Refuse a backup destination an unplugged volume left empty (closes #239 )

Every backup now writes vaultik-destination.txt at the root of the backup destination store. While the local index holds snapshots, a destination without it is not present: snapshot create refuses before writing, prune and snapshot purge fail, and snapshot list and snapshot remove warn, as for a destination that cannot be listed. remote nuke deletes the marker last. The file:// backend no longer creates its destination directory and checks for it on every write. Tests now back up into existing directories, and fixtures standing for a written destination carry the marker. Judgement call: the marker is rewritten on every backup. Deviation: for the complexity limit, snapshot name selection left CreateSnapshot and the --force/--json test moved into confirmRemoveSnapshot, both unchanged. Model: opus-5-5
Make snapshot remove fail for an unknown snapshot ID (closes #293 )
2026-10-13 04:27:54 +00:00 · 2026-10-13 05:55:22 +02:00 · 2026-10-13 03:48:36 +02:00 · 2026-10-13 01:51:24 +02:00 · 2026-10-08 15:12:07 +02:00 · 2026-10-08 14:17:20 +02:00
43 changed files with 1134 additions and 177 deletions
@@ -311,6 +311,8 @@ Repository interfaces:

 ```
 CreateSnapshot(opts)
+    │
+    ├─► markDestination()   // Refuse a destination without the marker, then write it
    │
    ├─► PruneDatabase()   // Critical: avoid dedup errors
    │
@@ -367,6 +369,8 @@ CreateSnapshot(opts)

 ```
 bucket/
+├── vaultik-destination.txt          # Marker written by every backup
+│
 ├── blobs/
 │   └── {hash[0:2]}/
 │       └── {hash[2:4]}/
@@ -378,6 +382,15 @@ bucket/
        └── manifest.json.zst        # Blob list (for pruning/verification)
 ```

+While the local index holds snapshots, a destination without
+`vaultik-destination.txt` is treated as not present
+(`checkDestinationMarker` in `internal/vaultik/destination_marker.go`):
+`snapshot create` refuses to write to it, and listing it fails as for a
+destination that cannot be listed. An unplugged volume's empty mount point
+is therefore never taken for a destination whose snapshots are all gone.
+The `file://` backend never creates its destination directory, so a write
+to a missing one fails.
+
 The `{remote-key}` directory name is a one-way double SHA-256 hash of the human
 snapshot ID, so the human ID (hostname, snapshot name, timestamp) is never
 written to the store as a directory name. See
@@ -24,6 +24,10 @@ grep 'public key' vaultik_backup_private_key.txt
 vaultik config set age_recipients.0 age1YOUR_PUBLIC_KEY_HERE
 vaultik config set storage_url "file:///Volumes/usbstick/mybackup"

+# create the destination directory; vaultik never creates it, so a backup
+# to a volume that is not plugged in fails instead of filling the disk
+mkdir /Volumes/usbstick/mybackup
+
 # macOS only: grant your terminal app Full Disk Access first
 # (System Settings → Privacy & Security → Full Disk Access), otherwise
 # the backup will abort with a permission error on protected directories
@@ -287,6 +291,10 @@ needed.
  snapshot per name; use `--keep-newer-than` for a rolling window.
 * `--keep-newer-than <duration>`: With `--prune`, keep snapshots newer than
  this duration instead of only the latest (e.g. `4w`, `30d`, `6mo`, `1y`)
+* Fails before it writes anything when a `file://` destination directory
+  does not exist, or when the local index holds snapshots and the
+  destination has no `vaultik-destination.txt` (see
+  [remote storage layout](#remote-storage-layout))

 **`snapshot list`**: Show every snapshot known to this host — the union
 of the local index and the backup destination store — with timestamps
@@ -315,7 +323,10 @@ invocation that reconciles them.

 If the destination store cannot be listed (unmounted volume,
 permission denied, network down), the command warns, falls back to the
-local index alone, and still exits zero.
+local index alone, and still exits zero. It does the same when the
+local index holds snapshots and the destination has no
+`vaultik-destination.txt`, as when a volume mounted at the destination
+is unplugged and leaves its empty mount point behind.
 * `--json`: Output in JSON format. Each entry carries `locally_tracked`
  (whether the snapshot is in the local index), `remote_key` (the full
  64-character storage key), and `remote_present` (whether it was seen
@@ -349,13 +360,17 @@ 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. 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`.
+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
+cleanup (files, chunks, blobs the snapshot was the last referrer for)
+runs automatically. If the destination store is unreachable, or the
+local index holds snapshots and the destination has no
+`vaultik-destination.txt`, 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`.
 * `--local-only`: Skip remote cleanup; only touch the local index
 * `--dry-run`: Show what would be deleted without deleting
 * `--force`: Skip confirmation prompt
@@ -382,7 +397,10 @@ manifest on the destination store to compute the still-referenced blob
 set and delete any blob not in that set. Step (3) reads all remote
 manifests — network cost scales with the number of snapshots. `snapshot
 create --prune` runs the same cleanup automatically; this is the
-manual entry point for the same work.
+manual entry point for the same work. If the destination store cannot
+be listed, or the local index holds snapshots and the destination has
+no `vaultik-destination.txt` (an unplugged volume's empty mount point),
+prune fails and deletes nothing. `snapshot purge` does the same.
 * `--force`: Skip confirmation prompt
 * `--json`: Output stats as JSON. Also skips the confirmation prompt, as
  `--force` does.
@@ -402,17 +420,18 @@ orphaned blob figures are reported as unknown; `--json` gives them as
 snapshot's blob count and blob size unknown, `null` in `--json`.
 * `--json`: Output as JSON

-**`remote nuke`**: Delete every snapshot's metadata and every blob from the
-backup destination store, leaving the bucket prefix empty. Destructive and
-irreversible. This is the single supported way to wipe the entire
-destination store.
+**`remote nuke`**: Delete every snapshot's metadata, every blob and
+`vaultik-destination.txt` from the backup destination store, leaving the
+bucket prefix empty. Destructive and irreversible. This is the single
+supported way to wipe the entire destination store.
 * `--force`: Required to confirm destruction.

 **`database delete`**: Delete the local SQLite state database file
 entirely. Remote storage is unaffected; the next backup will do a full
 scan and re-deduplicate against existing remote blobs, and the local
 index will re-bind to the currently configured storage destination.
-Use this after changing `storage_url` to a different destination.
+Use this after changing `storage_url`, or `s3.endpoint`, `s3.bucket` or
+`s3.prefix`, to a different destination.
 * `--force`: Skip confirmation prompt

 ---
@@ -426,7 +445,10 @@ object store. Credentials are read from `s3.access_key_id` and
 `s3.secret_access_key` in the config file.

 **Local filesystem** (`file:///path/to/backup`): Stores blobs and metadata on
-a local or mounted filesystem. Useful for testing or backing up to a NAS.
+a local or mounted filesystem. Useful for testing or backing up to a NAS. The
+directory must exist before the first backup: vaultik never creates it, so a
+backup to a volume that is not mounted fails instead of writing to the disk
+under its mount point.

 **Rclone** (`rclone://remote/path`): Uses rclone's 70+ supported cloud
 providers. Requires rclone to be configured separately (`rclone config`).
@@ -457,6 +479,7 @@ For an implementation-level view of the internals — the data model, the

 ```
 <bucket>/<prefix>/
+├── vaultik-destination.txt     # Marker written by every backup
 ├── blobs/
 │   └── <aa>/<bb>/<full_blob_hash>
 └── metadata/
@@ -465,6 +488,15 @@ For an implementation-level view of the internals — the data model, the
        └── manifest.json.zst   # Unencrypted blob list (for pruning)
 ```

+* `vaultik-destination.txt` holds one fixed line of text, with no host
+  name, path or time. While the local index holds snapshots, a
+  destination without it is treated as not present: `snapshot create`
+  refuses to write to it, `prune` and `snapshot purge` fail, and
+  `snapshot list` and `snapshot remove` warn, as for a destination that
+  cannot be listed. This keeps an unplugged volume's empty mount point
+  from being taken for a destination whose snapshots are all gone. Mount
+  the volume if it is removable; if the destination was emptied on
+  purpose, run `vaultik database delete` and back up again.
 * Blobs are two-level directory sharded using the first 4 hex chars of the blob hash
 * `db.zst.age` is a binary SQLite database (zstd compressed, age encrypted)
  containing all file metadata, chunk mappings, and relationships for the snapshot
@@ -22,6 +22,56 @@ the tag exists and is exercised; what is left is merging `next` to

 # Completed Steps

+- 2026-10-13: Stopped an unplugged volume's empty mount point from being
+  taken for an empty destination
+  ([issue #239](https://git.eeqj.de/sneak/vaultik/issues/239)). With
+  `storage_url` at a mount point, `prune` dropped every local snapshot
+  record, and `snapshot create` wrote the whole backup to the disk under
+  it. Every backup now writes `vaultik-destination.txt` at the root of
+  the destination. While the local index holds snapshots, a destination
+  without it is not present: `snapshot create` refuses to write, `prune`
+  and `snapshot purge` fail, and `snapshot list` and `snapshot remove`
+  warn. The `file://` backend no longer creates its destination
+  directory, so a write to a missing one fails; the README quickstart
+  creates it.
+
+- 2026-10-13: Made `snapshot remove` fail for a snapshot that does not
+  exist ([issue #293](https://git.eeqj.de/sneak/vaultik/issues/293)).
+  The command never checked the ID: it reported the snapshot removed
+  from the local database and from the destination store and exited 0,
+  under `--json`, `--dry-run` and `--local-only` too. An ID that names
+  no snapshot in the local index or on the destination store is now an
+  error; with `--local-only`, the snapshot must be in the local index.
+  The command now reports a removal from either side only when one
+  happened, and `remote_removed` is true only when metadata was deleted.
+
+- 2026-10-12: Bound the local index to the destination an `s3.*` config
+  names ([issue #298](https://git.eeqj.de/sneak/vaultik/issues/298)).
+  Only `storage_url` was checked, so after `s3.bucket` or `s3.prefix`
+  changed, the next backup treated every chunk as already stored,
+  uploaded nothing, and completed a snapshot that could not be restored.
+  Without `storage_url`, the local index is now bound to `s3.endpoint`,
+  `s3.bucket` and `s3.prefix`, and a change is refused as a changed
+  `storage_url` is.
+
+- 2026-10-12: Rejected a retention duration longer than about 292 years
+  ([issue #289](https://git.eeqj.de/sneak/vaultik/issues/289)). The
+  number given to `--older-than` or `--keep-newer-than` was multiplied
+  by the length of its unit with no limit, so from `293y`, `15251w`,
+  `3559mo` or `106752d`, or a sum of parts such as `200y200y`, the
+  result wrapped to a negative duration. The cutoff then lay in the
+  future, every snapshot of the name was deleted, the one just made
+  included, and the command exited 0. Such a duration is now rejected
+  as invalid and nothing is deleted.
+
+- 2026-10-08: Made a backup cancelled under `--skip-errors` stop at once
+  ([issue #286](https://git.eeqj.de/sneak/vaultik/issues/286)). After
+  Ctrl-C or SIGTERM, phase 2 treated the cancellation error from each
+  remaining file like an unreadable file: it opened the file, printed an
+  error line for it, counted it as failed and went on to the next one.
+  The run now stops at the first file after the cancellation, and no
+  file is counted as failed because of it.
+
 - 2026-10-08: Made `remote nuke` delete the `.partial` files that
  uploads cut off part-way leave on the destination store
  ([issue #281](https://git.eeqj.de/sneak/vaultik/issues/281)). The
@@ -29,6 +79,15 @@ the tag exists and is exercised; what is left is merging `next` to
  place and still reported the store empty. It now removes them under
  `metadata/` and `blobs/` as its last step.

+- 2026-10-08: Made a local index error while recording a directory or
+  symlink stop a backup under `--skip-errors`
+  ([issue #284](https://git.eeqj.de/sneak/vaultik/issues/284)). Phase 2
+  only records such an entry in the local index, since it has no data
+  to open or read, but an error doing so was skipped like an unreadable
+  file. The snapshot then completed without the entry, and a restore
+  did not recreate it. The error now stops the backup, as it does
+  without the flag.
+
 - 2026-10-08: Counted a file that a backup could not store as failed
  ([issue #280](https://git.eeqj.de/sneak/vaultik/issues/280)). A file
  that phase 1 counted and phase 2 could not open, because it was
@@ -4,7 +4,7 @@ This document describes the structure and organization of data stored in the S3

 ## Overview

-Vaultik stores all backup data in an S3-compatible object store. The repository consists of two main components:
+Vaultik stores all backup data in an S3-compatible object store. The repository consists of two main components, plus a marker file:
 1. **Blobs** - The actual backup data (content-addressed, encrypted)
 2. **Metadata** - Snapshot information and manifests (partially encrypted)

@@ -12,6 +12,7 @@ Vaultik stores all backup data in an S3-compatible object store. The repository

