Accept a remote key for restore and verify, and document it (closes #124)

A host restoring after the original is gone has no local index and cannot
know a snapshot's human ID; `snapshot list` shows such snapshots only by
their remote key. Restore and verify now resolve an identifier to that
remote key: a human ID is hashed as before, and a remote key (or an
unambiguous leading part of it, as the table prints) is used directly,
resolved against the store's metadata listing. Deep verify reads the one
snapshot in the exported database rather than filtering by the human ID.

Adds an integration test that backs up with one index and hostname, then
lists, restores, and deep-verifies from the store with a fresh empty
index, a different hostname, and no age_recipients — comparing restored
bytes to the source. The empty index is what makes it fail if restore
ever needed the original one.

Adds a "Restoring on another machine" README section walking the flow end
to end, and drops the now-done roadmap item.

Model: claude-opus-4-8

AGENTS.md

@@ -104,7 +104,12 @@ Version: 2025-06-08
 
 13. Pre-1.0: NEVER write database migrations. There are no live databases
     anywhere — every user's local index can be rebuilt from a fresh full
-    backup. When the schema changes, just change `schema.sql` (and any code
-    that touches the affected tables). The local index is disposable until
-    1.0 ships and is tagged.
+    backup. To change the schema, edit `internal/database/schema/001.sql`
+    (and any code that touches the affected tables) directly; do not add new
+    numbered schema files. Those numbered files and the `schema_migrations`
+    table they populate only bootstrap a fresh database — they are not an
+    upgrade path. The local index is disposable until 1.0 ships and is
+    tagged; once 1.0 is tagged that clause expires and the question of
+    upgrading existing indexes returns. See [`docs/DATAMODEL.md`](docs/DATAMODEL.md)
+    for the full explanation.
 

README.md

@@ -84,6 +84,57 @@ VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' vaultik snapshot restore <snapshot-i
 # 0 3 * * * vaultik snapshot create --cron --prune --keep-newer-than 4w
 ```
 
+## restoring on another machine
+
+Restoring on a host that never ran the backup — a replacement machine
+after the original is gone — is the case vaultik is built for. That host
+needs only three things: the `vaultik` binary, the age **private** key,
+and the storage credentials for the destination. It does **not** need the
+local index, the original config file, or the original hostname.
+
+```sh
+# install
+go install sneak.berlin/go/vaultik/cmd/vaultik@latest
+
+# create a config and point it at the ORIGINAL backup destination
+vaultik config init
+vaultik config set storage_url "s3://bucket/prefix?endpoint=https://s3.example.com"
+vaultik config set s3.access_key_id "..."
+vaultik config set s3.secret_access_key "..."
+
+# see what is on the destination store
+vaultik snapshot list
+```
+
+`snapshot list` reads the destination store without the private key. A
+snapshot that is not in this host's (empty) local index is shown as
+remote-only: its row is identified by `<remote only:...>` rather than by
+a `hostname_name_timestamp` name, because the name lives only in the
+local index and the encrypted database and cannot be recovered from the
+store. Its timestamp and compressed size are real. (See the `snapshot
+list` description under [command details](#command-details) for the full
+explanation.)
+
+Use that remote key — the hex printed inside `<remote only:...>`, or the
+full `remote_key` from `snapshot list --json` — to restore and verify:
+
+```sh
+# restore everything to /tmp/restored, then check every restored file's
+# chunk hashes
+VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' \
+  vaultik snapshot restore --verify <remote-key> /tmp/restored
+
+# optionally, deep-verify the snapshot against the store (downloads and
+# cryptographically checks every blob)
+VAULTIK_AGE_SECRET_KEY='AGE-SECRET-KEY-...' \
+  vaultik snapshot verify --deep <remote-key>
+```
+
+`age_recipients` (the public key) is not needed to restore — only the
+private key in `VAULTIK_AGE_SECRET_KEY`. Both the abbreviated key printed
+in the table and the full 64-character key from `--json` are accepted; a
+leading part of the key is enough as long as it is unambiguous.
+
 ---
 
 ## cli
@@ -245,6 +296,8 @@ local index alone, and still exits zero.
 * Default (shallow): checks that all blobs referenced in the manifest exist in storage
 * `--deep`: Downloads and decrypts each blob, verifies chunk hashes against the
   encrypted metadata database
+* Accepts the same identifiers as `snapshot restore`: a snapshot ID, or a
+  remote-only snapshot's remote key (or an unambiguous leading part of it)
 * `--json`: Output results as JSON
 
 **`snapshot purge`**: Remove old snapshots based on criteria. Retention is
@@ -275,6 +328,10 @@ on the destination in one go, use `vaultik remote nuke --force`.
 
 **`snapshot restore`**: Restore files from a backup snapshot.
 * Requires `VAULTIK_AGE_SECRET_KEY` environment variable
+* Accepts a snapshot ID, or — for a snapshot only on the destination
+  store — its remote key (or an unambiguous leading part of it) as shown
+  by `snapshot list`. See
+  [restoring on another machine](#restoring-on-another-machine).
 * Optional path arguments to restore specific files/directories (default: all)
 * Preserves file permissions, timestamps, ownership (ownership requires root),
   symlinks, and empty directories
@@ -457,9 +514,13 @@ Key fields:
   sequentially. Restore speed is bound by single-stream throughput.
 * **Device nodes, named pipes, and sockets are silently skipped.** Only
   regular files, directories, and symlinks are backed up.
-* **No database migrations.** If the local SQLite schema changes between
-  versions, delete the local database (`vaultik database delete`) and run
-  a full backup. Remote storage is unaffected.
+* **No upgrade path between versions.** There is no supported way to carry
+  an existing local index across a schema change; if the local SQLite
+  schema changes between versions, delete the local database (`vaultik
+  database delete`) and run a full backup. Remote storage is unaffected.
+  (The binary does embed numbered schema files and a `schema_migrations`
+  table to bootstrap a fresh database — see [`docs/DATAMODEL.md`](docs/DATAMODEL.md)
+  — but that is not an upgrade path.)
 * **Files that change during backup may be inconsistent.** There is no
   filesystem snapshot or freeze. If a file is modified between the scan
   and chunk phases, the backed-up copy may reflect a partial write.
@@ -525,14 +586,12 @@ priority.
 
 ### infrastructure
 
-* **Cross-machine restore documentation.** The "restore from
-  another host" workflow works but isn't documented as a
-  first-class operation in this README. Worth a dedicated section
-  once it's settled.
-* **Schema migrations.** Currently nonexistent — pre-1.0 schema
-  changes are handled by `vaultik database delete` plus a full
-  re-scan. Post-1.0 we'll need a migration story to keep existing
-  index databases usable across upgrades.
+* **Cross-version schema upgrades.** There is no upgrade path between
+  released versions — pre-1.0 schema changes are handled by `vaultik
+  database delete` plus a full re-scan (see
+  [`docs/DATAMODEL.md`](docs/DATAMODEL.md)). Post-1.0 we'll need a
+  migration story to keep existing index databases usable across
+  upgrades.
