Refuse credentials in a storage URL's endpoint or rclone remote name (closes #322)

storage_url refused only the outer URL's userinfo and unknown query
parameters. Userinfo inside the s3 endpoint= value, and rclone's
remote,param=value parameters in the remote name, were accepted and
then printed by info, remote info and snapshot create. Both are now
refused without echoing the value: a host name never contains "@", and
an rclone remote name never contains a comma. An s3 or rclone query
that cannot be decoded (a ";" or a bad "%" escape) is refused too,
because decoding drops that part before it can be checked. The comma
is checked before url.Parse, whose error for such a name prints part of
it. The rclone remote name case has its own error pointing at rclone
config.

Model: opus-5-5

README.md

@@ -360,16 +360,20 @@ snapshot from the local index and strips the snapshot's metadata from
 the backup destination store. Blobs are NOT touched — deleting blobs
 requires reading every remaining remote manifest (the destination store
 may hold snapshots this host doesn't know about), which is what
-`vaultik prune` does. On success the command prints the exact `vaultik
-prune` invocation to run as a follow-up. An ID that names no snapshot in
-the local index or on the destination store is an error; with
-`--local-only`, the snapshot must be in the local index. Local row
+`vaultik prune` does. The command prints the `vaultik prune` invocation
+to run as a follow-up only when it removed the snapshot's metadata from
+the destination store, and never under `--json`. An ID that names no
+snapshot in the local index or on the destination store is an error;
+with `--local-only`, the snapshot must be in the local index. Local row
 cleanup (files, chunks, blobs the snapshot was the last referrer for)
-runs automatically. If the destination store is unreachable, the local-DB
-removal still completes and a warning is emitted; run `vaultik snapshot
-remove <snapshot-id>` again once the store is reachable to remove the
-snapshot's metadata from it (`vaultik prune` does not). To wipe everything
-on the destination in one go, use `vaultik remote nuke --force`.
+runs automatically. If removing the snapshot's metadata from the
+destination store fails (for example because the store is unreachable),
+the local-DB removal still completes and a warning is emitted; run
+`vaultik snapshot remove <snapshot-id>` again once the store is reachable
+to remove the snapshot's metadata from it (`vaultik prune` does not). For
+a snapshot that is only on the destination store, that failure is an
+error. To wipe everything on the destination in one go, use `vaultik
+remote nuke --force`.
 * `--local-only`: Skip remote cleanup; only touch the local index
 * `--dry-run`: Show what would be deleted without deleting
 * `--force`: Skip confirmation prompt

internal/cli/snapshot.go

@@ -270,8 +270,9 @@ By default, this removes the snapshot from the local index database and
 strips the snapshot's metadata from the backup destination store. Blobs
 are NOT touched: deleting them requires reading every remaining remote
 manifest (the destination store may hold snapshots this host doesn't
-know about), which is what 'vaultik prune' does. On success the command
-prints the exact 'vaultik prune' invocation to run as a follow-up.
+know about), which is what 'vaultik prune' does. The command prints the
+'vaultik prune' invocation to run as a follow-up only when it removed the
+snapshot's metadata from the destination store, and never under --json.
 
 An ID that names no snapshot in the local index or on the destination
 store is an error.
@@ -280,10 +281,12 @@ Use --local-only to skip the remote half (e.g. when you want to forget a
 snapshot locally without touching the destination store); the snapshot
 must then be in the local index.
 
-If the remote is unreachable, the local-database removal still completes
-and a warning is emitted; run 'vaultik snapshot remove <snapshot-id>' again
-once the destination store is reachable to remove the snapshot's metadata
-from it ('vaultik prune' does not).
+If removing the snapshot's metadata from the destination store fails (for
+example because the remote is unreachable), the local-database removal
+still completes and a warning is emitted; run 'vaultik snapshot remove
+<snapshot-id>' again once the destination store is reachable to remove
+the snapshot's metadata from it ('vaultik prune' does not). For a
+snapshot that is only on the destination store, that failure is an error.
 
