internal/api/admin_duplicates.go

@@ -449,3 +449,90 @@ func (h *handlers) handleMergeDuplicateGroup(w http.ResponseWriter, r *http.Requ
 	}
 	writeJSON(w, http.StatusOK, resp)
 }
+
+// refetchDuplicateRequest is the operator's answer for one recording filling
+// several of an album's slots. keep_track_id is the copy whose title the
+// recording is; empty means they cannot say, and every copy goes.
+type refetchDuplicateRequest struct {
+	KeepTrackID string `json:"keep_track_id"`
+}
+
+// refetchDuplicateResponse reports what went. Blocked names the releases set
+// aside; empty when the album came from before Minstrel downloaded anything.
+type refetchDuplicateResponse struct {
+	KeptTrackID  *string  `json:"kept_track_id"`
+	RemovedPaths []string `json:"removed_paths"`
+	Blocked      []string `json:"blocked"`
+}
+
+// handleRefetchDuplicateGroup implements POST
+// /api/admin/library/duplicates/{id}/refetch (#6184): settle a group of one
+// recording in several slots of an album the way the resolver would, with the
+// operator's answer. The copies in slots that are not the recording's are
+// removed and marked missing, the release they came from is set aside, and the
+// album is wanted again. Merge is the wrong action there: it keeps one title
+// whether or not it is the audio's, and fetches nothing.
+//
+// Errors:
+//   - 409 library_not_writable / 500 file_delete_failed when a file could not be
+//     removed (fileRemoveAPIError)
+//   - 404 duplicate_group_not_pending when the group was already resolved
+//   - 400 not_wrong_slot when the group is not one recording in several slots
+//   - 400 survivor_not_in_group, invalid_id, invalid_body
+func (h *handlers) handleRefetchDuplicateGroup(w http.ResponseWriter, r *http.Request) {
+	admin, ok := requireUser(w, r)
+	if !ok {
+		return
+	}
+	groupID, ok := parseUUID(chi.URLParam(r, "id"))
+	if !ok {
+		writeAdminJSONErr(w, http.StatusBadRequest, "invalid_id")
+		return
+	}
+	var body refetchDuplicateRequest
+	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, mergeRequestBodyLimit)).Decode(&body); err != nil && !errors.Is(err, io.EOF) {
+		writeAdminJSONErr(w, http.StatusBadRequest, "invalid_body")
+		return
+	}
+	var keepID pgtype.UUID // invalid: every copy goes
+	if body.KeepTrackID != "" {
+		if keepID, ok = parseUUID(body.KeepTrackID); !ok {
+			writeAdminJSONErr(w, http.StatusBadRequest, "invalid_id")
+			return
+		}
+	}
+
+	res, err := library.SettleWrongSlot(r.Context(), h.pool, h.logger, groupID, keepID, admin.ID)
+	if err != nil {
+		if apiErr, ok := fileRemoveAPIError(err); ok {
+			logFileRemoveFailure(h.logger, apiErr, "group_id", uuidToString(groupID))
+			writeErr(w, apiErr)
+			return
+		}
+		switch {
+		case errors.Is(err, library.ErrDuplicateGroupNotPending):
+			writeAdminJSONErr(w, http.StatusNotFound, "duplicate_group_not_pending")
+		case errors.Is(err, library.ErrNotWrongSlot):
+			writeAdminJSONErr(w, http.StatusBadRequest, "not_wrong_slot")
+		case errors.Is(err, library.ErrSurvivorNotInGroup):
+			writeAdminJSONErr(w, http.StatusBadRequest, "survivor_not_in_group")
+		default:
+			h.logger.Error("admin: refetch duplicate group", "group_id", uuidToString(groupID), "err", err)
+			writeAdminJSONErr(w, http.StatusInternalServerError, "server_error")
+		}
+		return
+	}
+
+	resp := refetchDuplicateResponse{RemovedPaths: make([]string, 0, len(res.Removed)), Blocked: res.Blocked}
+	if resp.Blocked == nil {
+		resp.Blocked = []string{}
+	}
+	if res.Kept != nil {
+		id := uuidToString(res.Kept.TrackID)
+		resp.KeptTrackID = &id
+	}
+	for _, c := range res.Removed {
+		resp.RemovedPaths = append(resp.RemovedPaths, c.FilePath)
+	}
+	writeJSON(w, http.StatusOK, resp)
+}

internal/api/api.go

@@ -333,6 +333,7 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playev
 				admin.Post("/library/duplicates/sweep", h.handleRunDuplicateSweep)
 				admin.Post("/library/duplicates/{id}/dismiss", h.handleDismissDuplicateGroup)
 				admin.Post("/library/duplicates/{id}/merge", h.handleMergeDuplicateGroup)
+				admin.Post("/library/duplicates/{id}/refetch", h.handleRefetchDuplicateGroup)
 
 				admin.Get("/invites", h.handleListInvites)
 				admin.Post("/invites", h.handleCreateInvite)

internal/db/dbq/duplicates.sql.go

@@ -328,6 +328,7 @@ SELECT g.id                  AS group_id,
   LEFT JOIN track_acoustid_lookups l ON l.track_id = t.id
  WHERE g.status = 'pending'
    AND t.missing_since IS NULL
+   AND ($1::uuid IS NULL OR g.id = $1::uuid)
  ORDER BY g.id, t.id
 `
 