 ```
 <bucket>/<prefix>/
+├── vaultik-destination.txt
 ├── blobs/
 │   └── <hash[0:2]>/
 │       └── <hash[2:4]>/
@@ -24,6 +25,10 @@ Vaultik stores all backup data in an S3-compatible object store. The repository

 The metadata subdirectory is named with the **remote key**, a one-way hash of the snapshot ID, not with the human-readable snapshot ID itself. See [Remote Key Derivation](#remote-key-derivation).

+## Marker File (`vaultik-destination.txt`)
+
+Every backup writes this file at the root before it uploads anything. It holds one fixed line of plain text and names no host, path or time. While the local index holds snapshots, a destination without it is treated as not present: `snapshot create` refuses to write to it, and `prune`, `snapshot purge`, `snapshot remove` and `snapshot list` behave as for a destination that cannot be listed. An unplugged volume leaves an empty directory at its mount point, and without the marker that directory would read as a destination whose snapshots are all gone. `remote nuke` deletes the marker last.
+
 ## Blobs Directory (`blobs/`)

 ### Structure
@@ -98,10 +98,11 @@ func TestEntryPruneJSONStdoutIsExactlyOneDocument(t *testing.T) {
 	}
 }

-// writeHermeticPruneConfig builds a config over a temp directory with an
-// empty destination directory and, if seedStale is set, creates the
-// index database up front with one snapshot record that has no
-// counterpart on the destination store. Returns the config path.
+// writeHermeticPruneConfig builds a config over a temp directory with a
+// destination directory that holds only the marker a backup writes and,
+// if seedStale is set, creates the index database up front with one
+// snapshot record that has no counterpart on the destination store.
+// Returns the config path.
 func writeHermeticPruneConfig(t *testing.T, seedStale bool) string {
 	t.Helper()

@@ -118,9 +119,12 @@ func writeHermeticPruneConfig(t *testing.T, seedStale bool) string {
 	require.NoError(t,
 		os.WriteFile(configPath, []byte(contents), configFileMode))

-	// prune fails on a destination directory that does not exist, so the
-	// empty store is created here rather than left to a first backup.
+	// prune fails on a destination directory that does not exist, and on
+	// one without the marker a backup writes while the local index holds
+	// a snapshot, so both are created here as a first backup leaves them.
 	require.NoError(t, os.Mkdir(storeDir, 0o750))
+	require.NoError(t, os.WriteFile(
+		filepath.Join(storeDir, "vaultik-destination.txt"), nil, 0o600))

 	// The PID lock lives under xdg.DataHome, which xdg resolves at
 	// package init; point it at the temp dir so the test neither
@@ -255,8 +255,12 @@ 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.
+
 Use --local-only to skip the remote half (e.g. when you want to forget a
-snapshot locally without touching the destination store).
+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
@@ -1312,6 +1312,13 @@ func (s *Scanner) processPhase(

 	// Process each file
 	for _, fileToProcess := range filesToProcess {
+		// Check context cancellation
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
+
 		// Update progress
 		if s.progress != nil {
 			s.progress.GetStats().CurrentFile.Store(fileToProcess.Path)
@@ -1348,13 +1355,32 @@ func (s *Scanner) processPhase(
 	return s.finalizeProcessPhase(ctx, result)
 }

-// processFileWithErrorHandling wraps processFileStreaming with error recovery for
-// deleted files and skip-errors mode. Returns (skipped, error).
+// processFileWithErrorHandling records a directory or symlink, or wraps
+// processFileStreaming for a regular file with error recovery for deleted
+// files and skip-errors mode. Returns (skipped, error).
 func (s *Scanner) processFileWithErrorHandling(
 	ctx context.Context, fileToProcess *FileToProcess, result *ScanResult,
 ) (bool, error) {
+	// A directory or symlink has no data to open or read; it is only
+	// recorded in the local index. An error recording it stops the run
+	// even under --skip-errors, or the snapshot would complete without it.
+	mode := os.FileMode(fileToProcess.File.Mode)
+	if mode&os.ModeSymlink != 0 || mode.IsDir() {
+		err := s.recordNonRegularFile(ctx, fileToProcess)
+		if err != nil {
+			return false, fmt.Errorf("processing file %s: %w", fileToProcess.Path, err)
+		}
+
+		return false, nil
+	}
+
 	err := s.processFileStreaming(ctx, fileToProcess, result)
 	if err != nil {
+		// A cancelled run stops here even under --skip-errors, rather than
+		// counting this file as failed and going on to the next one.
+		if ctx.Err() != nil {
+			return false, fmt.Errorf("processing file %s: %w", fileToProcess.Path, err)
+		}
 		// A packer/database/encryption/upload failure means the chunk's data
 		// may not have been stored. Skipping the file would let the snapshot
 		// record a file whose chunk is in no blob and cannot be restored, so
@@ -1392,12 +1418,7 @@ func (s *Scanner) processFileWithErrorHandling(

 // countFailedFile counts a file that phase 2 could not store as failed
 // and takes its size back out of BytesScanned, where phase 1 put it.
-// Phase 1 counts no directories, so a directory is not counted here.
 func countFailedFile(fileToProcess *FileToProcess, result *ScanResult) {
-	if fileToProcess.FileInfo.IsDir() {
-		return
-	}
-
 	result.FilesFailed++
 	result.BytesScanned -= fileToProcess.FileInfo.Size()
 }
@@ -1770,16 +1791,11 @@ func (e *packerError) Error() string { return e.err.Error() }

 func (e *packerError) Unwrap() error { return e.err }

-// processFileStreaming processes a file by streaming chunks directly to the packer
+// processFileStreaming processes a regular file by streaming chunks directly
+// to the packer
 func (s *Scanner) processFileStreaming(
 	ctx context.Context, fileToProcess *FileToProcess, result *ScanResult,
 ) error {
-	// Symlinks and directories have no data to chunk — just record them in the DB.
-	mode := os.FileMode(fileToProcess.File.Mode)
-	if mode&os.ModeSymlink != 0 || mode.IsDir() {
-		return s.recordNonRegularFile(ctx, fileToProcess)
-	}
-
 	file, err := s.fs.Open(fileToProcess.Path)
 	if err != nil {
 		return fmt.Errorf("opening file: %w", wrapPermissionError(fileToProcess.Path, err))
@@ -82,6 +82,32 @@ func (f *readFailFs) Open(name string) (afero.File, error) {
 	return file, nil
 }

+// cancelOnOpenFs cancels the run when the scanner opens the target file to
+// back it up, as Ctrl-C partway through processing would, and records each
+// file opened after that.
+type cancelOnOpenFs struct {
+	afero.Fs
+
+	target            string
+	cancel            context.CancelFunc
+	cancelled         bool
+	openedAfterCancel []string
+}
+
+//nolint:ireturn // afero.Fs.Open is defined to return the interface.
+func (f *cancelOnOpenFs) Open(name string) (afero.File, error) {
+	if f.cancelled {
+		f.openedAfterCancel = append(f.openedAfterCancel, name)
+	}
+
+	if name == f.target {
+		f.cancel()
+		f.cancelled = true
+	}
+
+	return f.Fs.Open(name)
+}
+
 // linkRemovedAfterLstatFs is the real filesystem, except that the symlink at
 // target is removed right after the walk lstats it, as happens when a link is
 // deleted during a backup. The scanner's readlink of it then fails.
@@ -128,15 +154,16 @@ func writeSkipErrorTestFile(t *testing.T, fs afero.Fs, path, content string) {
 	}
 }

-// runSkipErrorScan scans source on fs with the given skip-errors setting,
-// printing user-facing messages to uiw (nil discards them), and returns the
-// repositories (for inspection) and the scan error.
+// runSkipErrorScan scans source on fs under ctx with the given skip-errors
+// setting, printing user-facing messages to uiw (nil discards them), and
+// returns the repositories (for inspection) and the scan error.
 func runSkipErrorScan(
-	t *testing.T, fs afero.Fs, source string, skipErrors bool, uiw *ui.Writer,
+	ctx context.Context, t *testing.T, fs afero.Fs, source string,
+	skipErrors bool, uiw *ui.Writer,
 ) (*database.Repositories, error) {
 	t.Helper()

-	db, err := database.NewTestDB()
+	db, err := database.New(ctx, ":memory:")
 	if err != nil {
 		t.Fatalf("create test db: %v", err)
 	}
@@ -161,7 +188,6 @@ func runSkipErrorScan(
 		SkipErrors:       skipErrors,
 	})

-	ctx := context.Background()
 	snapshotID := "test-snapshot-skip-errors"
 	createTestSnapshotRecord(ctx, t, repos, snapshotID)