 To wipe the entire destination store and start over, use 'vaultik remote
 nuke --force' — it is the single supported entry point for that.`,

internal/vaultik/blobcache.go

@@ -39,9 +39,9 @@ type blobDiskCacheEntry struct {
 // internally and will fall back to LRU eviction if curBytes exceeds
 // maxBytes. Restore passes math.MaxInt64 as maxBytes and drives
 // eviction itself via Delete() through restoreSweeper, which deletes
-// each blob the moment every file that references its chunks has been
-// written. LRU never fires under that configuration; it is kept as a
-// safety net for callers that don't manage eviction themselves.
+// each blob once no file still to be restored in this run needs it.
+// LRU never fires under that configuration; it is kept as a safety net
+// for callers that don't manage eviction themselves.
 //
 // Get/ReadAt/peak-Len counters are debugging instrumentation used by
 // tests to assert that the restore code path uses ReadAt rather than

internal/vaultik/prune_count_test.go

@@ -1,13 +1,17 @@
 package vaultik //nolint:testpackage // exercises unexported count helpers
 
 import (
+	"bytes"
 	"context"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/vaultik/internal/database"
 	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/snapshot"
+	"sneak.berlin/go/vaultik/internal/ui"
 )
 
 // TestTableCountForReportSurfacesReadFailure is the regression guard for
@@ -76,3 +80,59 @@ func TestCountDiffUnknownWhenEitherSideUnknown(t *testing.T) {
 	assert.Nil(t, countDiff(&before, nil), "unknown after yields unknown delta")
 	assert.Nil(t, countDiff(nil, nil))
 }
+
+// TestPruneDatabaseSummaryLabelsTotals removes the only incomplete
+// snapshot from an index that also holds a complete one. The figure in
+// brackets is every snapshot left in the local index, so the line must
+// say so rather than read as incomplete snapshots that remain.
+func TestPruneDatabaseSummaryLabelsTotals(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+
+	db, err := database.New(ctx, ":memory:")
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = db.Close() })
+
+	repos := database.NewRepositories(db)
+
+	startedAt := time.Date(2026, 1, 2, 3, 4, 5, 0, time.UTC)
+	completedAt := startedAt.Add(time.Minute)
+
+	require.NoError(t, repos.Snapshots.Create(ctx, nil, &database.Snapshot{
+		ID:          "host_complete_2026-01-02T03:04:05Z",
+		Hostname:    "host",
+		StartedAt:   startedAt,
+		CompletedAt: &completedAt,
+	}))
+	require.NoError(t, repos.Snapshots.Create(ctx, nil, &database.Snapshot{
+		ID:        "host_incomplete_2026-01-02T03:04:05Z",
+		Hostname:  "host",
+		StartedAt: startedAt,
+	}))
+
+	var out bytes.Buffer
+
+	v := &Vaultik{
+		DB:           db,
+		Repositories: repos,
+		SnapshotManager: snapshot.NewSnapshotManager(
+			snapshot.SnapshotManagerParams{Repos: repos}),
+		UI: ui.NewWithColor(&out, false),
+	}
+	v.SetContext(ctx)
+
+	result, err := v.PruneDatabase()
+	require.NoError(t, err)
+	require.Equal(t, int64(1), result.SnapshotsDeleted)
+
+	assert.Contains(t, out.String(), "Incomplete snapshots: 1 removed "+
+		"(total snapshots left in the local index: 1).")
+	assert.Contains(t, out.String(), "Orphaned files: 0 removed "+
+		"(total files left in the local index: 0).")
+	assert.Contains(t, out.String(), "Orphaned chunks: 0 removed "+
+		"(total chunks left in the local index: 0).")
+	assert.Contains(t, out.String(), "Orphaned blobs: 0 removed "+
+		"(total blobs left in the local index: 0).")
+}

internal/vaultik/remove_snapshot_test.go

@@ -17,6 +17,7 @@ import (
 	"sneak.berlin/go/vaultik/internal/log"
 	"sneak.berlin/go/vaultik/internal/snapshot"
 	"sneak.berlin/go/vaultik/internal/storage"
+	"sneak.berlin/go/vaultik/internal/storage/faultstore"
 	"sneak.berlin/go/vaultik/internal/types"
 	"sneak.berlin/go/vaultik/internal/vaultik"
 )
@@ -431,6 +432,40 @@ func TestRemoveSnapshot_NotInLocalIndex(t *testing.T) {
 	assert.Contains(t, out, "Removed snapshot metadata from remote storage")
 }
 