@@ -366,9 +367,10 @@ type ListDuplicateGroupsForResolveRow struct {
 // tags or the library listing's match; ” when neither names one.
 // acoustid_state and acoustid_recording are what AcoustID said of the file,
 // when it was looked up (#6169: which song one recording cut to several slots
-// is).
-func (q *Queries) ListDuplicateGroupsForResolve(ctx context.Context) ([]ListDuplicateGroupsForResolveRow, error) {
-	rows, err := q.db.Query(ctx, listDuplicateGroupsForResolve)
+// is). group_id narrows it to one group, for the operator settling it (#6184);
+// NULL reads them all.
+func (q *Queries) ListDuplicateGroupsForResolve(ctx context.Context, groupID pgtype.UUID) ([]ListDuplicateGroupsForResolveRow, error) {
+	rows, err := q.db.Query(ctx, listDuplicateGroupsForResolve, groupID)
 	if err != nil {
 		return nil, err
 	}

internal/db/queries/duplicates.sql

@@ -197,7 +197,8 @@ UPDATE duplicate_groups
 -- tags or the library listing's match; '' when neither names one.
 -- acoustid_state and acoustid_recording are what AcoustID said of the file,
 -- when it was looked up (#6169: which song one recording cut to several slots
--- is).
+-- is). group_id narrows it to one group, for the operator settling it (#6184);
+-- NULL reads them all.
 SELECT g.id                  AS group_id,
        g.tier,
        g.worst_bit_error_rate,
@@ -232,6 +233,7 @@ SELECT g.id                  AS group_id,
   LEFT JOIN track_acoustid_lookups l ON l.track_id = t.id
  WHERE g.status = 'pending'
    AND t.missing_since IS NULL
+   AND (sqlc.narg(group_id)::uuid IS NULL OR g.id = sqlc.narg(group_id)::uuid)
  ORDER BY g.id, t.id;
 
 -- name: SetDuplicateGroupClasses :exec

internal/library/duplicate_resolve.go

@@ -160,7 +160,7 @@ func ResolveDuplicatesWith(
 	q := dbq.New(pool)
 	res := DuplicateResolveResult{Classes: map[DuplicateClass]int{}}
 
-	rows, err := q.ListDuplicateGroupsForResolve(ctx)
+	rows, err := q.ListDuplicateGroupsForResolve(ctx, pgtype.UUID{})
 	if err != nil {
 		return res, fmt.Errorf("list duplicate groups: %w", err)
 	}
@@ -168,12 +168,7 @@ func ResolveDuplicatesWith(
 	res.Groups = len(groups)
 
 	for _, g := range groups {
-		cm := make([]ClassifyMember, len(g.members))
-		for i, m := range g.members {
-			cm[i] = ClassifyMember{AlbumID: syncpkg.FormatUUID(m.AlbumID), Title: m.Title, ArtistName: m.ArtistName}
-		}
-		g.class = ClassifyDuplicateGroup(g.tier, cm)
-		g.note = resolveNote(g)
+		g.classify()
 		res.Classes[g.class]++
 	}
 	if err := writeResolveVerdicts(ctx, q, groups); err != nil {
@@ -444,6 +439,16 @@ func foldResolveGroups(rows []dbq.ListDuplicateGroupsForResolveRow) []*resolveGr
 	return out
 }
 
+// classify sets the group's class and the note the report shows beside it.
+func (g *resolveGroup) classify() {
+	cm := make([]ClassifyMember, len(g.members))
+	for i, m := range g.members {
+		cm[i] = ClassifyMember{AlbumID: syncpkg.FormatUUID(m.AlbumID), Title: m.Title, ArtistName: m.ArtistName}
+	}
+	g.class = ClassifyDuplicateGroup(g.tier, cm)
+	g.note = resolveNote(g)
+}
+
 // resolveNote is what the report says beside a group, when there is something
 // to say.
 func resolveNote(g *resolveGroup) string {

internal/library/duplicate_settle.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
-	"os"
 	"slices"
 
 	"github.com/jackc/pgx/v5"
@@ -45,7 +44,8 @@ import (
 // Whenever copies go, the release the files came from is set aside, so the
 // album fetched again is not the same files (#6169).
 //
-// Anything less certain stays with the operator.
+// Anything less certain stays with the operator, who settles it the same way
+// with their own answer (SettleWrongSlot).
 
 const (
 	// trackListFetchesPerPass is how many albums' track lists a pass may ask
@@ -239,7 +239,7 @@ func settleWrongSlots(
 		// still does not fetch the same files again.
 		blocked := blockReleasesHolding(ctx, pool, logger, g)
 		emptied := emptiedSlots(ctx, q, logger, g, losers, tracks)
-		n, err := removeWrongSlots(ctx, pool, logger, g, keep, losers, emptied, blocked)
+		n, err := removeWrongSlots(ctx, pool, logger, g, keep, losers, emptied, blocked, pgtype.UUID{})
 		removed += n
 		if err != nil {
 			logger.Warn("duplicate resolve: removing wrong-slot copies failed", "group_id", syncpkg.FormatUUID(g.id), "err", err)
@@ -253,6 +253,86 @@ func settleWrongSlots(
 	return removed, names
 }
 