 * **Storage backend coverage tests.** S3, file://, and rclone://
   all share the Storer interface but the rclone path is the least
   exercised in CI.

TODO.md

@@ -25,6 +25,16 @@ release" is exactly the contradiction
 
 # Completed Steps
 
+- 2026-09-21: Stopped `prune` from reporting a failed row count as 0
+  ([issue #96](https://git.eeqj.de/sneak/vaultik/issues/96)). The seven
+  `getTableCount` reads in `PruneDatabase` discarded their error, so a
+  query that could not run became a plausible `0` and the before/after
+  delta computed from it looked like real work. Each read now logs at
+  warn on failure and renders as `unknown`, never `0`, so an empty table
+  is distinguishable from one that could not be queried. The counts have
+  no `--json` representation — under `--json` the summary is suppressed
+  entirely — so nothing there can show a false `0`.
+
 - 2026-09-21: Made the s3 storage backend report a missing object as
   `storage.ErrNotFound`, like the `file` and `rclone` backends and as the
   `Storer` interface documents. `S3Storer.Get` and `Stat` returned the raw
@@ -33,7 +43,6 @@ release" is exactly the contradiction
   helper (reused by `HeadObject`) and a test that a missing key maps to
   `ErrNotFound`
   ([issue #129](https://git.eeqj.de/sneak/vaultik/issues/129)).
-
 - 2026-09-21: Fixed `verify --deep` reporting healthy snapshots as
   corrupt. Its final blob-integrity check hashed the encrypted
   downloaded bytes with a single SHA256 and compared that to the blob

docs/DATAMODEL.md

@@ -5,11 +5,30 @@
 Vaultik uses a local SQLite database to track file metadata, chunk mappings, and blob associations during the backup process. This database serves as an index for incremental backups and enables efficient deduplication.
 
 **Important Notes:**
-- **No Migration Support (pre-1.0)**: Vaultik does not support database schema
-  migrations. The local index is treated as disposable — if the schema changes,
-  delete the local SQLite database (`vaultik database delete`) and run a full
-  backup. The remote storage is unaffected; the new index will re-deduplicate
-  against existing remote blobs.
+
+This section is the authoritative explanation of the schema/migration story;
+other documents (the README and `AGENTS.md`) link here.
+
+- **No upgrade path between versions (pre-1.0)**: Vaultik has no supported way to
+  carry an existing local index across a schema change. The index is disposable
+  — if the on-disk schema changes between versions, delete the local SQLite
+  database (`vaultik database delete`) and run a full backup. Remote storage is
+  unaffected; the new index re-deduplicates against existing remote blobs. This
+  is the standing project policy, and it is separate from the schema bootstrap
+  described next.
+- **Schema bootstrap**: a fresh database is populated from numbered SQL files
+  embedded in the binary under `internal/database/schema/`. `000.sql` creates the
+  `schema_migrations` table; `001.sql` creates the application tables. On opening
+  a database the code applies each numbered file that has not yet run and records
+  its version in `schema_migrations`. This bootstraps a new database; it does not
+  upgrade an existing one between released versions.
+- **Changing the schema (pre-1.0)**: edit `internal/database/schema/001.sql` (and
+  the code that touches the affected tables) directly. Do not add new numbered
+  files — there is no installed base to migrate.
+- **Disposability expires at 1.0**: the index is treated as disposable only until
+  1.0 ships and is tagged. Once 1.0 is tagged that clause expires and the
+  question of upgrading existing indexes returns. It is deliberately left open
+  here.
 - **Version Compatibility**: In rare cases, you may need to use the same version
   of Vaultik to restore a backup as was used to create it. This ensures
   compatibility with the metadata format stored in S3.

internal/cli/snapshot.go

@@ -221,8 +221,11 @@ func newSnapshotVerifyCommand() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "verify <snapshot-id>",
 		Short: "Verify snapshot integrity",
-		Long:  "Verifies that all blobs referenced in a snapshot exist",
-		Args:  requireSnapshotIDArg,
+		Long: "Verifies that all blobs referenced in a snapshot exist.\n\n" +
+			"The snapshot may be named by its ID or, on a host with no local\n" +
+			"index, by the remote key that 'snapshot list' prints for a\n" +
+			"remote-only snapshot (an unambiguous leading part is enough).",
+		Args: requireSnapshotIDArg,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			snapshotID := args[0]
 

internal/cli/snapshot_restore.go

@@ -48,6 +48,10 @@ target directory.
 If no paths are specified, all files are restored.
 If paths are specified, only matching files/directories are restored.
 
+The snapshot may be named by its ID or, when restoring on a host with no
+local index, by the remote key that 'snapshot list' prints for a
+remote-only snapshot (an unambiguous leading part is enough).
+
 Requires the VAULTIK_AGE_SECRET_KEY environment variable to be set with
 the age private key.
 

internal/storage/file.go

@@ -46,31 +46,18 @@ func (f *FileStorer) SetFilesystem(fs afero.Fs) {
 // storage base path.
 const storageDirPerm = 0o755
 
+// tempSuffix marks a partially written object. writeAtomic streams into a
+// 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.
+const tempSuffix = ".partial"
+
 // Put stores data at the specified key.
 func (f *FileStorer) Put(_ context.Context, key string, data io.Reader) error {
-	path := f.fullPath(key)
-
-	// Create parent directories
-	dir := filepath.Dir(path)
-
-	err := f.fs.MkdirAll(dir, storageDirPerm)
-	if err != nil {
-		return fmt.Errorf("creating directories: %w", err)
-	}
-
-	file, err := f.fs.Create(path)
-	if err != nil {
-		return fmt.Errorf("creating file: %w", err)
-	}
-
-	defer func() { _ = file.Close() }()
-
-	_, err = io.Copy(file, data)
-	if err != nil {
-		return fmt.Errorf("writing file: %w", err)
-	}
-
-	return nil
+	return f.writeAtomic(key, data, nil)
 }
 
 // PutWithProgress stores data with progress reporting.
@@ -78,35 +65,7 @@ func (f *FileStorer) PutWithProgress(
 	_ context.Context, key string, data io.Reader,
 	_ int64, progress ProgressCallback,
 ) error {
-	path := f.fullPath(key)
-
-	// Create parent directories
-	dir := filepath.Dir(path)
-
-	err := f.fs.MkdirAll(dir, storageDirPerm)
-	if err != nil {
-		return fmt.Errorf("creating directories: %w", err)
-	}
-
-	file, err := f.fs.Create(path)
-	if err != nil {
-		return fmt.Errorf("creating file: %w", err)
-	}
-
-	defer func() { _ = file.Close() }()
-
-	// Wrap with progress tracking
-	pw := &progressWriter{
-		writer:   file,
-		callback: progress,
-	}
-
-	_, err = io.Copy(pw, data)
-	if err != nil {
-		return fmt.Errorf("writing file: %w", err)
-	}
-
-	return nil
+	return f.writeAtomic(key, data, progress)
 }
 
 // Get retrieves data from the specified key.
