fix: apply library filter to smart playlist track generation (#4739)

Smart playlists were including tracks from all libraries regardless of the
user's library access permissions. This resulted in ghost tracks that users
could not see or play, while the playlist showed incorrect song counts.

Added applyLibraryFilter to the refreshSmartPlaylist function to ensure only
tracks from libraries the user has access to are included when populating
smart playlist tracks. Added regression test to verify the fix.

Closes #4738

persistence/playlist_repository.go

@@ -264,6 +264,11 @@ func (r *playlistRepository) refreshSmartPlaylist(pls *model.Playlist) bool {
 		"annotation.item_id = media_file.id" +
 		" AND annotation.item_type = 'media_file'" +
 		" AND annotation.user_id = '" + usr.ID + "')")
+
+	// Only include media files from libraries the user has access to
+	sq = r.applyLibraryFilter(sq, "media_file")
+
+	// Apply the criteria rules
 	sq = r.addCriteria(sq, rules)
 	insSql := Insert("playlist_tracks").Columns("id", "playlist_id", "media_file_id").Select(sq)
 	_, err = r.executeSQL(insSql)

persistence/playlist_repository_test.go

@@ -366,4 +366,133 @@ var _ = Describe("PlaylistRepository", func() {
 			Expect(foundWithoutGrouping).To(BeTrue())
 		})
 	})
+
+	Describe("Smart Playlists Library Filtering", func() {
+		var mfRepo model.MediaFileRepository
+		var testPlaylistID string
+		var lib2ID int
+		var restrictedUserID string
+
+		BeforeEach(func() {
+			db := GetDBXBuilder()
+
+			// Generate unique IDs for this test run
+			restrictedUserID = "restricted-user-" + time.Now().Format("20060102150405.000")
+
+			// Create a second library
+			_, err := db.DB().Exec("INSERT INTO library (name, path, created_at, updated_at) VALUES ('Library 2', '/music/lib2', datetime('now'), datetime('now'))")
+			Expect(err).ToNot(HaveOccurred())
+			err = db.DB().QueryRow("SELECT last_insert_rowid()").Scan(&lib2ID)
+			Expect(err).ToNot(HaveOccurred())
+
+			// Create a restricted user with access only to library 1
+			_, err = db.DB().Exec("INSERT INTO user (id, user_name, name, is_admin, password, created_at, updated_at) VALUES (?, ?, 'Restricted User', false, 'pass', datetime('now'), datetime('now'))", restrictedUserID, restrictedUserID)
+			Expect(err).ToNot(HaveOccurred())
+			_, err = db.DB().Exec("INSERT INTO user_library (user_id, library_id) VALUES (?, 1)", restrictedUserID)
+			Expect(err).ToNot(HaveOccurred())
+
+			// Create test media files in each library
+			ctx := log.NewContext(GinkgoT().Context())
+			ctx = request.WithUser(ctx, model.User{ID: "userid", UserName: "userid", IsAdmin: true})
+			mfRepo = NewMediaFileRepository(ctx, db)
+
+			// Song in library 1 (accessible by restricted user)
+			songLib1 := model.MediaFile{
+				ID:           "lib1-song",
+				Title:        "Song in Lib1",
+				Artist:       "Test Artist",
+				ArtistID:     "1",
+				Album:        "Test Album",
+				AlbumID:      "101",
+				Path:         "/music/lib1/song.mp3",
+				LibraryID:    1,
+				Participants: model.Participants{},
+				Tags:         model.Tags{},
+				Lyrics:       "[]",
+			}
+			Expect(mfRepo.Put(&songLib1)).To(Succeed())
+
+			// Song in library 2 (NOT accessible by restricted user)
+			songLib2 := model.MediaFile{
+				ID:           "lib2-song",
+				Title:        "Song in Lib2",