+// ErrNotWrongSlot means a group is not one recording filling several of an
+// album's track slots, so there is no slot to empty and nothing to fetch again.
+var ErrNotWrongSlot = errors.New("library: duplicate group is not one recording in several slots")
+
+// WrongSlotResult is what settling a wrong slot by hand did. Kept is nil when
+// every copy went.
+type WrongSlotResult struct {
+	Kept    *MergedCopy
+	Removed []MergedCopy
+	// Blocked names the releases set aside. None when the album was imported
+	// before Minstrel downloaded anything: the same files may come back.
+	Blocked []string
+}
+
+// SettleWrongSlot settles a one-album mismatch the resolver left for the
+// operator (#6184), with their answer in place of MusicBrainz's lengths and
+// AcoustID's. keepID is the copy whose title they say the recording is; an
+// invalid id means they cannot say, and every copy goes. Either way it is the
+// resolver's own path: the release the files came from is set aside, the
+// copies removed are marked missing, and the album is wanted again for them.
+// A merge does none of that, and keeps one copy's title whether or not it is
+// the audio's.
+//
+// Copies sharing the kept copy's title are one song held twice and stay, as in
+// wrongSlots: the next sweep finds the pair and the resolver merges it.
+func SettleWrongSlot(
+	ctx context.Context, pool *pgxpool.Pool, logger *slog.Logger, groupID, keepID, actorID pgtype.UUID,
+) (WrongSlotResult, error) {
+	if logger == nil {
+		logger = slog.Default()
+	}
+	q := dbq.New(pool)
+	rows, err := q.ListDuplicateGroupsForResolve(ctx, groupID)
+	if err != nil {
+		return WrongSlotResult{}, fmt.Errorf("read duplicate group: %w", err)
+	}
+	groups := foldResolveGroups(rows)
+	if len(groups) == 0 {
+		return WrongSlotResult{}, ErrDuplicateGroupNotPending
+	}
+	g := groups[0]
+	if g.classify(); g.class != ClassMismatch {
+		return WrongSlotResult{}, ErrNotWrongSlot
+	}
+	keep := -1
+	if keepID.Valid {
+		keep = slices.IndexFunc(g.members, func(m dbq.ListDuplicateGroupsForResolveRow) bool { return m.TrackID == keepID })
+		if keep < 0 {
+			return WrongSlotResult{}, ErrSurvivorNotInGroup
+		}
+	}
+	var losers []int
+	for i, m := range g.members {
+		if keep >= 0 && MatchTitleKey(m.Title, m.ArtistName) == MatchTitleKey(g.members[keep].Title, m.ArtistName) {
+			continue
+		}
+		losers = append(losers, i)
+	}
+	if len(losers) == 0 {
+		return WrongSlotResult{}, ErrNotWrongSlot
+	}
+	var tracks []dbq.MbReleaseTrack
+	if rg := g.members[0].ReleaseGroupMbid; rg != "" {
+		if tracks, err = q.ListMBReleaseTracksForGroup(ctx, rg); err != nil {
+			return WrongSlotResult{}, fmt.Errorf("read the album's track list: %w", err)
+		}
+	}
+
+	res := WrongSlotResult{Blocked: blockReleasesHolding(ctx, pool, logger, g)}
+	emptied := emptiedSlots(ctx, q, logger, g, losers, tracks)
+	n, err := removeWrongSlots(ctx, pool, logger, g, keep, losers, emptied, res.Blocked, actorID)
+	if keep >= 0 {
+		res.Kept = &MergedCopy{TrackID: g.members[keep].TrackID, FilePath: g.members[keep].FilePath}
+	}
+	for _, i := range losers[:n] {
+		res.Removed = append(res.Removed, MergedCopy{TrackID: g.members[i].TrackID, FilePath: g.members[i].FilePath})
+	}
+	return res, err
+}
+
 // sameAudio reports whether a group's copies are one recording, cut however:
 // identical audio, or fingerprints all but identical (sameAudioBER).
 func sameAudio(g *resolveGroup) bool {
@@ -442,18 +522,19 @@ func neverRead(ctx context.Context, q *dbq.Queries, rg string) bool {
 // are stamped to wait for a copy fetched again (emptiedSlots). blocked names
 // the releases set aside, for the record. A file that cannot be removed stops
 // the group; the ones already gone are still marked, and the group waits for
-// the next pass.
+// the next pass. actorID is the operator settling it by hand, invalid for the
+// resolver.
 func removeWrongSlots(
 	ctx context.Context, pool *pgxpool.Pool, logger *slog.Logger, g *resolveGroup, keep int, losers []int,
-	emptied []pgtype.UUID, blocked []string,
+	emptied []pgtype.UUID, blocked []string, actorID pgtype.UUID,
 ) (int, error) {
 	var gone []pgtype.UUID
 	var removedFiles []map[string]string
 	var removeErr error
 	for _, i := range losers {
 		m := g.members[i]
-		if err := removeFile(m.FilePath); err != nil && !errors.Is(err, os.ErrNotExist) {
-			removeErr = fmt.Errorf("remove %s: %w", m.FilePath, err)
+		if err := removeTrackFileOnDisk(m.FilePath); err != nil {
+			removeErr = err
 			break
 		}
 		gone = append(gone, m.TrackID)
@@ -481,6 +562,10 @@ func removeWrongSlots(
 		if removeErr != nil {
 			return nil
 		}
+		if actorID.Valid {
+			_, err := tq.MarkDuplicateGroupMerged(ctx, g.id)
+			return err
+		}
 		_, err := tq.SettleDuplicateGroupAutomatically(ctx, dbq.SettleDuplicateGroupAutomaticallyParams{
 			ID: g.id, Status: "merged",
 		})
@@ -490,7 +575,7 @@ func removeWrongSlots(
 		return 0, err
 	}
 	details := map[string]any{
-		"automatic": true,
+		"automatic": !actorID.Valid,
 		"group_id":  syncpkg.FormatUUID(g.id),
 		"artist":    g.members[0].ArtistName,
 		"removed":   removedFiles,
@@ -504,7 +589,7 @@ func removeWrongSlots(
 		details["kept_title"], details["kept_path"] = kept.Title, kept.FilePath
 		keptPath = kept.FilePath
 	}
-	audit.WriteOrLog(ctx, pool, logger, pgtype.UUID{}, pgtype.UUID{}, audit.ActionDuplicateWrongFile, details)
+	audit.WriteOrLog(ctx, pool, logger, actorID, pgtype.UUID{}, audit.ActionDuplicateWrongFile, details)
 	logger.Info("duplicate resolve: removed copies from slots that were not theirs",
 		"group_id", syncpkg.FormatUUID(g.id), "kept", keptPath, "removed", len(gone))
 	return len(gone), removeErr

