migration consolidation patch

packages/memory-service/src/db/migrations.js

@@ -0,0 +1,43 @@
+const { logger } = require('@nexusai/shared');
+
+// Forward-only schema migrations. Entry i takes the database from user_version i
+// to i+1, so migrations[0] is the v0→v1 step, migrations[1] the v1→v2 step, etc.
+//
+// schema.js already holds the COMPLETE current shape, so a fresh database is
+// created whole and stamped straight to LATEST_VERSION — these run only to carry
+// an OLDER database forward. Add a new schema change by appending a function here
+// (which bumps LATEST_VERSION by one); never edit an existing entry once shipped,
+// since databases already stamped past it will not re-run it.
+//
+// Each migration receives the better-sqlite3 db handle and runs inside a
+// transaction together with its version bump, so a failure rolls back cleanly.
+const migrations = [
+  // v0 → v1: baseline. The historical ALTER TABLE / CREATE INDEX statements that
+  // used to run (wrapped in try/catch) on every boot are folded into schema.js.
+  // Nothing to do here — this entry exists to mark v1 as the consolidated baseline.
+  (_db) => {},
+];
+
+const LATEST_VERSION = migrations.length;
+
+// Applies any migrations newer than the database's current user_version, one at a
+// time, each with its version bump, inside a transaction. Returns the resulting
+// version. A no-op when the database is already current. The migrations list and
+// target version are injectable for testing; production callers pass just `db`.
+function migrate(db, migs = migrations, latest = migs.length) {
+  const current = db.pragma('user_version', { simple: true });
+  if (current >= latest) return current;
+
+  for (let v = current; v < latest; v++) {
+    const step = db.transaction(() => {
+      migs[v](db);
+      db.pragma(`user_version = ${v + 1}`);
+    });
+    step();
+  }
+
+  logger.info(`[db] schema migrated ${current} -> ${latest}`);
+  return latest;
+}
+
+module.exports = { migrate, migrations, LATEST_VERSION };