}",
+	} {
+		t.Run(pattern, func(t *testing.T) {
+			tpl, err := ParseTemplate(pattern)
+			if err != nil {
+				t.Fatal(err)
+			}
+			input := in(Fields{Artist: "A", Album: "B", Title: "C", Track: "1"}, 1, "mp3")
+			got, err := tpl.RenderWithoutMissingYear(input)
+			if err != nil || got != "A/B/01 - C.mp3" {
+				t.Fatalf("got %q, %v", got, err)
+			}
+			input.Fields.Title = ""
+			if _, err := tpl.RenderWithoutMissingYear(input); err == nil {
+				t.Fatal("missing title must still fail")
+			}
+			input.Fields.Title, input.Fields.Year = "C", "2026"
+			want, err := tpl.Render(input)
+			if err != nil {
+				t.Fatal(err)
+			}
+			got, err = tpl.RenderWithoutMissingYear(input)
+			if err != nil || got != want {
+				t.Fatalf("known year: got %q, %v; want %q", got, err, want)
+			}
+		})
+	}
+}
+
 func in(f Fields, discs int, ext string) TemplateInput {
 	return TemplateInput{Fields: f, DiscCount: discs, Ext: ext}
 }