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

ARCHITECTURE.md

@@ -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

README.md

@@ -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
@@ -349,17 +360,22 @@ 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
-* `--json`: Output result as JSON
+* `--json`: Output result as JSON. Also skips the confirmation prompt, as
+  `--force` does.
 
 **`snapshot restore`**: Restore files from a backup snapshot.
 * Requires `VAULTIK_AGE_SECRET_KEY` environment variable
@@ -381,9 +397,13 @@ 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
+* `--json`: Output stats as JSON. Also skips the confirmation prompt, as
+  `--force` does.
 
 **`info`**: Display system configuration, storage settings, encryption
 recipients, and local database statistics.
@@ -396,20 +416,22 @@ key is skipped with a warning and is not printed. If a listed
 orphaned blob figures are reported as unknown; `--json` gives them as
 `null`, lists the remote key of each unreadable manifest in
 `unreadable_manifests` and counts the manifests under skipped names in
-`skipped_manifest_count`.
+`skipped_manifest_count`. An unreadable manifest also leaves its
+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
 
 ---
@@ -423,11 +445,24 @@ 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`).
 
+An upload cut off part-way leaves nothing under the object's name on S3, which
+shows an object only once its upload has completed, and on the local filesystem
+backend, which writes a temporary file and renames it into place. Rclone
+remotes with a server-side move (local and sftp among them) are written under a
+temporary name ending in `.partial` and moved into place. Rclone remotes without
+one are written in place: where such a remote shows a file while it is still
+being written, a killed upload can leave a truncated object under its name,
+which a later backup takes for complete. A leftover `.partial` file is ignored
+and can be deleted.
+
 Legacy S3 configuration via `s3.*` fields (endpoint, bucket, prefix, etc.) is
 still supported for backward compatibility. `storage_url` takes precedence if
 both are set.
@@ -444,6 +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/
@@ -452,6 +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

TODO.md

@@ -22,6 +22,144 @@ 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
+  file and rclone listings skip such a file, so the command left it in
+  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
+  unreadable under `--skip-errors` or removed in between, was reported
+  in the summary as unchanged with its bytes as backed up, and the
+  `snapshots` row's `file_count` and `total_size` included it. The
+  summary now counts it as failed, and its data total and the row leave
+  it out.
+
+- 2026-10-08: Made `remote info` report a snapshot's blob count and
+  blob size as unknown when its manifest cannot be read
+  ([issue #272](https://git.eeqj.de/sneak/vaultik/issues/272)). The
+  orphan figures were already unknown in that case, but the snapshot's
+  row still gave 0 blobs and 0 B, in the table and in `--json`. The row
+  now reads `unknown` and `--json` gives `null`. A directory with no
+  manifest still shows 0, since the orphan figures count its blobs as
+  orphaned.
+
+- 2026-10-08: Kept the progress line of a snapshot with more than one
+  path within 100%
+  ([issue #271](https://git.eeqj.de/sneak/vaultik/issues/271)). The
+  bytes and files processed counted every path, but the totals they
+  were divided by held only the current path's, so a second path
+  smaller than the first showed more than 100% and an ETA of `unknown`.
+  The totals now add up over the paths scanned so far. The rate behind
+  the ETA restarts when each path's scan phase ends, so that phase does
+  not lower the rate while the path is processed; until then the rate
+  is the previous path's.
+
+- 2026-10-08: Made a second `snapshot create` of one name succeed when
+  it starts in the same second as the first
+  ([issue #270](https://git.eeqj.de/sneak/vaultik/issues/270)). The
+  timestamp in a snapshot ID is in whole seconds, so the second run got
+  the first run's ID and failed with `UNIQUE constraint failed:
+  snapshots.id`. When the local index already has a snapshot with the
+  ID, the create now waits a second and takes a new timestamp.
+
+- 2026-10-07: Documented that `--json` skips the confirmation prompt of
+  `snapshot remove` and `prune`
+  ([issue #268](https://git.eeqj.de/sneak/vaultik/issues/268)). Both
+  commands delete without asking under `--json`, since a prompt on stdout
+  would break the JSON document, but the help and the README described
+  only `--force` as skipping it. The `--json` help of both commands and
+  their README entries now say so.
+
+- 2026-10-07: Made a symlink whose target cannot be read stop the backup
+  ([issue #269](https://git.eeqj.de/sneak/vaultik/issues/269)). It was
+  left out of the snapshot with only a debug log line, even without
+  `--skip-errors`. It now aborts the run, or with `--skip-errors` is
+  skipped with the `Failed to access` error line that any other entry
+  the scan cannot read gets.
+
+- 2026-10-07: Stopped a killed rclone upload from leaving a truncated
+  object under its key
+  ([issue #266](https://git.eeqj.de/sneak/vaultik/issues/266)). The
+  rclone backend wrote each object straight to its key, so killing an
+  upload to a local or sftp remote left a truncated object there; the
+  next backup found the key with `Stat`, skipped the upload and recorded
+  a snapshot that could not be restored. On a remote with a server-side
+  move, an object is now written under a temporary name ending in
+  `.partial` and moved into place, and listings skip such names. Remotes
+  without one are still written in place.
+
+- 2026-10-07: Made an interrupted command exit 130 and say so
+  ([issue #267](https://git.eeqj.de/sneak/vaultik/issues/267)). Ctrl-C
+  or SIGTERM during `snapshot create`, `snapshot restore` or `snapshot
+  verify` exited 0 with no error line (`snapshot verify --json` exited
+  1, also without one), so a `--cron` run that never finished looked
+  like a success. A command stopped by either signal now exits 130 and
+  prints `interrupted before the command finished` on stderr, under
+  `--cron` and `--json` too.
+
 - 2026-10-07: Corrected documentation, help text and comments that were
   false about the code
   ([issue #233](https://git.eeqj.de/sneak/vaultik/issues/233)). A blob

docs/REPOSTRUCTURE.md

@@ -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

internal/cli/app.go

@@ -206,6 +206,10 @@ func RunApp(ctx context.Context, app *fx.App) error {
 // RunOperation through cobra to Entry.
 var errReported = errors.New("operation failed")
 
+// errInterrupted marks an operation that SIGINT or SIGTERM stopped
+// before it finished. Entry shows it and returns exitCodeInterrupted.
+var errInterrupted = errors.New("interrupted before the command finished")
+
 // RunOperation runs op against the Vaultik instance inside the fx app
 // and turns a failure into a returned error rather than an os.Exit from
 // within the goroutine. An os.Exit there skipped main's deferred
@@ -220,17 +224,21 @@ var errReported = errors.New("operation failed")
 // interrupt OnStop cancels op and waits for the goroutine to return, so
 // op's cleanup (removing decrypted scratch files) runs before the
 // process exits; the wait is bounded by shutdownTimeout. report is
-// called with a non-canceled failure so the caller can show it to the
-// user before it becomes errReported. A context cancellation is the
-// interrupt path, not a failure: it is neither reported nor counted as
-// one.
+// called with a failure so the caller can show it to the user before
+// it becomes errReported.
+//
+// The run counts as interrupted unless op returned, without an
+// interrupt having cancelled it, before RunWithApp returned. An
+// interrupted op is not reported, whatever it returned; RunOperation
+// returns errInterrupted instead.
 func RunOperation(
 	ctx context.Context, opts AppOptions,
 	op func(v *vaultik.Vaultik) error, report func(err error),
 ) error {
 	var (
-		mu     sync.Mutex
-		failed bool
+		mu       sync.Mutex
+		finished bool // op returned before any interrupt cancelled it
+		failed   bool // op finished with an error
 	)
 
 	opts.Invokes = append(opts.Invokes,
@@ -241,11 +249,21 @@ func RunOperation(
 				OnStart: func(_ context.Context) error {
 					stop = v.StartOperation(func() {
 						err := op(v)
-						if err != nil && !errors.Is(err, context.Canceled) {
-							report(err)
+
+						// Only stop, called from OnStop below, cancels the
+						// Vaultik context, so a live context means no
+						// interrupt cancelled op. Check the context, not
+						// err: an interrupted op need not return
+						// context.Canceled (`snapshot verify --json`
+						// returns a verification failure).
+						if v.Context().Err() == nil {
+							if err != nil {
+								report(err)
+							}
 
 							mu.Lock()
-							failed = true
+							finished = true
+							failed = err != nil
 							mu.Unlock()
 						}
 
@@ -278,16 +296,23 @@ func RunOperation(
 		return err
 	}
 
-	// The goroutine sets failed before triggering the shutdown that lets
-	// RunWithApp return, so the write is in place by the time we read it.
+	// RunWithApp returns only after the app was asked to stop, either by
+	// an interrupt or by the goroutine's Shutdown call. When op finished
+	// without being cancelled, the goroutine set finished before that
+	// call. So if finished is unset here, an interrupt stopped the app,
+	// and op either returned after it was cancelled or is still running
+	// because the shutdown timed out.
 	mu.Lock()
 	defer mu.Unlock()
 
-	if failed {
+	switch {
+	case !finished:
+		return errInterrupted
+	case failed:
 		return errReported
+	default:
+		return nil
 	}
-
-	return nil
 }
 
 // runVaultikApp runs the standard single-operation command lifecycle

internal/cli/entry.go

@@ -15,6 +15,11 @@ import (
 // the startup banner.
 const shortCommitLen = 12
 
+// exitCodeInterrupted is the exit status of a command that SIGINT or
+// SIGTERM stopped. It is 128 plus SIGINT's number, 2, which is what a
+// shell reports for a command stopped by Ctrl-C.
+const exitCodeInterrupted = 130
+
 // Entry is the main entry point for the CLI application.
 // It prints the startup banner to stderr (unless a banner-suppressing
 // flag is present in os.Args — see bannerSuppressedInArgs), executes the
@@ -23,9 +28,10 @@ const shortCommitLen = 12
 // The banner goes to stderr because stdout carries only the output the
 // user asked for, such as a completion script or a `config get` value.
 //
-// It returns the process exit code (0 on success, 1 on error) rather
-// than calling os.Exit, so that main's deferred profile writers run
-// before the process ends. See run in cmd/vaultik/main.go.
+// It returns the process exit code (0 on success, 130 when interrupted,
+// 1 on any other error) rather than calling os.Exit, so that main's
+// deferred profile writers run before the process ends. See run in
+// cmd/vaultik/main.go.
 func Entry() int {
 	emitStartupBanner(os.Args[1:], os.Stderr)
 
@@ -39,11 +45,16 @@ func Entry() int {
 		// document instead); errReported says so. Printing it again
 		// here would double the error line.
 		// Every other error — bad arguments, a config that would not
-		// load — reaches Entry unreported, so it is shown here.
+		// load, an interrupt — reaches Entry unreported, so it is shown
+		// here.
 		if !errors.Is(err, errReported) {
 			ReportErrorf("%s", err.Error())
 		}
 