internal/library/duplicate_settle_test.go

@@ -0,0 +1,148 @@
+package library
+
+import (
+	"context"
+	"errors"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/dbtest"
+	syncpkg "git.fabledsword.com/bvandeusen/minstrel/internal/sync"
+)
+
+// undecidedSlot is one recording filed as Void and as Reach, two songs
+// MusicBrainz lists at lengths that cannot tell them apart, from a download
+// Minstrel imported: the resolver leaves it pending for the operator (#6184).
+func undecidedSlot(t *testing.T) (oneAlbumFixture, dbq.User) {
+	t.Helper()
+	f := newOneAlbumFixture(t, "acoustic", "Void", "Reach")
+	ctx := context.Background()
+	seedTrackList(t, f.pool, f.album, map[string]int{"Void": 220500, "Reach": 221000})
+	if _, err := f.pool.Exec(ctx,
+		`INSERT INTO grabs (info_hash, name, key, client, save_path, origin, import_state, destination)
+		 VALUES ('abc123', 'Savant - Void [WEB]', 'k', 'qbit', '/dl', 'schedule', 'imported', $1)`,
+		filepath.Dir(f.aPath)); err != nil {
+		t.Fatal(err)
+	}
+	if res, err := ResolveDuplicates(ctx, f.pool, nil, "", true); err != nil || res.WrongFiles != 0 {
+		t.Fatalf("resolve = %+v, %v; want the group left for the operator", res, err)
+	}
+	name := strings.NewReplacer("/", "-", " ", "-").Replace(t.Name())
+	u, err := dbq.New(f.pool).CreateUser(ctx, dbq.CreateUserParams{
+		Username: dbtest.TestUserPrefix + name, PasswordHash: "x", ApiTokenHash: name + "-token",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return f, u
+}
+
+// emptiedTrack says whether a copy's track is marked missing and waiting for
+// the album to be fetched again.
+func emptiedTrack(t *testing.T, f oneAlbumFixture, id pgtype.UUID) bool {
+	t.Helper()
+	var emptied bool
+	if err := f.pool.QueryRow(context.Background(),
+		`SELECT missing_since IS NOT NULL AND emptied_at IS NOT NULL FROM tracks WHERE id = $1`, id).Scan(&emptied); err != nil {
+		t.Fatalf("track %s is gone: %v", syncpkg.FormatUUID(id), err)
+	}
+	return emptied
+}
+
+// settledByHand checks the group closed as the operator's and the audit row
+// names them.
+func settledByHand(t *testing.T, f oneAlbumFixture, actor dbq.User) {
+	t.Helper()
+	if status, _, _, auto := (resolveFixture{pool: f.pool, groupID: f.groupID}).group(t); status != "merged" || auto {
+		t.Errorf("group = (%s, auto=%v), want merged by the operator", status, auto)
+	}
+	var n int
+	if err := f.pool.QueryRow(context.Background(),
+		`SELECT count(*) FROM audit_log WHERE action = 'duplicate_wrong_file' AND actor_id = $1
+		    AND metadata->>'group_id' = $2 AND NOT (metadata->>'automatic')::boolean`,
+		actor.ID, syncpkg.FormatUUID(f.groupID)).Scan(&n); err != nil {
+		t.Fatal(err)
+	}
+	if n != 1 {
+		t.Errorf("operator's wrong-file audit rows = %d, want 1", n)
+	}
+}
+
+// "Get it again": the operator cannot say which song the recording is, so
+// every copy goes, the download they came from is set aside, and both slots
+// wait for the album fetched again. A merge would have kept one title.
+func TestSettleWrongSlot_GetItAgainRemovesEveryCopy_Integration(t *testing.T) {
+	f, op := undecidedSlot(t)
+	ctx := context.Background()
+	res, err := SettleWrongSlot(ctx, f.pool, nil, f.groupID, pgtype.UUID{}, op.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.Kept != nil || len(res.Removed) != 2 || exists(f.aPath) || exists(f.bPath) {
+		t.Fatalf("result %+v, void exists %v, reach exists %v; want both copies removed",
+			res, exists(f.aPath), exists(f.bPath))
+	}
+	for _, id := range []pgtype.UUID{f.a.ID, f.b.ID} {