@@ -185,7 +211,7 @@ func TestScannerPackingFailureAbortsUnderSkipErrors(t *testing.T) {
 	writeSkipErrorTestFile(t, fs, "/source/file1.txt", "first file content")
 	writeSkipErrorTestFile(t, fs, "/source/file2.txt", "second file content")

-	repos, err := runSkipErrorScan(t, fs, "/source", true, nil)
+	repos, err := runSkipErrorScan(context.Background(), t, fs, "/source", true, nil)
 	if err == nil {
 		t.Fatal("expected scan to abort on the packer error, got nil")
 	}
@@ -212,7 +238,7 @@ func TestScannerReadErrorAbortsWithoutSkipErrors(t *testing.T) {
 	fs := &readFailFs{Fs: afero.NewMemMapFs(), target: target}
 	writeSkipErrorTestFile(t, fs, target, "content that cannot be read")

-	_, err := runSkipErrorScan(t, fs, "/source", false, nil)
+	_, err := runSkipErrorScan(context.Background(), t, fs, "/source", false, nil)
 	if err == nil {
 		t.Fatal("expected scan to fail on the read error, got nil")
 	}
@@ -228,7 +254,7 @@ func TestScannerReadErrorSkippedWithSkipErrors(t *testing.T) {
 	fs := &readFailFs{Fs: afero.NewMemMapFs(), target: target}
 	writeSkipErrorTestFile(t, fs, target, "content that cannot be read")

-	repos, err := runSkipErrorScan(t, fs, "/source", true, nil)
+	repos, err := runSkipErrorScan(context.Background(), t, fs, "/source", true, nil)
 	if err != nil {
 		t.Fatalf("expected scan to complete with --skip-errors, got %v", err)
 	}
@@ -267,7 +293,7 @@ func TestScannerUnreadableSymlinkAbortsWithoutSkipErrors(t *testing.T) {
 	sourceDir, linkPath := writeSymlinkSource(t)
 	fs := &linkRemovedAfterLstatFs{t: t, target: linkPath}

-	_, err := runSkipErrorScan(t, fs, sourceDir, false, nil)
+	_, err := runSkipErrorScan(context.Background(), t, fs, sourceDir, false, nil)
 	if !errors.Is(err, os.ErrNotExist) {
 		t.Fatalf("expected scan to fail on the removed symlink, got %v", err)
 	}
@@ -283,7 +309,7 @@ func TestScannerUnreadableSymlinkSkippedWithSkipErrors(t *testing.T) {
 	fs := &linkRemovedAfterLstatFs{t: t, target: linkPath}
 	uiw := ui.NewWithColor(io.Discard, false)

-	repos, err := runSkipErrorScan(t, fs, sourceDir, true, uiw)
+	repos, err := runSkipErrorScan(context.Background(), t, fs, sourceDir, true, uiw)
 	if err != nil {
 		t.Fatalf("expected scan to complete with --skip-errors, got %v", err)
 	}
@@ -302,3 +328,56 @@ func TestScannerUnreadableSymlinkSkippedWithSkipErrors(t *testing.T) {
 		t.Fatalf("expected %s not to be recorded", linkPath)
 	}
 }
+
+// TestScannerCancelStopsSkipErrorsRun checks that a --skip-errors backup
+// cancelled partway through processing returns the cancellation error,
+// opens no further file, and reports no file as failed.
+func TestScannerCancelStopsSkipErrorsRun(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name          string
+		targetContent string
+	}{
+		// The cancellation lands while the target is being read.
+		{name: "while reading a file", targetContent: "first file content"},
+		// An empty target has no chunks, so the cancellation goes unnoticed
+		// until the run moves on to the next file.
+		{name: "between files", targetContent: ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			const target = "/source/a.txt"
+
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+
+			fs := &cancelOnOpenFs{
+				Fs: afero.NewMemMapFs(), target: target, cancel: cancel,
+			}
+			writeSkipErrorTestFile(t, fs, target, tt.targetContent)
+			writeSkipErrorTestFile(t, fs, "/source/b.txt", "second file content")
+			writeSkipErrorTestFile(t, fs, "/source/c.txt", "third file content")
+
+			uiw := ui.NewWithColor(io.Discard, false)
+
+			_, err := runSkipErrorScan(ctx, t, fs, "/source", true, uiw)
+			if !errors.Is(err, context.Canceled) {
+				t.Fatalf("expected the cancellation error, got %v", err)
+			}
+
+			if len(fs.openedAfterCancel) != 0 {
+				t.Fatalf("expected no file opened after the cancellation, got %v",
+					fs.openedAfterCancel)
+			}
+
+			if uiw.ErrorCount() != 0 {
+				t.Fatalf("expected no file reported as failed, got %d error lines",
+					uiw.ErrorCount())
+			}
+		})
+	}
+}
@@ -21,9 +21,10 @@ type FileStorer struct {
 // NewFileStorer creates a new filesystem storage backend.
 //
 // Construction is intentionally cheap and does not touch the filesystem.
-// The basePath is recorded; the directory is created lazily on first
-// write. Write operations (Put/PutWithProgress) call MkdirAll for the
-// per-blob parent directory, which also covers basePath on first use.
+// The backend never creates basePath: the user does, so that a write to
+// an unplugged volume fails instead of landing on the disk under its
+// empty mount point. Put and PutWithProgress fail on a missing basePath
+// and create the directories below it as needed.
 // Get and Stat report a key under a missing basePath as ErrNotFound.
 // List and ListStream fail on a missing basePath, because listing it as
 // an empty store would make `prune` drop every local snapshot record.
@@ -297,7 +298,19 @@ func (f *FileStorer) writeAtomic(
 	path := f.fullPath(key)
 	dir := filepath.Dir(path)

-	err := f.fs.MkdirAll(dir, storageDirPerm)
+	// Checked on every write, so a destination that disappears part-way
+	// through a backup fails it rather than being recreated by MkdirAll.
+	_, err := f.fs.Stat(f.basePath)
+	if os.IsNotExist(err) {
+		return fmt.Errorf("destination directory does not exist; "+
+			"create it, or mount the volume it is on: %w", err)
+	}
+
+	if err != nil {
+		return fmt.Errorf("checking destination directory: %w", err)
+	}
+
+	err = f.fs.MkdirAll(dir, storageDirPerm)
 	if err != nil {
 		return fmt.Errorf("creating directories: %w", err)
 	}
@@ -4,7 +4,9 @@ import (
 	"context"
 	"errors"
 	"io/fs"
+	"os"
 	"path/filepath"
+	"strings"
 	"testing"

 	"sneak.berlin/go/vaultik/internal/storage"
@@ -60,3 +62,43 @@ func TestFileStorerListMissingDestination(t *testing.T) {
 		t.Errorf("ListStream error = %v, want a not-exist error", streamErr)
 	}
 }
+
+// TestFileStorerPutMissingDestination checks that a write fails when the
+// destination directory has gone, even after earlier writes to it
+// succeeded, and that it does not create the directory again.
+func TestFileStorerPutMissingDestination(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	base := filepath.Join(t.TempDir(), "usbstick")
+
+	err := os.Mkdir(base, 0o750)
+	if err != nil {
+		t.Fatalf("Mkdir: %v", err)
+	}
+
+	s, err := storage.NewFileStorer(base)
+	if err != nil {
+		t.Fatalf("NewFileStorer: %v", err)
+	}
+
+	err = s.Put(ctx, "blobs/aa/bb/first", strings.NewReader("first"))
+	if err != nil {
+		t.Fatalf("first Put: %v", err)
+	}
+
+	err = os.Rename(base, base+"-unplugged")
+	if err != nil {
+		t.Fatalf("Rename: %v", err)
+	}
+
+	err = s.Put(ctx, "blobs/aa/bb/second", strings.NewReader("second"))
+	if !errors.Is(err, fs.ErrNotExist) {
+		t.Errorf("Put = %v, want a not-exist error", err)
+	}
+
+	_, err = os.Stat(base)
+	if !errors.Is(err, fs.ErrNotExist) {
+		t.Errorf("Put created the destination directory again (Stat = %v)", err)
+	}
+}
@@ -41,7 +41,8 @@ type Info struct {
 // directory for filesystem).
 type Storer interface {
 	// Put stores data at the specified key.
-	// Parent directories are created automatically for filesystem backends.
+	// The filesystem backend fails when its destination directory does
+	// not exist, and creates the directories below it as needed.
 	Put(ctx context.Context, key string, data io.Reader) error