+		if errors.Is(err, errInterrupted) {
+			return exitCodeInterrupted
+		}
+
 		return 1
 	}
 

internal/cli/entry_interrupt_test.go

@@ -0,0 +1,203 @@
+package cli //nolint:testpackage // shares runEntry and the argument constants
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/adrg/xdg"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// stalledStoreConfig is hermeticConfig with an s3:// destination store
+// in place of the file:// one. The server behind it accepts any
+// credentials.
+const stalledStoreConfig = `age_recipients:
+  - age1278m9q7dp3chsh2dcy82qk27v047zywyvtxwnj4cvt0z65jw6a7q5dqhfj
+snapshots:
+  test:
+    paths:
+      - %s
+storage_url: s3://bucket?endpoint=%s&ssl=false
+s3:
+  access_key_id: key
+  secret_access_key: secret
+index_path: %s
+hostname: test-host
+`
+
+// interruptRepeat is how often interruptOnFirstRequest sends SIGINT.
+const interruptRepeat = 50 * time.Millisecond
+
+// TestEntryInterruptedRun sends SIGINT to the test process while a
+// command waits on the destination store, and checks that Entry returns
+// 130 and prints one line on stderr saying the run was interrupted. The
+// store is a local HTTP server that holds every request open, so the
+// command is always mid-operation when the signal arrives. The two
+// cases cover --cron and --json, which silence other output.
+//
+// Not parallel: it signals the process and replaces os.Args, os.Stdout,
+// os.Stderr and the xdg globals.
+//
+//nolint:paralleltest // signals the process and replaces process globals
+func TestEntryInterruptedRun(t *testing.T) {
+	for _, testCase := range []struct {
+		name string
+		args []string
+	}{
+		{
+			name: "snapshot create --cron",
+			args: []string{cmdSnapshot, cmdCreate, "--cron"},
+		},
+		{
+			name: "snapshot verify --json",
+			args: []string{cmdSnapshot, cmdVerify, someSnapshotID, flagJSON},
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			endpoint, requestArrived := startStalledStore(t)
+			configPath := writeStalledStoreConfig(t, endpoint)
+			interruptOnFirstRequest(t, requestArrived)
+
+			code, _, stderr := runEntry(t,
+				append([]string{flagConfig, configPath}, testCase.args...)...)
+
+			assert.Equal(t, 130, code)
+			assert.Equal(t, 1,
+				strings.Count(stderr, errInterrupted.Error()), stderr)
+		})
+	}
+}
+
+// interruptOnFirstRequest sends SIGINT to the test process every
+// interruptRepeat, from the first request to the destination store until
+// the test ends. One signal is not enough: the command can reach the
+// store before fx has started catching signals. The test catches SIGINT
+// too, so that a signal fx is not catching does not kill the test
+// binary.
+func interruptOnFirstRequest(t *testing.T, requestArrived <-chan struct{}) {
+	t.Helper()
+
+	self, err := os.FindProcess(os.Getpid())
+	require.NoError(t, err)
+
+	caught := make(chan os.Signal, 1)
+	signal.Notify(caught, os.Interrupt)
+
+	testEnded := make(chan struct{})
+	senderDone := make(chan struct{})
+
+	// Stop catching SIGINT only after the sender has returned. The sender
+	// waits for each SIGINT it sends to arrive on caught; one still on
+	// its way after signal.Stop would kill the test binary.
+	t.Cleanup(func() {
+		close(testEnded)
+		<-senderDone
+		signal.Stop(caught)
+	})
+
+	go func() {
+		defer close(senderDone)
+
+		select {
+		case <-requestArrived:
+		case <-testEnded:
+			return
+		}
+
+		ticker := time.NewTicker(interruptRepeat)
+		defer ticker.Stop()
+
+		for {
+			// Empty caught, so that the receive below waits for this
+			// SIGINT rather than an earlier one.
+			select {
+			case <-caught:
+			default:
+			}
+
+			sendErr := self.Signal(os.Interrupt)
+			if sendErr != nil {
+				t.Errorf("sending SIGINT: %v", sendErr)
+
+				return
+			}
+
+			<-caught
+
+			select {
+			case <-testEnded:
+				return
+			case <-ticker.C:
+			}
+		}
+	}()
+}
+
+// startStalledStore starts an HTTP server that never answers: each
+// request is held until the client gives up on it or the test ends.
+// It returns the server's host:port and a channel that receives a value
+// when the first request arrives.
+func startStalledStore(t *testing.T) (string, <-chan struct{}) {
+	t.Helper()
+
+	requestArrived := make(chan struct{}, 1)
+	release := make(chan struct{})
+
+	server := httptest.NewServer(http.HandlerFunc(
+		func(_ http.ResponseWriter, r *http.Request) {
+			select {
+			case requestArrived <- struct{}{}:
+			default:
+			}
+
+			select {
+			case <-r.Context().Done():
+			case <-release:
+			}
+		}))
+
+	// Cleanups run last-registered first, so release lets any held
+	// request return before Close waits for it.
+	t.Cleanup(server.Close)
+	t.Cleanup(func() { close(release) })
+
+	return server.Listener.Addr().String(), requestArrived
+}
+
+// writeStalledStoreConfig writes a config whose destination store is the
+// server at endpoint and whose snapshot source holds one small file, so
+// that `snapshot create` has a blob to upload. Returns the config path.
+func writeStalledStoreConfig(t *testing.T, endpoint string) string {
+	t.Helper()
+
+	dir := t.TempDir()
+	configPath := filepath.Join(dir, "config.yml")
+	sourceDir := filepath.Join(dir, "source")
+
+	require.NoError(t, os.Mkdir(sourceDir, 0o750))
+	require.NoError(t, os.WriteFile(filepath.Join(sourceDir, "file.txt"),
+		[]byte("contents"), 0o600))
+
+	contents := fmt.Sprintf(stalledStoreConfig,
+		sourceDir, endpoint, filepath.Join(dir, "index.sqlite"))
+
+	require.NoError(t,
+		os.WriteFile(configPath, []byte(contents), configFileMode))
+
+	// The PID lock lives under xdg.DataHome, which xdg resolves at
+	// package init; point it at the temp dir so the test neither
+	// touches nor collides with the real one.
+	t.Setenv("XDG_DATA_HOME", filepath.Join(dir, "data"))
+	xdg.Reload()
+	t.Cleanup(xdg.Reload)
+
+	return configPath
+}

internal/cli/entry_prune_json_test.go

@@ -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

internal/cli/json_help_test.go

@@ -0,0 +1,24 @@
+package cli //nolint:testpackage // exercises the unexported command constructor
+
+import (
+	"testing"
+
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/assert"
+)
+
+// TestJSONHelpSaysConfirmationPromptIsSkipped checks that the --json help
+// of `snapshot remove` and `prune` says the flag skips the confirmation
+// prompt. Both delete without asking under --json, since a prompt on
+// stdout would break the JSON document.
+func TestJSONHelpSaysConfirmationPromptIsSkipped(t *testing.T) {
+	t.Parallel()
+
+	for _, cmd := range []*cobra.Command{
+		newSnapshotRemoveCommand(),
+		NewPruneCommand(),
+	} {
+		assert.Contains(t, cmd.Flags().Lookup("json").Usage,
+			"skips the confirmation prompt", cmd.Name())
+	}
+}

internal/cli/prune.go

@@ -57,7 +57,8 @@ referenced.`,
 	}
 
 	cmd.Flags().BoolVar(&opts.Force, "force", false, "Skip confirmation prompt")
-	cmd.Flags().BoolVar(&opts.JSON, "json", false, "Output pruning stats as JSON")
+	cmd.Flags().BoolVar(&opts.JSON, "json", false,
+		"Output pruning stats as JSON; skips the confirmation prompt, as --force does")
 
 	return cmd
 }

internal/cli/snapshot.go

@@ -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
@@ -280,7 +284,8 @@ nuke --force' — it is the single supported entry point for that.`,
 	cmd.Flags().BoolVarP(&opts.Force, "force", "f", false, "Skip confirmation prompt")
 	cmd.Flags().BoolVar(&opts.DryRun, "dry-run", false,
 		"Show what would be removed without removing")
-	cmd.Flags().BoolVar(&opts.JSON, "json", false, "Output result as JSON")
+	cmd.Flags().BoolVar(&opts.JSON, "json", false,
+		"Output result as JSON; skips the confirmation prompt, as --force does")
 	cmd.Flags().BoolVar(&opts.LocalOnly, "local-only", false,
 		"Skip remote cleanup; only touch the local index")
 

internal/snapshot/progress.go

@@ -56,23 +56,27 @@ const (
 
 // ProgressStats holds atomic counters for progress tracking
 type ProgressStats struct {
-	FilesScanned     atomic.Int64 // Total files seen during scan (includes skipped)
-	FilesProcessed   atomic.Int64 // Files actually processed in phase 2
-	FilesSkipped     atomic.Int64 // Files skipped due to no changes
-	BytesScanned     atomic.Int64 // Bytes from new/changed files only
-	BytesSkipped     atomic.Int64 // Bytes from unchanged files
-	BytesProcessed   atomic.Int64 // Actual bytes processed (for ETA calculation)
-	ChunksCreated    atomic.Int64
-	BlobsCreated     atomic.Int64
-	BlobsUploaded    atomic.Int64
-	BytesUploaded    atomic.Int64
-	CurrentFile      atomic.Value // stores string
-	TotalSize        atomic.Int64 // Total size to process (set after scan phase)
-	TotalFiles       atomic.Int64 // Total files to process in phase 2
-	ProcessStartTime atomic.Value // stores time.Time when processing starts
-	StartTime        time.Time
-	mu               sync.RWMutex
-	lastDetailTime   time.Time
+	FilesScanned   atomic.Int64 // Total files seen during scan (includes skipped)
+	FilesProcessed atomic.Int64 // Files actually processed in phase 2
+	FilesSkipped   atomic.Int64 // Files skipped due to no changes
+	BytesScanned   atomic.Int64 // Bytes from new/changed files only
+	BytesSkipped   atomic.Int64 // Bytes from unchanged files
+	BytesProcessed atomic.Int64 // Actual bytes processed (for ETA calculation)
+	ChunksCreated  atomic.Int64
+	BlobsCreated   atomic.Int64
+	BlobsUploaded  atomic.Int64
+	BytesUploaded  atomic.Int64
+	CurrentFile    atomic.Value // stores string
+	TotalSize      atomic.Int64 // Size to process in the paths scanned so far
+	TotalFiles     atomic.Int64 // Files to process in the paths scanned so far
+	StartTime      time.Time
+	mu             sync.RWMutex
+	lastDetailTime time.Time
+
+	// Guarded by mu: when the last scan phase ended, and
+	// BytesProcessed at that moment.
+	processStartTime  time.Time
+	processStartBytes int64
 
 	// Upload tracking
 	CurrentUpload    atomic.Value // stores *UploadInfo
@@ -148,10 +152,36 @@ func (pr *ProgressReporter) GetStats() *ProgressStats {
 	return pr.stats
 }
 
-// SetTotalSize sets the total size to process (after scan phase)
-func (pr *ProgressReporter) SetTotalSize(size int64) {
-	pr.stats.TotalSize.Store(size)
-	pr.stats.ProcessStartTime.Store(time.Now().UTC())
+// AddTotalSize adds the size one path of the snapshot has to process to
+// the total, once that path's scan phase is done, and starts measuring
+// the processing rate again. The processed counts run across every path,
+// so the total does too. Restarting the rate keeps a path's scan phase,
+// which processes nothing, out of the rate while that path is processed.
+// During a later path's scan phase the rate is still the previous
+// path's, and falls as that scan goes on.
+func (pr *ProgressReporter) AddTotalSize(size int64) {
+	pr.stats.TotalSize.Add(size)
+
+	pr.stats.mu.Lock()
+	defer pr.stats.mu.Unlock()
+
+	pr.stats.processStartTime = time.Now().UTC()
+	pr.stats.processStartBytes = pr.stats.BytesProcessed.Load()
+}
+
+// processRate returns the bytes processed per second since the last scan
+// phase ended, or 0 before the first path's scan phase is done.
+func (s *ProgressStats) processRate() float64 {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	if s.processStartTime.IsZero() {
+		return 0
+	}
+
+	processed := s.BytesProcessed.Load() - s.processStartBytes
+
+	return float64(processed) / time.Since(s.processStartTime).Seconds()
 }
 
