fix(library): preserve playlist phantoms on incremental scan and removal

The incremental scan's orphan cleanup and RemoveFromLibrary deleted
audio_files rows without first filling the playlist phantom columns, so
a track removed from the library folder outside YellowJacket (or
removed from the library) became a permanently empty playlist row that
nothing could re-link — the same bug #183 fixed on the full-rescan and
retire paths, on the two paths it missed.

Add a scoped PreservePlaylistPhantomsForFiles and run it in the same
transaction as the deletes on both paths.

Closes #246

backend/database/playlistphantoms.go

@@ -5,6 +5,7 @@ import (
 	"database/sql"
 	"fmt"
 	"log/slog"
+	"strings"
 )
 
 // Preserving a playlist entry across the loss of its track is two
@@ -89,12 +90,14 @@ const (
 // metadata on the entry itself, so the entry survives the rows being
 // deleted underneath it.
 //
-// Every path that empties `audio_files` must call this first, inside
-// the same transaction as the delete.  There are two such paths and
-// they had drifted: the full rescan in backend/library did this and the
-// stale-shape retire in this package did not, so the *documented*
-// repair ("delete and rescan") preserved playlists while the automatic
-// one that exists to spare the user that work silently emptied them.
+// Every path that empties `audio_files` must call this (or the scoped
+// variant below) first, inside the same transaction as the delete.
+// These paths have drifted before: the full rescan in backend/library
+// did this and the stale-shape retire in this package did not, so the
+// *documented* repair ("delete and rescan") preserved playlists while
+// the automatic one that exists to spare the user that work silently
+// emptied them (#183).  The incremental scan's orphan cleanup and
+// RemoveFromLibrary drifted the same way and are #246.
 //
 // The display half is skipped, with a warning, when `track_metadata`
 // cannot answer -- see the note above.  Skipping it costs a phantom
@@ -103,13 +106,39 @@ const (
 func PreservePlaylistPhantoms(
 	ctx context.Context, tx *sql.Tx, logger *slog.Logger,
 ) error {
-	if _, err := tx.ExecContext(ctx, preservePhantomPathSQL); err != nil {
+	return preservePlaylistPhantoms(ctx, tx, nil, logger)
+}
+
+// PreservePlaylistPhantomsForFiles is PreservePlaylistPhantoms scoped to
+// the given audio file ids, for the two removal paths that delete a
+// known subset of the table rather than all of it: the incremental
+// scan's orphan cleanup and RemoveFromLibrary.  A bulk pass there would
+// rewrite every linked playlist row on every scan for nothing.
+func PreservePlaylistPhantomsForFiles(
+	ctx context.Context, tx *sql.Tx, ids []int64, logger *slog.Logger,
+) error {
+	return preservePlaylistPhantoms(ctx, tx, ids, logger)
+}
+
+func preservePlaylistPhantoms(
+	ctx context.Context, tx *sql.Tx, ids []int64, logger *slog.Logger,
+) error {
+	clause, args, skip := phantomIDFilter(ids)
+	if skip {
+		return nil
+	}
+
+	if _, err := tx.ExecContext(
+		ctx, preservePhantomPathSQL+clause, args...,
+	); err != nil {
 		return fmt.Errorf(
 			"could not preserve playlist track file paths: %w", err,
 		)
 	}
 
-	if _, err := tx.ExecContext(ctx, preservePhantomDisplaySQL); err != nil {
+	if _, err := tx.ExecContext(
+		ctx, preservePhantomDisplaySQL+clause, args...,
+	); err != nil {
 		// A failed statement does not roll back a SQLite transaction,
 		// so the path half above stands and the entries remain
 		// re-linkable.
@@ -123,3 +152,26 @@ func PreservePlaylistPhantoms(
 
 	return nil
 }
+
+// phantomIDFilter builds the extra WHERE terms and arguments that scope
+// a preservation pass to a set of audio file ids.  A nil ids returns the
+// empty clause (a bulk run over every linked entry); an empty slice
+// reports skip, since there is nothing to preserve.
+func phantomIDFilter(ids []int64) (clause string, args []any, skip bool) {
+	switch {
+	case ids == nil:
+		return "", nil, false
+	case len(ids) == 0:
+		return "", nil, true
+	}
+
+	clause = " AND audio_file_id IN (" +
+		strings.Repeat("?,", len(ids)-1) + "?)"
+
+	args = make([]any, len(ids))
+	for i, id := range ids {
+		args[i] = id
+	}
+
+	return clause, args, false
+}

