Every backup now writes vaultik-destination.txt at the destination
root. 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.
remote nuke deletes the marker last. The file:// backend no longer
creates its destination directory and checks for it on every write;
that protects a directory on a removable volume, not the mount point
itself.
Tests back up into existing directories; 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
Restore and deep verify downloaded and decrypted metadata/<key>/db.zst.age by object name alone. age decryption proves the database is readable, not that it is the snapshot that was asked for: an attacker who swaps in another valid db.zst.age could redirect the operation, and deep verify with a swapped database plus an empty manifest reported success with zero blobs verified.
After the database is opened, both paths now confirm its identity: an exported per-snapshot database holds one snapshot row, and a snapshot remote key derives from that row ID, so the database is the requested one exactly when its sole snapshot hashes back to the remote key fetched. The shared check lives in verifySnapshotDBIdentity, backed by a new SnapshotRepository.GetOnlySnapshot.
Model: opus-4-8