@@ -188,7 +147,7 @@ func (f *FileStorer) List(ctx context.Context, prefix string) ([]string, error)
 		default:
 		}
 
-		if !info.IsDir() {
+		if !info.IsDir() && !strings.HasSuffix(info.Name(), tempSuffix) {
 			// Convert back to key (relative path from basePath)
 			relPath, err := filepath.Rel(f.basePath, path)
 			if err != nil {
@@ -245,7 +204,7 @@ func (f *FileStorer) ListStream(ctx context.Context, prefix string) <-chan Objec
 				return nil //nolint:nilerr // continue walking despite errors
 			}
 
-			if !info.IsDir() {
+			if !info.IsDir() && !strings.HasSuffix(info.Name(), tempSuffix) {
 				relPath, err := filepath.Rel(f.basePath, path)
 				if err != nil {
 					ch <- ObjectInfo{Err: fmt.Errorf("computing relative path: %w", err)}
@@ -275,6 +234,72 @@ func (f *FileStorer) Info() Info {
 	}
 }
 
+// writeAtomic streams data into a temp file in the destination directory,
+// fsyncs it, and renames it onto the final key. The key therefore appears
+// only once the whole object has been durably written; a failure part-way
+// leaves a temp file (removed here on the failing path) rather than a
+// truncated object at the key.
+func (f *FileStorer) writeAtomic(
+	key string, data io.Reader, progress ProgressCallback,
+) error {
+	path := f.fullPath(key)
+	dir := filepath.Dir(path)
+
+	err := f.fs.MkdirAll(dir, storageDirPerm)
+	if err != nil {
+		return fmt.Errorf("creating directories: %w", err)
+	}
+
+	tmp, err := afero.TempFile(f.fs, dir, filepath.Base(path)+"-*"+tempSuffix)
+	if err != nil {
+		return fmt.Errorf("creating temp file: %w", err)
+	}
+
+	tmpPath := tmp.Name()
+
+	// Remove the temp file unless the rename below claims it. On the success
+	// path renamed is true, so the deferred Close and Remove are harmless
+	// no-ops on a name that no longer exists.
+	renamed := false
+
+	defer func() {
+		_ = tmp.Close()
+
+		if !renamed {
+			_ = f.fs.Remove(tmpPath)
+		}
+	}()
+
+	var w io.Writer = tmp
+	if progress != nil {
+		w = &progressWriter{writer: tmp, callback: progress}
+	}
+
+	_, err = io.Copy(w, data)
+	if err != nil {
+		return fmt.Errorf("writing file: %w", err)
+	}
+
+	err = tmp.Sync()
+	if err != nil {
+		return fmt.Errorf("syncing temp file: %w", err)
+	}
+
+	err = tmp.Close()
+	if err != nil {
+		return fmt.Errorf("closing temp file: %w", err)
+	}
+
+	err = f.fs.Rename(tmpPath, path)
+	if err != nil {
+		return fmt.Errorf("renaming temp file: %w", err)
+	}
+
+	renamed = true
+
+	return nil
+}
+
 // fullPath returns the full filesystem path for a key.
 func (f *FileStorer) fullPath(key string) string {
 	return filepath.Join(f.basePath, key)

internal/storage/file_atomic_test.go

@@ -0,0 +1,119 @@
+package storage_test
+
+import (
+	"context"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"sneak.berlin/go/vaultik/internal/storage"
+)
+
+// errStreamInterrupted stands in for an upload cut off mid-stream.
+var errStreamInterrupted = errors.New("connection reset mid-upload")
+
+// failingReader yields its data once, then fails.
+type failingReader struct {
+	data []byte
+	done bool
+}
+
+func (r *failingReader) Read(p []byte) (int, error) {
+	if r.done {
+		return 0, errStreamInterrupted
+	}
+
+	n := copy(p, r.data)
+	r.done = true
+
+	return n, nil
+}
+
+// TestFileStorer_InterruptedWriteLeavesNoTrustedObject checks that a write
+// cut off mid-stream leaves nothing at the destination key, so a later run
+// cannot Stat a truncated object and trust it as a complete blob.
+func TestFileStorer_InterruptedWriteLeavesNoTrustedObject(t *testing.T) {
+	t.Parallel()
+
+	f, err := storage.NewFileStorer(t.TempDir())
+	if err != nil {
+		t.Fatalf("NewFileStorer: %v", err)
+	}
+
+	ctx := context.Background()
+	key := "blobs/aa/bb/aabbccddeeff"
+
+	err = f.PutWithProgress(ctx, key, &failingReader{data: []byte("partial")}, 4096, nil)
+	if err == nil {
+		t.Fatal("expected the interrupted write to fail, got nil")
+	}
+
+	_, err = f.Stat(ctx, key)
+	if !errors.Is(err, storage.ErrNotFound) {
+		t.Fatalf("expected key absent after interrupted write, got Stat err %v", err)
+	}
+
+	keys, err := f.List(ctx, "blobs/")
+	if err != nil {
+		t.Fatalf("List: %v", err)
+	}
+
+	if len(keys) != 0 {
+		t.Fatalf("expected no keys listed after interrupted write, got %v", keys)
+	}
+}
+
+// TestFileStorer_ListSkipsPartialFiles checks that a leftover temp file (the
+// storage layer names them with a ".partial" suffix) is never surfaced as a
+// key by List or ListStream.
+func TestFileStorer_ListSkipsPartialFiles(t *testing.T) {
+	t.Parallel()
+
+	base := t.TempDir()
+
+	f, err := storage.NewFileStorer(base)
+	if err != nil {
+		t.Fatalf("NewFileStorer: %v", err)
+	}
+
+	ctx := context.Background()
+	realKey := "blobs/aa/bb/aabbccddeeff"
+
+	err = f.Put(ctx, realKey, strings.NewReader("blob-bytes"))
+	if err != nil {
+		t.Fatalf("Put: %v", err)
+	}
+
+	// A stray temp file, as an interrupted write would leave behind.
+	leftover := filepath.Join(base, "blobs/aa/bb/aabbccddeeff-123456.partial")
+
+	err = os.WriteFile(leftover, []byte("half"), 0o600)
+	if err != nil {
+		t.Fatalf("writing leftover temp file: %v", err)
+	}
+
+	keys, err := f.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 f.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)
+	}
+}

internal/storage/file_backend_test.go

@@ -1,214 +0,0 @@
-package storage_test
-
-import (
-	"bytes"
-	"context"
-	"errors"
-	"io"
-	"reflect"
-	"sort"
-	"testing"
-
-	"sneak.berlin/go/vaultik/internal/storage"
-)
-
-// newFileStorer builds a file:// backend rooted at a fresh temp directory.