backend/database/playlistphantoms_test.go

@@ -0,0 +1,94 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+)
+
+// TestPreservePlaylistPhantomsForFilesScopesToTheRequestedIDs is the
+// scoping half of the scoped variant: a run over one file's id must
+// fill that file's playlist entries and leave every other entry alone,
+// because the incremental scan calls this once per orphan batch and a
+// pass that rewrote the whole table would touch every playlist row on
+// every scan.
+func TestPreservePlaylistPhantomsForFilesScopesToTheRequestedIDs(t *testing.T) {
+	ctx := context.Background()
+	db := openRaw(t, t.TempDir())
+
+	if _, err := db.ExecContext(ctx, "PRAGMA foreign_keys = ON"); err != nil {
+		t.Fatalf("pragma: %v", err)
+	}
+
+	if err := applySchema(ctx, db); err != nil {
+		t.Fatalf("applySchema: %v", err)
+	}
+
+	if _, err := db.ExecContext(ctx, `
+		INSERT INTO playlists (id, name) VALUES (1, 'keepme');
+		INSERT INTO libraries (id, name, path) VALUES (0, 'test', '/music');
+		INSERT INTO artists (id, name) VALUES (3, 'Aurora Fields');
+		INSERT INTO cover_art (id, file_path, mime_type)
+			VALUES (9, 'covers/7.jpg', 'image/jpeg');
+		INSERT INTO albums (id, name, artist_id, cover_art_id)
+			VALUES (4, 'Tideline', 3, 9);
+		INSERT INTO audio_files
+			(id, file_path, file_type_id, length_milliseconds,
+			 title, artist_credit, artist_id, album_id)
+			VALUES
+				(7, '/music/a.flac', 1, 1000,
+				 'Slack Water', 'Aurora Fields', 3, 4),
+				(8, '/music/b.flac', 1, 2000,
+				 'Second Tide', 'Aurora Fields', 3, 4);
+		INSERT INTO playlist_tracks (playlist_id, audio_file_id, position)
+			VALUES (1, 7, 0), (1, 8, 1);
+	`); err != nil {
+		t.Fatalf("seed: %v", err)
+	}
+
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		t.Fatalf("begin: %v", err)
+	}
+
+	defer func() { _ = tx.Rollback() }()
+
+	if err := PreservePlaylistPhantomsForFiles(
+		ctx, tx, []int64{7}, testLogger(),
+	); err != nil {
+		t.Fatalf("preserve: %v", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		t.Fatalf("commit: %v", err)
+	}
+
+	var filled, untouched sql.NullString
+
+	if err := db.QueryRowContext(ctx,
+		"SELECT phantom_file_path FROM playlist_tracks WHERE audio_file_id = 7",
+	).Scan(&filled); err != nil {
+		t.Fatalf("read the requested entry: %v", err)
+	}
+
+	if filled.String != "/music/a.flac" {
+		t.Errorf(
+			"requested entry phantom_file_path = %q, want %q",
+			filled.String, "/music/a.flac",
+		)
+	}
+
+	if err := db.QueryRowContext(ctx,
+		"SELECT phantom_file_path FROM playlist_tracks WHERE audio_file_id = 8",
+	).Scan(&untouched); err != nil {
+		t.Fatalf("read the untouched entry: %v", err)
+	}
+
+	if untouched.Valid {
+		t.Errorf(
+			"untouched entry got phantom_file_path = %q, want NULL "+
+				"(a scoped run must not rewrite the whole table)",
+			untouched.String,
+		)
+	}
+}

backend/library/library.go

@@ -911,30 +911,96 @@ func (l *Library) scanInternal(
 
 		orphanStart := time.Now()
 
