detect: an absence is raised when its deadline passes, and after a restart

[cpoder]

What was wrong

The alert waited for the next event. A detect unit with an absence (Order as o -> NOT Ack where id == o.id within 4h) raised it only when the next event reached the pattern. On subjects that go quiet after the order, that event never comes, so the alert never did.

A restart lost the pending absences. Take an absence the unit was waiting out when it was killed. The snapshot kept the open sequence, but not what its negated step waited for. After the restart the acknowledgement no longer cancelled it, and the deadline dropped it without an alert.

The fix

The engine is pinned at varpulis 21f3ba4 (varpulis/varpulis#287).

• An absence completes on the event time of the types feeding the pattern, which moves forward on its own once they go quiet (VEJAS_IDLE_CLOSE_SECS, v0.3.3).
• A restore rebuilds each run's negated step.

No change to the runtime itself.

Proof on NATS: e2e/detect

• D8: two orders at 20:00:00; o-2 is acknowledged at 20:00:01, o-1 is not. Nothing else is ever published on either subject.
  • This build: o-1 is raised about the 5 s window plus the 1 s grace later, and only o-1.
  • The v0.3.3 runtime (VEJAS_BIN=...): nothing.
• D9: order o-3, a snapshot that holds it, then kill -9 with o-3 still open (asserted: it had not been raised before the crash). Then restart, and silence.
  • This build: o-3 is raised once after the restart.
  • v0.3.3: never.
• The D4 topology check now expects five units.

Run locally: every invariant passes on this build (D1–D9). On v0.3.3, D8 and D9 fail and the rest pass.

Docs

concepts/detects.md: an absence is raised when its deadline passes, and a restart does not lose it.

🤖 Generated with Claude Code

https://claude.ai/code/session_01N3K1TGnWTvwYzt9rKuJXES