+// TestRemoveSnapshot_NotInLocalIndexDeleteFails checks that removing a
+// snapshot only the destination store holds fails when its metadata
+// cannot be deleted there, under --force and under --json: nothing was
+// removed, so the command must not succeed.
+func TestRemoveSnapshot_NotInLocalIndexDeleteFails(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	for name, opts := range map[string]vaultik.RemoveOptions{
+		"force": {Force: true},
+		"json":  {JSON: true},
+	} {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			store := newTestStorer()
+			addManifest(t, store, "snapshot-001", nil)
+
+			faulty := faultstore.New(store)
+			faulty.OnDelete = func(string) bool { return true }
+
+			tv := vaultik.NewForTesting(faulty)
+			tv.Repositories = newLocalIndex(t)
+
+			result, err := tv.RemoveSnapshot("snapshot-001", &opts)
+
+			require.ErrorIs(t, err, faultstore.ErrInjectedDelete)
+			assert.False(t, result.RemoteRemoved)
+			assert.True(t, store.hasKey(remoteKeyPath("snapshot-001")))
+			assert.Empty(t, tv.Stdout.String())
+		})
+	}
+}
+
 func TestRemoveAllSnapshots_RequiresForce(t *testing.T) {
 	log.Initialize(log.Config{})
 	t.Parallel()

internal/vaultik/restore.go

@@ -323,12 +323,6 @@ func (v *Vaultik) restoreAllFiles(
 		_ = blobCache.Close()
 	}()
 
-	// Per-restore sweep state: every blob_size_limit/100 bytes written,
-	// scan the cache and delete any blob whose remaining file references
-	// are all already restored.
-	sweeper := newRestoreSweeper(v.ctx, repos, blobCache,
-		v.Config.BlobSizeLimit.Int64()/sweepIntervalDivisor)
-
 	blobByHash, blobIDToHash, err := v.buildBlobIndexes(repos)
 	if err != nil {
 		return nil, err
@@ -340,6 +334,12 @@ func (v *Vaultik) restoreAllFiles(
 		return nil, fmt.Errorf("building restore plan: %w", err)
 	}
 
+	// Per-restore sweep state: every blob_size_limit/100 bytes written,
+	// scan the cache and delete any blob that no pending file in the
+	// plan references.
+	sweeper := newRestoreSweeper(plan, blobCache,
+		v.Config.BlobSizeLimit.Int64()/sweepIntervalDivisor)
+
 	// Ranging over files rather than the map reports them in a stable order.
 	for _, file := range files {
 		if planErr, ok := unplanned[file.ID]; ok {
@@ -427,10 +427,8 @@ func (v *Vaultik) runRestoreLoop(
 			continue
 		}
 
-		// Record the file as restored so the sweeper can free blobs
-		// once all referencing files are done, and drop it from the
-		// plan's indexes so future picks ignore it.
-		session.sweeper.fileRestored(fileID.String())
+		// Drop the file from the plan's indexes so future picks ignore
+		// it and the sweeper can free blobs no pending file needs.
 		plan.finishFile(fileID)
 
 		processed++

internal/vaultik/restore_interrupt_test.go

@@ -74,7 +74,8 @@ func TestRestoreCleansTempDirOnInterrupt(t *testing.T) {
 	buildLocalityFixture(t, fs, dataDir)
 
 	cfg, storer, snapshotID := setupLocalityBackup(
-		context.Background(), t, fs, dataDir, storeDir, dbPath)
+		context.Background(), t, fs, dataDir, storeDir, dbPath,
+		localitySourceBytes)
 
 	// Point the "" temp paths (the blob cache directory and the
 	// snapshot-database directory) at a private directory so the test can

internal/vaultik/restore_locality_test.go

@@ -63,6 +63,10 @@ type localityCopy struct {
 	data []byte
 }
 
+// localitySourceBytes is the size of each source file of the locality
+// fixture.
+const localitySourceBytes = 1024 * 1024
+
 // buildLocalityFixture writes the adversarial source layout described
 // in TestRestoreLocalityAndReadAt: 15 sources of 1 MiB each (which the
 // backup packs into 3 blobs of 5 chunks) plus 9 interleaved-name copies
@@ -73,7 +77,6 @@ func buildLocalityFixture(
 	t.Helper()
 