+				Artist:       "Test Artist",
+				ArtistID:     "1",
+				Album:        "Test Album",
+				AlbumID:      "101",
+				Path:         "/music/lib2/song.mp3",
+				LibraryID:    lib2ID,
+				Participants: model.Participants{},
+				Tags:         model.Tags{},
+				Lyrics:       "[]",
+			}
+			Expect(mfRepo.Put(&songLib2)).To(Succeed())
+		})
+
+		AfterEach(func() {
+			db := GetDBXBuilder()
+			if testPlaylistID != "" {
+				_ = repo.Delete(testPlaylistID)
+				testPlaylistID = ""
+			}
+			// Clean up test data
+			_, _ = db.Delete("media_file", dbx.HashExp{"id": "lib1-song"}).Execute()
+			_, _ = db.Delete("media_file", dbx.HashExp{"id": "lib2-song"}).Execute()
+			_, _ = db.Delete("user_library", dbx.HashExp{"user_id": restrictedUserID}).Execute()
+			_, _ = db.Delete("user", dbx.HashExp{"id": restrictedUserID}).Execute()
+			_, _ = db.DB().Exec("DELETE FROM library WHERE id = ?", lib2ID)
+		})
+
+		It("should only include tracks from libraries the user has access to (issue #4738)", func() {
+			db := GetDBXBuilder()
+			ctx := log.NewContext(GinkgoT().Context())
+
+			// Create the smart playlist as the restricted user
+			restrictedUser := model.User{ID: restrictedUserID, UserName: restrictedUserID, IsAdmin: false}
+			ctx = request.WithUser(ctx, restrictedUser)
+			restrictedRepo := NewPlaylistRepository(ctx, db)
+
+			// Create a smart playlist that matches all songs
+			rules := &criteria.Criteria{
+				Expression: criteria.All{
+					criteria.Gt{"playCount": -1}, // Matches everything
+				},
+			}
+			newPls := model.Playlist{Name: "All Songs", OwnerID: restrictedUserID, Rules: rules}
+			Expect(restrictedRepo.Put(&newPls)).To(Succeed())
+			testPlaylistID = newPls.ID
+
+			By("refreshing the smart playlist")
+			conf.Server.SmartPlaylistRefreshDelay = -1 * time.Second // Force refresh
+			pls, err := restrictedRepo.GetWithTracks(newPls.ID, true, false)
+			Expect(err).ToNot(HaveOccurred())
+
+			By("verifying only the track from library 1 is in the playlist")
+			var foundLib1Song, foundLib2Song bool
+			for _, track := range pls.Tracks {
+				if track.MediaFileID == "lib1-song" {
+					foundLib1Song = true
+				}
+				if track.MediaFileID == "lib2-song" {
+					foundLib2Song = true
+				}
+			}
+			Expect(foundLib1Song).To(BeTrue(), "Song from library 1 should be in the playlist")
+			Expect(foundLib2Song).To(BeFalse(), "Song from library 2 should NOT be in the playlist")
+
+			By("verifying playlist_tracks table only contains the accessible track")
+			var playlistTracksCount int
+			err = db.DB().QueryRow("SELECT count(*) FROM playlist_tracks WHERE playlist_id = ?", newPls.ID).Scan(&playlistTracksCount)
+			Expect(err).ToNot(HaveOccurred())
+			// Count should only include tracks visible to the user (lib1-song)
+			// The count may include other test songs from library 1, but NOT lib2-song
+			var lib2TrackCount int
+			err = db.DB().QueryRow("SELECT count(*) FROM playlist_tracks WHERE playlist_id = ? AND media_file_id = 'lib2-song'", newPls.ID).Scan(&lib2TrackCount)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(lib2TrackCount).To(Equal(0), "lib2-song should not be in playlist_tracks")
+
+			By("verifying SongCount matches visible tracks")
+			Expect(pls.SongCount).To(Equal(len(pls.Tracks)), "SongCount should match the number of visible tracks")
+		})
+	})
 })