backend/queue/emit.go

@@ -81,6 +81,7 @@ func (q *Queue) emitTracksModified(
 			Index:        index,
 			Positions:    positions,
 			CurrentIndex: q.currentIndex,
+			Source:       q.source,
 		},
 	)
 }

backend/queue/emit_test.go

@@ -219,6 +219,56 @@ func TestEmit_AddTrackSendsDeltaNotSnapshot(t *testing.T) {
 	}
 }
 
+// The append clears the source, and the delta is the only event those
+// paths emit — so if it does not carry the source, the frontend keeps
+// the label it was last given and goes on offering a link back to an
+// album the queue no longer holds until something forces a full state.
+func TestEmit_AppendDeltaCarriesClearedSource(t *testing.T) {
+	t.Parallel()
+
+	q, db, rec := setupRecordedQueue(t)
+	paths := seedAudioFiles(t, db, 4)
+
+	q.SetQueue(
+		paths[:3], 0, false,
+		Source{Type: "album", ID: 1, Label: "Abbey Road"},
+	)
+
+	if _, ok := rec.Wait(events.QueueChanged, waitFor); !ok {
+		t.Fatalf("no QueueChanged after SetQueue; got %v", rec.Names())
+	}
+
+	rec.Reset()
+	q.AddTrack(paths[3])
+
+	if got := modifiedOf(t, rec).Source; got != (Source{}) {
+		t.Errorf("delta source = %+v, want zero value", got)
+	}
+}
+
+// And a delta that did not clear it still reports the source it has,
+// or the frontend would drop a perfectly good label on every removal.
+func TestEmit_NonAppendDeltaCarriesSource(t *testing.T) {
+	t.Parallel()
+
+	q, db, rec := setupRecordedQueue(t)
+	paths := seedAudioFiles(t, db, 4)
+
+	album := Source{Type: "album", ID: 1, Label: "Abbey Road"}
+	q.SetQueue(paths, 0, false, album)
+
+	if _, ok := rec.Wait(events.QueueChanged, waitFor); !ok {
+		t.Fatalf("no QueueChanged after SetQueue; got %v", rec.Names())
+	}
+
+	rec.Reset()
+	q.RemoveTrack(3)
+
+	if got := modifiedOf(t, rec).Source; got != album {
+		t.Errorf("delta source = %+v, want %+v", got, album)
+	}
+}
+
 func TestEmit_RemoveTracksReportsPositions(t *testing.T) {
 	t.Parallel()
 

backend/queue/queue.go

@@ -156,12 +156,21 @@ type PlaybackFailure struct {
 }
 
 // TracksModified is the payload for the QueueTracksModified event.
+//
+// Source is carried because an append is exactly what can *invalidate*
+// it: a queue built from one album stops being that album the moment a
+// track from somewhere else is added to it. The delta is the only event
+// those paths emit, so without this the frontend would keep the label
+// it was last given and go on saying "Playing from" an album that is no
+// longer what is queued — an event carrying what its consumer needs, so
+// nothing has to invalidate anything.
 type TracksModified struct {
 	Action       string  `json:"action"`
 	Tracks       []Track `json:"tracks,omitempty"`
 	Index        int     `json:"index"`
 	Positions    []int   `json:"positions,omitempty"`
 	CurrentIndex int     `json:"currentIndex"`
+	Source       Source  `json:"source"`
 }
 
 // Queue manages an ordered list of tracks for playback.
@@ -455,6 +464,8 @@ func (q *Queue) AddTrack(filePath string) {
 		q.generateShuffleOrder()
 	}
 
+	q.dropSource()
+
 	q.persistAddTrack(track)
 	q.persistState()
 	q.emitTracksModified(
@@ -505,6 +516,8 @@ func (q *Queue) AddTracks(filePaths []string) {
 		q.generateShuffleOrder()
 	}
 
+	q.dropSource()
+
 	q.persistAddTracks(newTracks)
 	q.persistState()
 	q.emitTracksModified(
@@ -563,6 +576,8 @@ func (q *Queue) InsertNextTracks(filePaths []string) {
 		q.generateShuffleOrder()
 	}
 