-//
-//nolint:ireturn // conformance runs against the Storer interface by design
-func newFileStorer(t *testing.T) storage.Storer {
-	t.Helper()
-
-	s, err := storage.NewFileStorer(t.TempDir())
-	if err != nil {
-		t.Fatalf("NewFileStorer: %v", err)
-	}
-
-	return s
-}
-
-// TestFileStorer runs the Storer contract against the file:// backend.
-// The conformance helper is backend-agnostic, so a new backend inherits
-// this coverage by passing its own constructor.
-func TestFileStorer(t *testing.T) {
-	t.Parallel()
-	runStorerConformance(t, newFileStorer)
-}
-
-// runStorerConformance exercises the public Storer contract: round-trip,
-// stat, list, overwrite, delete, and not-found behaviour. Each section
-// uses its own backend instance so ordering never matters.
-func runStorerConformance(t *testing.T, newStorer func(*testing.T) storage.Storer) {
-	t.Helper()
-
-	conformanceRoundTrip(t, newStorer(t))
-	conformanceOverwrite(t, newStorer(t))
-	conformanceList(t, newStorer(t))
-	conformanceDelete(t, newStorer(t))
-	conformanceNotFound(t, newStorer(t))
-}
-
-// conformanceRoundTrip stores a nested key, then reads it back and stats it.
-func conformanceRoundTrip(t *testing.T, s storage.Storer) {
-	t.Helper()
-
-	ctx := context.Background()
-	key := "blobs/aa/bb/object.bin"
-	want := []byte("round-trip payload")
-
-	err := s.Put(ctx, key, bytes.NewReader(want))
-	if err != nil {
-		t.Fatalf("Put: %v", err)
-	}
-
-	got := getBytes(t, s, key)
-	if !bytes.Equal(got, want) {
-		t.Errorf("Get returned %q, want %q", got, want)
-	}
-
-	info, err := s.Stat(ctx, key)
-	if err != nil {
-		t.Fatalf("Stat: %v", err)
-	}
-
-	if info.Key != key {
-		t.Errorf("Stat key = %q, want %q", info.Key, key)
-	}
-
-	if info.Size != int64(len(want)) {
-		t.Errorf("Stat size = %d, want %d", info.Size, len(want))
-	}
-}
-
-// conformanceOverwrite checks that a second Put replaces the first.
-func conformanceOverwrite(t *testing.T, s storage.Storer) {
-	t.Helper()
-
-	ctx := context.Background()
-	key := "meta/snapshot.json"
-
-	err := s.Put(ctx, key, bytes.NewReader([]byte("first")))
-	if err != nil {
-		t.Fatalf("first Put: %v", err)
-	}
-
-	want := []byte("second and longer payload")
-
-	err = s.Put(ctx, key, bytes.NewReader(want))
-	if err != nil {
-		t.Fatalf("second Put: %v", err)
-	}
-
-	got := getBytes(t, s, key)
-	if !bytes.Equal(got, want) {
-		t.Errorf("after overwrite Get returned %q, want %q", got, want)
-	}
-}
-
-// conformanceList checks prefix filtering and the empty result for a
-// prefix that matches nothing.
-func conformanceList(t *testing.T, s storage.Storer) {
-	t.Helper()
-
-	ctx := context.Background()
-	keys := []string{"blobs/aa/one", "blobs/bb/two", "meta/three"}
-
-	for _, k := range keys {
-		err := s.Put(ctx, k, bytes.NewReader([]byte("data")))
-		if err != nil {
-			t.Fatalf("Put %q: %v", k, err)
-		}
-	}
-
-	if got := listSorted(t, s, ""); !reflect.DeepEqual(got, keys) {
-		t.Errorf("List(\"\") = %v, want %v", got, keys)
-	}
-
-	wantBlobs := []string{"blobs/aa/one", "blobs/bb/two"}
-	if got := listSorted(t, s, "blobs/"); !reflect.DeepEqual(got, wantBlobs) {
-		t.Errorf("List(\"blobs/\") = %v, want %v", got, wantBlobs)
-	}
-
-	if got := listSorted(t, s, "absent/"); len(got) != 0 {
-		t.Errorf("List(\"absent/\") = %v, want empty", got)
-	}
-}
-
-// conformanceDelete checks that Delete removes an object and that deleting
-// a missing key is not an error.
-func conformanceDelete(t *testing.T, s storage.Storer) {
-	t.Helper()
-
-	ctx := context.Background()
-	key := "blobs/cc/gone.bin"
-
-	err := s.Put(ctx, key, bytes.NewReader([]byte("temporary")))
-	if err != nil {
-		t.Fatalf("Put: %v", err)
-	}
-
-	err = s.Delete(ctx, key)
-	if err != nil {
-		t.Fatalf("Delete: %v", err)
-	}
-
-	_, err = s.Get(ctx, key)
-	if !errors.Is(err, storage.ErrNotFound) {
-		t.Errorf("Get after Delete error = %v, want ErrNotFound", err)
-	}
-
-	err = s.Delete(ctx, key)
-	if err != nil {
-		t.Errorf("Delete of missing key = %v, want nil", err)
-	}
-}
-
-// conformanceNotFound checks Get and Stat on an absent key.
-func conformanceNotFound(t *testing.T, s storage.Storer) {
-	t.Helper()
-
-	ctx := context.Background()
-	key := "never/written"
-
-	_, err := s.Get(ctx, key)
-	if !errors.Is(err, storage.ErrNotFound) {
-		t.Errorf("Get error = %v, want ErrNotFound", err)
-	}
-
-	_, err = s.Stat(ctx, key)
-	if !errors.Is(err, storage.ErrNotFound) {
-		t.Errorf("Stat error = %v, want ErrNotFound", err)
-	}
-}
-
-// getBytes reads a key fully and closes the reader.
-func getBytes(t *testing.T, s storage.Storer, key string) []byte {
-	t.Helper()
-
-	rc, err := s.Get(context.Background(), key)
-	if err != nil {
-		t.Fatalf("Get %q: %v", key, err)
-	}
-
-	defer func() { _ = rc.Close() }()
-
-	data, err := io.ReadAll(rc)
-	if err != nil {
-		t.Fatalf("read %q: %v", key, err)
-	}
-
-	return data
-}
-
-// listSorted returns the keys under a prefix in a stable order.
-func listSorted(t *testing.T, s storage.Storer, prefix string) []string {
-	t.Helper()
-
-	keys, err := s.List(context.Background(), prefix)
-	if err != nil {
-		t.Fatalf("List %q: %v", prefix, err)
-	}
-
-	sort.Strings(keys)
-
-	return keys
-}

internal/storage/url_parse_test.go

@@ -1,110 +0,0 @@
-package storage_test
-
-import (
-	"errors"
-	"reflect"
-	"testing"
-
-	"sneak.berlin/go/vaultik/internal/storage"
-)
-
-// TestParseStorageURLValid checks that each supported scheme parses into
-// the expected fields, since those fields decide which backend is built.