 	const (
-		srcBytes   = 1024 * 1024
 		srcCount   = 15
 		blobsCount = 3
 		perBlob    = srcCount / blobsCount
@@ -83,7 +86,7 @@ func buildLocalityFixture(
 	for i := range srcCount {
 		s := &localitySource{
 			path: fmt.Sprintf("src-%03d.bin", i+1),
-			data: randomBytes(t, srcBytes),
+			data: randomBytes(t, localitySourceBytes),
 		}
 		sources[i] = s
 		require.NoError(t, afero.WriteFile(
@@ -115,19 +118,20 @@ func buildLocalityFixture(
 
 // setupLocalityBackup runs the backup half of the locality test: a
 // snapshot of dataDir into a file storer with sizes tuned so 15 one-chunk
-// files pack into 3 blobs. The index database is closed before returning
-// so the restore half runs from remote bytes only.
+// files of srcBytes pack into 3 blobs. The index database is closed
+// before returning so the restore half runs from remote bytes only.
 func setupLocalityBackup(
 	ctx context.Context, t *testing.T, fs afero.Fs,
-	dataDir, storeDir, dbPath string,
+	dataDir, storeDir, dbPath string, srcBytes int64,
 ) (*config.Config, *storage.FileStorer, string) {
 	t.Helper()
 
-	// chunkSize avg = 4 MiB makes minSize = 1 MiB, so a 1 MiB file
-	// becomes one chunk. maxBlobSize = 5 MiB packs exactly 5 chunks
-	// per blob, yielding 3 blobs from 15 source files.
-	chunkSize := int64(4 * 1024 * 1024)
-	maxBlobSize := int64(5 * 1024 * 1024)
+	// An average chunk size of four times srcBytes makes the minimum
+	// chunk srcBytes, so each source file becomes one chunk. A blob limit
+	// of five times srcBytes packs exactly 5 chunks per blob, yielding 3
+	// blobs from 15 source files.
+	chunkSize := 4 * srcBytes
+	maxBlobSize := 5 * srcBytes
 
 	storer, err := storage.NewFileStorer(storeDir)
 	require.NoError(t, err)
@@ -208,7 +212,7 @@ func TestRestoreLocalityAndReadAt(t *testing.T) {
 	ctx := context.Background()
 
 	cfg, storer, snapshotID := setupLocalityBackup(
-		ctx, t, fs, dataDir, storeDir, dbPath)
+		ctx, t, fs, dataDir, storeDir, dbPath, localitySourceBytes)
 
 	// Wrap the storer so we can count downloads per blob key.
 	counter := newCountingStorer(storer)

internal/vaultik/restore_plan.go

@@ -31,7 +31,8 @@ var (
 //     with no further downloads.
 //   - blobFiles: for each blob, the set of pending files referencing
 //     it. Used to short-circuit "when this blob lands, which files
-//     become ready" without a global scan.
+//     become ready" without a global scan, and by the sweeper to tell
+//     whether a cached blob is still needed.
 type restorePlan struct {
 	fileBlobs map[types.FileID]map[string]struct{}
 	blobFiles map[string]map[types.FileID]struct{}
@@ -237,6 +238,12 @@ func (p *restorePlan) filesReferencingBlob(blobHash string) []types.FileID {
 	return out
 }
 
+// pendingFileUsesBlob reports whether any pending file references the
+// named blob, whether or not the blob is cached.
+func (p *restorePlan) pendingFileUsesBlob(blobHash string) bool {
+	return len(p.blobFiles[blobHash]) > 0
+}
+
 // hasPending reports whether any unfinished files remain.
 func (p *restorePlan) hasPending() bool {
 	return len(p.fileBlobs) > 0

internal/vaultik/restore_plan_test.go

@@ -63,15 +63,6 @@ func TestRunRestoreLoopFailsOnAbandonedFiles(t *testing.T) {
 
 	t.Cleanup(func() { _ = cache.Close() })
 