 	// PutWithProgress stores data with progress reporting.
@@ -137,7 +137,7 @@ func TestBackupAfterRemovingNewestSnapshotRestoresChangedFile(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")
 	changedPath := filepath.Join(dataDir, "appended.bin")
@@ -184,7 +184,7 @@ func TestBackupAfterInterruptedRunRestoresChangedFile(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")
 	changedPath := filepath.Join(dataDir, "appended.bin")
@@ -30,7 +30,7 @@ func TestDeepVerifyAcceptsHealthyAndRejectsCorruptBlob(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	chunkSize := int64(64 * 1024)
@@ -0,0 +1,74 @@
+package vaultik
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"sneak.berlin/go/vaultik/internal/storage"
+)
+
+// destinationMarkerKey is the object every backup writes at the root of
+// the backup destination store. While the local index holds a snapshot,
+// a destination without it is treated as not present: an unplugged
+// volume leaves an empty directory at its mount point, which would
+// otherwise read as a store whose snapshots are all gone.
+const destinationMarkerKey = "vaultik-destination.txt"
+
+// destinationMarkerText is the whole content of the marker. It names no
+// host, path or time.
+const destinationMarkerText = "This is a vaultik backup destination store.\n"
+
+// errDestinationNotPresent is returned when the local index holds a
+// snapshot and the backup destination store has no marker.
+var errDestinationNotPresent = errors.New("backup destination store is not present")
+
+// checkDestinationMarker returns errDestinationNotPresent when the local
+// index holds a snapshot and the backup destination store has no marker.
+// With no snapshot in the local index, as on a first backup or on
+// another machine, there is nothing to check.
+func (v *Vaultik) checkDestinationMarker() error {
+	ids, err := v.localSnapshotIDs()
+	if err != nil {
+		return fmt.Errorf("listing local snapshots: %w", err)
+	}
+
+	if len(ids) == 0 {
+		return nil
+	}
+
+	_, err = v.Storage.Stat(v.ctx, destinationMarkerKey)
+	if errors.Is(err, storage.ErrNotFound) {
+		return fmt.Errorf("%w: %s has no %s, but the local index holds "+
+			"snapshots stored there; mount the volume if it is removable, "+
+			"or if the destination was emptied on purpose, run "+
+			"'vaultik database delete' and back up again",
+			errDestinationNotPresent, v.Storage.Info().Location,
+			destinationMarkerKey)
+	}
+
+	if err != nil {
+		return fmt.Errorf("checking for %s: %w", destinationMarkerKey, err)
+	}
+
+	return nil
+}
+
+// markDestination checks the backup destination store with
+// checkDestinationMarker and then writes the marker, so a first backup
+// marks its destination and a later one writes the same text again.
+func (v *Vaultik) markDestination() error {
+	err := v.checkDestinationMarker()
+	if err != nil {
+		return err
+	}
+
+	err = v.Storage.Put(v.ctx, destinationMarkerKey,
+		strings.NewReader(destinationMarkerText))
+	if err != nil {
+		return fmt.Errorf("writing %s to the backup destination store: %w",
+			destinationMarkerKey, err)
+	}
+
+	return nil
+}
@@ -0,0 +1,184 @@
+package vaultik_test
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"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/vaultik"
+)
+
+// These tests cover https://git.eeqj.de/sneak/vaultik/issues/239: a
+// file:// destination at a volume's mount point leaves an empty directory
+// behind when the volume is unplugged. While the local index holds
+// snapshots, a destination without vaultik-destination.txt is not present,
+// so no command may write to it or conclude from it that the local
+// snapshots are gone.
+
+// markerFile is the name of the file a backup writes at the root of the
+// destination.
+const markerFile = "vaultik-destination.txt"
+
+// backUpThenUnplugMountPoint backs up to a file:// destination, then
+// moves the destination directory away and leaves an empty directory in
+// its place, as unplugging a volume mounted there would. It returns the
+// path of that empty directory.
+func backUpThenUnplugMountPoint(
+	ctx context.Context, t *testing.T,
+) (*vaultik.Vaultik, *database.Repositories, *bytes.Buffer, string) {
+	t.Helper()
+
+	storeDir := filepath.Join(t.TempDir(), "mnt")
+	v, repos, out := backUpToFileDestination(ctx, t, storeDir)
+
+	require.NoError(t, os.Rename(storeDir, storeDir+"-unplugged"))
+	require.NoError(t, os.Mkdir(storeDir, 0o750))
+
+	return v, repos, out, storeDir
+}
+
+// assertUntouched checks that the local index still holds its one
+// snapshot and that nothing was written to the empty mount point.
+func assertUntouched(
+	ctx context.Context, t *testing.T,
+	repos *database.Repositories, storeDir string,
+) {
+	t.Helper()
+
+	snapshots, err := repos.Snapshots.ListRecent(ctx, listRecentTestLimit)
+	require.NoError(t, err)
+	assert.Len(t, snapshots, 1, "no local snapshot record may be deleted")
+
+	entries, err := os.ReadDir(storeDir)
+	require.NoError(t, err)
+	assert.Empty(t, entries, "nothing may be written to the empty mount point")
+}
+
+// TestFirstBackupWritesMarker checks that a backup writes the marker
+// file at the root of the destination.
+func TestFirstBackupWritesMarker(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	storeDir := t.TempDir()
+	backUpToFileDestination(context.Background(), t, storeDir)
+
+	assert.FileExists(t, filepath.Join(storeDir, markerFile))
+}
+
+// TestBackupRefusesDestinationWithoutMarker checks that snapshot create
+// --prune writes nothing and drops no local snapshot record when the
+// destination has no marker.
+func TestBackupRefusesDestinationWithoutMarker(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+	v, repos, _, storeDir := backUpThenUnplugMountPoint(ctx, t)
+
+	err := v.CreateSnapshot(&vaultik.SnapshotCreateOptions{
+		Cron:  true,
+		Prune: true,
+	})
+	require.ErrorContains(t, err, markerFile)
+
+	assertUntouched(ctx, t, repos, storeDir)
+}
+
+// TestPruneRefusesDestinationWithoutMarker checks that prune fails and
+// deletes no local snapshot record when the destination has no marker.
+func TestPruneRefusesDestinationWithoutMarker(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+	v, repos, _, storeDir := backUpThenUnplugMountPoint(ctx, t)
+
+	err := v.Prune(&vaultik.PruneOptions{Force: true})
+	require.ErrorContains(t, err, markerFile)
+
+	assertUntouched(ctx, t, repos, storeDir)
+}
+
+// TestPurgeRefusesDestinationWithoutMarker checks that snapshot purge
+// fails and deletes no local snapshot record when the destination has no
+// marker.
+func TestPurgeRefusesDestinationWithoutMarker(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+	v, repos, _, storeDir := backUpThenUnplugMountPoint(ctx, t)
+
+	err := v.PurgeSnapshotsWithOptions(&vaultik.SnapshotPurgeOptions{
+		KeepLatest: true,
+		Force:      true,
+	})
+	require.ErrorContains(t, err, markerFile)
+
+	assertUntouched(ctx, t, repos, storeDir)
+}
+
+// TestRemoveSnapshotWarnsWhenDestinationHasNoMarker checks that snapshot
+// remove warns that the metadata could not be removed from a destination
+// without a marker, instead of reporting that it was.
+func TestRemoveSnapshotWarnsWhenDestinationHasNoMarker(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+	v, repos, out, _ := backUpThenUnplugMountPoint(ctx, t)
+
+	result, err := v.RemoveSnapshot(localSnapshotID(ctx, t, repos, "first"),
+		&vaultik.RemoveOptions{Force: true})
+	require.NoError(t, err)
+
+	assert.False(t, result.RemoteRemoved)
+	assert.Contains(t, out.String(),
+		"Could not remove snapshot metadata from remote")
+	assert.Contains(t, out.String(), markerFile)
+	assert.NotContains(t, out.String(),
+		"Removed snapshot metadata from remote storage")
+}
+
+// TestListSnapshotsWarnsWhenDestinationHasNoMarker checks that snapshot
+// list warns and shows the local index alone when the destination has no
+// marker, without reporting the local snapshot as missing from it.
+func TestListSnapshotsWarnsWhenDestinationHasNoMarker(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+	v, repos, out, _ := backUpThenUnplugMountPoint(ctx, t)
+	id := localSnapshotID(ctx, t, repos, "first")
+
+	require.NoError(t, v.ListSnapshots(false))
+
+	assert.Contains(t, out.String(), "Could not list backup destination store")
+	assert.Contains(t, out.String(), markerFile)
+	assert.Contains(t, out.String(), id)
+	assert.NotContains(t, out.String(), "not found in backup destination store")
+}
+
+// TestBackupAfterNukeRemoteSucceeds checks that remote nuke leaves the
+// destination ready for a new first backup, which writes the marker
+// again.
+func TestBackupAfterNukeRemoteSucceeds(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	storeDir := t.TempDir()
+	v, _, _ := backUpToFileDestination(context.Background(), t, storeDir)
+
+	require.NoError(t, v.NukeRemote(true))
+	assert.NoFileExists(t, filepath.Join(storeDir, markerFile))
+
+	require.NoError(t, backUp(v, "second"))
+	assert.FileExists(t, filepath.Join(storeDir, markerFile))
+}
@@ -192,7 +192,7 @@ func assertRestoreRejectsDamagedBlob(
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -238,7 +238,7 @@ func TestDeepVerifyCatchesLyingBackend(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	ctx := context.Background()
@@ -290,7 +290,7 @@ func TestInterruptedBlobUploadRecordsNoUploadedBlob(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	ctx := context.Background()
@@ -298,10 +298,6 @@ func TestInterruptedBlobUploadRecordsNoUploadedBlob(t *testing.T) {

 	writeFaultSourceTree(t, fs, dataDir)

-	// No upload succeeds, so nothing creates the destination directory.
-	// It must exist for the listing below to show that no blob survived.
-	require.NoError(t, os.Mkdir(storeDir, 0o750))
-
 	inner, err := storage.NewFileStorer(storeDir)
 	require.NoError(t, err)

@@ -365,7 +361,7 @@ func TestBackupRetryAfterInterruptedUploadIsRestorable(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -429,7 +425,7 @@ func TestBackupSurvivesMetadataExportInterruption(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	ctx := context.Background()
@@ -511,7 +507,7 @@ func TestBackupCompletesOnlyAfterMetadataExport(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -686,7 +682,7 @@ func TestRestoreReportsDiskFull(t *testing.T) {
 	osFS := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -3,6 +3,7 @@ package vaultik
 import (
 	"errors"
 	"fmt"
+	"math"
 	"regexp"
 	"strconv"
 	"strings"
@@ -47,6 +48,10 @@ const (
 	year  = 365 * day
 )

+// maxDuration is the largest value a time.Duration can hold, about 292
+// years.
+const maxDuration = time.Duration(math.MaxInt64)
+
 // A snapshot ID split on "_" has at least a hostname and a trailing
 // timestamp.
 const minSnapshotIDParts = 2
@@ -145,10 +150,10 @@ func parseSnapshotName(snapshotID, hostname string) string {
 // parseDuration parses a duration string with support for human-friendly units:
 // d/day/days, w/week/weeks, mo/month/months, y/year/years, plus standard Go
 // duration units. Following Go, m is minutes and mo is months. A bare number,
-// an unknown unit, and a negative value are all rejected. Outside the Go
-// units the input must be whole numbers each followed directly by a unit
-// (2w3d), so 1.0y and 30 days are errors; decimals work only in Go units
-// (1.5h).
+// an unknown unit, a negative value, and a total longer than maxDuration are
+// all rejected. Outside the Go units the input must be whole numbers each
+// followed directly by a unit (2w3d), so 1.0y and 30 days are errors;
+// decimals work only in Go units (1.5h).
 func parseDuration(s string) (time.Duration, error) {
 	if strings.HasPrefix(strings.TrimSpace(s), "-") {
 		return 0, errNegativeDuration
@@ -181,19 +186,30 @@ func parseDuration(s string) (time.Duration, error) {
 			return 0, fmt.Errorf("invalid number %q: %w", match[1], err)
 		}

+		var unitLength time.Duration
+
 		unit := strings.ToLower(match[2])
 		switch unit {
 		case "d", "day", "days":
-			total += time.Duration(n) * day
+			unitLength = day
 		case "w", "week", "weeks":
-			total += time.Duration(n) * week
+			unitLength = week
 		case "mo", "month", "months":
-			total += time.Duration(n) * month
+			unitLength = month
 		case "y", "year", "years":
-			total += time.Duration(n) * year
+			unitLength = year
 		default:
 			return 0, fmt.Errorf("%w %q", errUnknownTimeUnit, unit)
 		}
+
+		// Past maxDuration the sum wraps to a negative value, which would
+		// put the purge cutoff in the future.
+		if time.Duration(n) > (maxDuration-total)/unitLength {
+			return 0, fmt.Errorf("%w: %q is longer than about 292 years",
+				errInvalidDuration, s)
+		}
+
+		total += time.Duration(n) * unitLength
 	}

 	return total, nil
@@ -111,6 +111,17 @@ func TestParseDuration(t *testing.T) {
 		{"30 days", 0, true},
 		{"30 days ago", 0, true},
 		{"x7d", 0, true},
+		// The largest time.Duration is about 292 years. A larger value
+		// must be rejected, not wrapped to a negative one, which would
+		// put the cutoff in the future and select every snapshot.
+		{"292y", 292 * 365 * 24 * time.Hour, false},
+		{"293y", 0, true},
+		{"3559mo", 0, true},
+		{"15251w", 0, true},
+		{"106752d", 0, true},
+		{"2562048h", 0, true},
+		{"200y200y", 0, true},
+		{"292y6mo", 0, true},
 	}

 	for _, tt := range tests {
@@ -771,7 +771,7 @@ func TestEndToEndFileStorage(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -964,7 +964,7 @@ func TestDedupOnlySnapshotRestores(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -24,13 +24,11 @@ import (
 // that is not plugged in, cannot be listed. It is not an empty store, so
 // no command may conclude from it that the local snapshots are gone.