 // Helper functions
@@ -357,19 +387,12 @@ func (pr *ProgressReporter) printSummaryStatus() {
 	// Calculate ETA if we have total size and are processing
 	etaStr := ""
 
-	if totalSize > 0 && bytesProcessed > 0 {
-		processStart, ok := pr.stats.ProcessStartTime.Load().(time.Time)
-		if ok && !processStart.IsZero() {
-			processElapsed := time.Since(processStart)
-
-			rate := float64(bytesProcessed) / processElapsed.Seconds()
-			if rate > 0 {
-				remainingBytes := totalSize - bytesProcessed
-				remainingSeconds := float64(remainingBytes) / rate
-				eta := time.Duration(remainingSeconds * float64(time.Second))
-				etaStr = " | ETA: " + formatDuration(eta)
-			}
-		}
+	processRate := pr.stats.processRate()
+	if totalSize > 0 && processRate > 0 {
+		remainingBytes := totalSize - bytesProcessed
+		remainingSeconds := float64(remainingBytes) / processRate
+		eta := time.Duration(remainingSeconds * float64(time.Second))
+		etaStr = " | ETA: " + formatDuration(eta)
 	}
 
 	rate := float64(bytesScanned+bytesSkipped) / elapsed.Seconds()
@@ -421,25 +444,18 @@ func (pr *ProgressReporter) printDetailedStatus() {
 	log.Info("Elapsed time", "duration", formatDuration(elapsed))
 
 	// Calculate and show ETA if we have data
-	if totalSize > 0 && bytesProcessed > 0 {
-		processStart, ok := pr.stats.ProcessStartTime.Load().(time.Time)
-		if ok && !processStart.IsZero() {
-			processElapsed := time.Since(processStart)
-
-			processRate := float64(bytesProcessed) / processElapsed.Seconds()
-			if processRate > 0 {
-				remainingBytes := totalSize - bytesProcessed
-				remainingSeconds := float64(remainingBytes) / processRate
-				eta := time.Duration(remainingSeconds * float64(time.Second))
-				percentComplete := float64(bytesProcessed) / float64(totalSize) * percentScale
-				log.Info("Overall progress",
-					"percent", fmt.Sprintf("%.1f%%", percentComplete),
-					"processed", humanize.Bytes(safeUint64(bytesProcessed)),
-					"total", humanize.Bytes(safeUint64(totalSize)),
-					"rate", humanize.Bytes(uint64(processRate))+"/s",
-					"eta", formatDuration(eta))
-			}
-		}
+	processRate := pr.stats.processRate()
+	if totalSize > 0 && processRate > 0 {
+		remainingBytes := totalSize - bytesProcessed
+		remainingSeconds := float64(remainingBytes) / processRate
+		eta := time.Duration(remainingSeconds * float64(time.Second))
+		percentComplete := float64(bytesProcessed) / float64(totalSize) * percentScale
+		log.Info("Overall progress",
+			"percent", fmt.Sprintf("%.1f%%", percentComplete),
+			"processed", humanize.Bytes(safeUint64(bytesProcessed)),
+			"total", humanize.Bytes(safeUint64(totalSize)),
+			"rate", humanize.Bytes(uint64(processRate))+"/s",
+			"eta", formatDuration(eta))
 	}
 
 	log.Info("Files processed",

internal/snapshot/progress_rate_test.go

@@ -0,0 +1,54 @@
+//nolint:testpackage // exercises the unexported processRate helper
+package snapshot
+
+import (
+	"testing"
+	"time"
+)
+
+// TestProcessRateNotLoweredByLaterScanPhase feeds the reporter two paths
+// that each take 10 seconds to process, the second after a 30-second scan
+// phase. That scan phase processes nothing, so the rate while the second
+// path is processed must be that path's own.
+func TestProcessRateNotLoweredByLaterScanPhase(t *testing.T) {
+	t.Parallel()
+
+	const (
+		pathSize       = 1000
+		processingTime = 10 * time.Second
+		scanTime       = 30 * time.Second
+	)
+
+	// Never started, but Stop releases its tickers and signal handler.
+	progress := NewProgressReporter()
+	defer progress.Stop()
+
+	stats := progress.GetStats()
+
+	// Moves the processing start time back instead of sleeping.
+	elapse := func(d time.Duration) {
+		stats.mu.Lock()
+		defer stats.mu.Unlock()
+
+		stats.processStartTime = stats.processStartTime.Add(-d)
+	}
+
+	progress.AddTotalSize(pathSize)
+	stats.BytesProcessed.Add(pathSize)
+	elapse(processingTime)
+
+	elapse(scanTime)
+	progress.AddTotalSize(pathSize)
+	stats.BytesProcessed.Add(pathSize)
+	elapse(processingTime)
+
+	want := pathSize / processingTime.Seconds()
+	got := stats.processRate()
+
+	// The test's own run time adds to the elapsed time, so got is a hair
+	// under want.
+	if got > want || got < want*0.99 {
+		t.Errorf("rate while the second path is processed is %.1f bytes/s, "+
+			"want %.1f", got, want)
+	}
+}

internal/snapshot/progress_test.go

@@ -0,0 +1,94 @@
+package snapshot_test
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/spf13/afero"
+	"sneak.berlin/go/vaultik/internal/database"
+	"sneak.berlin/go/vaultik/internal/snapshot"
+)
+
+// TestProgressPercentWithSecondPathSmaller backs up two paths with one
+// scanner, as a snapshot with two paths does, the second path smaller
+// than the first. The progress line divides the bytes processed by the
+// total size, so both must count both paths to stay within 100%.
+func TestProgressPercentWithSecondPathSmaller(t *testing.T) {
+	t.Parallel()
+
+	fs := afero.NewMemMapFs()
+	files := map[string]string{
+		"/large/one.txt":   strings.Repeat("1", 4000),
+		"/large/two.txt":   strings.Repeat("2", 4000),
+		"/small/three.txt": strings.Repeat("3", 1000),
+	}
+
+	for path, content := range files {
+		err := fs.MkdirAll(filepath.Dir(path), 0755)
+		if err != nil {
+			t.Fatalf("mkdir: %v", err)
+		}
+
+		err = afero.WriteFile(fs, path, []byte(content), 0644)
+		if err != nil {
+			t.Fatalf("write %s: %v", path, err)
+		}
+	}
+
+	db, err := database.NewTestDB()
+	if err != nil {
+		t.Fatalf("create test db: %v", err)
+	}
+
+	t.Cleanup(func() {
+		cerr := db.Close()
+		if cerr != nil {
+			t.Errorf("close db: %v", cerr)
+		}
+	})
+
+	repos := database.NewRepositories(db)
+
+	scanner := snapshot.NewScanner(snapshot.ScannerConfig{
+		FS:               fs,
+		ChunkSize:        int64(1024 * 16),
+		Repositories:     repos,
+		MaxBlobSize:      int64(1024 * 1024),
+		CompressionLevel: 3,
+		AgeRecipients:    []string{testAgePublicKey},
+		EnableProgress:   true,
+	})
+
+	// Never started, but Stop releases its tickers and signal handler.
+	progress := scanner.GetProgress()
+	defer progress.Stop()
+
+	ctx := context.Background()
+	snapshotID := "test-snapshot-progress"
+	createTestSnapshotRecord(ctx, t, repos, snapshotID)
+
+	for _, path := range []string{"/large", "/small"} {
+		_, err := scanner.Scan(ctx, path, snapshotID)
+		if err != nil {
+			t.Fatalf("scanning %s: %v", path, err)
+		}
+	}
+
+	stats := progress.GetStats()
+
+	// Directories count toward the total size but produce no chunks, so
+	// the percentage ends just under 100%.
+	percent := float64(stats.BytesProcessed.Load()) /
+		float64(stats.TotalSize.Load()) * 100
+	if percent > 100 {
+		t.Errorf("progress after both paths is %.1f%%, want at most 100%%",
+			percent)
+	}
+
+	if stats.FilesProcessed.Load() != stats.TotalFiles.Load() {
+		t.Errorf("progress after both paths is %d of %d files, want all",
+			stats.FilesProcessed.Load(), stats.TotalFiles.Load())
+	}
+}

internal/snapshot/scanner.go

@@ -133,10 +133,13 @@ type ScannerConfig struct {
 
 // ScanResult contains the results of a scan operation. Files and bytes
 // are counted per file: BytesScanned is the size of the new and changed
-// files, BytesSkipped that of the unchanged ones.
+// files, BytesSkipped that of the unchanged ones. FilesFailed counts the
+// new and changed files that phase 2 could not store; FilesScanned
+// includes them and BytesScanned does not.
 type ScanResult struct {
 	FilesScanned   int
 	FilesSkipped   int
+	FilesFailed    int
 	FilesDeleted   int
 	BytesScanned   int64
 	BytesSkipped   int64
@@ -407,8 +410,8 @@ func (s *Scanner) summarizeScanPhase(
 	}
 
 	if s.progress != nil {
-		s.progress.SetTotalSize(totalSizeToProcess)
-		s.progress.GetStats().TotalFiles.Store(int64(len(filesToProcess)))
+		s.progress.AddTotalSize(totalSizeToProcess)
+		s.progress.GetStats().TotalFiles.Add(int64(len(filesToProcess)))
 	}
 
 	log.Info("Phase 1 complete",
@@ -889,9 +892,10 @@ func (s *Scanner) scanPhase(
 		}
 
 		// Handle symlinks and directories
-		if handled := s.recordSpecialEntry(
-			filePath, info, existingFiles, collector, result); handled {
-			return nil
+		handled, err := s.recordSpecialEntry(
+			filePath, info, existingFiles, collector, result)
+		if handled {
+			return err
 		}
 
 		// Skip other non-regular files (devices, sockets, etc.)
@@ -933,22 +937,25 @@ func (s *Scanner) scanPhase(
 }
 
 // recordSpecialEntry records symlinks and directories (which have no
-// data to chunk) and reports whether it handled the entry.
+// data to chunk) and reports whether it handled the entry. For a symlink
+// whose target cannot be read it returns handleWalkError's result.
 func (s *Scanner) recordSpecialEntry(
 	filePath string, info os.FileInfo,
 	existingFiles map[string]struct{},
 	collector *scanCollector, result *ScanResult,
-) bool {
+) (bool, error) {
 	// Handle symlinks
 	if info.Mode()&os.ModeSymlink != 0 {
-		file := s.buildSymlinkEntry(filePath, info)
-		if file != nil {
-			existingFiles[filePath] = struct{}{}
-			collector.addToProcess(filePath, info, file)
-			s.updateScanEntryStats(result, true, info)
+		file, err := s.buildSymlinkEntry(filePath, info)
+		if err != nil {
+			return true, s.handleWalkError(filePath, err)
 		}
 
-		return true
+		existingFiles[filePath] = struct{}{}
+		collector.addToProcess(filePath, info, file)
+		s.updateScanEntryStats(result, true, info)
+
+		return true, nil
 	}
 
 	// Handle directories (record for permission/ownership preservation
@@ -958,10 +965,10 @@ func (s *Scanner) recordSpecialEntry(
 		existingFiles[filePath] = struct{}{}
 		collector.addToProcess(filePath, info, file)
 
-		return true
+		return true, nil
 	}
 
-	return false
+	return false, nil
 }
 
 // handleWalkError deals with a filesystem error surfaced by the walk:
@@ -1111,13 +1118,12 @@ func (s *Scanner) printScanProgressLine(
 }
 