+		if !emptiedTrack(t, f, id) {
+			t.Errorf("track %s is not waiting to be fetched again", syncpkg.FormatUUID(id))
+		}
+	}
+	if !releaseBlocked(t, f.pool, "abc123") || len(res.Blocked) != 1 {
+		t.Errorf("blocked %v; want the download the files came from set aside", res.Blocked)
+	}
+	settledByHand(t, f, op)
+
+	if _, err := SettleWrongSlot(ctx, f.pool, nil, f.groupID, pgtype.UUID{}, op.ID); !errors.Is(err, ErrDuplicateGroupNotPending) {
+		t.Errorf("settling it twice: err = %v, want ErrDuplicateGroupNotPending", err)
+	}
+}
+
+// "This one is Reach": the copy the operator names stays, and only Void's slot
+// is emptied and wanted again.
+func TestSettleWrongSlot_KeepsTheCopyTheOperatorNames_Integration(t *testing.T) {
+	f, op := undecidedSlot(t)
+	res, err := SettleWrongSlot(context.Background(), f.pool, nil, f.groupID, f.b.ID, op.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res.Kept == nil || res.Kept.TrackID != f.b.ID || len(res.Removed) != 1 || exists(f.aPath) || !exists(f.bPath) {
+		t.Fatalf("result %+v, void exists %v, reach exists %v; want only Void's copy removed",
+			res, exists(f.aPath), exists(f.bPath))
+	}
+	if !emptiedTrack(t, f, f.a.ID) {
+		t.Error("Void's track is not waiting to be fetched again")
+	}
+	if !releaseBlocked(t, f.pool, "abc123") {
+		t.Error("the download the files came from is not set aside")
+	}
+	settledByHand(t, f, op)
+}
+
+// Only a group of one recording in several slots is settled this way, and only
+// with a copy from it.
+func TestSettleWrongSlot_RefusesWhatItCannotSettle_Integration(t *testing.T) {
+	ctx := context.Background()
+	t.Run("two versions of a song", func(t *testing.T) {
+		f := newOneAlbumFixture(t, "acoustic", "Lovesick", "Lovesick (Instrumental)")
+		if _, err := SettleWrongSlot(ctx, f.pool, nil, f.groupID, pgtype.UUID{}, pgtype.UUID{}); !errors.Is(err, ErrNotWrongSlot) {
+			t.Errorf("err = %v, want ErrNotWrongSlot", err)
+		}
+		if !exists(f.aPath) || !exists(f.bPath) {
+			t.Error("a file was removed")
+		}
+	})
+	t.Run("a copy from another group", func(t *testing.T) {
+		f, op := undecidedSlot(t)
+		other := pgtype.UUID{Bytes: [16]byte{1}, Valid: true}
+		if _, err := SettleWrongSlot(ctx, f.pool, nil, f.groupID, other, op.ID); !errors.Is(err, ErrSurvivorNotInGroup) {
+			t.Errorf("err = %v, want ErrSurvivorNotInGroup", err)
+		}
+		if !exists(f.aPath) || !exists(f.bPath) || releaseBlocked(t, f.pool, "abc123") {
+			t.Error("something changed")
+		}
+	})
+}

web/src/lib/api/admin.ts

@@ -9,6 +9,7 @@ import type {
   AdminDuplicatesResponse,
   DuplicatesView,
   MergeDuplicateResult,
+  RefetchDuplicateResult,
   ResolvedDuplicatesResponse,
   AdminPlaybackError,
   AdminQuarantineRow,
@@ -893,6 +894,18 @@ export async function mergeDuplicateGroup(
   );
 }
 
+// One recording in several of an album's slots (#6184): keep the copy whose
+// title it is, or none (empty keep_track_id), and fetch the album again.
+export async function refetchDuplicateGroup(
+  id: string,
+  body: { keep_track_id: string }
+): Promise<RefetchDuplicateResult> {
+  return api.post<RefetchDuplicateResult>(
+    `/api/admin/library/duplicates/${encodeURIComponent(id)}/refetch`,
+    body
+  );
+}
+
 export async function dismissDuplicateGroup(id: string): Promise<void> {
   await api.post(`/api/admin/library/duplicates/${encodeURIComponent(id)}/dismiss`, {});
 }

web/src/lib/api/types.ts

@@ -485,6 +485,15 @@ export type MergeDuplicateResult = {
   removed_paths: string[];
 };
 