+	q.dropSource()
+
 	q.persistInsertTracks(newTracks, insertPos)
 	q.persistState()
 	q.emitTracksModified(
@@ -613,6 +628,8 @@ func (q *Queue) InsertNext(filePath string) {
 		q.generateShuffleOrder()
 	}
 
+	q.dropSource()
+
 	q.persistInsertTracks([]Track{track}, insertPos)
 	q.persistState()
 	q.emitTracksModified(
@@ -680,6 +697,8 @@ func (q *Queue) InsertTracksAt(filePaths []string, index int) {
 		q.generateShuffleOrder()
 	}
 
+	q.dropSource()
+
 	q.persistInsertTracks(newTracks, index)
 	q.persistState()
 	q.emitTracksModified(
@@ -1537,6 +1556,31 @@ func (q *Queue) reindexPositions() {
 	}
 }
 
+// dropSource forgets which collection the queue was built from.
+//
+// A Source is a claim that everything queued came from one album,
+// playlist, genre or artist, and the frontend renders it as a
+// "Playing from X" link back to that page. Adding or inserting a track
+// makes the claim false — the queue is now that album *plus* something
+// else — so every path that does so calls this.
+//
+// It was set by SetQueue and cleared in exactly one place, Clear, so a
+// label survived every append. It is persisted too (source_type /
+// source_id / source_label on the queue state row), which is what made
+// a wrong label outlive the session that earned it: an album queued on
+// Monday, added to on Tuesday, still offered a link back to that album
+// on Friday.
+//
+// Removing, reordering and shuffling deliberately do not call this. A
+// queue with a track taken out of it, or played in another order, is
+// still that album — the link still goes somewhere true. Only the
+// arrival of a track from elsewhere makes it a lie.
+//
+// The caller must hold q.mu.
+func (q *Queue) dropSource() {
+	q.source = Source{}
+}
+
 // commitMutation persists the current queue state after a mutation.
 // When reindex is true, track positions are renumbered first.
 // The caller must hold q.mu.

backend/queue/queue_test.go

@@ -126,6 +126,117 @@ func TestClear_ResetsSource(t *testing.T) {
 	}
 }
 
+// A queue built from one album stops being that album the moment a
+// track from somewhere else joins it, so every path that adds one
+// drops the source. Before this, SetQueue was the only writer and
+// Clear the only clearer, so "Playing from Abbey Road" outlived every
+// append — and, being persisted, every restart too.
+func TestAppendPathsDropSource(t *testing.T) {
+	t.Parallel()
+
+	album := Source{Type: "album", ID: 1, Label: "Abbey Road"}
+
+	tests := []struct {
+		name   string
+		append func(q *Queue, paths []string)
+	}{
+		{
+			name: "AddTrack",
+			append: func(q *Queue, paths []string) {
+				q.AddTrack(paths[5])
+			},
+		},
+		{
+			name: "AddTracks",
+			append: func(q *Queue, paths []string) {
+				q.AddTracks(paths[5:7])
+			},
+		},
+		{
+			name: "InsertNext",
+			append: func(q *Queue, paths []string) {
+				q.InsertNext(paths[5])
+			},
+		},
+		{
+			name: "InsertNextTracks",
+			append: func(q *Queue, paths []string) {
+				q.InsertNextTracks(paths[5:7])
+			},
+		},
+		{
+			name: "InsertTracksAt",
+			append: func(q *Queue, paths []string) {
+				q.InsertTracksAt(paths[5:7], 1)
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			q, db := setupTestQueue(t)
+			paths := seedAudioFiles(t, db, 8)
+
+			q.SetQueue(paths[:5], 0, false, album)
+
+			if got := q.GetState().Source; got != album {
+				t.Fatalf("source before append: got %+v, want %+v", got, album)
+			}
+
+			tt.append(q, paths)
+
+			if got := q.GetState().Source; got != (Source{}) {
+				t.Errorf(
+					"source after %s: got %+v, want zero value",
+					tt.name, got,
+				)
+			}
+		})
+	}
+}
+
+// Removing and reordering deliberately do not drop it: a queue with a
+// track taken out of it is still that album, and the link still goes
+// somewhere true.
+func TestRemoveAndMoveKeepSource(t *testing.T) {
+	t.Parallel()
+
+	album := Source{Type: "album", ID: 1, Label: "Abbey Road"}
+
+	t.Run("RemoveTrack", func(t *testing.T) {
+		t.Parallel()
+
+		q, db := setupTestQueue(t)
+		paths := seedAudioFiles(t, db, 5)
+
+		q.SetQueue(paths, 0, false, album)
+		q.RemoveTrack(3)
+
+		if got := q.GetState().Source; got != album {
+			t.Errorf("source after RemoveTrack: got %+v, want %+v", got, album)
+		}
+	})
+
+	t.Run("MoveQueueTracks", func(t *testing.T) {
+		t.Parallel()
+
+		q, db := setupTestQueue(t)
+		paths := seedAudioFiles(t, db, 5)
+
+		q.SetQueue(paths, 0, false, album)
+		q.MoveQueueTracks([]int{0}, 3)
+
+		if got := q.GetState().Source; got != album {
+			t.Errorf(
+				"source after MoveQueueTracks: got %+v, want %+v",
+				got, album,
+			)
+		}
+	})
+}
+
 func TestSetQueue_WithStartIndex(t *testing.T) {
 	t.Parallel()
 