 // buildSymlinkEntry creates a File record for a symlink.
-// Returns nil if the link target cannot be read.
-func (s *Scanner) buildSymlinkEntry(path string, info os.FileInfo) *database.File {
+func (s *Scanner) buildSymlinkEntry(
+	path string, info os.FileInfo,
+) (*database.File, error) {
 	target, err := os.Readlink(path)
 	if err != nil {
-		log.Debug("Cannot read symlink target", "path", path, "error", err)
-
-		return nil
+		return nil, err
 	}
 
 	var uid, gid uint32
@@ -1136,7 +1142,7 @@ func (s *Scanner) buildSymlinkEntry(path string, info os.FileInfo) *database.Fil
 		UID:        uid,
 		GID:        gid,
 		LinkTarget: types.FilePath(target),
-	}
+	}, nil
 }
 
 // buildDirectoryEntry creates a File record for a directory.
@@ -1306,6 +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)
@@ -1342,13 +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
@@ -1362,7 +1394,7 @@ func (s *Scanner) processFileWithErrorHandling(
 			log.Warn("File was deleted during backup, skipping",
 				"path", fileToProcess.Path)
 
-			result.FilesSkipped++
+			countFailedFile(fileToProcess, result)
 
 			return true, nil
 		}
@@ -1373,7 +1405,7 @@ func (s *Scanner) processFileWithErrorHandling(
 			s.ui.Errorf("Failed to process %s: %v. Skipping (--skip-errors).",
 				s.ui.Path(fileToProcess.Path), err)
 
-			result.FilesSkipped++
+			countFailedFile(fileToProcess, result)
 
 			return true, nil
 		}
@@ -1384,6 +1416,13 @@ func (s *Scanner) processFileWithErrorHandling(
 	return false, nil
 }
 
+// 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.
+func countFailedFile(fileToProcess *FileToProcess, result *ScanResult) {
+	result.FilesFailed++
+	result.BytesScanned -= fileToProcess.FileInfo.Size()
+}
+
 // printProcessingProgress prints a periodic progress line during the process phase,
 // showing files processed, bytes transferred, throughput, and ETA
 func (s *Scanner) printProcessingProgress(
@@ -1752,16 +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))

internal/snapshot/skip_errors_test.go

@@ -3,6 +3,7 @@ package snapshot_test
 import (
 	"context"
 	"errors"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -13,6 +14,7 @@ import (
 	"github.com/spf13/afero"
 	"sneak.berlin/go/vaultik/internal/database"
 	"sneak.berlin/go/vaultik/internal/snapshot"
+	"sneak.berlin/go/vaultik/internal/ui"
 )
 
 // errSimTempFail is the one-time temp-file creation failure blobTempFailFs
@@ -80,6 +82,56 @@ 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.
+type linkRemovedAfterLstatFs struct {
+	afero.OsFs
+
+	t      *testing.T
+	target string
+}
+
+func (f *linkRemovedAfterLstatFs) LstatIfPossible(
+	name string,
+) (os.FileInfo, bool, error) {
+	info, lstatCalled, err := f.OsFs.LstatIfPossible(name)
+	if err == nil && name == f.target {
+		rmErr := os.Remove(name)
+		if rmErr != nil {
+			f.t.Errorf("removing %s: %v", name, rmErr)
+		}
+	}
+
+	return info, lstatCalled, err
+}
+
 // writeSkipErrorTestFile writes one file into fs with a fixed mtime.
 func writeSkipErrorTestFile(t *testing.T, fs afero.Fs, path, content string) {
 	t.Helper()
@@ -102,14 +154,16 @@ func writeSkipErrorTestFile(t *testing.T, fs afero.Fs, path, content string) {
 	}
 }
 
-// runSkipErrorScan scans /source on fs with the given skip-errors setting and
+// 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, skipErrors bool,
+	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)
 	}
@@ -130,14 +184,14 @@ func runSkipErrorScan(
 		MaxBlobSize:      int64(1024 * 1024),
 		CompressionLevel: 3,
 		AgeRecipients:    []string{testAgePublicKey},
+		UI:               uiw,
 		SkipErrors:       skipErrors,
 	})
 
-	ctx := context.Background()
 	snapshotID := "test-snapshot-skip-errors"
 	createTestSnapshotRecord(ctx, t, repos, snapshotID)
 
-	_, err = scanner.Scan(ctx, "/source", snapshotID)
+	_, err = scanner.Scan(ctx, source, snapshotID)
 
 	return repos, err
 }
@@ -157,7 +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, true)
+	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")
 	}
@@ -184,7 +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, false)
+	_, err := runSkipErrorScan(context.Background(), t, fs, "/source", false, nil)
 	if err == nil {
 		t.Fatal("expected scan to fail on the read error, got nil")
 	}
@@ -200,7 +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, true)
+	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)
 	}
@@ -214,3 +268,116 @@ func TestScannerReadErrorSkippedWithSkipErrors(t *testing.T) {
 		t.Fatalf("expected unreadable file skipped, got %d chunks", len(chunks))
 	}
 }
+
+// writeSymlinkSource creates a source directory on disk holding one symlink
+// and returns the directory and the symlink's path.
+func writeSymlinkSource(t *testing.T) (string, string) {
+	t.Helper()
+
+	sourceDir := t.TempDir()
+	linkPath := filepath.Join(sourceDir, "link")
+
+	err := os.Symlink("target.txt", linkPath)
+	if err != nil {
+		t.Fatalf("creating symlink: %v", err)
+	}
+
+	return sourceDir, linkPath
+}
+
+// TestScannerUnreadableSymlinkAbortsWithoutSkipErrors checks that a symlink
+// whose target cannot be read aborts the run when --skip-errors is not set.
+func TestScannerUnreadableSymlinkAbortsWithoutSkipErrors(t *testing.T) {
+	t.Parallel()
+
+	sourceDir, linkPath := writeSymlinkSource(t)
+	fs := &linkRemovedAfterLstatFs{t: t, target: linkPath}
+
+	_, 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)
+	}
+}
+
+// TestScannerUnreadableSymlinkSkippedWithSkipErrors checks that a symlink
+// whose target cannot be read is skipped with an error line, and the run
+// completes, when --skip-errors is set.
+func TestScannerUnreadableSymlinkSkippedWithSkipErrors(t *testing.T) {
+	t.Parallel()
+
+	sourceDir, linkPath := writeSymlinkSource(t)
+	fs := &linkRemovedAfterLstatFs{t: t, target: linkPath}
+	uiw := ui.NewWithColor(io.Discard, false)
+
+	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)
+	}
+
+	if uiw.ErrorCount() != 1 {
+		t.Fatalf("expected one error line for the symlink, got %d",
+			uiw.ErrorCount())
+	}
+
+	file, err := repos.Files.GetByPath(context.Background(), linkPath)
+	if err != nil {
+		t.Fatalf("getting %s: %v", linkPath, err)
+	}
+
+	if file != nil {
+		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())
+			}
+		})
+	}
+}

internal/snapshot/snapshot.go

@@ -115,20 +115,37 @@ func ShortHostname(hostname string) string {
 
 // CreateSnapshotWithName creates a new snapshot record with an optional
 // snapshot name. The snapshot ID format is: hostname_name_timestamp or
-// hostname_timestamp if name is empty.
+// hostname_timestamp if name is empty. The timestamp is in whole seconds.
+// If the local index already has a snapshot with that ID, from a run of the
+// same name that started in the same second, it waits a second and takes a
+// new timestamp.
 func (sm *SnapshotManager) CreateSnapshotWithName(
 	ctx context.Context, hostname, name, version, gitRevision string,
 ) (string, error) {
 	shortHostname := ShortHostname(hostname)
 
-	// Build snapshot ID with optional name
-	timestamp := time.Now().UTC().Format("2006-01-02T15:04:05Z")
-
 	var snapshotID string
-	if name != "" {
-		snapshotID = fmt.Sprintf("%s_%s_%s", shortHostname, name, timestamp)
-	} else {
-		snapshotID = fmt.Sprintf("%s_%s", shortHostname, timestamp)
+
+	for {
+		// Build snapshot ID with optional name
+		timestamp := time.Now().UTC().Format("2006-01-02T15:04:05Z")
+
+		if name != "" {
+			snapshotID = fmt.Sprintf("%s_%s_%s", shortHostname, name, timestamp)
+		} else {
+			snapshotID = fmt.Sprintf("%s_%s", shortHostname, timestamp)
+		}
+
+		existing, err := sm.repos.Snapshots.GetByID(ctx, snapshotID)
+		if err != nil {
+			return "", fmt.Errorf("looking up snapshot %s: %w", snapshotID, err)
+		}
+
+		if existing == nil {
+			break
+		}
+
+		time.Sleep(time.Second)
 	}
 
 	snapshot := &database.Snapshot{
@@ -875,7 +892,7 @@ func (sm *SnapshotManager) getFileSize(path string) int64 {
 // BackupStats contains statistics from a backup operation
 type BackupStats struct {
 	FilesScanned  int
-	TotalSize     int64 // Total size of all files examined
+	TotalSize     int64 // Total size of the files in the snapshot
 	ChunksCreated int
 	BlobsCreated  int
 	BytesUploaded int64

internal/snapshot/snapshot_test.go

@@ -386,3 +386,36 @@ func TestCleanSnapshotDBNonExistentSnapshot(t *testing.T) {
 		t.Fatalf("unexpected error: %v", err)
 	}
 }
+
+// Two creates of one snapshot name back to back start within one second,
+// the resolution of the timestamp in a snapshot ID. See
+// https://git.eeqj.de/sneak/vaultik/issues/270.
+func TestCreateSnapshotWithNameTwiceBackToBack(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+
+	db, err := database.New(ctx, filepath.Join(t.TempDir(), "index.sqlite"))
+	if err != nil {
+		t.Fatalf("failed to create database: %v", err)
+	}
+
+	defer func() { _ = db.Close() }()
+
+	sm := &SnapshotManager{repos: database.NewRepositories(db)}
+
+	first, err := sm.CreateSnapshotWithName(ctx, "test-host", "data", "v", "g")
+	if err != nil {
+		t.Fatalf("first create failed: %v", err)
+	}
+
+	second, err := sm.CreateSnapshotWithName(ctx, "test-host", "data", "v", "g")
+	if err != nil {
+		t.Fatalf("second create failed: %v", err)
+	}
+
+	if first == second {
+		t.Fatalf("both creates returned snapshot ID %s", first)
+	}
+}

internal/storage/conformance_test.go

@@ -14,8 +14,9 @@ import (
 
 // runStorerConformance is the shared Storer contract. Every backend that
 // can run in-process is expected to pass it: TestFileStorer runs it against
-// file://, TestS3Storer against s3://. A new backend inherits this coverage
-// by passing its own constructor, so the contract is defined once.
+// file://, TestS3Storer against s3://, TestRcloneStorer against rclone's
+// local backend. A new backend inherits this coverage by passing its own
+// constructor, so the contract is defined once.
 //
 // It exercises the public Storer interface: round-trip, stat, list with
 // prefix filtering, overwrite, delete, delete-of-missing, and not-found on

internal/storage/faultstore/faultstore.go

@@ -171,6 +171,11 @@ func (f *Storer) ListStream(
 	return f.inner.ListStream(ctx, prefix)
 }
 