+// What settling one recording in several slots did (#6184). kept_track_id is
+// null when every copy went; blocked names the releases set aside, empty when
+// the album came from before Minstrel downloaded anything.
+export type RefetchDuplicateResult = {
+  kept_track_id: string | null;
+  removed_paths: string[];
+  blocked: string[];
+};
+
 export type AdminDuplicatesResponse = {
   sweep: AdminDuplicateSweep;
   fingerprints: {

web/src/routes/collection/duplicates/+page.svelte

@@ -9,7 +9,8 @@
     createResolvedDuplicatesQuery,
     runDuplicateSweep,
     dismissDuplicateGroup,
-    mergeDuplicateGroup
+    mergeDuplicateGroup,
+    refetchDuplicateGroup
   } from '#lib/api/admin.js';
   import { errMessage } from '#lib/api/errors.js';
   import { pushToast } from '#lib/stores/toast.svelte.js';
@@ -38,6 +39,14 @@
   // song" and also undoes the link that made the copies one song (#5438). Merging (#3911) keeps one copy, moves the others'
   // likes, plays and playlist entries onto it, and deletes their files, so it
   // asks twice.
+  //
+  // Except for one recording filling several of an album's slots (class
+  // mismatch, #6184), where a merge is the wrong answer: it keeps one copy's
+  // title whether or not it is the audio's, and fetches nothing. There the
+  // operator says which song the recording is, or that they can't tell, and the
+  // group settles as the resolver would have: copies in other songs' slots are
+  // removed, the release they came from is set aside, and the album is fetched
+  // again. Operator, 2026-10-21: "for some of these I don't have any idea".
 
   type Tab = DuplicatesView | 'resolved';
   const fromUrl = page.url.searchParams.get('view');
@@ -53,6 +62,11 @@
   let keepChoice = $state<Record<string, string>>({});
   let confirmingMerge = $state<string | null>(null);
   let merging = $state<string | null>(null);
+  // Per wrong-slot group: the copy whose title the recording is, absent when
+  // the operator can't tell, and the same two-click confirm.
+  let slotPick = $state<Record<string, string>>({});
+  let confirmingRefetch = $state<string | null>(null);
+  let refetching = $state<string | null>(null);
 
   const queryStore = $derived(createDuplicatesQuery(groupView));
   const query = $derived($queryStore);
@@ -126,6 +140,51 @@
     }
   }
 
+  function wrongSlot(g: AdminDuplicateGroup): boolean {
+    return g.class === 'mismatch';
+  }
+
+  function pickedOf(g: AdminDuplicateGroup): AdminDuplicateMember | undefined {
+    return g.members.find((m) => m.track_id === slotPick[g.id]);
+  }
+
+  // Close to the server's MatchTitleKey: case, "&" and punctuation aside.
+  function songKey(title: string): string {
+    return title.toLowerCase().replace(/&/g, 'and').replace(/[^\p{L}\p{N}]/gu, '');
+  }
+
+  // The copies that go: every one when the operator can't tell, else those
+  // under another title. A copy under the picked title is the song held twice,
+  // and the next sweep merges it.
+  function refetchRemoves(g: AdminDuplicateGroup): AdminDuplicateMember[] {
+    const picked = pickedOf(g);
+    if (!picked) return g.members;
+    return g.members.filter((m) => songKey(m.title) !== songKey(picked.title));
+  }
+
+  async function onRefetch(group: AdminDuplicateGroup) {
+    if (confirmingRefetch !== group.id) {
+      confirmingRefetch = group.id;
+      return;
+    }
+    confirmingRefetch = null;
+    refetching = group.id;
+    try {
+      const result = await refetchDuplicateGroup(group.id, { keep_track_id: slotPick[group.id] ?? '' });
+      const removed = `Removed ${plural(result.removed_paths.length, 'file', 'files')}`;
+      pushToast(
+        result.blocked.length > 0
+          ? `${removed} and set aside the release they came from. The album will be fetched again.`
+          : `${removed}. The album will be fetched again, but Minstrel didn't download these files, so the same ones may come back.`
+      );
+      query.refetch();
+    } catch (e: unknown) {
+      pushToast(errMessage(e), 'error');
+    } finally {
+      refetching = null;
+    }
+  }
+
   // "Identical audio" and "same recording" are different claims, and an
   // operator deciding whether to merge needs to know which one they are
   // looking at before anything else.
@@ -377,27 +436,49 @@
               <button
                 type="button"
                 onclick={() => onDismiss(group)}
-                disabled={dismissing === group.id || merging === group.id}
+                disabled={dismissing === group.id || merging === group.id || refetching === group.id}
                 class="rounded-md border border-border px-3 py-1.5 text-sm text-text-secondary hover:bg-surface-hover hover:text-text-primary disabled:opacity-50"
               >
                 {tab === 'cross_release' ? 'Not the same song' : 'Not duplicates'}
               </button>
-              <button
-                type="button"
-                onclick={() => onMerge(group)}
-                disabled={merging === group.id}
-                class="rounded-md px-3 py-1.5 text-sm disabled:opacity-50 {confirmingMerge === group.id
-                  ? 'bg-action-destructive text-action-fg hover:opacity-90'
-                  : 'border border-border text-text-primary hover:bg-surface-hover'}"
-              >
-                {#if merging === group.id}
-                  Merging…
-                {:else if confirmingMerge === group.id}
-                  Remove {plural(group.members.length - 1, 'file', 'files')} and merge
-                {:else}
-                  Merge…
-                {/if}
-              </button>
+              {#if wrongSlot(group)}
+                {@const picked = pickedOf(group)}
+                <button
+                  type="button"
+                  onclick={() => onRefetch(group)}
+                  disabled={refetching === group.id}
+                  class="rounded-md px-3 py-1.5 text-sm disabled:opacity-50 {confirmingRefetch === group.id
+                    ? 'bg-action-destructive text-action-fg hover:opacity-90'
+                    : 'border border-border text-text-primary hover:bg-surface-hover'}"
+                >
+                  {#if refetching === group.id}
+                    Removing…
+                  {:else if confirmingRefetch === group.id}
+                    Remove {plural(refetchRemoves(group).length, 'file', 'files')} and get it again
+                  {:else if picked}
+                    Keep “{picked.title}”…
+                  {:else}
+                    Get it again…
+                  {/if}
+                </button>
+              {:else}
+                <button
+                  type="button"
+                  onclick={() => onMerge(group)}
+                  disabled={merging === group.id}
+                  class="rounded-md px-3 py-1.5 text-sm disabled:opacity-50 {confirmingMerge === group.id
+                    ? 'bg-action-destructive text-action-fg hover:opacity-90'
+                    : 'border border-border text-text-primary hover:bg-surface-hover'}"
+                >
+                  {#if merging === group.id}
+                    Merging…
+                  {:else if confirmingMerge === group.id}
+                    Remove {plural(group.members.length - 1, 'file', 'files')} and merge
+                  {:else}
+                    Merge…
+                  {/if}
+                </button>
+              {/if}
             </div>
           </div>
 