-// backUpToFileDestination backs up the snapshot named "first" to a
-// file:// destination at storeDir, which need not exist yet. Everything
-// the returned Vaultik prints after the backup goes to the returned
-// buffer.
-func backUpToFileDestination(
+// newFileDestinationVaultik returns a Vaultik that backs up the
+// snapshot named "first" to a file:// destination at storeDir.
+func newFileDestinationVaultik(
 	ctx context.Context, t *testing.T, storeDir string,
-) (*vaultik.Vaultik, *database.Repositories, *bytes.Buffer) {
+) (*vaultik.Vaultik, *database.Repositories) {
 	t.Helper()

 	osFs := afero.NewOsFs()
@@ -49,8 +47,22 @@ func backUpToFileDestination(

 	repos := database.NewRepositories(db)
 	cfg := changedFileConfig(dataDir, dbPath)
-	v := newBackupVaultik(ctx, cfg, store, repos, db, osFs)

+	return newBackupVaultik(ctx, cfg, store, repos, db, osFs), repos
+}
+
+// backUpToFileDestination creates the directory storeDir, as a user must
+// before the first backup, and backs up the snapshot named "first" to a
+// file:// destination there. Everything the returned Vaultik prints
+// after the backup goes to the returned buffer.
+func backUpToFileDestination(
+	ctx context.Context, t *testing.T, storeDir string,
+) (*vaultik.Vaultik, *database.Repositories, *bytes.Buffer) {
+	t.Helper()
+
+	require.NoError(t, os.MkdirAll(storeDir, 0o750))
+
+	v, repos := newFileDestinationVaultik(ctx, t, storeDir)
 	require.NoError(t, backUp(v, "first"))

 	out := &bytes.Buffer{}
@@ -75,21 +87,28 @@ func backUpThenUnplug(
 	return v, repos, out
 }

-// TestFirstBackupCreatesDestinationDirectory checks that a first backup
-// to a destination directory that does not exist yet creates it, and
-// that the destination can be listed afterwards.
-func TestFirstBackupCreatesDestinationDirectory(t *testing.T) {
+// TestBackupFailsWhenDestinationDirectoryMissing checks that a backup to
+// a file:// destination whose directory does not exist fails before it
+// records a snapshot, and does not create the directory.
+func TestBackupFailsWhenDestinationDirectoryMissing(t *testing.T) {
 	log.Initialize(log.Config{})
 	t.Parallel()

 	ctx := context.Background()
-	storeDir := filepath.Join(t.TempDir(), "volume", "backup")
-	v, _, out := backUpToFileDestination(ctx, t, storeDir)
+	volume := filepath.Join(t.TempDir(), "volume")
+	v, repos := newFileDestinationVaultik(ctx, t, filepath.Join(volume, "backup"))

-	require.NoError(t, v.ListSnapshots(false))
+	err := backUp(v, "first")
+	require.ErrorIs(t, err, fs.ErrNotExist)
+	require.ErrorContains(t, err, "create it, or mount the volume it is on")

-	assert.NotContains(t, out.String(), "Could not list backup destination store")
-	assert.NotContains(t, out.String(), "not found in backup destination store")
+	_, err = os.Stat(volume)
+	require.ErrorIs(t, err, fs.ErrNotExist,
+		"the backup must not create the destination directory")
+
+	snapshots, err := repos.Snapshots.ListRecent(ctx, listRecentTestLimit)
+	require.NoError(t, err)
+	assert.Empty(t, snapshots)
 }

 // TestListSnapshotsWarnsWhenDestinationMissing checks that snapshot list
@@ -25,8 +25,9 @@ const metadataDirName = "metadata"

 // NukeRemote deletes every snapshot's metadata and every blob from remote
 // storage, along with any object an upload cut off part-way left under a
-// temporary `.partial` name. After this returns successfully the bucket
-// prefix is empty and the next backup starts from scratch.
+// temporary `.partial` name, and the destination marker. After this
+// returns successfully the bucket prefix is empty and the next backup
+// starts from scratch.
 //
 // Refuses to run unless force is true. The caller is responsible for
 // confirming with the user.
@@ -58,6 +59,13 @@ func (v *Vaultik) NukeRemote(force bool) error {
 		}
 	}

+	// Last, once the local snapshot records are gone: the next backup
+	// then has none and writes the marker again.
+	err = v.Storage.Delete(v.ctx, destinationMarkerKey)
+	if err != nil {
+		return fmt.Errorf("deleting %s: %w", destinationMarkerKey, err)
+	}
+
 	v.UI.Completef("Backup destination store is now empty.")

 	return nil
@@ -34,6 +34,9 @@ func setupConsistencyTest(
 	repos := database.NewRepositories(db)
 	mockStorage := NewMockStorer()

+	// A backup wrote to this destination, so it carries the marker.
+	require.NoError(t, mockStorage.Put(ctx, markerFile, strings.NewReader("")))
+
 	for _, id := range snapshotIDs {
 		parts := strings.Split(id, "_")
 		startedAt, err := time.Parse(time.RFC3339, parts[len(parts)-1])
@@ -44,6 +44,9 @@ func setupPurgeTest(
 	repos := database.NewRepositories(db)
 	mockStorage := NewMockStorer()

+	// A backup wrote to this destination, so it carries the marker.
+	require.NoError(t, mockStorage.Put(ctx, markerFile, strings.NewReader("")))
+
 	// Insert each snapshot into the DB and create remote metadata stubs.
 	// Use timestamps parsed from snapshot IDs for realistic ordering.
 	for _, id := range snapshotIDs {
@@ -267,6 +270,29 @@ func TestPurgeOlderThan_WithNameFilter(t *testing.T) {
 	assert.Contains(t, remaining, snapHomeT0)
 }

+func TestPurgeOlderThan_TooLargeDeletesNothing(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	snapshotIDs := []string{snapHomeT0, snapHomeT1}
+
+	v := setupPurgeTest(t, snapHostname, snapshotIDs)
+
+	err := v.PurgeSnapshotsWithOptions(&vaultik.SnapshotPurgeOptions{
+		OlderThan: "1000y",
+		Force:     true,
+	})
+	require.Error(t, err)
+
+	err = v.PurgeSnapshotsWithOptions(&vaultik.SnapshotPurgeOptions{
+		OlderThan: "292y",
+		Force:     true,
+	})
+	require.NoError(t, err)
+
+	assert.ElementsMatch(t, snapshotIDs, listRemainingSnapshots(t, v))
+}
+
 func TestPurgeKeepLatest_ThreeNames(t *testing.T) {
 	log.Initialize(log.Config{})
 	t.Parallel()
@@ -3,17 +3,21 @@ package vaultik_test
 import (
 	"bytes"
 	"context"
+	"database/sql"
 	"io"
 	"strings"
 	"sync"
 	"testing"
+	"time"

 	"github.com/klauspost/compress/zstd"
 	"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/storage"
+	"sneak.berlin/go/vaultik/internal/types"
 	"sneak.berlin/go/vaultik/internal/vaultik"
 )

@@ -214,6 +218,37 @@ func addBlob(t *testing.T, store *testStorer, hash string) {
 	require.NoError(t, err)
 }

+// newLocalIndex returns an in-memory local index holding a completed
+// snapshot row for each of ids.
+func newLocalIndex(t *testing.T, ids ...string) *database.Repositories {
+	t.Helper()
+
+	ctx := context.Background()
+
+	db, err := database.New(ctx, ":memory:")
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = db.Close() })
+
+	repos := database.NewRepositories(db)
+
+	for _, id := range ids {
+		completedAt := time.Now().UTC()
+		snap := &database.Snapshot{
+			ID:          types.SnapshotID(id),
+			Hostname:    snapHostname,
+			StartedAt:   completedAt,
+			CompletedAt: &completedAt,
+		}
+
+		err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
+			return repos.Snapshots.Create(ctx, tx, snap)
+		})
+		require.NoError(t, err)
+	}
+
+	return repos
+}
+
 // ============================================================================
 // Unit Tests for RemoveSnapshot
 // ============================================================================
@@ -233,6 +268,7 @@ func TestRemoveSnapshot_LocalOnly_PreservesRemote(t *testing.T) {
 	addBlob(t, store, blobA)

 	tv := vaultik.NewForTesting(store)
+	tv.Repositories = newLocalIndex(t, "snapshot-001")

 	opts := &vaultik.RemoveOptions{Force: true, LocalOnly: true}
 	result, err := tv.RemoveSnapshot("snapshot-001", opts)
@@ -267,7 +303,12 @@ func TestRemoveSnapshot_DefaultRemovesMetadataNotBlobs(t *testing.T) {
 	addBlob(t, store, blobUnique)
 	addBlob(t, store, blobShared)

+	// A backup wrote to this destination, so it carries the marker.
+	require.NoError(t, store.Put(context.Background(), markerFile,
+		bytes.NewReader(nil)))
+
 	tv := vaultik.NewForTesting(store)
+	tv.Repositories = newLocalIndex(t, "snapshot-001", "snapshot-002")

 	opts := &vaultik.RemoveOptions{Force: true}
 	result, err := tv.RemoveSnapshot("snapshot-001", opts)
@@ -316,6 +357,89 @@ func TestRemoveSnapshot_DryRun(t *testing.T) {
 	assert.Contains(t, tv.Stdout.String(), "[Dry run - no changes made]")
 }