+// DeletePartialUploads delegates unchanged.
+func (f *Storer) DeletePartialUploads(ctx context.Context, prefix string) error {
+	return f.inner.DeletePartialUploads(ctx, prefix)
+}
+
 // Info delegates unchanged.
 func (f *Storer) Info() storage.Info {
 	return f.inner.Info()

internal/storage/file.go

@@ -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.
@@ -50,9 +51,10 @@ const storageDirPerm = 0o755
 // temp file carrying this suffix and only renames it onto the real key once
 // the whole object is on disk, so an interrupted write can never leave a
 // truncated object at the key a later run would Stat and trust as a complete
-// blob. List and ListStream skip these files, so a leftover from an
-// interrupted write is never listed or trusted as a blob; it is otherwise
-// harmless and is overwritten when the same key is written again.
+// blob. The rclone backend's upload does the same on remotes with a
+// server-side move. List and ListStream skip these files, so a leftover from
+// an interrupted write is never listed or trusted as a blob; it is otherwise
+// harmless.
 const tempSuffix = ".partial"
 
 // Put stores data at the specified key.
@@ -241,6 +243,42 @@ func (f *FileStorer) ListStream(ctx context.Context, prefix string) <-chan Objec
 	return ch
 }
 
+// DeletePartialUploads removes every file under prefix whose name ends in
+// tempSuffix. A missing prefix has none to remove.
+func (f *FileStorer) DeletePartialUploads(ctx context.Context, prefix string) error {
+	basePath := f.fullPath(prefix)
+
+	exists, err := afero.Exists(f.fs, basePath)
+	if err != nil {
+		return fmt.Errorf("checking path: %w", err)
+	}
+
+	if !exists {
+		return nil
+	}
+
+	err = afero.Walk(f.fs, basePath, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+
+		if info.IsDir() || !strings.HasSuffix(info.Name(), tempSuffix) {
+			return nil
+		}
+
+		return f.fs.Remove(path)
+	})
+	if err != nil {
+		return fmt.Errorf("walking directory: %w", err)
+	}
+
+	return nil
+}
+
 // Info returns human-readable storage location information.
 func (f *FileStorer) Info() Info {
 	return Info{
@@ -260,7 +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)
 	}

internal/storage/file_atomic_test.go

@@ -14,6 +14,9 @@ import (
 // errStreamInterrupted stands in for an upload cut off mid-stream.
 var errStreamInterrupted = errors.New("connection reset mid-upload")
 
+// testBlobKey is a key laid out as a blob's key is.
+const testBlobKey = "blobs/aa/bb/aabbccddeeff"
+
 // failingReader yields its data once, then fails.
 type failingReader struct {
 	data []byte
@@ -43,7 +46,7 @@ func TestFileStorer_InterruptedWriteLeavesNoTrustedObject(t *testing.T) {
 	}
 
 	ctx := context.Background()
-	key := "blobs/aa/bb/aabbccddeeff"
+	key := testBlobKey
 
 	err = f.PutWithProgress(ctx, key, &failingReader{data: []byte("partial")}, 4096, nil)
 	if err == nil {
@@ -79,7 +82,7 @@ func TestFileStorer_ListSkipsPartialFiles(t *testing.T) {
 	}
 
 	ctx := context.Background()
-	realKey := "blobs/aa/bb/aabbccddeeff"
+	realKey := testBlobKey
 
 	err = f.Put(ctx, realKey, strings.NewReader("blob-bytes"))
 	if err != nil {
@@ -117,3 +120,45 @@ func TestFileStorer_ListSkipsPartialFiles(t *testing.T) {
 		t.Fatalf("ListStream should return only the real key, got %v", streamed)
 	}
 }
+
+// TestFileStorer_DeletePartialUploads checks that a leftover temp file is
+// removed and the object at the real key is kept.
+func TestFileStorer_DeletePartialUploads(t *testing.T) {
+	t.Parallel()
+
+	base := t.TempDir()
+
+	f, err := storage.NewFileStorer(base)
+	if err != nil {
+		t.Fatalf("NewFileStorer: %v", err)
+	}
+
+	ctx := context.Background()
+
+	err = f.Put(ctx, testBlobKey, strings.NewReader("blob-bytes"))
+	if err != nil {
+		t.Fatalf("Put: %v", err)
+	}
+
+	leftover := filepath.Join(base, testBlobKey+"-123456.partial")
+
+	err = os.WriteFile(leftover, []byte("half"), 0o600)
+	if err != nil {
+		t.Fatalf("writing leftover temp file: %v", err)
+	}
+
+	err = f.DeletePartialUploads(ctx, "blobs/")
+	if err != nil {
+		t.Fatalf("DeletePartialUploads: %v", err)
+	}
+
+	_, err = os.Stat(leftover)
+	if !os.IsNotExist(err) {
+		t.Errorf("leftover temp file was not removed: %v", err)
+	}
+
+	_, err = f.Stat(ctx, testBlobKey)
+	if err != nil {
+		t.Errorf("Stat of the real key: %v", err)
+	}
+}

internal/storage/file_backend_test.go

@@ -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)
+	}
+}

internal/storage/rclone.go

@@ -3,6 +3,7 @@ package storage
 import (
 	"bytes"
 	"context"
+	"crypto/rand"
 	"errors"
 	"fmt"
 	"io"
@@ -68,14 +69,7 @@ func (r *RcloneStorer) Put(ctx context.Context, key string, data io.Reader) erro
 		return fmt.Errorf("reading data: %w", err)
 	}
 
-	// Upload the object
-	_, err = operations.Rcat(ctx, r.fsys, key,
-		io.NopCloser(bytes.NewReader(buf)), time.Now(), nil)
-	if err != nil {
-		return fmt.Errorf("uploading object: %w", err)
-	}
-
-	return nil
+	return r.upload(ctx, key, bytes.NewReader(buf))
 }
 
 // PutWithProgress stores data with progress reporting.
@@ -89,13 +83,7 @@ func (r *RcloneStorer) PutWithProgress(
 		callback: progress,
 	}
 
-	// Upload the object
-	_, err := operations.Rcat(ctx, r.fsys, key, io.NopCloser(pr), time.Now(), nil)
-	if err != nil {
-		return fmt.Errorf("uploading object: %w", err)
-	}
-
-	return nil
+	return r.upload(ctx, key, pr)
 }
 
 // Get retrieves data from the specified key.
@@ -173,6 +161,10 @@ func (r *RcloneStorer) List(ctx context.Context, prefix string) ([]string, error
 
 	err := operations.ListFn(ctx, r.fsys, func(obj fs.Object) {
 		key := obj.Remote()
+		if strings.HasSuffix(key, tempSuffix) {
+			return
+		}
+
 		if prefix == "" || strings.HasPrefix(key, prefix) {
 			keys = append(keys, key)
 		}
@@ -202,6 +194,10 @@ func (r *RcloneStorer) ListStream(
 			}
 
 			key := obj.Remote()
+			if strings.HasSuffix(key, tempSuffix) {
+				return
+			}
+
 			if prefix == "" || strings.HasPrefix(key, prefix) {
 				ch <- ObjectInfo{
 					Key:  key,
@@ -217,6 +213,31 @@ func (r *RcloneStorer) ListStream(
 	return ch
 }
 
+// DeletePartialUploads removes every object under prefix whose name ends
+// in tempSuffix.
+func (r *RcloneStorer) DeletePartialUploads(ctx context.Context, prefix string) error {
+	var partial []fs.Object
+
+	err := operations.ListFn(ctx, r.fsys, func(obj fs.Object) {
+		key := obj.Remote()
+		if strings.HasPrefix(key, prefix) && strings.HasSuffix(key, tempSuffix) {
+			partial = append(partial, obj)
+		}
+	})
+	if err != nil {
+		return fmt.Errorf("listing objects: %w", err)
+	}
+
+	for _, obj := range partial {
+		err = obj.Remove(ctx)
+		if err != nil {
+			return fmt.Errorf("removing object: %w", err)
+		}
+	}
+
+	return nil
+}
+
 // Info returns human-readable storage location information.
 func (r *RcloneStorer) Info() Info {
 	location := r.remote
@@ -230,6 +251,59 @@ func (r *RcloneStorer) Info() Info {
 	}
 }
 
+// upload writes data to key. Where the remote has a server-side move, it
+// writes under a temporary name ending in tempSuffix and moves the object
+// onto key once it is complete, so a killed upload cannot leave a truncated
+// object at key; a remote without one is written in place. List and
+// ListStream skip a temporary object left behind.
+//
+// rclone's own copy does this only where the remote also sets
+// PartialUploads. That flag is not checked here: hdfs, for one, shows a
+// file while it is written without setting it.
+func (r *RcloneStorer) upload(ctx context.Context, key string, data io.Reader) error {
+	if r.fsys.Features().Move == nil {
+		_, err := operations.Rcat(ctx, r.fsys, key, io.NopCloser(data), time.Now(), nil)
+		if err != nil {
+			return fmt.Errorf("uploading object: %w", err)
+		}
+
+		return nil
+	}
+
+	tempKey := key + "-" + rand.Text() + tempSuffix
+
+	obj, err := operations.Rcat(ctx, r.fsys, tempKey, io.NopCloser(data), time.Now(), nil)
+	if err != nil {
+		// Rcat returns the object it wrote when the written data fails its check.
+		if obj != nil {
+			_ = obj.Remove(ctx)
+		}
+
+		return fmt.Errorf("uploading object: %w", err)
+	}
+
+	// On drive, dropbox, onedrive and others the remote's own move does not
+	// replace an object already at key. operations.Move removes the object
+	// it is given first, and copies where the remote refuses the move.
+	existing, err := r.fsys.NewObject(ctx, key)
+	if errors.Is(err, fs.ErrorObjectNotFound) {
+		existing = nil
+	} else if err != nil {
+		_ = obj.Remove(ctx)
+
+		return fmt.Errorf("looking up existing object: %w", err)
+	}
+
+	_, err = operations.Move(ctx, r.fsys, existing, key, obj)
+	if err != nil {
+		_ = obj.Remove(ctx)
+
+		return fmt.Errorf("moving object into place: %w", err)
+	}
+
+	return nil
+}
+
 // progressReader wraps an io.Reader to track read progress.
 type progressReader struct {
 	reader   io.Reader

internal/storage/rclone_test.go

@@ -1,28 +1,47 @@
 package storage_test
 
 import (
+	"bytes"
 	"context"
 	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
 	"testing"
 
+	"github.com/rclone/rclone/fs"
+	"github.com/rclone/rclone/fs/config/configmap"
 	"sneak.berlin/go/vaultik/internal/storage"
 )
 
-// The rclone backend is a thin adapter over the rclone library: it turns a
-// (remote, path) pair into rclone's "remote:path" string, hands it to
-// rclone, and maps rclone's own results back to the Storer interface. What
-// can be tested in-process, without a configured remote or network, is that
-// adapter layer — how the arguments are shaped and how construction errors
-// are reported. The data-plane operations (Put/Get/List/Delete) are rclone's
-// own, exercised against a real provider (drive, s3-via-rclone, ...), which
-// needs a configured remote with credentials and network access and so is
-// out of reach of a unit test. The shared Storer conformance suite therefore
-// runs against the in-process file and s3 backends; the rclone backend
-// inherits that contract once a remote is configured.
-//
 // These tests use rclone's ":local:" on-the-fly backend, which addresses the
-// local filesystem directly without any configured remote, so construction
-// runs entirely in-process.
+// local filesystem directly without any configured remote, so they run
+// entirely in-process. A remote that needs credentials and network access
+// (drive, s3 via rclone, ...) is out of reach of a unit test.
+
+// newRcloneStorer builds an rclone backend on rclone's local backend,
+// rooted at a fresh temp directory.
+//
+//nolint:ireturn // conformance runs against the Storer interface by design
+func newRcloneStorer(t *testing.T) storage.Storer {
+	t.Helper()
+
+	s, err := storage.NewRcloneStorer(context.Background(), ":local", t.TempDir())
+	if err != nil {
+		t.Fatalf("NewRcloneStorer: %v", err)
+	}
+
+	return s
+}
+
+// TestRcloneStorer runs the shared Storer contract against the rclone
+// backend.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorer(t *testing.T) {
+	runStorerConformance(t, newRcloneStorer)
+}
 