-func TestParseStorageURLValid(t *testing.T) {
-	t.Parallel()
-
-	const bucket = "mybucket"
-
-	cases := []struct {
-		name string
-		raw  string
-		want *storage.URL
-	}{
-		{
-			name: "file absolute path",
-			raw:  "file:///var/backups/vaultik",
-			want: &storage.URL{Scheme: "file", Prefix: "/var/backups/vaultik"},
-		},
-		{
-			name: "s3 bucket and prefix, ssl defaults on",
-			raw:  "s3://mybucket/backups/host",
-			want: &storage.URL{
-				Scheme: "s3", Bucket: bucket,
-				Prefix: "backups/host", UseSSL: true,
-			},
-		},
-		{
-			name: "s3 bucket only",
-			raw:  "s3://mybucket",
-			want: &storage.URL{Scheme: "s3", Bucket: bucket, UseSSL: true},
-		},
-		{
-			name: "s3 with endpoint, region, ssl off",
-			raw:  "s3://mybucket?endpoint=minio.example.com&region=us-west-2&ssl=false",
-			want: &storage.URL{
-				Scheme: "s3", Bucket: bucket,
-				Endpoint: "minio.example.com", Region: "us-west-2", UseSSL: false,
-			},
-		},
-		{
-			name: "rclone remote and path",
-			raw:  "rclone://gdrive/backups/host",
-			want: &storage.URL{
-				Scheme: "rclone", RcloneRemote: "gdrive", Prefix: "backups/host",
-			},
-		},
-		{
-			name: "rclone remote only",
-			raw:  "rclone://gdrive",
-			want: &storage.URL{Scheme: "rclone", RcloneRemote: "gdrive"},
-		},
-	}
-
-	for _, tc := range cases {
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-
-			got, err := storage.ParseStorageURL(tc.raw)
-			if err != nil {
-				t.Fatalf("ParseStorageURL(%q) returned error: %v", tc.raw, err)
-			}
-
-			if !reflect.DeepEqual(got, tc.want) {
-				t.Errorf("ParseStorageURL(%q) = %+v, want %+v", tc.raw, got, tc.want)
-			}
-		})
-	}
-}
-
-// TestParseStorageURLErrors checks that empty, missing, and unknown-scheme
-// inputs fail with the documented sentinel errors instead of parsing to a
-// wrong destination.
-func TestParseStorageURLErrors(t *testing.T) {
-	t.Parallel()
-
-	cases := []struct {
-		name    string
-		raw     string
-		wantErr error
-	}{
-		{"empty url", "", storage.ErrEmptyStorageURL},
-		{"file empty path", "file://", storage.ErrEmptyFilePath},
-		{"s3 missing bucket", "s3://", storage.ErrMissingBucket},
-		{"s3 missing bucket with path", "s3:///justprefix", storage.ErrMissingBucket},
-		{"rclone missing remote", "rclone://", storage.ErrMissingRemote},
-		{"unknown scheme", "gs://bucket/x", storage.ErrUnsupportedScheme},
-		{"no scheme", "/local/path", storage.ErrUnsupportedScheme},
-	}
-
-	for _, tc := range cases {
-		t.Run(tc.name, func(t *testing.T) {
-			t.Parallel()
-
-			_, err := storage.ParseStorageURL(tc.raw)
-			if !errors.Is(err, tc.wantErr) {
-				t.Errorf("ParseStorageURL(%q) error = %v, want %v",
-					tc.raw, err, tc.wantErr)
-			}
-		})
-	}
-}

internal/vaultik/prune_count_test.go

@@ -0,0 +1,79 @@
+package vaultik //nolint:testpackage // exercises unexported count helpers
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/database"
+	"sneak.berlin/go/vaultik/internal/log"
+)
+
+// TestTableCountForReportSurfacesReadFailure is the regression guard for
+// the discarded-error bug: getTableCount for a table its query cannot
+// resolve must not silently become 0. A count that could not be read is
+// reported as unknown, which a reader can tell apart from an empty table.
+//
+//nolint:paralleltest // installs the global logger via log.Initialize
+func TestTableCountForReportSurfacesReadFailure(t *testing.T) {
+	log.Initialize(log.Config{})
+
+	ctx := context.Background()
+
+	db, err := database.New(ctx, ":memory:")
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = db.Close() })
+
+	v := &Vaultik{DB: db}
+	v.SetContext(ctx)
+
+	// A table present in the schema reads as a real count.
+	blobs := v.tableCountForReport("blobs")
+	require.NotNil(t, blobs, "an existing table must read as a real count")
+	assert.Equal(t, int64(0), *blobs)
+
+	// A syntactically valid name the sanitizer accepts but whose table
+	// the query cannot resolve is the exact shape #96 describes: a
+	// would-be loud failure that used to be discarded into a 0.
+	_, err = v.getTableCount("snapshots_missing")
+	require.Error(t, err, "a query against a nonexistent table must fail")
+
+	missing := v.tableCountForReport("snapshots_missing")
+	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.NotEqual(t, "0", countText(missing))
+}
+
+// TestCountTextDistinguishesEmptyFromUnknown pins the distinction the
+// output has to preserve: 0 means the table was empty, "unknown" means
+// the count could not be read.
+func TestCountTextDistinguishesEmptyFromUnknown(t *testing.T) {
+	t.Parallel()
+
+	zero := int64(0)
+	seven := int64(7)
+
+	assert.Equal(t, "0", countText(&zero))
+	assert.Equal(t, "7", countText(&seven))
+	assert.Equal(t, countUnknown, countText(nil))
+}
+
+// TestCountDiffUnknownWhenEitherSideUnknown checks that a delta computed
+// from an unreadable count is itself unknown rather than a plausible
+// number.
+func TestCountDiffUnknownWhenEitherSideUnknown(t *testing.T) {
+	t.Parallel()
+
+	before := int64(10)
+	after := int64(3)
+
+	require.NotNil(t, countDiff(&before, &after))
+	assert.Equal(t, int64(7), *countDiff(&before, &after))
+
+	assert.Nil(t, countDiff(nil, &after), "unknown before yields unknown delta")
+	assert.Nil(t, countDiff(&before, nil), "unknown after yields unknown delta")
+	assert.Nil(t, countDiff(nil, nil))
+}

internal/vaultik/restore.go

@@ -18,7 +18,6 @@ import (
 	"sneak.berlin/go/vaultik/internal/blobgen"
 	"sneak.berlin/go/vaultik/internal/database"
 	"sneak.berlin/go/vaultik/internal/log"
-	"sneak.berlin/go/vaultik/internal/snapshot"
 	"sneak.berlin/go/vaultik/internal/types"
 )
 
@@ -577,14 +576,20 @@ func (v *Vaultik) handleRestoreVerification(
 }
 
 // downloadSnapshotDB downloads and decrypts the snapshot metadata
-// database. The snapshotID is the human ID; we hash it to the remote
-// key for the storage path.