frontend/src/store/queue-store.ts

@@ -57,6 +57,12 @@ interface TracksModified {
   index: number;
   positions?: number[];
   currentIndex: number;
+  /** The queue's source *after* the mutation. An append clears it
+   *  backend-side — a queue built from one album is not that album
+   *  once a track from elsewhere joins it — and this delta is the
+   *  only event those paths emit, so the label would otherwise keep
+   *  pointing at a collection the queue no longer holds. */
+  source?: QueueSource;
 }
 
 type Subscriber = () => void;
@@ -198,6 +204,7 @@ class QueueStore {
     }
 
     this.state.currentIndex = delta.currentIndex;
+    this.state.source = delta.source ?? EMPTY_QUEUE_SOURCE;
   }
 
   // ===================================================================

frontend/test/stores/queue-store.test.ts

@@ -198,6 +198,61 @@ describe('queue store: move', () => {
   });
 });
 
+/**
+ * "Playing from X" is a claim that everything queued came from X, and
+ * appending a track from anywhere else makes it false. The backend
+ * clears the source on every add/insert path — but the delta is the
+ * only event those paths emit, so the label corrects itself here or
+ * not at all.
+ */
+describe('queue store: the source travels on the delta', () => {
+  function syncWithAlbum(): void {
+    emit(Events.QueueChanged, {
+      tracks: [track(1), track(2)],
+      currentIndex: 0,
+      shuffleMode: false,
+      repeatMode: 'off',
+      source: { type: 'album', id: 7, label: 'Abbey Road' },
+    });
+  }
+
+  beforeEach(() => {
+    syncWithAlbum();
+  });
+
+  it('drops the label when an append clears it backend-side', () => {
+    emit(Events.QueueTracksModified, {
+      action: 'add',
+      tracks: [track(3)],
+      index: 2,
+      currentIndex: 0,
+      source: { type: '', id: 0, label: '' },
+    });
+
+    expect(queueStore.getState().source).toEqual({
+      type: '',
+      id: 0,
+      label: '',
+    });
+  });
+
+  it('keeps a label the backend still reports, as on a removal', () => {
+    emit(Events.QueueTracksModified, {
+      action: 'remove',
+      positions: [1],
+      index: 0,
+      currentIndex: 0,
+      source: { type: 'album', id: 7, label: 'Abbey Road' },
+    });
+
+    expect(queueStore.getState().source).toEqual({
+      type: 'album',
+      id: 7,
+      label: 'Abbey Road',
+    });
+  });
+});
+
 describe('queue store: mode deltas', () => {
   beforeEach(() => {
     sync([track(1)], 0);