 // TestNewRcloneStorerConstruction checks that a valid remote constructs a
 // backend and that Info() reports the shaped "remote:path" location.
@@ -44,6 +63,321 @@ func TestNewRcloneStorerConstruction(t *testing.T) {
 	}
 }
 
+// unbufferedUploadContext returns a context in which rclone neither reads
+// ahead of the write nor holds a small upload in memory. Without it, a
+// progress callback runs before anything is written to the remote.
+func unbufferedUploadContext() context.Context {
+	ctx, ci := fs.AddConfig(context.Background())
+	ci.BufferSize = 0
+	ci.StreamingUploadCutoff = 0
+
+	return ctx
+}
+
+// objectAtKeyDuringUpload uploads data to testBlobKey and reports whether
+// an object was at the key before the upload finished. It fails the test
+// unless the key then reads back as the uploaded data.
+func objectAtKeyDuringUpload(
+	ctx context.Context, t *testing.T, s *storage.RcloneStorer,
+) bool {
+	t.Helper()
+
+	data := bytes.Repeat([]byte("blob-bytes"), 1000)
+	seen := false
+
+	err := s.PutWithProgress(ctx, testBlobKey, bytes.NewReader(data),
+		int64(len(data)), func(int64) error {
+			_, statErr := s.Stat(ctx, testBlobKey)
+			if statErr == nil {
+				seen = true
+			}
+
+			return nil
+		})
+	if err != nil {
+		t.Fatalf("PutWithProgress: %v", err)
+	}
+
+	got := readObject(ctx, t, s, testBlobKey)
+	if !bytes.Equal(got, data) {
+		t.Errorf("object read back as %d bytes, want the %d uploaded",
+			len(got), len(data))
+	}
+
+	return seen
+}
+
+// readObject returns the contents of the object at key.
+func readObject(
+	ctx context.Context, t *testing.T, s *storage.RcloneStorer, key string,
+) []byte {
+	t.Helper()
+
+	rc, err := s.Get(ctx, key)
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+
+	defer func() { _ = rc.Close() }()
+
+	got, err := io.ReadAll(rc)
+	if err != nil {
+		t.Fatalf("reading object: %v", err)
+	}
+
+	return got
+}
+
+// TestRcloneStorerObjectAppearsOnlyWhenComplete checks that on a remote
+// with a server-side move, such as local, nothing is at the key until the
+// upload has finished, so a killed upload cannot leave a truncated object
+// there.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorerObjectAppearsOnlyWhenComplete(t *testing.T) {
+	ctx := unbufferedUploadContext()
+
+	s, err := storage.NewRcloneStorer(ctx, ":local", t.TempDir())
+	if err != nil {
+		t.Fatalf("NewRcloneStorer: %v", err)
+	}
+
+	if objectAtKeyDuringUpload(ctx, t, s) {
+		t.Error("object was at its key before the upload finished")
+	}
+}
+
+// TestRcloneStorerListSkipsPartialFiles checks that a temporary file left
+// by a killed upload is never listed as a key.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorerListSkipsPartialFiles(t *testing.T) {
+	dir := t.TempDir()
+	ctx := context.Background()
+
+	s, err := storage.NewRcloneStorer(ctx, ":local", dir)
+	if err != nil {
+		t.Fatalf("NewRcloneStorer: %v", err)
+	}
+
+	realKey := testBlobKey
+
+	err = s.Put(ctx, realKey, strings.NewReader("blob-bytes"))
+	if err != nil {
+		t.Fatalf("Put: %v", err)
+	}
+
+	leftover := filepath.Join(dir, realKey+"-123456.partial")
+
+	err = os.WriteFile(leftover, []byte("half"), 0o600)
+	if err != nil {
+		t.Fatalf("writing leftover temp file: %v", err)
+	}
+
+	keys, err := s.List(ctx, "blobs/")
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+
+	if len(keys) != 1 || keys[0] != realKey {
+		t.Fatalf("List should return only the real key, got %v", keys)
+	}
+
+	var streamed []string
+
+	for obj := range s.ListStream(ctx, "blobs/") {
+		if obj.Err != nil {
+			t.Fatalf("ListStream: %v", obj.Err)
+		}
+
+		streamed = append(streamed, obj.Key)
+	}
+
+	if len(streamed) != 1 || streamed[0] != realKey {
+		t.Fatalf("ListStream should return only the real key, got %v", streamed)
+	}
+}
+
+// TestRcloneStorerDeletePartialUploads checks that a temporary file left
+// by a killed upload is removed and the object at the real key is kept.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorerDeletePartialUploads(t *testing.T) {
+	dir := t.TempDir()
+	ctx := context.Background()
+
+	s, err := storage.NewRcloneStorer(ctx, ":local", dir)
+	if err != nil {
+		t.Fatalf("NewRcloneStorer: %v", err)
+	}
+
+	err = s.Put(ctx, testBlobKey, strings.NewReader("blob-bytes"))
+	if err != nil {
+		t.Fatalf("Put: %v", err)
+	}
+
+	leftover := filepath.Join(dir, testBlobKey+"-123456.partial")
+
+	err = os.WriteFile(leftover, []byte("half"), 0o600)
+	if err != nil {
+		t.Fatalf("writing leftover temp file: %v", err)
+	}
+
+	err = s.DeletePartialUploads(ctx, "blobs/")
+	if err != nil {
+		t.Fatalf("DeletePartialUploads: %v", err)
+	}
+
+	_, err = os.Stat(leftover)
+	if !os.IsNotExist(err) {
+		t.Errorf("leftover temp file was not removed: %v", err)
+	}
+
+	_, err = s.Stat(ctx, testBlobKey)
+	if err != nil {
+		t.Errorf("Stat of the real key: %v", err)
+	}
+}
+
+// newRcloneStorerOnWrappedLocal registers name as rclone's local backend
+// wrapped by wrap, and builds an rclone backend on it rooted at a fresh
+// temp directory. wrap changes the features the local backend reports, so
+// that it behaves like a remote a unit test cannot reach.
+func newRcloneStorerOnWrappedLocal(
+	ctx context.Context, t *testing.T, name string, wrap func(fs.Fs) fs.Fs,
+) *storage.RcloneStorer {
+	t.Helper()
+
+	fs.Register(&fs.RegInfo{
+		Name: name,
+		NewFs: func(
+			ctx context.Context, _, root string, _ configmap.Mapper,
+		) (fs.Fs, error) {
+			local, err := fs.NewFs(ctx, ":local:"+root)
+			if err != nil {
+				return nil, err
+			}
+
+			return wrap(local), nil
+		},
+	})
+
+	s, err := storage.NewRcloneStorer(ctx, ":"+name, t.TempDir())
+	if err != nil {
+		t.Fatalf("NewRcloneStorer: %v", err)
+	}
+
+	return s
+}
+
+// withoutPartialUploads is rclone's local backend with the PartialUploads
+// flag cleared. Like hdfs, it then has a server-side move and shows a file
+// while it is written, without setting that flag.
+type withoutPartialUploads struct {
+	fs.Fs
+}
+
+func (f *withoutPartialUploads) Features() *fs.Features {
+	features := *f.Fs.Features()
+	features.PartialUploads = false
+
+	return &features
+}
+
+// TestRcloneStorerMovesIntoPlaceWithoutPartialUploads checks that on a
+// remote with a server-side move nothing is at the key until the upload has
+// finished, even when rclone does not mark the remote as showing partial
+// uploads.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorerMovesIntoPlaceWithoutPartialUploads(t *testing.T) {
+	ctx := unbufferedUploadContext()
+	s := newRcloneStorerOnWrappedLocal(ctx, t, "withoutpartialuploads",
+		func(local fs.Fs) fs.Fs { return &withoutPartialUploads{Fs: local} })
+
+	if objectAtKeyDuringUpload(ctx, t, s) {
+		t.Error("object was at its key before the upload finished")
+	}
+}
+
+// withoutMove is rclone's local backend reporting no server-side move.
+type withoutMove struct {
+	fs.Fs
+}
+
+func (f *withoutMove) Features() *fs.Features {
+	features := *f.Fs.Features()
+	features.Move = nil
+
+	return &features
+}
+
+// TestRcloneStorerWritesInPlaceWithoutMove checks that on a remote with no
+// server-side move an object is written straight to its key and reads back
+// from there.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorerWritesInPlaceWithoutMove(t *testing.T) {
+	ctx := unbufferedUploadContext()
+	s := newRcloneStorerOnWrappedLocal(ctx, t, "withoutmove",
+		func(local fs.Fs) fs.Fs { return &withoutMove{Fs: local} })
+
+	if !objectAtKeyDuringUpload(ctx, t, s) {
+		t.Error("object was not at its key while it was uploaded")
+	}
+}
+
+var errNameConflict = errors.New("an object with this name already exists")
+
+// moveRefusesExisting is rclone's local backend with a server-side move
+// that, like dropbox's or onedrive's, refuses to move onto an existing
+// object.
+type moveRefusesExisting struct {
+	fs.Fs
+}
+
+func (f *moveRefusesExisting) Features() *fs.Features {
+	features := *f.Fs.Features()
+	features.Move = f.move
+
+	return &features
+}
+
+//nolint:ireturn // the signature is rclone's
+func (f *moveRefusesExisting) move(
+	ctx context.Context, src fs.Object, remote string,
+) (fs.Object, error) {
+	_, err := f.NewObject(ctx, remote)
+	if err == nil {
+		return nil, errNameConflict
+	}
+
+	return f.Fs.Features().Move(ctx, src, remote)
+}
+
+// TestRcloneStorerOverwritesWhereMoveRefusesExisting checks that writing a
+// key twice replaces the object on a remote whose server-side move will not
+// replace an existing object.
+//
+//nolint:paralleltest // NewRcloneStorer installs the process-global rclone config
+func TestRcloneStorerOverwritesWhereMoveRefusesExisting(t *testing.T) {
+	ctx := context.Background()
+	s := newRcloneStorerOnWrappedLocal(ctx, t, "moverefusesexisting",
+		func(local fs.Fs) fs.Fs { return &moveRefusesExisting{Fs: local} })
+
+	for _, content := range []string{"first", "second"} {
+		err := s.Put(ctx, testBlobKey, strings.NewReader(content))
+		if err != nil {
+			t.Fatalf("Put %q: %v", content, err)
+		}
+	}
+
+	got := readObject(ctx, t, s, testBlobKey)
+	if string(got) != "second" {
+		t.Errorf("object = %q, want %q", got, "second")
+	}
+}
+
 // TestNewRcloneStorerUnknownRemote checks that a remote that is not in the
 // rclone config fails construction with the ErrRemoteNotFound sentinel,
 // rather than silently returning a backend pointed nowhere.

internal/storage/s3.go

@@ -99,6 +99,12 @@ func (s *S3Storer) ListStream(ctx context.Context, prefix string) <-chan ObjectI
 	return ch
 }
 