+// TestRemoveSnapshot_UnknownIDIsError checks that an ID naming no
+// snapshot in the local index or on the destination store is an error
+// under every option, and that nothing is reported as removed.
+func TestRemoveSnapshot_UnknownIDIsError(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	for name, opts := range map[string]vaultik.RemoveOptions{
+		"force":      {Force: true},
+		"json":       {JSON: true},
+		"dry-run":    {Force: true, DryRun: true},
+		"local-only": {Force: true, LocalOnly: true},
+	} {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			store := newTestStorer()
+			addManifest(t, store, "snapshot-001", nil)
+
+			tv := vaultik.NewForTesting(store)
+			tv.Repositories = newLocalIndex(t, "snapshot-001")
+
+			result, err := tv.RemoveSnapshot("snapshot-999", &opts)
+
+			require.ErrorContains(t, err, "snapshot not found")
+			assert.False(t, result.RemoteRemoved)
+			assert.Empty(t, tv.Stdout.String())
+			assert.True(t, store.hasKey(remoteKeyPath("snapshot-001")))
+		})
+	}
+}
+
+// TestRemoveSnapshot_NoMetadataOnDestination checks that removing a
+// snapshot whose metadata is not on the destination store does not
+// report metadata removed from it.
+func TestRemoveSnapshot_NoMetadataOnDestination(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	// A backup wrote to this destination, so it carries the marker.
+	store := newTestStorer()
+	require.NoError(t, store.Put(context.Background(), markerFile,
+		bytes.NewReader(nil)))
+
+	tv := vaultik.NewForTesting(store)
+	tv.Repositories = newLocalIndex(t, "snapshot-001")
+
+	result, err := tv.RemoveSnapshot("snapshot-001",
+		&vaultik.RemoveOptions{Force: true})
+
+	require.NoError(t, err)
+	assert.False(t, result.RemoteRemoved)
+
+	out := tv.Stdout.String()
+	assert.Contains(t, out, "Removed snapshot 'snapshot-001' from local database")
+	assert.NotContains(t, out, "Removed snapshot metadata from remote storage")
+}
+
+// TestRemoveSnapshot_NotInLocalIndex checks that removing a snapshot
+// only the destination store holds removes its metadata there without
+// reporting a removal from the local database.
+func TestRemoveSnapshot_NotInLocalIndex(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	store := newTestStorer()
+	addManifest(t, store, "snapshot-001", nil)
+
+	tv := vaultik.NewForTesting(store)
+	tv.Repositories = newLocalIndex(t)
+
+	result, err := tv.RemoveSnapshot("snapshot-001",
+		&vaultik.RemoveOptions{Force: true})
+
+	require.NoError(t, err)
+	assert.True(t, result.RemoteRemoved)
+	assert.False(t, store.hasKey(remoteKeyPath("snapshot-001")))
+
+	out := tv.Stdout.String()
+	assert.NotContains(t, out, "from local database")
+	assert.Contains(t, out, "Removed snapshot metadata from remote storage")
+}
+
 func TestRemoveAllSnapshots_RequiresForce(t *testing.T) {
 	log.Initialize(log.Config{})
 	t.Parallel()
@@ -42,7 +42,7 @@ func TestRestoreOnAnotherMachine(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -65,7 +65,7 @@ func TestRestoreCleansTempDirOnInterrupt(t *testing.T) {
 	root := t.TempDir()

 	dataDir := filepath.Join(root, "source")
-	storeDir := filepath.Join(root, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(root, "restored")
 	dbPath := filepath.Join(root, "index.sqlite")

@@ -197,7 +197,7 @@ func TestRestoreLocalityAndReadAt(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -107,7 +107,7 @@ func backupOneFile(
 	require.NoError(t, afero.WriteFile(fs, srcPath, content, mode))
 	require.NoError(t, fs.Chmod(srcPath, mode))

-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	storer, err := storage.NewFileStorer(storeDir)
@@ -127,7 +127,7 @@ func backupThenDeleteOneBlob(
 		require.NoError(t, afero.WriteFile(fs, path, files[path], 0o644))
 	}

-	storer, err := storage.NewFileStorer(filepath.Join(tempDir, "remote"))
+	storer, err := storage.NewFileStorer(t.TempDir())
 	require.NoError(t, err)

 	db, err := database.New(ctx, dbPath)
@@ -29,7 +29,7 @@ func TestRestoreAndDeepVerifyRejectSwappedDatabase(t *testing.T) {

 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()

 	chunkSize := int64(64 * 1024)

@@ -100,7 +100,7 @@ func TestDeepVerifyRejectsSwappedDatabaseWithEmptyManifest(t *testing.T) {

 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()

 	chunkSize := int64(64 * 1024)

@@ -186,7 +186,7 @@ func TestRestoreSweeperEvictsBlobs(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -33,7 +33,7 @@ func TestRestoreRejectsTruncatedMetadataDB(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -25,7 +25,7 @@ func TestBackupOfSameSecondRewriteRestoresNewContent(t *testing.T) {
 	fs := afero.NewOsFs()
 	tempDir := t.TempDir()
 	dataDir := filepath.Join(tempDir, "src")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")
 	rewrittenPath := filepath.Join(dataDir, "small.txt")
@@ -31,7 +31,7 @@ func TestShallowVerifyDetectsWrongBlobSize(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	chunkSize := int64(32 * 1024)
@@ -105,7 +105,7 @@ func TestShallowVerifyDetectsMissingDatabase(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	chunkSize := int64(32 * 1024)
@@ -23,6 +23,7 @@ var (
 	errNoSnapshotsInConfig  = errors.New("no snapshots configured")
 	errSnapshotVerifyFailed = errors.New("verification failed")
 	errRemoveAllNeedsForce  = errors.New("--all requires --force")
+	errSnapshotNotFound     = errors.New("snapshot not found")
 	errInvalidTableName     = errors.New("invalid table name")
 	errNoAgeRecipients      = errors.New(
 		"creating a snapshot needs at least one public key in " +
@@ -65,6 +66,13 @@ func (v *Vaultik) CreateSnapshot(opts *SnapshotCreateOptions) error {
 		return err
 	}

+	// Before PruneDatabase: it drops incomplete snapshots, which could
+	// leave the local index without one and so skip the marker check.
+	err = v.markDestination()
+	if err != nil {
+		return err
+	}
+
 	// Clean up incomplete snapshots FIRST, before any scanning.
 	// This is critical for data safety; PruneDatabase below does it.
 	hostname := v.Config.Hostname
@@ -87,21 +95,9 @@ func (v *Vaultik) CreateSnapshot(opts *SnapshotCreateOptions) error {
 		return fmt.Errorf("prune database: %w", err)
 	}

-	// Determine which snapshots to process
-	snapshotNames := opts.Snapshots
-	if len(snapshotNames) == 0 {
-		snapshotNames = v.Config.SnapshotNames()
-	} else {
-		// Validate requested snapshot names exist
-		for _, name := range snapshotNames {
-			if _, ok := v.Config.Snapshots[name]; !ok {
-				return fmt.Errorf("%w: %q", errSnapshotNotInConfig, name)
-			}
-		}
-	}
-
-	if len(snapshotNames) == 0 {
-		return errNoSnapshotsInConfig
+	snapshotNames, err := v.snapshotNamesToCreate(opts.Snapshots)
+	if err != nil {
+		return err
 	}

 	// Process each named snapshot
@@ -141,6 +137,28 @@ func (v *Vaultik) CreateSnapshot(opts *SnapshotCreateOptions) error {
 	return nil
 }

+// snapshotNamesToCreate returns the requested snapshot names, each checked
+// against the config, or every configured name when none was requested.
+func (v *Vaultik) snapshotNamesToCreate(requested []string) ([]string, error) {
+	snapshotNames := requested
+	if len(snapshotNames) == 0 {
+		snapshotNames = v.Config.SnapshotNames()
+	} else {
+		// Validate requested snapshot names exist
+		for _, name := range snapshotNames {
+			if _, ok := v.Config.Snapshots[name]; !ok {
+				return nil, fmt.Errorf("%w: %q", errSnapshotNotInConfig, name)
+			}
+		}
+	}
+
+	if len(snapshotNames) == 0 {
+		return nil, errNoSnapshotsInConfig
+	}
+
+	return snapshotNames, nil
+}
+
 // runPostBackupPrune drops older snapshots of the given names and removes
 // orphan blobs from remote storage. If keepNewerThan is set (e.g. "4w"),
 // snapshots newer than that duration are kept. Otherwise only the latest
@@ -643,7 +661,7 @@ func (v *Vaultik) confirmAndExecutePurge(
 				"snapshot_id", snapshotID, "error", err)
 		}

-		err = v.deleteRemoteSnapshotByKey(snapshot.RemoteSnapshotKey(snapshotID))
+		_, err = v.deleteRemoteSnapshotByKey(snapshot.RemoteSnapshotKey(snapshotID))
 		if err != nil {
 			return fmt.Errorf("deleting snapshot %s from remote: %w", snapshotID, err)
 		}
@@ -1153,23 +1171,38 @@ func (v *Vaultik) RemoveSnapshot(
 		return result, err
 	}

+	inLocalIndex, err := v.findSnapshotToRemove(snapshotID, opts)
+	if err != nil {
+		return result, err
+	}
+
 	if opts.DryRun {
 		return v.removeSnapshotDryRun(result, snapshotID, opts)
 	}

-	if !opts.Force && !opts.JSON && !v.confirmRemoveSnapshot(snapshotID, opts) {
+	if !v.confirmRemoveSnapshot(snapshotID, opts) {
 		return result, nil
 	}

-	log.Info("Removing snapshot from local database", "snapshot_id", snapshotID)
+	// Checked before the local record is deleted: it may be the last
+	// snapshot in the local index, and the check applies only while the
+	// local index holds one.
+	var markerErr error
+	if !opts.LocalOnly {
+		markerErr = v.checkDestinationMarker()
+	}

-	err = v.deleteSnapshotFromLocalDB(snapshotID)
-	if err != nil {
-		return result, fmt.Errorf("removing from local database: %w", err)
+	if inLocalIndex {
+		log.Info("Removing snapshot from local database", "snapshot_id", snapshotID)
+
+		err = v.deleteSnapshotFromLocalDB(snapshotID)
+		if err != nil {
+			return result, fmt.Errorf("removing from local database: %w", err)
+		}
 	}

 	if !opts.LocalOnly {
-		result.RemoteRemoved = v.removeSnapshotRemote(snapshotID, opts)
+		result.RemoteRemoved = v.removeSnapshotRemote(snapshotID, markerErr, opts)
 	}

 	if v.SnapshotManager != nil {
@@ -1184,9 +1217,11 @@ func (v *Vaultik) RemoveSnapshot(
 		return result, v.outputRemoveJSON(result)
 	}

-	v.stdoutf("Removed snapshot '%s' from local database\n", snapshotID)
+	if inLocalIndex {
+		v.stdoutf("Removed snapshot '%s' from local database\n", snapshotID)
+	}

-	if !opts.LocalOnly && result.RemoteRemoved {
+	if result.RemoteRemoved {
 		v.printlnStdout("Removed snapshot metadata from remote storage")
 		v.stdoutf("\nNote: The removed snapshot's blobs remain on the remote. "+
 			"Run '%s' to delete any blobs no longer referenced by any "+
@@ -1196,6 +1231,45 @@ func (v *Vaultik) RemoveSnapshot(
 	return result, nil
 }