+		// Snapshot the orphan set first.  The playlist-phantom
+		// preservation and the deletes are one transaction (the
+		// preservation has to land before the ON DELETE SET NULL, and
+		// both have to succeed or neither does), and the ids are what
+		// scope that preservation to just these files instead of
+		// rewriting every playlist row on a routine scan.
+		var (
+			orphans     []sqlcgen.AudioFile
+			orphanPaths []string
+		)
+
 		existingPaths.Range(func(key, value any) bool {
-			path := key.(string)
-			audioFile := value.(sqlcgen.AudioFile)
+			orphanPaths = append(orphanPaths, key.(string))
+			orphans = append(orphans, value.(sqlcgen.AudioFile))
 
-			l.logger.Debug(
-				"removing orphaned database entry",
-				"path", path, "id", audioFile.ID,
-			)
+			return true
+		})
 
-			if err := l.db.Queries.DeleteAudioFile(
-				l.ctx, audioFile.ID,
-			); err != nil {
-				l.logger.Warn(
-					"failed to delete orphaned audio file",
-					"path", path,
-					"id", audioFile.ID,
-					"err", err,
-				)
+		deleted := make([]bool, len(orphans))
 
-				metrics.addWarning(path, "orphan", err)
-
-				return true
+		if len(orphans) > 0 {
+			orphanIDs := make([]int64, len(orphans))
+			for i, f := range orphans {
+				orphanIDs[i] = f.ID
 			}
 
+			tx, beginErr := l.db.BeginTx()
+			if beginErr != nil {
+				metrics.addWarning("", "orphan", beginErr)
+			} else {
+				defer func() { _ = tx.Rollback() }() // no-op after commit
+
+				if err := database.PreservePlaylistPhantomsForFiles(
+					l.ctx, tx, orphanIDs, l.logger,
+				); err != nil {
+					// Deleting without the phantoms is exactly the
+					// playlist-emptying bug the preservation exists to
+					// prevent, so leave the rows for the next scan
+					// rather than empty the playlists now.
+					l.logger.Error(
+						"skipping orphan deletion: could not preserve "+
+							"playlist entries",
+						"err", err,
+					)
+
+					metrics.addWarning("", "orphan", err)
+
+					_ = tx.Rollback()
+				} else {
+					txq := l.db.Queries.WithTx(tx)
+
+					for i, f := range orphans {
+						if err := txq.DeleteAudioFile(
+							l.ctx, f.ID,
+						); err != nil {
+							l.logger.Warn(
+								"failed to delete orphaned audio file",
+								"path", orphanPaths[i],
+								"id", f.ID,
+								"err", err,
+							)
+
+							metrics.addWarning(orphanPaths[i], "orphan", err)
+
+							continue
+						}
+
+						deleted[i] = true
+					}
+
+					if err := tx.Commit(); err != nil {
+						l.logger.Error(
+							"could not commit orphan deletion",
+							"err", err,
+						)
+
+						metrics.addWarning("", "orphan", err)
+					}
+				}
+			}
+		}
+
+		// Post-commit bookkeeping for the files that actually went.
+		for i, f := range orphans {
+			if !deleted[i] {
+				continue
+			}
+
+			path := orphanPaths[i]
+
 			// Keep the file's tagging group in sync: drop the group's
 			// track count and clear it out once empty, mirroring the
 			// bookkeeping maybeRebindTaggingGroup does for a group_key
@@ -942,25 +1008,25 @@ func (l *Library) scanInternal(
 			// and replaced leaves a stale tagging_items row behind —
 			// its track_count still counts the deleted files, and it
 			// never clears from the autotag queue.
-			if audioFile.GroupKey != "" {
+			if f.GroupKey != "" {
 				if err := l.db.Queries.DecrementTaggingItemTrackCount(
-					l.ctx, audioFile.GroupKey,
+					l.ctx, f.GroupKey,
 				); err != nil {
 					l.logger.Warn(
 						"failed to decrement tagging group for orphan",
 						"path", path,
-						"group_key", audioFile.GroupKey,
+						"group_key", f.GroupKey,
 						"err", err,
 					)
 
 					metrics.addWarning(path, "orphan", err)
 				} else if err := l.db.Queries.DeleteTaggingItemIfEmpty(
-					l.ctx, audioFile.GroupKey,
+					l.ctx, f.GroupKey,
 				); err != nil {
 					l.logger.Warn(
 						"failed to clean up emptied tagging group for orphan",
 						"path", path,
-						"group_key", audioFile.GroupKey,
+						"group_key", f.GroupKey,
 						"err", err,
 					)
 