+// DeletePartialUploads has nothing to remove: S3 shows an object only once
+// its upload has completed, so an upload cut off part-way leaves none.
+func (s *S3Storer) DeletePartialUploads(_ context.Context, _ string) error {
+	return nil
+}
+
 // Info returns human-readable storage location information.
 func (s *S3Storer) Info() Info {
 	return Info{

internal/storage/storer.go

@@ -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.
@@ -71,6 +72,12 @@ type Storer interface {
 	// If an error occurs during listing, the final item will have Err set.
 	ListStream(ctx context.Context, prefix string) <-chan ObjectInfo
 
+	// DeletePartialUploads removes every object under prefix that an
+	// upload cut off part-way left under a temporary name ending in
+	// `.partial`. The file and rclone backends' List and ListStream skip
+	// such an object.
+	DeletePartialUploads(ctx context.Context, prefix string) error
+
 	// Info returns human-readable storage location information.
 	Info() Info
 }

internal/vaultik/changed_file_restore_test.go

@@ -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")

internal/vaultik/deep_verify_test.go

@@ -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)

internal/vaultik/destination_marker.go

@@ -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
+}

internal/vaultik/destination_marker_test.go

@@ -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))
+}

internal/vaultik/destination_validation_test.go

@@ -257,6 +257,10 @@ func (s *stubLister) List(_ context.Context, _ string) ([]string, error) {
 	return nil, errStubUnused
 }
 
+func (s *stubLister) DeletePartialUploads(_ context.Context, _ string) error {
+	return errStubUnused
+}
+
 func (s *stubLister) Info() storage.Info {
 	return storage.Info{}
 }

internal/vaultik/fault_injection_test.go

@@ -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")
 

internal/vaultik/helpers.go

@@ -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

internal/vaultik/helpers_test.go

@@ -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 {

internal/vaultik/info.go

@@ -181,8 +181,11 @@ type SnapshotMetadataInfo struct {
 	ManifestSize int64  `json:"manifest_size"`
 	DatabaseSize int64  `json:"database_size"`
 	TotalSize    int64  `json:"total_size"`
-	BlobCount    int    `json:"blob_count"`
-	BlobsSize    int64  `json:"blobs_size"`
+
+	// Both stay nil (null in the JSON) when the snapshot's manifest was
+	// listed but could not be read.
+	BlobCount *int   `json:"blob_count"`
+	BlobsSize *int64 `json:"blobs_size"`
 
 	// Set when the listing holds this snapshot's manifest.json.zst. A
 	// backup interrupted before its manifest upload leaves a directory
@@ -380,6 +383,10 @@ func (v *Vaultik) collectReferencedBlobsFromManifests(
 	for _, snapshotID := range snapshotIDs {
 		info := snapshotMetadata[snapshotID]
 		if !info.hasManifest {
+			// The orphan figures count this directory's blobs as
+			// orphaned, so it references none.
+			info.BlobCount, info.BlobsSize = new(int), new(int64)
+
 			continue
 		}
 
@@ -395,7 +402,7 @@ func (v *Vaultik) collectReferencedBlobsFromManifests(
 			continue
 		}
 
-		info.BlobCount = manifest.BlobCount
+		blobCount := manifest.BlobCount
 
 		var blobsSize int64
 
@@ -404,7 +411,8 @@ func (v *Vaultik) collectReferencedBlobsFromManifests(
 			blobsSize += blob.CompressedSize
 		}
 
-		info.BlobsSize = blobsSize
+		info.BlobCount = &blobCount
+		info.BlobsSize = &blobsSize
 	}
 
 	return referencedBlobs, unreadable
@@ -516,13 +524,23 @@ func (v *Vaultik) printRemoteInfoTable(result *RemoteInfoResult) {
 		v.stdoutf("%s", separator)
 
 		for _, info := range result.Snapshots {
+			blobCount := unknownText
+			if info.BlobCount != nil {
+				blobCount = humanize.Comma(int64(*info.BlobCount))
+			}
+
+			blobsSize := unknownText
+			if info.BlobsSize != nil {
+				blobsSize = ubytes(*info.BlobsSize)
+			}
+
 			v.stdoutf(rowFormat,
 				truncateString(info.SnapshotID, snapshotIDColWidth),
 				ubytes(info.ManifestSize),
 				ubytes(info.DatabaseSize),
 				ubytes(info.TotalSize),
-				humanize.Comma(int64(info.BlobCount)),
-				ubytes(info.BlobsSize),
+				blobCount,
+				blobsSize,
 			)
 		}
 

internal/vaultik/integration_test.go

@@ -155,6 +155,12 @@ func (m *MockStorer) ListStream(
 	return ch
 }
 
+// DeletePartialUploads has nothing to remove: Put stores each object
+// under its key at once.
+func (m *MockStorer) DeletePartialUploads(_ context.Context, _ string) error {
+	return nil
+}
+
 func (m *MockStorer) Info() storage.Info {
 	return storage.Info{
 		Type:     "mock",
@@ -765,7 +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")
 
@@ -958,7 +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")
 

internal/vaultik/missing_destination_test.go

@@ -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

internal/vaultik/nuke_remote_test.go

@@ -0,0 +1,64 @@
+package vaultik_test
+
+import (
+	"context"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/snapshot"
+)
+
+// TestNukeRemoteLeavesNoFiles checks that remote nuke leaves no file
+// under a file:// destination, including the `.partial` files uploads
+// killed part-way leave next to a snapshot's metadata and next to where a
+// blob would have been.
+func TestNukeRemoteLeavesNoFiles(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	ctx := context.Background()
+	storeDir := filepath.Join(t.TempDir(), "store")
+	v, repos, _ := backUpToFileDestination(ctx, t, storeDir)
+
+	snapshots, err := repos.Snapshots.ListRecent(ctx, listRecentTestLimit)
+	require.NoError(t, err)
+	require.Len(t, snapshots, 1)
+
+	snapshotKey := snapshot.RemoteSnapshotKey(snapshots[0].ID.String())
+	hash := testBlobHashA
+	leftovers := []string{
+		filepath.Join(storeDir, "metadata", snapshotKey,
+			"db.zst.age-123456.partial"),
+		filepath.Join(storeDir, "blobs", hash[:2], hash[2:4],
+			hash+"-123456.partial"),
+	}
+
+	for _, leftover := range leftovers {
+		require.NoError(t, os.MkdirAll(filepath.Dir(leftover), 0o750))
+		require.NoError(t, os.WriteFile(leftover, []byte("half an upload"), 0o600))
+	}
+
+	require.NoError(t, v.NukeRemote(true))
+
+	var files []string
+
+	err = filepath.WalkDir(storeDir,
+		func(path string, entry fs.DirEntry, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if !entry.IsDir() {
+				files = append(files, path)
+			}
+
+			return nil
+		})
+	require.NoError(t, err)
+	assert.Empty(t, files)
+}

internal/vaultik/prune.go

@@ -24,8 +24,10 @@ var errNukeRequiresForce = errors.New(
 const metadataDirName = "metadata"
 
 // NukeRemote deletes every snapshot's metadata and every blob from remote
-// storage. After this returns successfully the bucket prefix is empty and
-// the next backup starts from scratch.
+// storage, along with any object an upload cut off part-way left under a
+// 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.
@@ -48,6 +50,22 @@ func (v *Vaultik) NukeRemote(force bool) error {
 		return fmt.Errorf("pruning blobs: %w", err)
 	}
 
+	// The file and rclone listings skip `.partial` objects, so the two
+	// steps above never delete them.
+	for _, prefix := range []string{"metadata/", "blobs/"} {
+		err = v.Storage.DeletePartialUploads(v.ctx, prefix)
+		if err != nil {
+			return fmt.Errorf("deleting partial uploads: %w", err)
+		}
+	}
+
+	// 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

internal/vaultik/prune_count_test.go

@@ -42,7 +42,7 @@ func TestTableCountForReportSurfacesReadFailure(t *testing.T) {
 	assert.Nil(t, missing, "a failed read is unknown, not a count")
 
 	// The rendered count for a failed read must say unknown, never 0.
-	assert.Equal(t, countUnknown, countText(missing))
+	assert.Equal(t, unknownText, countText(missing))
 	assert.NotEqual(t, "0", countText(missing))
 }
 
@@ -57,7 +57,7 @@ func TestCountTextDistinguishesEmptyFromUnknown(t *testing.T) {
 
 	assert.Equal(t, "0", countText(&zero))
 	assert.Equal(t, "7", countText(&seven))
-	assert.Equal(t, countUnknown, countText(nil))
+	assert.Equal(t, unknownText, countText(nil))
 }
 
 // TestCountDiffUnknownWhenEitherSideUnknown checks that a delta computed

internal/vaultik/prune_json_test.go

@@ -0,0 +1,40 @@
+package vaultik_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// TestPruneBlobs_JSONDeletesWithoutAsking checks that prune with --json
+// and without --force deletes an unreferenced blob without the
+// confirmation prompt. Stdin is empty, so a prompt would read no answer
+// and cancel, and its text would come before the JSON document.
+func TestPruneBlobs_JSONDeletesWithoutAsking(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	env := newListEnv(t)
+
+	// The store holds no manifest, so nothing references this blob.
+	addBlob(t, env.store.testStorer, testBlobHashA)
+
+	err := env.v.PruneBlobs(&vaultik.PruneOptions{JSON: true})
+	require.NoError(t, err)
+
+	blobKey := "blobs/" + testBlobHashA[:2] + "/" + testBlobHashA[2:4] +
+		"/" + testBlobHashA
+	assert.False(t, env.store.hasKey(blobKey),
+		"the unreferenced blob must be deleted")
+
+	var result vaultik.PruneBlobsResult
+
+	require.NoError(t, json.Unmarshal(env.stdout.Bytes(), &result),
+		"stdout must hold only the JSON document, got:\n%s",
+		env.stdout.String())
+	assert.Equal(t, 1, result.BlobsDeleted)
+}

internal/vaultik/purge_local_remote_consistency_test.go

@@ -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])

internal/vaultik/purge_per_name_test.go

@@ -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()

internal/vaultik/remote_info_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"strings"
 	"testing"
 	"time"
 
@@ -69,6 +70,74 @@ func TestRemoteInfo_UnreadableManifestLeavesOrphansUnknown(t *testing.T) {
 	assert.Equal(t, []any{unreadableKey}, doc["unreadable_manifests"])
 }
 