-	v := &Vaultik{ctx: ctx}
-	session := &restoreSession{
-		v:       v,
-		ctx:     ctx,
-		repos:   repos,
-		sweeper: newRestoreSweeper(ctx, repos, cache, 1),
-		result:  &RestoreResult{},
-	}
-
 	// A file that is still pending but whose uncached-blob set is empty
 	// and which was never queued as ready: the loop can neither restore
 	// nor download it. This is the abandonment the guard must catch.
@@ -83,6 +74,15 @@ func TestRunRestoreLoopFailsOnAbandonedFiles(t *testing.T) {
 		cached:    map[string]struct{}{},
 	}
 
+	v := &Vaultik{ctx: ctx}
+	session := &restoreSession{
+		v:       v,
+		ctx:     ctx,
+		repos:   repos,
+		sweeper: newRestoreSweeper(plan, cache, 1),
+		result:  &RestoreResult{},
+	}
+
 	err = v.runRestoreLoop(session, plan, map[types.FileID]*database.File{}, 0)
 	require.ErrorIs(t, err, errRestoreIncomplete)
 }

internal/vaultik/restore_sweeper.go

@@ -1,46 +1,30 @@
 package vaultik
 
-import (
-	"context"
-	"fmt"
-
-	"sneak.berlin/go/vaultik/internal/database"
-	"sneak.berlin/go/vaultik/internal/log"
-)
-
-// restoreSweeper frees cached blobs once all files that reference any of
-// their chunks have been restored. It works as follows:
+// restoreSweeper frees cached blobs once no file still to be restored in
+// this run needs them. It works as follows:
 //
-//  1. Callers add a file's ID to an in-memory restored set via
-//     fileRestored once the file is fully written to disk.
-//  2. After each chunk is restored, chunkRestored accumulates a running
+//  1. After each chunk is restored, chunkRestored accumulates a running
 //     byte count.
-//  3. When the accumulator crosses a threshold (one hundredth of the
+//  2. When the accumulator crosses a threshold (one hundredth of the
 //     configured blob size — so a sweep runs about a hundred times per
 //     blob's worth of restored bytes), the sweeper iterates every key in
-//     the cache. For each cached blob it asks the DB which files
-//     reference any chunk in that blob, then compares that list against
-//     the in-memory restored set. If any referencing file is missing
-//     from the set the blob is kept; otherwise the cache entry is
-//     deleted.
+//     the cache and deletes each blob that the restore plan no longer
+//     needs.
 //
-// All DB reads happen against the snapshot's temporary metadata DB,
-// which is local, indexed, and not under contention — the queries are
-// cheap and run at most once per blob per sweep interval.
+// The plan drops a file once it is restored or has failed, and holds
+// only the files this run restores, so files outside the requested paths
+// never keep a blob.
 type restoreSweeper struct {
-	ctx        context.Context //nolint:containedctx // ctx bound at construction by design
-	repos      *database.Repositories
+	plan       *restorePlan
 	cache      *blobDiskCache
 	threshold  int64
 	bytesAccum int64
-	restored   map[string]struct{}
 }
 
 // newRestoreSweeper returns a sweeper that triggers eviction every
 // `threshold` bytes restored. Callers should pass blob_size_limit/100.
 func newRestoreSweeper(
-	ctx context.Context,
-	repos *database.Repositories,
+	plan *restorePlan,
 	cache *blobDiskCache,
 	threshold int64,
 ) *restoreSweeper {
@@ -49,21 +33,12 @@ func newRestoreSweeper(
 	}
 
 	return &restoreSweeper{
-		ctx:       ctx,
-		repos:     repos,
+		plan:      plan,
 		cache:     cache,
 		threshold: threshold,
-		restored:  make(map[string]struct{}),
 	}
 }
 
-// fileRestored records a file as fully restored. After this call, any
-// blob whose only remaining references come from files in the restored
-// set may be evicted on the next sweep.
-func (s *restoreSweeper) fileRestored(fileID string) {
-	s.restored[fileID] = struct{}{}
-}
-
 // chunkRestored accounts n bytes against the sweep threshold and runs a
 // sweep if the threshold has been crossed since the last sweep.
 func (s *restoreSweeper) chunkRestored(n int64) {
@@ -76,60 +51,11 @@ func (s *restoreSweeper) chunkRestored(n int64) {
 	s.sweep()
 }
 