+// database. The identifier is resolved to the snapshot's remote key: a
+// human ID is hashed, and a remote key (or its abbreviation, as printed
+// for a remote-only snapshot) is used as-is, so a host with no local
+// index can restore the snapshots it can only see on the store.
 func (v *Vaultik) downloadSnapshotDB(
 	snapshotID string, identity age.Identity,
 ) (*database.DB, error) {
+	remoteKey, err := v.resolveSnapshotRemoteKey(snapshotID)
+	if err != nil {
+		return nil, err
+	}
+
 	// Download encrypted database from storage
-	dbKey := fmt.Sprintf("metadata/%s/db.zst.age",
-		snapshot.RemoteSnapshotKey(snapshotID))
+	dbKey := fmt.Sprintf("metadata/%s/db.zst.age", remoteKey)
 
 	reader, err := v.Storage.Get(v.ctx, dbKey)
 	if err != nil {

internal/vaultik/restore_another_machine_test.go

@@ -0,0 +1,167 @@
+package vaultik_test
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/config"
+	"sneak.berlin/go/vaultik/internal/database"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/snapshot"
+	"sneak.berlin/go/vaultik/internal/storage"
+	"sneak.berlin/go/vaultik/internal/ui"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// TestRestoreOnAnotherMachine proves the disaster-recovery path: a host
+// that has only the vaultik binary, the age secret key, and the storage
+// credentials — no local index, a different hostname, and no
+// age_recipients configured — can list, restore, and verify a snapshot
+// straight from the destination store.
+//
+// The backup half writes a snapshot with one index and hostname. The
+// restore half throws that index away entirely: a fresh, empty index and
+// a config that shares nothing with the original but the storage location
+// and the secret key. If restore or verify needed the original local
+// index — or the human snapshot ID that only that index holds — this test
+// could not run, because the recovery host can know neither.
+func TestRestoreOnAnotherMachine(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	fs := afero.NewOsFs()
+	tempDir := t.TempDir()
+
+	dataDir := filepath.Join(tempDir, "source")
+	storeDir := filepath.Join(tempDir, "remote")
+	restoreDir := filepath.Join(tempDir, "restored")
+	dbPath := filepath.Join(tempDir, "index.sqlite")
+
+	chunkSize := int64(64 * 1024)
+	maxBlobSize := int64(512 * 1024)
+
+	sourceFiles := writeRecoverySourceTree(t, fs, dataDir, chunkSize)
+
+	ctx := context.Background()
+
+	// Backup host: one index, hostname test-host, age_recipients set.
+	// runFileStorageBackup closes the index before returning, so nothing
+	// below can lean on it.
+	_, storer, originalID := runFileStorageBackup(
+		ctx, t, fs, dataDir, storeDir, dbPath, chunkSize, maxBlobSize)
+
+	// Recovery host: a fresh empty index, a different hostname, and no
+	// age_recipients — only the secret key and the same storage location.
+	recovery, stdout := newRecoveryHost(ctx, t, fs, storer)
+
+	// The recovery index really is empty. This is the assertion that makes
+	// the test a guard against restore quietly depending on the original
+	// index: if it did, an empty index would make restore fail.
+	localSnaps, err := recovery.Repositories.Snapshots.ListRecent(ctx, 100)
+	require.NoError(t, err)
+	require.Empty(t, localSnaps, "recovery host must start with no local index")
+
+	// List: the snapshot shows up as remote-only, identified by its remote
+	// key, with no recoverable human ID.
+	require.NoError(t, recovery.ListSnapshots(true))
+
+	rows := decodeListJSON(t, stdout.String())
+	require.Len(t, rows, 1)
+
+	remote := rows[0]
+	assert.False(t, remote.LocallyTracked, "snapshot must be remote-only here")
+	assert.Empty(t, remote.ID, "the human ID is unknown to the recovery host")
+	require.Len(t, remote.RemoteKey, 64)
+	assert.Equal(t, snapshot.RemoteSnapshotKey(originalID), remote.RemoteKey,
+		"the listed key is the hashed snapshot ID")
+
+	// Restore driven by the abbreviated identifier the table prints (the
+	// first 12 hex of the remote key), then deep-verify from the store
+	// keyed by the full remote key. Both are what a recovery host can know.
+	require.NoError(t, recovery.Restore(&vaultik.RestoreOptions{
+		SnapshotID: remote.RemoteKey[:12],
+		TargetDir:  restoreDir,
+		Verify:     true,
+	}))
+	require.NoError(t, recovery.RunDeepVerify(
+		remote.RemoteKey, &vaultik.VerifyOptions{Deep: true}))
+
+	assertRestoredTreeMatches(t, fs, restoreDir, sourceFiles)
+}
+
+// writeRecoverySourceTree writes a small source tree spanning several
+// chunks (so restore reassembles real multi-chunk files) and returns the
+// content keyed by absolute path.
+func writeRecoverySourceTree(
+	t *testing.T, fs afero.Fs, dataDir string, chunkSize int64,
+) map[string][]byte {
+	t.Helper()
+
+	sourceFiles := map[string][]byte{
+		filepath.Join(dataDir, "notes.txt"):        []byte("recover me"),
+		filepath.Join(dataDir, "sub", "big.bin"):   bytesPattern("big-", int(chunkSize*3)),
+		filepath.Join(dataDir, "sub", "small.bin"): bytesPattern("small-", 128),
+	}
+
+	for path, content := range sourceFiles {
+		require.NoError(t, fs.MkdirAll(filepath.Dir(path), 0o755))
+		require.NoError(t, afero.WriteFile(fs, path, content, 0o644))
+	}
+
+	return sourceFiles
+}
+
+// newRecoveryHost builds the Vaultik a replacement machine would run: an
+// empty in-memory index, a hostname different from the backup host, no
+// age_recipients, and only the secret key plus the shared storer. It
+// returns the instance and the buffer its stdout is wired to.
+func newRecoveryHost(
+	ctx context.Context, t *testing.T, fs afero.Fs, storer storage.Storer,
+) (*vaultik.Vaultik, *bytes.Buffer) {
+	t.Helper()
+
+	recoveryDB, err := database.New(ctx, ":memory:")
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = recoveryDB.Close() })
+
+	stdout := &bytes.Buffer{}
+
+	recovery := &vaultik.Vaultik{
+		Config: &config.Config{
+			AgeSecretKey: testAgeSecretKey,
+			Hostname:     "recovery-host",
+		},
+		Storage:      storer,
+		Fs:           fs,
+		Repositories: database.NewRepositories(recoveryDB),
+		DB:           recoveryDB,
+		Stdout:       stdout,
+		Stderr:       io.Discard,
+		UI:           ui.NewWithColor(io.Discard, false),
+	}
+	recovery.SetContext(ctx)
+
+	return recovery, stdout
+}
+
+// assertRestoredTreeMatches byte-compares every restored file against its
+// source content.