+// TestRemoteInfo_UnreadableManifestLeavesSnapshotBlobsUnknown checks
+// that the row of a snapshot whose manifest cannot be read gives its
+// blob count and blob size as unknown in the table and as null in
+// --json, not as 0. A directory without a manifest still shows 0: the
+// orphan figures count its blobs as orphaned, so it references none.
+func TestRemoteInfo_UnreadableManifestLeavesSnapshotBlobsUnknown(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	env := newListEnv(t)
+	readableKey := env.addRemote(t, listRemoteID,
+		time.Date(2026, 3, 2, 0, 0, 0, 0, time.UTC))
+
+	unreadableKey := snapshot.RemoteSnapshotKey(listLocalID)
+	require.NoError(t, env.store.Put(context.Background(),
+		"metadata/"+unreadableKey+"/manifest.json.zst",
+		bytes.NewReader([]byte("not a valid manifest"))))
+
+	noManifestKey := snapshot.RemoteSnapshotKey("testhost_home_2026-03-03T10:00:00Z")
+	require.NoError(t, env.store.Put(context.Background(),
+		"metadata/"+noManifestKey+"/db.zst.age",
+		bytes.NewReader([]byte("not a valid database"))))
+
+	require.NoError(t, env.v.RemoteInfo(false))
+
+	// The table truncates the remote key, so a row is found by a prefix.
+	wantUnknown := map[string]int{readableKey: 0, unreadableKey: 2, noManifestKey: 0}
+	for key, want := range wantUnknown {
+		var row string
+
+		for line := range strings.SplitSeq(env.stdout.String(), "\n") {
+			if strings.HasPrefix(line, key[:16]) {
+				row = line
+			}
+		}
+
+		require.NotEmpty(t, row, "no table row for %s", key)
+		assert.Equal(t, want, strings.Count(row, "unknown"), "row: %q", row)
+	}
+
+	env.stdout.Reset()
+	require.NoError(t, env.v.RemoteInfo(true))
+
+	var doc struct {
+		Snapshots []map[string]any `json:"snapshots"`
+	}
+
+	require.NoError(t, json.Unmarshal(env.stdout.Bytes(), &doc))
+	require.Len(t, doc.Snapshots, len(wantUnknown))
+
+	for _, entry := range doc.Snapshots {
+		switch entry["snapshot_id"] {
+		case readableKey:
+			assert.InDelta(t, 1, entry["blob_count"], 0)
+			assert.InDelta(t, fiveMegabytes, entry["blobs_size"], 0)
+		case noManifestKey:
+			assert.InDelta(t, 0, entry["blob_count"], 0)
+			assert.InDelta(t, 0, entry["blobs_size"], 0)
+		default:
+			assert.Equal(t, unreadableKey, entry["snapshot_id"])
+			assert.Contains(t, entry, "blob_count")
+			assert.Nil(t, entry["blob_count"])
+			assert.Contains(t, entry, "blobs_size")
+			assert.Nil(t, entry["blobs_size"])
+		}
+	}
+}
+
 // TestRemoteInfo_SkipsNonConformingMetadataName checks that a directory
 // under metadata/ whose name is not a remote key is left out of the
 // report, and that the orphan figures are unknown when it holds a

internal/vaultik/remove_snapshot_test.go

@@ -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"
 )
 
@@ -125,6 +129,12 @@ func (s *testStorer) ListStream(
 	return ch
 }
 
+// DeletePartialUploads has nothing to remove: Put stores each object
+// under its key at once.
+func (s *testStorer) DeletePartialUploads(_ context.Context, _ string) error {
+	return nil
+}
+
 func (s *testStorer) Info() storage.Info {
 	return storage.Info{
 		Type:     testLabel,
@@ -208,6 +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
 // ============================================================================
@@ -227,6 +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)
@@ -261,7 +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)
@@ -310,6 +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()

internal/vaultik/restore_another_machine_test.go

@@ -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")
 

internal/vaultik/restore_interrupt_test.go

@@ -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")
 

internal/vaultik/restore_locality_test.go

@@ -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")
 

internal/vaultik/restore_perms_test.go

@@ -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)

internal/vaultik/restore_skip_errors_test.go

@@ -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)

internal/vaultik/restore_snapshot_identity_test.go

@@ -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)
 

internal/vaultik/restore_sweeper_integration_test.go

@@ -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")
 

internal/vaultik/restore_truncated_db_test.go

@@ -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")
 

internal/vaultik/same_second_rewrite_test.go

@@ -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")

internal/vaultik/shallow_verify_test.go

@@ -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)

internal/vaultik/snapshot.go

@@ -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
@@ -185,6 +203,7 @@ type snapshotStats struct {
 	totalBlobs         int
 	totalBytesSkipped  int64
 	totalFilesSkipped  int
+	totalFilesFailed   int
 	totalFilesDeleted  int
 	totalBytesDeleted  int64
 	totalBytesUploaded int64
@@ -315,6 +334,7 @@ func (v *Vaultik) scanAllDirectories(
 		stats.totalChunks += result.ChunksCreated
 		stats.totalBlobs += result.BlobsCreated
 		stats.totalFilesSkipped += result.FilesSkipped
+		stats.totalFilesFailed += result.FilesFailed
 		stats.totalBytesSkipped += result.BytesSkipped
 		stats.totalFilesDeleted += result.FilesDeleted
 		stats.totalBytesDeleted += result.BytesDeleted
@@ -326,6 +346,7 @@ func (v *Vaultik) scanAllDirectories(
 			"path", dir,
 			"files", result.FilesScanned,
 			"files_skipped", result.FilesSkipped,
+			"files_failed", result.FilesFailed,
 			"bytes", result.BytesScanned,
 			"bytes_skipped", result.BytesSkipped,
 			"chunks", result.ChunksCreated,
@@ -359,9 +380,11 @@ func (v *Vaultik) finalizeSnapshotMetadata(
 		return fmt.Errorf("getting snapshot blob sizes: %w", err)
 	}
 
+	// file_count and total_size leave out the files that could not be
+	// stored; stats.totalBytes already does.
 	extStats := snapshot.ExtendedBackupStats{
 		BackupStats: snapshot.BackupStats{
-			FilesScanned:  stats.totalFiles,
+			FilesScanned:  stats.totalFiles - stats.totalFilesFailed,
 			TotalSize:     stats.totalBytes + stats.totalBytesSkipped,
 			ChunksCreated: stats.totalChunks,
 			BlobsCreated:  stats.totalBlobs,
@@ -409,7 +432,8 @@ func (v *Vaultik) printSnapshotSummary(
 	snapshotID string, startTime time.Time, stats *snapshotStats,
 ) {
 	snapshotDuration := time.Since(startTime)
-	totalFilesChanged := stats.totalFiles - stats.totalFilesSkipped
+	totalFilesChanged := stats.totalFiles - stats.totalFilesSkipped -
+		stats.totalFilesFailed
 	totalBytesAll := stats.totalBytes + stats.totalBytesSkipped
 
 	var compressionRatio float64
@@ -426,6 +450,10 @@ func (v *Vaultik) printSnapshotSummary(
 		v.UI.Count(stats.totalFiles),
 		v.UI.Count(totalFilesChanged),
 		v.UI.Count(stats.totalFilesSkipped))
+	if stats.totalFilesFailed > 0 {
+		filesMsg += fmt.Sprintf(", %s failed", v.UI.Count(stats.totalFilesFailed))
+	}
+
 	if stats.totalFilesDeleted > 0 {
 		filesMsg += fmt.Sprintf(", %s deleted", v.UI.Count(stats.totalFilesDeleted))
 	}
@@ -633,7 +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)
 		}
@@ -1143,23 +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 {
@@ -1174,9 +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 "+
@@ -1186,6 +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(
@@ -1210,9 +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)
@@ -1244,15 +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 "+
@@ -1270,7 +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
@@ -1356,8 +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")
 
@@ -1406,6 +1503,11 @@ func (v *Vaultik) listAllRemoteSnapshotKeys() ([]string, error) {
 		}
 	}
 
+	err := v.checkDestinationMarker()
+	if err != nil {
+		return nil, err
+	}
+
 	return keys, nil
 }
 
@@ -1562,7 +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",
@@ -1588,7 +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)
@@ -1635,34 +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
@@ -1756,9 +1868,9 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	return result, nil
 }
 
-// countUnknown is what a count reads as when its query could not be run,
-// distinct from "0", which means the table really was empty.
-const countUnknown = "unknown"
+// unknownText is what a count or size reads as when it could not be
+// determined, distinct from "0", which is a real zero.
+const unknownText = "unknown"
 
 // tableCountForReport returns the row count of a table for the prune
 // summary, or nil if the count could not be read. A read failure is
@@ -1795,7 +1907,7 @@ func countDiff(before, after *int64) *int64 {
 // one that could not be queried.
 func countText(count *int64) string {
 	if count == nil {
-		return countUnknown
+		return unknownText
 	}
 
 	return strconv.FormatInt(*count, 10)

internal/vaultik/snapshot_failed_file_test.go

@@ -0,0 +1,123 @@
+package vaultik_test
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"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/ui"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// openFailFs is the real filesystem, except that opening path fails
+// with err. Phase 1 of a backup only lstats a file, so it still counts
+// path; phase 2 is the first to open it.
+type openFailFs struct {
+	afero.OsFs
+
+	path string
+	err  error
+}
+
+//nolint:ireturn // afero.Fs.Open is defined to return the interface.
+func (f *openFailFs) Open(name string) (afero.File, error) {
+	if name == f.path {
+		return nil, &os.PathError{Op: "open", Path: name, Err: f.err}
+	}
+
+	return f.OsFs.Open(name)
+}
+
+// A file that phase 2 cannot open is reported as failed, not as
+// unchanged, and neither the summary's data total nor the snapshots row
+// counts it. See https://git.eeqj.de/sneak/vaultik/issues/280.
+func TestSnapshotSummaryCountsFileNotStoredAsFailed(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		openErr    error
+		skipErrors bool
+	}{
+		// What a normal user gets opening a file with mode 000.
+		{name: "unopenable under skip-errors",
+			openErr: os.ErrPermission, skipErrors: true},
+		// What opening a file removed after phase 1 gives.
+		{name: "removed between the phases",
+			openErr: os.ErrNotExist, skipErrors: false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			ctx := context.Background()
+
+			// The scan walks the source path with symlinks resolved, so
+			// failedPath must be spelled the same way to match.
+			tempDir, err := filepath.EvalSymlinks(t.TempDir())
+			require.NoError(t, err)
+
+			srcDir := filepath.Join(tempDir, "src")
+			failedPath := filepath.Join(srcDir, "failed.txt")
+			storedContent := []byte("this file is backed up")
+			storedSize := int64(len(storedContent))
+
+			fs := &openFailFs{path: failedPath, err: tt.openErr}
+			require.NoError(t, fs.MkdirAll(srcDir, 0o755))
+			require.NoError(t, afero.WriteFile(fs,
+				filepath.Join(srcDir, "stored.txt"), storedContent, 0o644))
+			require.NoError(t, afero.WriteFile(fs,
+				failedPath, []byte("this file cannot be opened"), 0o644))
+
+			cfg := faultTestConfig()
+			cfg.IndexPath = filepath.Join(tempDir, "index.sqlite")
+			cfg.Snapshots = map[string]config.SnapshotConfig{
+				"src": {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() })
+
+			repos := database.NewRepositories(db)
+			out := &bytes.Buffer{}
+			v := newBackupVaultik(ctx, cfg, store, repos, db, fs)
+			v.UI = ui.NewWithColor(out, false)
+
+			require.NoError(t, v.CreateSnapshot(&vaultik.SnapshotCreateOptions{
+				SkipErrors: tt.skipErrors,
+				Snapshots:  []string{"src"},
+			}))
+
+			summary := out.String()
+			assert.Contains(t, summary,
+				"Files: 2 examined, 1 backed up, 0 unchanged, 1 failed.")
+			assert.Contains(t, summary,
+				fmt.Sprintf("Data: %s total (%s backed up).",
+					v.UI.Size(storedSize), v.UI.Size(storedSize)))
+
+			snap, err := repos.Snapshots.GetByID(ctx,
+				localSnapshotID(ctx, t, repos, "src"))
+			require.NoError(t, err)
+			require.NotNil(t, snap)
+
+			assert.Equal(t, int64(1), snap.FileCount)
+			assert.Equal(t, storedSize, snap.TotalSize)
+		})
+	}
+}

internal/vaultik/snapshot_list_test.go

@@ -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: "",

internal/vaultik/snapshot_skip_errors_test.go

@@ -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)
+}

internal/vaultik/snapshot_summary_test.go

@@ -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)

internal/vaultik/storage_bind.go

@@ -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"
 }

internal/vaultik/storage_bind_test.go

@@ -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")
+		})
+	}
+}

internal/vaultik/two_path_snapshot_test.go

@@ -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")
 

internal/vaultik/verify_quiet_test.go

@@ -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)