-// sweep deletes any cached blob whose chunks are no longer referenced
-// by an unrestored file. Per-blob DB failures are logged and the blob
-// is kept — we'd rather hold a blob longer than risk a re-download.
+// sweep deletes every cached blob that no pending file references.
 func (s *restoreSweeper) sweep() {
 	for _, blobHash := range s.cache.Keys() {
-		needed, err := s.blobStillNeeded(blobHash)
-		if err != nil {
-			log.Debug("sweeper referencing-files query failed",
-				"blob_hash", blobHash[:16], "error", err)
-
-			continue
-		}
-
-		if !needed {
+		if !s.plan.pendingFileUsesBlob(blobHash) {
 			s.cache.Delete(blobHash)
 		}
 	}
 }
-
-// blobStillNeeded returns true if any file that references a chunk in
-// this blob has not yet been restored. On any error the function
-// returns true — keeping the blob is always the safe answer because we
-// can't prove we're done with it.
-func (s *restoreSweeper) blobStillNeeded(blobHash string) (bool, error) {
-	rows, err := s.repos.DB().Conn().QueryContext(s.ctx, `
-		SELECT DISTINCT fc.file_id
-		FROM file_chunks fc
-		JOIN blob_chunks bc ON bc.chunk_hash = fc.chunk_hash
-		JOIN blobs b ON b.id = bc.blob_id
-		WHERE b.blob_hash = ?
-	`, blobHash)
-	if err != nil {
-		return true, fmt.Errorf("querying referencing files: %w", err)
-	}
-
-	defer func() { _ = rows.Close() }()
-
-	for rows.Next() {
-		var fileID string
-
-		err := rows.Scan(&fileID)
-		if err != nil {
-			return true, fmt.Errorf("scanning file_id: %w", err)
-		}
-
-		if _, ok := s.restored[fileID]; !ok {
-			return true, nil
-		}
-	}
-
-	err = rows.Err()
-	if err != nil {
-		return true, err
-	}
-
-	return false, nil
-}

