The old migrate() helper only knew how to re-run a fixed slab of CREATE
TABLE IF NOT EXISTS plus per-column ensureColumnExists calls. That worked
while every schema change was a benign additive column; it falls apart
as soon as we need a data backfill, an index, a rename, or anything that
has to happen exactly once in a known order.
Replaces it with a schema_migrations table + ordered []migration slice.
Each migration has a unique id, a human-readable name, and a func(*Tx)
body; the runner opens a transaction per migration so DDL and any data
changes either both land and get recorded or both roll back together,
leaving the DB in a state where retrying on next Open() reapplies from
the same point.
Migration 1 ("baseline") collapses the current schema into one entry:
fresh databases apply it in one shot; existing dev databases see
idempotent `CREATE TABLE IF NOT EXISTS` + `ALTER TABLE … ADD COLUMN`
statements that succeed as no-ops, and the only net effect is the
schema_migrations row that brings them into the versioned system.
Tests cover fresh apply, idempotent re-open, skipping already-applied
ids, rollback on body error (the transient table the migration created
must not survive), and duplicate-id rejection.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Thales Maciel
34dd7644d8