@@ -424,12 +505,40 @@
               <span>
                 {group.tier === 'exact' ? 'The audio is identical' : 'The music is the same'}, but the
                 copies are titled {quotedList(titles)}. If those name different recordings, one file is
-                mislabelled and the other recording isn't in your library. Play each and keep the copy
-                whose title matches what you hear.
+                mislabelled and the other recording isn't in your library.
+                {#if wrongSlot(group)}
+                  Play them. If you know which song this is, pick the copy with that title. If you can't
+                  tell, get the album again: every copy goes, and it's fetched from another release.
+                {:else}
+                  Play each and keep the copy whose title matches what you hear.
+                {/if}
               </span>
             </p>
           {/if}
 
+          {#if confirmingRefetch === group.id}
+            {@const picked = pickedOf(group)}
+            <div class="space-y-2 border-b border-border bg-surface-hover px-4 py-3 text-sm" data-testid="refetch-confirm">
+              <p class="text-text-primary">
+                {#if picked}
+                  The copy titled “{picked.title}” stays, and {plural(refetchRemoves(group).length, 'copy', 'copies')}
+                  under other titles will be deleted from disk.
+                {:else}
+                  All {plural(group.members.length, 'copy', 'copies')} will be deleted from disk.
+                {/if}
+                Their tracks stay, marked missing, with their likes and plays. The release the files came
+                from is set aside, and the album is fetched again from another one.
+              </p>
+              <button
+                type="button"
+                class="text-xs text-text-secondary underline hover:text-text-primary"
+                onclick={() => (confirmingRefetch = null)}
+              >
+                Cancel
+              </button>
+            </div>
+          {/if}
+
           {#if confirmingMerge === group.id}
             <!-- What the second click will do, said plainly before it is done. -->
             <div class="space-y-2 border-b border-border bg-surface-hover px-4 py-3 text-sm" data-testid="merge-confirm">
@@ -449,20 +558,38 @@
 
           <ul class="divide-y divide-border">
             {#each group.members as m (m.track_id)}
-              {@const keep = keeperOf(group) === m.track_id}
+              {@const keep = !wrongSlot(group) && keeperOf(group) === m.track_id}
               {@const proposed = m.track_id === group.survivor_track_id}
               <li class="flex items-start gap-3 px-4 py-3" data-testid="duplicate-member">
-                <input
-                  type="radio"
-                  name="keep-{group.id}"
-                  class="mt-1"
-                  checked={keeperOf(group) === m.track_id}
-                  onchange={() => (keepChoice[group.id] = m.track_id)}
-                  aria-label="Keep {m.title}, {m.file_format.toUpperCase()}, {m.file_path}"
-                />
+                {#if wrongSlot(group)}
+                  <!-- No copy is proposed: which song the recording is, is the
+                       question, and nothing here can answer it. -->
+                  <input
+                    type="radio"
+                    name="song-{group.id}"
+                    class="mt-1"
+                    checked={slotPick[group.id] === m.track_id}
+                    onchange={() => (slotPick[group.id] = m.track_id)}
+                    aria-label="This is {m.title}, {m.file_path}"
+                  />
+                {:else}
+                  <input
+                    type="radio"
+                    name="keep-{group.id}"
+                    class="mt-1"
+                    checked={keeperOf(group) === m.track_id}
+                    onchange={() => (keepChoice[group.id] = m.track_id)}
+                    aria-label="Keep {m.title}, {m.file_format.toUpperCase()}, {m.file_path}"
+                  />
+                {/if}
                 <div class="min-w-0 flex-1 space-y-0.5">
                   <div class="flex flex-wrap items-center gap-2">
                     <span class="truncate text-sm text-text-primary">{m.title}</span>
+                    {#if wrongSlot(group) && slotPick[group.id] === m.track_id}
+                      <span class="shrink-0 rounded-full bg-accent-tint px-2 py-0.5 text-xs text-accent-fg" data-testid="song-badge">
+                        The recording is this song
+                      </span>
+                    {/if}
                     {#if keep}
                       <!-- The copy the merge will keep: the proposed one with the
                            rule that chose it, or the one the operator picked. The
@@ -499,6 +626,15 @@
               </li>
             {/each}
           </ul>
+          {#if wrongSlot(group) && pickedOf(group)}
+            <button
+              type="button"
+              class="w-full border-t border-border px-4 py-2 text-left text-xs text-text-secondary underline hover:text-text-primary"
+              onclick={() => delete slotPick[group.id]}
+            >
+              I can't tell which song it is
+            </button>
+          {/if}
         </li>
       {/each}
     </ul>