internal/vaultik/restore_sweeper_test.go

@@ -0,0 +1,163 @@
+package vaultik //nolint:testpackage // reads the restore blob cache's peak size
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/config"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/storage"
+	"sneak.berlin/go/vaultik/internal/ui"
+)
+
+// TestRestoreFreesBlobsNoPendingFileNeeds asserts that the restore cache
+// frees a blob once no file still to be restored in this run needs it.
+// Every original file has a copy with the same content, so every blob
+// holds chunks of copies: a restore that leaves the copies out of its
+// paths, or fails on them, must not keep the blobs for them.
+func TestRestoreFreesBlobsNoPendingFileNeeds(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	// Small files keep the backup and both restores quick.
+	const fileBytes = 16 * 1024
+
+	fs := afero.NewOsFs()
+	tempDir := t.TempDir()
+
+	dataDir := filepath.Join(tempDir, "source")
+	originalsDir := filepath.Join(dataDir, "originals")
+	copiesDir := filepath.Join(dataDir, "copies")
+	storeDir := filepath.Join(tempDir, "remote")
+	dbPath := filepath.Join(tempDir, "index.sqlite")
+
+	originals := writeFilesWithCopies(t, fs, originalsDir, copiesDir, fileBytes)
+
+	ctx := context.Background()
+
+	cfg, storer, snapshotID := setupLocalityBackup(
+		ctx, t, fs, dataDir, storeDir, dbPath, fileBytes)
+
+	t.Run("restore by path", func(t *testing.T) {
+		t.Parallel()
+
+		restoreDir := filepath.Join(tempDir, "by-path")
+
+		peak, err := restorePeakCachedBlobs(ctx, t, fs, cfg, storer,
+			&RestoreOptions{
+				SnapshotID: snapshotID,
+				TargetDir:  restoreDir,
+				Paths:      []string{originalsDir},
+			})
+		require.NoError(t, err)
+
+		requireRestoredFiles(t, fs, restoreDir, originals)
+		assert.LessOrEqualf(t, peak, 1,
+			"peak cached blobs was %d; blobs were kept for unselected files",
+			peak)
+	})
+
+	t.Run("restore with failed files", func(t *testing.T) {
+		t.Parallel()
+
+		restoreDir := filepath.Join(tempDir, "with-failures")
+
+		// A regular file where the copies directory belongs makes every
+		// copy fail to restore.
+		blocker := filepath.Join(restoreDir, copiesDir)
+		require.NoError(t, fs.MkdirAll(filepath.Dir(blocker), 0o755))
+		require.NoError(t, afero.WriteFile(fs, blocker, nil, 0o644))
+
+		peak, err := restorePeakCachedBlobs(ctx, t, fs, cfg, storer,
+			&RestoreOptions{
+				SnapshotID: snapshotID,
+				TargetDir:  restoreDir,
+				SkipErrors: true,
+			})
+		require.ErrorIs(t, err, errFilesFailedRestore)
+
+		requireRestoredFiles(t, fs, restoreDir, originals)
+		assert.LessOrEqualf(t, peak, 1,
+			"peak cached blobs was %d; blobs were kept for failed files", peak)
+	})
+}
+
+// writeFilesWithCopies writes 15 random files of fileBytes into
+// originalsDir and a copy of each into copiesDir. With
+// setupLocalityBackup given the same size, each file is one chunk and the
+// 15 chunks fill 3 blobs. Returns the originals' content by path.
+func writeFilesWithCopies(
+	t *testing.T, fs afero.Fs, originalsDir, copiesDir string, fileBytes int,
+) map[string][]byte {
+	t.Helper()
+
+	const fileCount = 15
+
+	require.NoError(t, fs.MkdirAll(originalsDir, 0o755))
+	require.NoError(t, fs.MkdirAll(copiesDir, 0o755))
+
+	originals := make(map[string][]byte, fileCount)
+
+	for i := range fileCount {
+		name := fmt.Sprintf("file-%02d.bin", i)
+		data := randomBytes(t, fileBytes)
+		original := filepath.Join(originalsDir, name)
+		originals[original] = data
+
+		require.NoError(t, afero.WriteFile(fs, original, data, 0o644))
+		require.NoError(t, afero.WriteFile(
+			fs, filepath.Join(copiesDir, name), data, 0o644))
+	}
+
+	return originals
+}
+
+// requireRestoredFiles requires every file in want to have been restored
+// under restoreDir with its content intact.
+func requireRestoredFiles(
+	t *testing.T, fs afero.Fs, restoreDir string, want map[string][]byte,
+) {
+	t.Helper()
+
+	for path, data := range want {
+		got, err := afero.ReadFile(fs, filepath.Join(restoreDir, path))
+		require.NoErrorf(t, err, "file missing after restore: %s", path)
+		require.Equalf(t, data, got, "byte mismatch for %s", path)
+	}
+}
+
+// restorePeakCachedBlobs runs a restore and returns the most blobs its
+// cache held at once, together with the restore's error.
+func restorePeakCachedBlobs(
+	ctx context.Context, t *testing.T, fs afero.Fs,
+	cfg *config.Config, storer storage.Storer, opts *RestoreOptions,
+) (int, error) {
+	t.Helper()
+
+	var cache *blobDiskCache
+
+	v := &Vaultik{
+		Config:  cfg,
+		Storage: storer,
+		Fs:      fs,
+		Stdout:  io.Discard,
+		Stderr:  io.Discard,
+		UI:      ui.NewWithColor(io.Discard, false),
+		restoreCacheObserver: func(c *blobDiskCache) {
+			cache = c
+		},
+	}
+	v.SetContext(ctx)
+
+	err := v.Restore(opts)
+
+	require.NotNil(t, cache, "restoreCacheObserver must fire during restore")
+
+	return cache.PeakLen(), err
+}

internal/vaultik/snapshot.go

@@ -1228,9 +1228,11 @@ const snapshotRemoveCommandHint = "vaultik snapshot remove"
 // destination store. Blobs are NOT touched: removing a snapshot's
 // blobs requires reading every remaining remote manifest (the remote
 // may hold snapshots this host doesn't know about), which is what
-// `vaultik prune` is for — the command prints the prune invocation to
-// run as a follow-up. When the remote is unreachable the command still
-// completes the local-DB removal and warns.
+// `vaultik prune` is for — when metadata was removed from the
+// destination store, the text output names the prune invocation to run
+// as a follow-up. When removing the metadata fails, a snapshot in the
+// local index is still removed from it, with a warning; a snapshot
+// only on the destination store is an error.
 func (v *Vaultik) RemoveSnapshot(
 	snapshotID string, opts *RemoveOptions,
 ) (*RemoveResult, error) {
@@ -1265,8 +1267,10 @@ func (v *Vaultik) RemoveSnapshot(
 		}
 	}
 