@@ -969,12 +1035,10 @@ func (l *Library) scanInternal(
 			}
 
 			// Remove from FTS5 search index.
-			if err := l.db.DeleteSearchIndex(
-				audioFile.ID,
-			); err != nil {
+			if err := l.db.DeleteSearchIndex(f.ID); err != nil {
 				l.logger.Warn(
 					"failed to delete FTS entry for orphan",
-					"id", audioFile.ID,
+					"id", f.ID,
 					"err", err,
 				)
 
@@ -982,9 +1046,7 @@ func (l *Library) scanInternal(
 			}
 
 			removed.Add(1)
-
-			return true
-		})
+		}
 
 		metrics.OrphanCleanup = time.Since(orphanStart)
 

backend/library/removal_test.go

@@ -94,6 +94,57 @@ func countRows(
 	return n
 }
 
+// RemoveFromLibrary is the one path that empties a track *deliberately*:
+// the file stays on disk but is excluded, so nothing re-imports it.  The
+// playlist entry must still survive as a re-linkable phantom rather than
+// an empty row, because a later full rescan clears the exclusion and is
+// what re-links the entry then (#246).
+func TestRemoveFromLibrary_PreservesPlaylistPhantoms(t *testing.T) {
+	t.Parallel()
+
+	lib, db := setupTestLibrary(t)
+
+	seedRemovableLibrary(t, lib, "/nonexistent/cover.jpg")
+
+	if _, err := lib.db.ExecContext(
+		`INSERT INTO playlists (name) VALUES ('keepme')`,
+	); err != nil {
+		t.Fatalf("seed playlist: %v", err)
+	}
+
+	playlistID := queryInt(
+		t, db, `SELECT id FROM playlists WHERE name = 'keepme'`,
+	)
+
+	if _, err := lib.db.ExecContext(
+		`INSERT INTO playlist_tracks (playlist_id, audio_file_id, position)
+		 SELECT ?, id, 0 FROM audio_files
+		 WHERE file_path = '/music/song.mp3'`,
+		playlistID,
+	); err != nil {
+		t.Fatalf("seed playlist_tracks: %v", err)
+	}
+
+	if _, err := lib.RemoveFromLibrary([]string{"/music/song.mp3"}); err != nil {
+		t.Fatalf("RemoveFromLibrary: %v", err)
+	}
+
+	phantomPath := queryString(
+		t, db,
+		`SELECT phantom_file_path FROM playlist_tracks
+		 WHERE playlist_id = ?`,
+		playlistID,
+	)
+
+	if phantomPath != "/music/song.mp3" {
+		t.Fatalf(
+			"phantom_file_path is %q, want %q -- the entry cannot be "+
+				"re-linked after a later full rescan",
+			phantomPath, "/music/song.mp3",
+		)
+	}
+}
+
 // A library with tagging_items must still be removable.  tagging_items
 // FK-references libraries with no ON DELETE clause, so leaving those
 // rows behind fails the DELETE and rolls back the entire removal.

backend/library/remove_tracks.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 
+	"yellowjacket/backend/database"
 	"yellowjacket/backend/events"
 )
 
@@ -57,6 +58,25 @@ func (l *Library) RemoveFromLibrary(filePaths []string) (*RemovalResult, error)
 
 	var result RemovalResult
 
+	// Preserve the playlist entries before the rows go, so they survive
+	// as re-linkable phantoms rather than empty rows.  The track is
+	// excluded and will not be re-imported on its own, but a later full
+	// rescan clears the exclusion and this is what lets the entry
+	// re-link then — the same preservation every other path that empties
+	// audio_files performs (#246).
+	rowIDs := make([]int64, len(rows))
+	for i, row := range rows {
+		rowIDs[i] = row.ID
+	}
+
+	if err := database.PreservePlaylistPhantomsForFiles(
+		l.ctx, tx, rowIDs, l.logger,
+	); err != nil {
+		return nil, fmt.Errorf(
+			"could not preserve playlist entries for removal: %w", err,
+		)
+	}
+
 	// Exclude every path the caller named, including one whose row has
 	// already gone: the user asked for that file to stay out, and a row
 	// that disappeared between the click and the commit is not a reason