+func assertRestoredTreeMatches(
+	t *testing.T, fs afero.Fs, restoreDir string, sourceFiles map[string][]byte,
+) {
+	t.Helper()
+
+	for origPath, expected := range sourceFiles {
+		restored := filepath.Join(restoreDir, origPath)
+		got, err := afero.ReadFile(fs, restored)
+		require.NoErrorf(t, err, "restored file missing: %s", restored)
+		require.Truef(t, bytes.Equal(got, expected),
+			"byte mismatch for %s", origPath)
+	}
+}

internal/vaultik/snapshot.go

@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
@@ -669,9 +670,11 @@ func (v *Vaultik) VerifySnapshotWithOptions(
 
 	v.printVerifyHeader(snapshotID, opts)
 
-	// Download and parse manifest. The caller supplies a human
-	// snapshot ID; we hash it to address remote storage.
-	manifest, err := v.downloadManifestByKey(snapshot.RemoteSnapshotKey(snapshotID))
+	// Resolve the identifier to the snapshot's remote key and download the
+	// manifest. A human ID is hashed; a remote key (or its abbreviation,
+	// as printed for a remote-only snapshot) is used as-is, so a host with
+	// no local index can verify a snapshot it can only see on the store.
+	manifest, err := v.resolveAndDownloadManifest(snapshotID)
 	if err != nil {
 		if opts.JSON {
 			result.Status = verifyStatusFailed
@@ -1540,12 +1543,17 @@ func (v *Vaultik) outputRemoveJSON(result *RemoveResult) error {
 	return encoder.Encode(result)
 }
 
-// PruneResult contains statistics about the prune operation
+// PruneResult contains statistics about the prune operation.
+// SnapshotsDeleted counts snapshots actually deleted. FilesDeleted,
+// ChunksDeleted, and BlobsDeleted are derived from before/after row
+// counts of the local index; each is nil when a count could not be read,
+// so an unreadable count is reported as unknown rather than silently
+// as 0.
 type PruneResult struct {
 	SnapshotsDeleted int64
-	FilesDeleted     int64
-	ChunksDeleted    int64
-	BlobsDeleted     int64
+	FilesDeleted     *int64
+	ChunksDeleted    *int64
+	BlobsDeleted     *int64
 }
 
 // PruneDatabase removes incomplete snapshots and orphaned files, chunks,
@@ -1560,7 +1568,7 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	result := &PruneResult{}
 
 	// Snapshot counts before deletion of incompletes.
-	snapshotCountBefore, _ := v.getTableCount("snapshots")
+	snapshotCountBefore := v.tableCountForReport("snapshots")
 
 	// First, delete any incomplete snapshots
 	incompleteSnapshots, err := v.Repositories.Snapshots.GetIncompleteSnapshots(v.ctx)
@@ -1575,9 +1583,9 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	}
 
 	// Get counts before cleanup for reporting
-	fileCountBefore, _ := v.getTableCount("files")
-	chunkCountBefore, _ := v.getTableCount("chunks")
-	blobCountBefore, _ := v.getTableCount("blobs")
+	fileCountBefore := v.tableCountForReport("files")
+	chunkCountBefore := v.tableCountForReport("chunks")
+	blobCountBefore := v.tableCountForReport("blobs")
 
 	// Run the cleanup
 	err = v.SnapshotManager.CleanupOrphanedData(v.ctx)
@@ -1586,36 +1594,83 @@ func (v *Vaultik) PruneDatabase() (*PruneResult, error) {
 	}
 
 	// Get counts after cleanup
-	fileCountAfter, _ := v.getTableCount("files")
-	chunkCountAfter, _ := v.getTableCount("chunks")
-	blobCountAfter, _ := v.getTableCount("blobs")
+	fileCountAfter := v.tableCountForReport("files")
+	chunkCountAfter := v.tableCountForReport("chunks")
+	blobCountAfter := v.tableCountForReport("blobs")
 
-	result.FilesDeleted = fileCountBefore - fileCountAfter
-	result.ChunksDeleted = chunkCountBefore - chunkCountAfter
-	result.BlobsDeleted = blobCountBefore - blobCountAfter
+	result.FilesDeleted = countDiff(fileCountBefore, fileCountAfter)
+	result.ChunksDeleted = countDiff(chunkCountBefore, chunkCountAfter)
+	result.BlobsDeleted = countDiff(blobCountBefore, blobCountAfter)
 
 	log.Info("Local database prune complete",
 		"incomplete_snapshots", result.SnapshotsDeleted,
-		"orphaned_files", result.FilesDeleted,
-		"orphaned_chunks", result.ChunksDeleted,
-		"orphaned_blobs", result.BlobsDeleted,
+		"orphaned_files", countText(result.FilesDeleted),
+		"orphaned_chunks", countText(result.ChunksDeleted),
+		"orphaned_blobs", countText(result.BlobsDeleted),
 	)
 
-	snapshotCountAfter := snapshotCountBefore - result.SnapshotsDeleted
+	// Snapshots remaining after removing the incomplete ones; unknown if
+	// the pre-prune snapshot count could not be read.
+	snapshotsRemain := countDiff(snapshotCountBefore, &result.SnapshotsDeleted)
 
 	v.UI.Completef("Pruned local index database.")
-	v.UI.Detailf("Incomplete snapshots: %d removed (%d remain).",
-		result.SnapshotsDeleted, snapshotCountAfter)
-	v.UI.Detailf("Orphaned files: %d removed (%d remain).",
-		result.FilesDeleted, fileCountAfter)
-	v.UI.Detailf("Orphaned chunks: %d removed (%d remain).",
-		result.ChunksDeleted, chunkCountAfter)
-	v.UI.Detailf("Orphaned blobs: %d removed (%d remain).",
-		result.BlobsDeleted, blobCountAfter)
+	v.UI.Detailf("Incomplete snapshots: %s removed (%s remain).",
+		countText(&result.SnapshotsDeleted), countText(snapshotsRemain))
+	v.UI.Detailf("Orphaned files: %s removed (%s remain).",
+		countText(result.FilesDeleted), countText(fileCountAfter))
+	v.UI.Detailf("Orphaned chunks: %s removed (%s remain).",
+		countText(result.ChunksDeleted), countText(chunkCountAfter))
+	v.UI.Detailf("Orphaned blobs: %s removed (%s remain).",
+		countText(result.BlobsDeleted), countText(blobCountAfter))
 
 	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"
+
+// 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
+// logged at warn — visible even under --json, which routes warnings to
+// stderr — and then rendered as unknown rather than silently becoming 0,
+// so a broken query is a visible failure instead of a plausible wrong
+// number.
+func (v *Vaultik) tableCountForReport(tableName string) *int64 {
+	count, err := v.getTableCount(tableName)
+	if err != nil {
+		log.Warn("could not read table row count for prune summary",
+			"table", tableName, "error", err)
+
+		return nil
+	}
+
+	return &count
+}
+
+// countDiff returns before-after, or nil if either count is unknown so
+// that an unreadable count does not collapse into a plausible delta.
+func countDiff(before, after *int64) *int64 {
+	if before == nil || after == nil {
+		return nil
+	}
+
+	diff := *before - *after
+
+	return &diff
+}
+
+// countText renders a count that may be unknown: nil (the read failed)
+// becomes "unknown", never "0", so a reader can tell an empty table from
+// one that could not be queried.