web/src/routes/collection/duplicates/duplicates.test.ts

@@ -15,6 +15,11 @@ vi.mock('#lib/api/admin.js', () => ({
   mergeDuplicateGroup: vi.fn().mockResolvedValue({
     survivor_track_id: 'www-01',
     removed_paths: ['/music/Moe Shop/WWW (2020)/www-02.mp3']
+  }),
+  refetchDuplicateGroup: vi.fn().mockResolvedValue({
+    kept_track_id: null,
+    removed_paths: ['/music/Moe Shop/WWW (2020)/www-01.mp3', '/music/Moe Shop/WWW (2020)/www-02.mp3'],
+    blocked: ['Moe Shop - WWW [WEB]']
   })
 }));
 vi.mock('#lib/player/store.svelte.js', () => ({ playQueue: vi.fn() }));
@@ -26,6 +31,7 @@ import {
   createResolvedDuplicatesQuery,
   dismissDuplicateGroup,
   mergeDuplicateGroup,
+  refetchDuplicateGroup,
   runDuplicateSweep
 } from '#lib/api/admin.js';
 
@@ -256,7 +262,64 @@ describe('admin duplicates', () => {
       renderWith(r);
       const notice = text(screen.getByTestId('title-mismatch'));
       expect(notice).toContain('The music is the same, but the copies are titled “WWW” and “WWW (instrumental)”');
-      expect(notice).toContain('Play each');
+      expect(notice).toContain("If you can't tell, get the album again");
+    });
+  });
+
+  // One recording in several of an album's slots (#6184). A merge would keep
+  // one title whether or not it is the audio's and fetch nothing, so it is not
+  // offered: the operator says which song it is, or that they can't tell.
+  describe('one recording in several slots', () => {
+    function slots() {
+      const r = response();
+      r.groups[0] = {
+        ...r.groups[0],
+        tier: 'acoustic',
+        worst_bit_error_rate: 0.04,
+        class: 'mismatch',
+        members: [member('www-01'), member('www-02', { title: 'WWW (instrumental)' })]
+      };
+      return r;
+    }
+
+    test('offers Get it again instead of Merge, with no copy proposed', () => {
+      renderWith(slots());
+      expect(screen.queryByRole('button', { name: 'Merge…' })).toBeNull();
+      expect(screen.getByRole('button', { name: 'Get it again…' })).toBeTruthy();
+      expect(screen.getAllByRole('radio').some((r) => (r as HTMLInputElement).checked)).toBe(false);
+      expect(screen.queryByTestId('survivor-badge')).toBeNull();
+    });
+
+    test("can't tell: every copy goes, after a second click", async () => {
+      renderWith(slots());
+      await fireEvent.click(screen.getByRole('button', { name: 'Get it again…' }));
+      expect(refetchDuplicateGroup).not.toHaveBeenCalled();
+      const confirm = text(screen.getByTestId('refetch-confirm'));
+      expect(confirm).toContain('All 2 copies will be deleted from disk');
+      expect(confirm).toContain('the album is fetched again from another one');
+
+      await fireEvent.click(screen.getByRole('button', { name: 'Remove 2 files and get it again' }));
+      expect(refetchDuplicateGroup).toHaveBeenCalledWith('g-1', { keep_track_id: '' });
+    });
+
+    test('naming the song keeps that copy and removes the others', async () => {
+      renderWith(slots());
+      await fireEvent.click(screen.getByRole('radio', { name: /This is WWW \(instrumental\)/ }));
+      expect(screen.getByTestId('song-badge')).toBeTruthy();
+      await fireEvent.click(screen.getByRole('button', { name: 'Keep “WWW (instrumental)”…' }));
+      expect(text(screen.getByTestId('refetch-confirm'))).toContain(
+        'The copy titled “WWW (instrumental)” stays, and 1 copy under other titles will be deleted from disk'
+      );
+      await fireEvent.click(screen.getByRole('button', { name: 'Remove 1 file and get it again' }));
+      expect(refetchDuplicateGroup).toHaveBeenCalledWith('g-1', { keep_track_id: 'www-02' });
+    });
+
+    test("I can't tell takes the pick back", async () => {
+      renderWith(slots());
+      await fireEvent.click(screen.getAllByRole('radio')[0]);
+      await fireEvent.click(screen.getByRole('button', { name: "I can't tell which song it is" }));
+      expect(screen.getByRole('button', { name: 'Get it again…' })).toBeTruthy();
+      expect(screen.queryByTestId('song-badge')).toBeNull();
     });
   });