+// findSnapshotToRemove reports whether the local index has a row for
+// snapshotID, and returns errSnapshotNotFound when there is nothing to
+// remove: no row and, unless LocalOnly is set, no metadata on the
+// destination store either. The destination store is consulted only
+// when the local index has no row, so a snapshot in the local index can
+// still be removed from it while the destination store is unreachable.
+func (v *Vaultik) findSnapshotToRemove(
+	snapshotID string, opts *RemoveOptions,
+) (bool, error) {
+	if v.Repositories != nil {
+		snap, err := v.Repositories.Snapshots.GetByID(v.ctx, snapshotID)
+		if err != nil {
+			return false, fmt.Errorf("looking up snapshot in local index: %w", err)
+		}
+
+		if snap != nil {
+			return true, nil
+		}
+	}
+
+	if opts.LocalOnly {
+		return false, fmt.Errorf("%w in the local index: %s",
+			errSnapshotNotFound, snapshotID)
+	}
+
+	objects, err := v.remoteSnapshotObjects(snapshot.RemoteSnapshotKey(snapshotID))
+	if err != nil {
+		return false, fmt.Errorf("looking up snapshot on destination store: %w", err)
+	}
+
+	if len(objects) == 0 {
+		return false, fmt.Errorf(
+			"%w in the local index or on the destination store: %s",
+			errSnapshotNotFound, snapshotID)
+	}
+
+	return false, nil
+}
+
 // removeSnapshotDryRun reports what RemoveSnapshot would do without
 // making changes.
 func (v *Vaultik) removeSnapshotDryRun(
@@ -1220,9 +1294,13 @@ func (v *Vaultik) removeSnapshotDryRun(
 }

 // confirmRemoveSnapshot prompts for confirmation before removing a
-// snapshot. Returns false (treating EOF/read errors as "no") unless the
-// user answers "y".
+// snapshot, unless --force or --json is set. Returns false (treating
+// EOF/read errors as "no") unless the user answers "y".
 func (v *Vaultik) confirmRemoveSnapshot(snapshotID string, opts *RemoveOptions) bool {
+	if opts.Force || opts.JSON {
+		return true
+	}
+
 	if opts.LocalOnly {
 		v.stdoutf("Remove snapshot '%s' from local database "+
 			"(remote untouched)? [y/N] ", snapshotID)
@@ -1254,15 +1332,24 @@ func (v *Vaultik) confirmRemoveSnapshot(snapshotID string, opts *RemoveOptions)
 // 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.
-func (v *Vaultik) removeSnapshotRemote(snapshotID string, opts *RemoveOptions) bool {
+// removes snapshot metadata). markerErr is the result of
+// checkDestinationMarker; when it is set, nothing is deleted and it is
+// the failure reported. Returns true when the remote removal succeeded
+// and deleted something.
+func (v *Vaultik) removeSnapshotRemote(
+	snapshotID string, markerErr error, opts *RemoveOptions,
+) bool {
 	log.Info("Removing snapshot metadata from remote storage",
 		"snapshot_id", snapshotID)

-	remoteKey := snapshot.RemoteSnapshotKey(snapshotID)
+	var deleted int
+
+	err := markerErr
+	if err == nil {
+		deleted, err = v.deleteRemoteSnapshotByKey(
+			snapshot.RemoteSnapshotKey(snapshotID))
+	}

-	err := v.deleteRemoteSnapshotByKey(remoteKey)
 	if err != nil {
 		log.Warn("Could not remove snapshot metadata from remote storage; "+
 			"run '"+snapshotRemoveCommandHint+"' with the snapshot's ID "+
@@ -1280,7 +1367,7 @@ func (v *Vaultik) removeSnapshotRemote(snapshotID string, opts *RemoveOptions) b
 		return false
 	}

-	return true
+	return deleted > 0
 }

 // RemoveAllSnapshots removes every snapshot known to the local
@@ -1366,8 +1453,8 @@ func (v *Vaultik) localSnapshotIDs() ([]string, error) {
 // listAllRemoteSnapshotKeys collects the hashed remote keys
 // (subdirectories under metadata/) currently present in the
 // destination store. Returns (nil, err) when the store cannot be
-// listed; callers must treat that as "no remote info available," not
-// fatal.
+// listed, or is not present by checkDestinationMarker; callers must
+// treat that as "no remote info available," not fatal.
 func (v *Vaultik) listAllRemoteSnapshotKeys() ([]string, error) {
 	log.Info("Listing all remote snapshots")

@@ -1416,6 +1503,11 @@ func (v *Vaultik) listAllRemoteSnapshotKeys() ([]string, error) {
 		}
 	}

+	err := v.checkDestinationMarker()
+	if err != nil {
+		return nil, err
+	}
+
 	return keys, nil
 }

@@ -1572,7 +1664,7 @@ func (v *Vaultik) removeAllLocalSnapshots(
 		}

 		if !opts.LocalOnly {
-			err = v.deleteRemoteSnapshotByKey(
+			_, err = v.deleteRemoteSnapshotByKey(
 				snapshot.RemoteSnapshotKey(snapshotID))
 			if err != nil {
 				log.Warn("Failed to remove snapshot metadata from remote",
@@ -1598,7 +1690,7 @@ func (v *Vaultik) removeAllOrphanRemotes(
 	for _, key := range orphanRemoteKeys {
 		log.Info("Removing orphan remote snapshot", "remote_key", key)

-		err := v.deleteRemoteSnapshotByKey(key)
+		_, err := v.deleteRemoteSnapshotByKey(key)
 		if err != nil {
 			log.Warn("Failed to remove orphan from remote",
 				"remote_key", key, "error", err)
@@ -1645,34 +1737,44 @@ func (v *Vaultik) deleteSnapshotFromLocalDB(snapshotID string) error {
 }

 // deleteRemoteSnapshotByKey removes everything under
-// metadata/<remoteKey>/ on the destination store. The argument is a
-// remote key (double-SHA256 derivation), not a human snapshot ID;
-// callers that have a human ID must hash via snapshot.RemoteSnapshotKey
-// first.
-func (v *Vaultik) deleteRemoteSnapshotByKey(remoteKey string) error {
-	prefix := fmt.Sprintf("metadata/%s/", remoteKey)
-	objectCh := v.Storage.ListStream(v.ctx, prefix)
-
-	var objectsToDelete []string
-
-	for object := range objectCh {
-		if object.Err != nil {
-			return fmt.Errorf("listing objects: %w", object.Err)
-		}
-
-		objectsToDelete = append(objectsToDelete, object.Key)
+// metadata/<remoteKey>/ on the destination store and returns how many
+// objects it deleted. The argument is a remote key (double-SHA256
+// derivation), not a human snapshot ID; callers that have a human ID
+// must hash via snapshot.RemoteSnapshotKey first.
+func (v *Vaultik) deleteRemoteSnapshotByKey(remoteKey string) (int, error) {
+	objectsToDelete, err := v.remoteSnapshotObjects(remoteKey)
+	if err != nil {
+		return 0, err
 	}

-	for _, key := range objectsToDelete {
-		err := v.Storage.Delete(v.ctx, key)
+	for i, key := range objectsToDelete {
+		err = v.Storage.Delete(v.ctx, key)
 		if err != nil {
-			return fmt.Errorf("removing %s: %w", key, err)
+			return i, fmt.Errorf("removing %s: %w", key, err)
 		}

 		log.Debug("Deleted remote object", "key", key)
 	}

-	return nil
+	return len(objectsToDelete), nil
+}
+
+// remoteSnapshotObjects lists the keys of every object under
+// metadata/<remoteKey>/ on the destination store.
+func (v *Vaultik) remoteSnapshotObjects(remoteKey string) ([]string, error) {
+	prefix := fmt.Sprintf("metadata/%s/", remoteKey)
+
+	var keys []string
+
+	for object := range v.Storage.ListStream(v.ctx, prefix) {
+		if object.Err != nil {
+			return nil, fmt.Errorf("listing objects: %w", object.Err)
+		}
+
+		keys = append(keys, object.Key)
+	}
+
+	return keys, nil
 }

 // outputRemoveJSON outputs the removal result as JSON
@@ -87,7 +87,7 @@ func TestSnapshotSummaryCountsFileNotStoredAsFailed(t *testing.T) {
 				"src": {Paths: []string{srcDir}},
 			}

-			store, err := storage.NewFileStorer(filepath.Join(tempDir, "remote"))
+			store, err := storage.NewFileStorer(t.TempDir())
 			require.NoError(t, err)

 			db, err := database.New(ctx, cfg.IndexPath)
@@ -122,6 +122,9 @@ func newListEnv(t *testing.T) *listEnv {
 	store := newObservingStorer()
 	stdout := &bytes.Buffer{}

+	// A backup wrote to this destination, so it carries the marker.
+	require.NoError(t, store.Put(ctx, markerFile, strings.NewReader("")))
+
 	v := &vaultik.Vaultik{
 		Config: &config.Config{
 			AgeSecretKey: "",
@@ -0,0 +1,75 @@
+package vaultik_test
+
+import (
+	"context"
+	"fmt"
+	"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/database"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/storage"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// --skip-errors skips only a file that cannot be opened or read. A local
+// index error while a directory is recorded stops the backup, and the
+// snapshot is not recorded as complete. See
+// https://git.eeqj.de/sneak/vaultik/issues/284.
+func TestSkipErrorsBackupStopsOnIndexErrorRecordingDirectory(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+
+	// The scan walks the source path with symlinks resolved, so dirPath
+	// must be spelled the same way to match the row the scan inserts.
+	tempDir, err := filepath.EvalSymlinks(t.TempDir())
+	require.NoError(t, err)
+
+	srcDir := filepath.Join(tempDir, "src")
+	dirPath := filepath.Join(srcDir, "dir")
+
+	fs := afero.NewOsFs()
+	require.NoError(t, fs.MkdirAll(dirPath, 0o755))
+	require.NoError(t, afero.WriteFile(fs,
+		filepath.Join(dirPath, "file.txt"), []byte("file content"), 0o644))
+
+	cfg := faultTestConfig()
+	cfg.IndexPath = filepath.Join(tempDir, "index.sqlite")
+	cfg.Snapshots = map[string]config.SnapshotConfig{
+		"tree": {Paths: []string{srcDir}},
+	}
+
+	store, err := storage.NewFileStorer(t.TempDir())
+	require.NoError(t, err)
+
+	db, err := database.New(ctx, cfg.IndexPath)
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = db.Close() })
+
+	// The local index refuses the directory's files row.
+	_, err = db.Conn().ExecContext(ctx, fmt.Sprintf(`
+		CREATE TRIGGER refuse_directory BEFORE INSERT ON files
+		WHEN NEW.path = '%s'
+		BEGIN SELECT RAISE(ABORT, 'simulated index error'); END`, dirPath))
+	require.NoError(t, err)
+
+	repos := database.NewRepositories(db)
+	v := newBackupVaultik(ctx, cfg, store, repos, db, fs)
+
+	err = v.CreateSnapshot(&vaultik.SnapshotCreateOptions{
+		SkipErrors: true,
+		Snapshots:  []string{"tree"},
+	})
+	require.ErrorContains(t, err, "simulated index error")
+
+	snapshots, err := repos.Snapshots.ListRecent(ctx, listRecentTestLimit)
+	require.NoError(t, err)
+	require.Len(t, snapshots, 1)
+	assert.Nil(t, snapshots[0].CompletedAt)
+}
@@ -84,7 +84,7 @@ func newSummaryEnv(t *testing.T) *summaryEnv {
 		"split":  {Paths: []string{dirOne, dirTwo}},
 	}

