The local index tracks which chunks and blobs already exist at the
backup destination. Nothing was recording *which* destination, so
changing storage_url and running a backup left the scanner treating
every already-seen chunk as still-present at the new (empty) location.
Uploads were skipped silently and the resulting snapshots pointed at
blobs that don't exist at the new destination.
Fix: record storage_url in a new local_meta key-value table on first
mutating command, and refuse to proceed when the configured URL later
differs from the stored one. The error explains the two recovery
paths (revert the config, or run 'vaultik database purge' to discard
the index and rebuild from a fresh full backup).
Wired into snapshot create / prune / snapshot remove / snapshot purge
/ snapshot cleanup. Read-only inspection commands (snapshot list,
remote info, store info) are exempt.
Closes #57
Adopts the [pixa migration pattern](sneak/pixa#36) for schema management. Replaces the monolithic `schema.sql` embed with a numbered migration system.
## Changes
### New: `schema/000.sql` — Bootstrap migration
- Creates `schema_migrations` table with `INTEGER PRIMARY KEY` version column
- Self-contained: includes both `CREATE TABLE IF NOT EXISTS` and `INSERT OR IGNORE` for version 0
- Go code does zero INSERTs for bootstrap — just reads and executes 000.sql
### Renamed: `schema.sql` → `schema/001.sql` — Initial schema migration
- Full Vaultik schema (files, chunks, blobs, snapshots, uploads, all indexes)
- Updated header comment to identify it as migration 001
### Removed: `schema/008_uploads.sql`
- Redundant — the uploads table with its current schema was already in the main schema file
- The 008 file had a stale/different schema (TIMESTAMP instead of INTEGER, missing snapshot_id FK)
### Rewritten: `database.go` — Migration engine
- `//go:embed schema/*.sql` replaces `//go:embed schema.sql`
- `bootstrapMigrationsTable()`: checks if `schema_migrations` table exists, applies 000.sql if missing
- `applyMigrations()`: iterates through numbered .sql files, checks `schema_migrations` for each version, applies and records pending ones
- `collectMigrations()`: reads embedded schema dir, returns sorted filenames
- `ParseMigrationVersion()`: extracts numeric version from filenames like `001.sql` or `001_description.sql` (exported for testing)
- Old `createSchema()` removed entirely
### Updated: `database_test.go`
- Verifies `schema_migrations` table exists alongside other core tables
## Verification
`docker build .` passes — formatting, linting, all tests green.
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: #58
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