backend/library/scan_dirdisc_test.go

@@ -231,3 +231,98 @@ func TestScan_MultipleDirectoriesDoNotCrossContaminate(t *testing.T) {
 		t.Errorf("Album A and Album B must not share a group_key: %+v", keys)
 	}
 }
+
+// TestScan_OrphanCleanupPreservesPlaylistPhantoms guards #246: a file
+// deleted from the library folder *outside* YellowJacket is discovered
+// as an orphan by the next scan, and its playlist entry must survive as
+// a re-linkable phantom — the same preservation the full rescan and
+// stale-retire paths already perform, scoped here to just the orphaned
+// file.  Before the fix the entry became an empty row (audio_file_id
+// NULL and no phantom_file_path), which nothing can ever re-link.
+func TestScan_OrphanCleanupPreservesPlaylistPhantoms(t *testing.T) {
+	t.Parallel()
+
+	lib, db := setupTestLibrary(t)
+
+	root := t.TempDir()
+	track := filepath.Join(root, "gone.mp3")
+
+	writeTestTrack(t, track, 0)
+
+	library, err := db.Queries.CreateLibrary(lib.ctx, sqlcgen.CreateLibraryParams{
+		Name: "orphans",
+		Path: root,
+	})
+	if err != nil {
+		t.Fatalf("create library: %v", err)
+	}
+
+	if metrics := lib.scanInternal(library.ID, library.Name, library.Path); metrics == nil {
+		t.Fatal("first scan returned nil metrics")
+	}
+
+	trackID := queryInt(
+		t, db, "SELECT id FROM audio_files WHERE file_path = ?", track,
+	)
+	if trackID == 0 {
+		t.Fatal("first scan did not import the track")
+	}
+
+	if _, err := db.ExecContext(
+		`INSERT INTO playlists (name) VALUES ('keepme')`,
+	); err != nil {
+		t.Fatalf("seed playlist: %v", err)
+	}
+
+	playlistID := queryInt(
+		t, db, "SELECT id FROM playlists WHERE name = 'keepme'",
+	)
+
+	if _, err := db.ExecContext(
+		`INSERT INTO playlist_tracks (playlist_id, audio_file_id, position)
+		 VALUES (?, ?, 0)`,
+		playlistID, trackID,
+	); err != nil {
+		t.Fatalf("seed playlist_tracks: %v", err)
+	}
+
+	// The file goes away outside the app.
+	if err := os.Remove(track); err != nil {
+		t.Fatalf("remove track: %v", err)
+	}
+
+	if metrics := lib.scanInternal(library.ID, library.Name, library.Path); metrics == nil {
+		t.Fatal("second scan returned nil metrics")
+	}
+
+	if n := queryInt(
+		t, db, "SELECT COUNT(*) FROM audio_files WHERE file_path = ?", track,
+	); n != 0 {
+		t.Fatalf("audio_files still holds the removed path: %d rows", n)
+	}
+
+	if n := queryInt(
+		t, db,
+		"SELECT COUNT(*) FROM playlist_tracks WHERE playlist_id = ? "+
+			"AND audio_file_id IS NULL",
+		playlistID,
+	); n != 1 {
+		t.Fatalf(
+			"playlist entry did not become a phantom: %d null-id rows, want 1",
+			n,
+		)
+	}
+
+	phantomPath := queryString(
+		t, db,
+		"SELECT phantom_file_path FROM playlist_tracks WHERE playlist_id = ?",
+		playlistID,
+	)
+	if phantomPath != track {
+		t.Fatalf(
+			"phantom_file_path = %q, want %q -- the entry cannot be "+
+				"re-linked if the file comes back",
+			phantomPath, track,
+		)
+	}
+}