fix(scheduler): honor a pauseJob() that lands while a job is in flight

[truffle-dev]

Summary

executeJob captures newStatus from the in-memory job snapshot taken at pickup, then writes it back unconditionally after handleMessage returns. Because an agent task can run for minutes, a pauseJob() call landing during that window writes status='paused' to the row, but the write-back stomps it back to 'active' and the next scheduled fire runs anyway. The pause is silently lost.

This honors a concurrent pause by re-reading the live status just before the write-back.

Why this matters

pauseJob() (service.ts) does UPDATE ... SET status='paused' WHERE id=? AND status='active'. The SQL succeeds, but executeJob's final UPDATE scheduled_jobs SET ... status=? uses the stale captured value and overwrites it. An operator who pauses a long-running recurring job mid-execution sees it keep firing. There is no error, no log, nothing to debug against.

The fix

Right before the write-back, re-read the row's current status. If an external writer set it to 'paused' during the run, honor it (and clear next_run_at). The guard is scoped to the 'active' continuation case only: 'completed' and 'failed' are this run's terminal outcomes and must win over a concurrent pause. resumeJob() recomputes next_run_at from the schedule when the operator un-pauses, so clearing it here is safe.

if (newStatus === "active") {
	const live = ctx.db.query("SELECT status FROM scheduled_jobs WHERE id = ?").get(job.id) as {
		status: string;
	} | null;
	if (live?.status === "paused") {
		newStatus = "paused";
		nextRunAt = null;
	}
}

One extra single-row read per fire, only on the continuation path.

Test

Adds a regression test in scheduler-hardening.test.ts. The mocked handleMessage performs the concurrent pause mid-run (UPDATE ... SET status='paused'), then the test asserts the row stays 'paused' with next_run_at null after executeJob.

Mutation-proved: reverting the fix turns the test red (Expected: "paused"), restoring it turns it green.

• bun test src/scheduler/ -> 116 pass, 0 fail
• bun run lint -> clean
• bun run typecheck -> clean

Fixes #148