-	inner, err := storage.NewFileStorer(filepath.Join(tempDir, "remote"))
+	inner, err := storage.NewFileStorer(t.TempDir())
 	require.NoError(t, err)

 	store := faultstore.New(inner)
@@ -9,7 +9,7 @@ import (
 )

 // errStorageBindingMismatch is returned when the local index database is
-// bound to a different destination than the configured storage_url.
+// bound to a different destination than the configured one.
 var errStorageBindingMismatch = errors.New(
 	"local index is bound to a different backup destination")

@@ -24,8 +24,9 @@ var errStorageBindingMismatch = errors.New(
 //
 // Behaviour:
 //   - On first use (empty stored value), record the configured
-//     storage_url and log the binding.
-//   - When the stored value matches the configured storage_url, do
+//     destination (storage_url, or the s3.* endpoint, bucket and
+//     prefix) and log the binding.
+//   - When the stored value matches the configured destination, do
 //     nothing and return nil.
 //   - When the two differ, refuse with an error that tells the user
 //     how to recover (revert the config, or run `vaultik database
@@ -46,12 +47,10 @@ func (v *Vaultik) EnsureStorageBinding() error {

 	configured := v.Config.StorageURL
 	if configured == "" {
-		// Some legacy configs still use the split s3.* keys instead of
-		// storage_url. Falling back to a synthetic URL for those would
-		// hide the fact that the binding is loose. Instead, treat
-		// unset as "nothing to bind against" — the check is
-		// necessarily best-effort for those configs.
-		return nil
+		// The s3.* form: bind on its endpoint, bucket and prefix,
+		// written the way storage_url would name the same destination.
+		s3 := v.Config.S3
+		configured = "s3://" + s3.Bucket + "/" + s3.Prefix + "?endpoint=" + s3.Endpoint
 	}

 	stored, err := v.Repositories.LocalMeta.Get(v.ctx, database.LocalMetaKeyStorageURL)
@@ -96,7 +95,8 @@ func buildBindingMismatchMessage(stored, configured string) string {
 		"future snapshots referencing blobs that don't exist at the new destination.\n" +
 		"\n" +
 		"To proceed, either:\n" +
-		"  - revert storage_url in your config to the bound destination, or\n" +
+		"  - revert storage_url (or the s3.* endpoint, bucket and prefix) in your\n" +
+		"    config to the bound destination, or\n" +
 		"  - run 'vaultik database delete' to discard the local index and rebuild it\n" +
 		"    from a fresh full backup against the new destination"
 }
@@ -76,3 +76,51 @@ func TestEnsureStorageBinding_MismatchRefuses(t *testing.T) {
 	assert.Contains(t, err.Error(), "file:///mnt/backups/new")
 	assert.Contains(t, err.Error(), "vaultik database delete")
 }
+
+// A config with no storage_url names its destination with s3.endpoint,
+// s3.bucket and s3.prefix; a change to any of them must be refused just
+// as a changed storage_url is.
+func TestEnsureStorageBinding_S3FieldsChangeRefuses(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	bound := config.S3Config{
+		Endpoint: "https://s3.example.com",
+		Bucket:   "bucket-a",
+		Prefix:   "backups",
+	}
+
+	tests := []struct {
+		name    string
+		changed config.S3Config
+	}{
+		{"bucket", config.S3Config{
+			Endpoint: bound.Endpoint, Bucket: "bucket-b", Prefix: bound.Prefix,
+		}},
+		{"prefix", config.S3Config{
+			Endpoint: bound.Endpoint, Bucket: bound.Bucket, Prefix: "other",
+		}},
+		{"endpoint", config.S3Config{
+			Endpoint: "https://s3.other.com", Bucket: bound.Bucket, Prefix: bound.Prefix,
+		}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			tv, _ := buildBindTestVaultik(t, "")
+
+			tv.Config.S3 = bound
+			require.NoError(t, tv.EnsureStorageBinding(), "first use binds")
+			require.NoError(t, tv.EnsureStorageBinding(), "same destination passes")
+
+			tv.Config.S3 = tt.changed
+			err := tv.EnsureStorageBinding()
+			require.Error(t, err)
+			assert.Contains(t, err.Error(),
+				"local index is bound to a different backup destination")
+			assert.Contains(t, err.Error(), "vaultik database delete")
+		})
+	}
+}
@@ -28,7 +28,7 @@ func TestBackupWithoutCronOfTwoPathSnapshotRestoresBothPaths(t *testing.T) {
 	tempDir := t.TempDir()
 	firstDir := filepath.Join(tempDir, "first")
 	secondDir := filepath.Join(tempDir, "second")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	restoreDir := filepath.Join(tempDir, "restored")
 	dbPath := filepath.Join(tempDir, "index.sqlite")

@@ -28,7 +28,7 @@ func TestVerify_QuietSuppressesReport(t *testing.T) {
 	tempDir := t.TempDir()

 	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
+	storeDir := t.TempDir()
 	dbPath := filepath.Join(tempDir, "index.sqlite")

 	chunkSize := int64(32 * 1024)
Author	SHA1	Message	Date
sneak	a8d209475b	Refuse a backup destination an unplugged volume left empty (closes #239 ) check / check (push) Waiting to run Details Every backup now writes vaultik-destination.txt at the root of the backup destination store. While the local index holds snapshots, a destination without it is not present: snapshot create refuses before writing, prune and snapshot purge fail, and snapshot list and snapshot remove warn, as for a destination that cannot be listed. remote nuke deletes the marker last. The file:// backend no longer creates its destination directory and checks for it on every write. Tests now back up into existing directories, and fixtures standing for a written destination carry the marker. Judgement call: the marker is rewritten on every backup. Deviation: for the complexity limit, snapshot name selection left CreateSnapshot and the --force/--json test moved into confirmRemoveSnapshot, both unchanged. Model: opus-5-5	2026-10-13 04:27:54 +00:00
clawbot	167c0a0746	Make snapshot remove fail for an unknown snapshot ID (closes #293 ) check / check (push) Waiting to run Details snapshot remove never checked that the ID existed: it deleted nothing, reported the snapshot removed from the local database and from the destination store, and exited 0, under --json, --dry-run and --local-only too. It now looks the ID up in the local index and, only when that has no row and --local-only is not set, on the destination store; finding neither is an error. The command reports a removal from the local database only when the local index had the row, and remote_removed is true only when metadata was actually deleted. Judgement call: under --local-only the destination store is not consulted, so the snapshot must be in the local index. Model: opus-5-5	2026-10-13 05:55:22 +02:00
clawbot	07c957f84b	Bind the local index to the s3.* destination too (closes #298 ) check / check (push) Waiting to run Details The local index was bound to its destination only through storage_url. With the s3.* form nothing was checked, so after s3.bucket or s3.prefix changed the next backup treated every chunk as already stored, uploaded nothing, and completed a snapshot that could not be restored. Without storage_url, the binding now records the destination the s3.* fields name, written as an s3:// URL from s3.endpoint, s3.bucket and s3.prefix, and a change is refused with the same error and advice. The advice line now names the s3.* fields as well as storage_url. Judgement call: the fields are compared as written, so an equivalent spelling (a trailing slash on the prefix, a scheme on the endpoint) is also refused, as it already is for storage_url. Model: opus-5-5	2026-10-13 03:48:36 +02:00
clawbot	c9a519c233	Reject a retention duration longer than about 292 years (closes #289 ) check / check (push) Waiting to run Details parseDuration multiplied each number by the length of its unit with no limit, so from 293y (or 15251w, 3559mo, 106752d, or a sum such as 200y200y) the result wrapped to a negative duration. The purge cutoff then lay in the future and every snapshot of the name was selected, for --older-than and --keep-newer-than alike. Each part is now checked before it is added, and a total past the largest time.Duration is rejected as an invalid duration, so nothing is deleted. Go units were already safe: time.ParseDuration rejects an overflow. With --prune the backup still runs before the duration is read; only the prune step fails. Model: opus-5-5	2026-10-13 01:51:24 +02:00
clawbot	fa56165fe4	Stop a cancelled backup at once under --skip-errors (closes #286 ) check / check (push) Canceled after 0s Details After Ctrl-C or SIGTERM, phase 2 of a --skip-errors backup treated the cancellation error from each remaining file like an unreadable file: it opened the file, printed an error line, counted it as failed and moved on to the next. The processing loop now checks for cancellation before each file, and an error from a file once the run is cancelled stops the run instead of being skipped. The loop check is what stops a run cancelled while an empty file is open, since an empty file has no chunks and nothing reads the context while it is backed up. The --skip-errors test helper now takes the scan's context. Model: opus-5-5	2026-10-08 15:12:07 +02:00
clawbot	34f61fb408	Make remote nuke delete leftover .partial uploads (closes #281 ) check / check (push) Canceled after 0s Details The file and rclone listings skip an object whose name ends in `.partial`, the temporary name a `file://` or rclone upload writes before moving the object into place. `remote nuke` deletes only what the listings return, so it left the `.partial` objects killed uploads leave behind and still reported the destination store empty. Storer gains DeletePartialUploads. The file and rclone backends remove every `.partial` object under the prefix; S3 has none to remove, since it shows an object only once its upload completes. `remote nuke` calls it for `metadata/` and `blobs/` as its last step. Empty directories under a `file://` destination are still left behind. Model: opus-5-5	2026-10-08 14:17:20 +02:00
clawbot	05bf73c48a	Never skip a local index error for a directory or symlink (closes #284 ) check / check (push) Canceled after 0s Details Under --skip-errors, an error recording a directory or symlink in the local index was skipped like an unreadable file. The snapshot completed without the entry, and a restore did not recreate it. processFileWithErrorHandling now records a directory or symlink itself and returns any error, which stops the backup with or without the flag. The skip sees only a regular file's errors, so countFailedFile no longer checks for a directory. The test injects the error with a SQLite trigger that refuses the directory's files row. Model: opus-5-5	2026-10-08 12:59:26 +02:00