`banger doctor` used to call store.Open, which unconditionally runs
migrations on the way up. Diagnostics mutating persistent state is a
surprise — particularly now that migration 2 drops a column, so a
plain `doctor` invocation against an old DB would silently schema-
evolve it.
Add store.OpenReadOnly: separate DSN builder with mode=ro and a
minimal pragma set (foreign_keys, busy_timeout — no journal_mode=WAL,
no wal_autocheckpoint), skips runMigrations, and pings on open so a
missing DB fails up front rather than at first query. doctor.go now
uses OpenReadOnly; the existing storeErr fallback path surfaces any
failure as a failing check, unchanged.
Tests pin two invariants:
- OpenReadOnly against a DB whose migration 2 marker was removed and
packages_path re-added must leave both alone (i.e. no drift is
applied behind the user's back).
- Any write attempted through the read-only handle is rejected at
the driver layer (belt-and-braces for future refactors).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Thales Maciel
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