-	if !opts.LocalOnly {
-		result.RemoteRemoved = v.removeSnapshotRemote(snapshotID, opts)
+	result.RemoteRemoved, err = v.removeSnapshotRemote(
+		snapshotID, inLocalIndex, opts)
+	if err != nil {
+		return result, err
 	}
 
 	if v.SnapshotManager != nil {
@@ -1391,19 +1395,33 @@ func (v *Vaultik) confirmRemoveSnapshot(snapshotID string, opts *RemoveOptions)
 }
 
 // removeSnapshotRemote strips the snapshot's metadata from the
-// destination store, warning and proceeding on failure: the local-DB
-// removal has already happened, so the user is told the remote half
-// didn't finish and to run `vaultik snapshot remove` for the snapshot
-// again once the destination store is reachable (`vaultik prune` never
-// removes snapshot metadata). Returns true when the remote removal
-// succeeded and deleted something.
-func (v *Vaultik) removeSnapshotRemote(snapshotID string, opts *RemoveOptions) bool {
+// destination store. It returns true only when the delete finished
+// without an error and removed at least one object; under LocalOnly it
+// does nothing. When the snapshot is only on the destination store, a
+// failure is returned as an error, because that removal is all the
+// command does. When the snapshot was in the local index, its removal
+// there has already happened, so a failure is only a warning telling the
+// user to run `vaultik snapshot remove` for the snapshot again once the
+// destination store is reachable (`vaultik prune` never removes snapshot
+// metadata).
+func (v *Vaultik) removeSnapshotRemote(
+	snapshotID string, inLocalIndex bool, opts *RemoveOptions,
+) (bool, error) {
+	if opts.LocalOnly {
+		return false, nil
+	}
+
 	log.Info("Removing snapshot metadata from remote storage",
 		"snapshot_id", snapshotID)
 
 	remoteKey := snapshot.RemoteSnapshotKey(snapshotID)
 
 	deleted, err := v.deleteRemoteSnapshotByKey(remoteKey)
+	if err != nil && !inLocalIndex {
+		return false, fmt.Errorf(
+			"removing snapshot metadata from destination store: %w", err)
+	}
+
 	if err != nil {
 		log.Warn("Could not remove snapshot metadata from remote storage; "+
 			"run '"+snapshotRemoveCommandHint+"' with the snapshot's ID "+
@@ -1418,10 +1436,10 @@ func (v *Vaultik) removeSnapshotRemote(snapshotID string, opts *RemoveOptions) b
 				err, snapshotRemoveCommandHint, snapshotID)
 		}
 
-		return false
+		return false, nil
 	}
 
-	return deleted > 0
+	return deleted > 0, nil
 }
 
 // RemoveAllSnapshots removes every snapshot known to the local
@@ -1902,13 +1920,17 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	snapshotsRemain := countDiff(snapshotCountBefore, &result.SnapshotsDeleted)
 
 	v.UI.Completef("Pruned local index database.")
-	v.UI.Detailf("Incomplete snapshots: %s removed (%s remain).",
+	v.UI.Detailf("Incomplete snapshots: %s removed "+
+		"(total snapshots left in the local index: %s).",
 		countText(&result.SnapshotsDeleted), countText(snapshotsRemain))
-	v.UI.Detailf("Orphaned files: %s removed (%s remain).",
+	v.UI.Detailf("Orphaned files: %s removed "+
+		"(total files left in the local index: %s).",
 		countText(result.FilesDeleted), countText(fileCountAfter))
-	v.UI.Detailf("Orphaned chunks: %s removed (%s remain).",
+	v.UI.Detailf("Orphaned chunks: %s removed "+
+		"(total chunks left in the local index: %s).",
 		countText(result.ChunksDeleted), countText(chunkCountAfter))
-	v.UI.Detailf("Orphaned blobs: %s removed (%s remain).",
+	v.UI.Detailf("Orphaned blobs: %s removed "+
+		"(total blobs left in the local index: %s).",
 		countText(result.BlobsDeleted), countText(blobCountAfter))
 
 	return result, nil