fix(subsonic): stop serving artwork for a deleted radio

artworkAccessible checked every kind except radio, which fell through to
the default "no per-user access control" branch and returned true without
a lookup. Radio deletion removes only the entity row -- item_artwork and
the uploaded file survive until the next prune -- so the old ra- id kept
serving the removed radio's image for up to a day.

This is a regression against master, where newRadioArtworkReader loaded
the radio first and returned its error, so deletion took effect at once.
Radios stay globally visible; only existence is checked.

CreateMockedRadioRepo left Data nil, so its own Put panicked on first
use; initialized it.

Reported by Codex on #5847.

server/subsonic/media_retrieval.go

@@ -120,13 +120,15 @@ func (api *Router) artworkAccessible(ctx context.Context, id string) bool {
 		_, lookupErr = api.ds.MediaFile(ctx).Get(artID.ID)
 	case model.KindPlaylistArtwork:
 		_, lookupErr = api.ds.Playlist(ctx).Get(artID.ID)
+	case model.KindRadioArtwork:
+		_, lookupErr = api.ds.Radio(ctx).Get(artID.ID)
 	case model.KindDiscArtwork:
 		albumID, _, perr := model.ParseDiscArtworkID(artID.ID)
 		if perr != nil {
 			return false
 		}
 		_, lookupErr = api.ds.Album(ctx).Get(albumID)
-	default: // radio and anything else has no per-user artwork access control
+	default: // anything else has no per-user artwork access control
 		return true
 	}
 	return lookupErr == nil

server/subsonic/media_retrieval_test.go

@@ -32,9 +32,12 @@ var _ = Describe("MediaRetrievalController", func() {
 	BeforeEach(func() {
 		albumRepo := &tests.MockAlbumRepo{}
 		albumRepo.SetData(model.Albums{{ID: "34"}}) // the id the specs request, made accessible
+		radioRepo := tests.CreateMockedRadioRepo()
+		Expect(radioRepo.Put(&model.Radio{ID: "rd1", Name: "Radio"})).To(Succeed())
 		ds = &tests.MockDataStore{
 			MockedMediaFile: mockRepo,
 			MockedAlbum:     albumRepo,
+			MockedRadio:     radioRepo,
 		}
 		artwork = &fakeArtwork{data: "image data"}
 		router = New(ds, artwork, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, lyrics.NewLyrics(ds, nil), nil, nil)
@@ -63,6 +66,26 @@ var _ = Describe("MediaRetrievalController", func() {
 			Expect(w.Body.String()).To(Equal(artwork.data))
 		})
 
+		It("serves radio artwork while the radio exists", func() {
+			r := newGetRequest("id=ra-rd1")
+			_, err := router.GetCoverArt(w, r)
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(w.Body.String()).To(Equal(artwork.data))
+		})
+
+		// A deleted radio keeps its item_artwork row and uploaded file until the next prune, so
+		// existence has to be re-checked or the old id keeps serving the removed radio's image.
+		It("serves a placeholder once the radio is gone", func() {
+			r := newGetRequest("id=ra-deleted")
+			_, err := router.GetCoverArt(w, r)
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(w.Code).To(Equal(200))
+			Expect(w.Body.String()).ToNot(Equal(artwork.data))
+			Expect(w.Header().Get("Cache-Control")).To(Equal("no-store"))
+		})
+
 		It("serves a placeholder for an entity the caller cannot access", func() {
 			// al-99 is not in the (filtered) album repo, so the caller must not get its bytes.
 			r := newGetRequest("id=al-99")

tests/mock_radio_repository.go

@@ -16,7 +16,7 @@ type MockedRadioRepo struct {
 }
 
 func CreateMockedRadioRepo() *MockedRadioRepo {
-	return &MockedRadioRepo{}
+	return &MockedRadioRepo{Data: map[string]*model.Radio{}}
 }
 
 func (m *MockedRadioRepo) SetError(err bool) {