+func countText(count *int64) string {
+	if count == nil {
+		return countUnknown
+	}
+
+	return strconv.FormatInt(*count, 10)
+}
+
 // validTableNameRe matches table names containing only lowercase
 // alphanumeric characters and underscores.
 var validTableNameRe = regexp.MustCompile(`^[a-z0-9_]+$`)

internal/vaultik/snapshot_identifier.go

@@ -0,0 +1,101 @@
+package vaultik
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"sneak.berlin/go/vaultik/internal/snapshot"
+)
+
+// remoteKeyHexLen is the length of a full remote snapshot key: a SHA256
+// digest rendered as lowercase hex.
+const remoteKeyHexLen = 64
+
+// Sentinel errors for resolving a snapshot identifier against the store.
+var (
+	errSnapshotKeyNotFound = errors.New(
+		"no snapshot on the destination store matches this identifier")
+	errSnapshotKeyAmbiguous = errors.New(
+		"identifier matches more than one snapshot on the destination store")
+)
+
+// resolveSnapshotRemoteKey turns a snapshot identifier supplied on the
+// command line into the remote key that names the snapshot's metadata
+// directory on the destination store. Every remote path a restore or
+// verify reads is built from that key.
+//
+// Two forms are accepted, matching the two things a host can know:
+//
+//   - A human snapshot ID (hostname_name_timestamp), which a host holding
+//     the local index has. It is hashed to its remote key; the store is
+//     not consulted.
+//   - A remote key, or the leading part of one, which is all a host with
+//     no local index can know — it is exactly what `snapshot list` prints
+//     for a remote-only snapshot (see formatRemoteOnlyID). It is resolved
+//     against the destination store's metadata listing; an identifier that
+//     matches no snapshot, or more than one, is an error.
+//
+// The two are told apart by shape: a remote key is lowercase hex, and a
+// human snapshot ID never is (it carries a hostname, underscores, and an
+// RFC3339 timestamp).
+func (v *Vaultik) resolveSnapshotRemoteKey(identifier string) (string, error) {
+	if !isRemoteKeyOrPrefix(identifier) {
+		return snapshot.RemoteSnapshotKey(identifier), nil
+	}
+
+	keys, err := v.listAllRemoteSnapshotKeys()
+	if err != nil {
+		return "", fmt.Errorf(
+			"listing destination store to resolve %q: %w", identifier, err)
+	}
+
+	var matches []string
+
+	for _, key := range keys {
+		if strings.HasPrefix(key, identifier) {
+			matches = append(matches, key)
+		}
+	}
+
+	switch len(matches) {
+	case 1:
+		return matches[0], nil
+	case 0:
+		return "", fmt.Errorf("%w: %s", errSnapshotKeyNotFound, identifier)
+	default:
+		return "", fmt.Errorf("%w: %s (%d matches)",
+			errSnapshotKeyAmbiguous, identifier, len(matches))
+	}
+}
+
+// resolveAndDownloadManifest resolves a snapshot identifier to its remote
+// key (see resolveSnapshotRemoteKey) and downloads that snapshot's
+// manifest.
+func (v *Vaultik) resolveAndDownloadManifest(
+	identifier string,
+) (*snapshot.Manifest, error) {
+	remoteKey, err := v.resolveSnapshotRemoteKey(identifier)
+	if err != nil {
+		return nil, err
+	}
+
+	return v.downloadManifestByKey(remoteKey)
+}
+
+// isRemoteKeyOrPrefix reports whether s is a full remote key or the
+// leading part of one: 1 to 64 lowercase hex characters. A human snapshot
+// ID is never all hex, so this shape test is enough to tell the two apart.
+func isRemoteKeyOrPrefix(s string) bool {
+	if s == "" || len(s) > remoteKeyHexLen {
+		return false
+	}
+
+	for _, r := range s {
+		if (r < '0' || r > '9') && (r < 'a' || r > 'f') {
+			return false
+		}
+	}
+
+	return true
+}

internal/vaultik/verify.go

@@ -138,8 +138,15 @@ func (v *Vaultik) RunDeepVerify(snapshotID string, opts *VerifyOptions) error {
 func (v *Vaultik) loadVerificationData(
 	snapshotID string, opts *VerifyOptions, result *VerifyResult,
 ) (*snapshot.Manifest, *tempDB, []snapshot.BlobInfo, error) {
-	// All remote paths use the hashed key derived from the human ID.
-	remoteKey := snapshot.RemoteSnapshotKey(snapshotID)
+	// Resolve the identifier to the snapshot's remote key. A human ID is
+	// hashed; a remote key (or its abbreviation, as printed for a
+	// remote-only snapshot) is used as-is, so a host with no local index
+	// can verify a snapshot it can only see on the store.
+	remoteKey, err := v.resolveSnapshotRemoteKey(snapshotID)
+	if err != nil {
+		return nil, nil, nil, v.deepVerifyFailure(result, opts,
+			fmt.Sprintf("resolving snapshot identifier: %v", err), err)
+	}
 
 	// Download manifest. downloadManifestByKey is the single reader for
 	// remote manifests; see its doc comment.
@@ -186,7 +193,7 @@ func (v *Vaultik) loadVerificationData(
 			fmt.Errorf("failed to decrypt database: %w", err))
 	}
 
-	dbBlobs, err := v.getBlobsFromDatabase(snapshotID, tdb.DB)
+	dbBlobs, err := v.getBlobsFromDatabase(tdb.DB)
 	if err != nil {
 		_ = tdb.Close()
 
@@ -501,19 +508,21 @@ func (v *Vaultik) verifyBlobFinalIntegrity(
 	return nil
 }
 
-// getBlobsFromDatabase gets all blobs for the snapshot from the database
-func (v *Vaultik) getBlobsFromDatabase(
-	snapshotID string, db *sql.DB,
-) ([]snapshot.BlobInfo, error) {
+// getBlobsFromDatabase gets all blobs for the snapshot from the database.
+//
+// The exported per-snapshot database holds exactly one snapshot's data
+// (see cleanSnapshotDB), so every row in snapshot_blobs belongs to it.
+// We select them directly rather than filtering by the human snapshot ID,
+// which a host restoring from the store alone does not have.
+func (v *Vaultik) getBlobsFromDatabase(db *sql.DB) ([]snapshot.BlobInfo, error) {
 	query := `
 		SELECT b.blob_hash, b.compressed_size
 		FROM snapshot_blobs sb
 		JOIN blobs b ON sb.blob_hash = b.blob_hash
-		WHERE sb.snapshot_id = ?
 		ORDER BY b.blob_hash
 	`
 
-	rows, err := db.QueryContext(v.ctx, query, snapshotID)
+	rows, err := db.QueryContext(v.ctx, query)
 	if err != nil {
 		return nil, fmt.Errorf("failed to query snapshot blobs: %w", err)
 	}