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Test, Build, and Deploy / test-build-deploy (push) Failing after 1m2s
Logical-clock timer wheel in the scheduler. send_after schedules a message-delivery event at an absolute deadline (clock + Time ms); cancel_timer marks a live timer cancelled and reports remaining ms, or false. Time advances only when the runnable queue drains, jumping to the earliest pending deadline (deterministic, no wall clock). monotonic_time/0,1 exposes the logical ms clock. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
81 lines
2.5 KiB
Plaintext
81 lines
2.5 KiB
Plaintext
;; erlang:send_after / cancel_timer — timer primitives.
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;;
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;; A process schedules a message to itself (or another pid / registered
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;; name) after N logical milliseconds. `cancel_timer` removes a pending
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;; timer and reports the time left. These are the same primitives the
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;; gen_server library uses to implement `{noreply, State, Timeout}`.
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;;
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;; The scheduler runs a synchronous logical clock (see runtime.sx
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;; `er-sched-advance-time!`): time advances only when the runnable
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;; queue drains, jumping to the earliest pending deadline. That makes
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;; delivery deterministic and time-travel-safe — no wall clock.
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(define er-sa-test-count 0)
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(define er-sa-test-pass 0)
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(define er-sa-test-fails (list))
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(define
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er-sa-test
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(fn
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(name actual expected)
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(set! er-sa-test-count (+ er-sa-test-count 1))
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(if
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(= actual expected)
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(set! er-sa-test-pass (+ er-sa-test-pass 1))
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(append!
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er-sa-test-fails
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{:actual actual :expected expected :name name}))))
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(define er-sa-pred
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(fn (name actual) (er-sa-test name (if actual true false) true)))
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(define sa-ev erlang-eval-ast)
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;; ── T1 — schedule a self-message, receive it after the deadline ──
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;; send_after returns a reference handle.
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(er-sa-pred
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"T1 send_after returns a ref"
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(er-ref?
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(sa-ev "erlang:send_after(50, self(), hello)")))
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;; The scheduled message lands and a plain receive picks it up.
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(er-sa-test
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"T1 delivered message received"
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(get
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(sa-ev
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"erlang:send_after(50, self(), hello),
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receive M -> M end")
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:name)
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"hello")
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;; Logical time advances exactly to the timer deadline (50ms) by the
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;; time the message is received — round-trip latency well under 100ms.
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(er-sa-test
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"T1 clock at deadline on receipt"
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(sa-ev
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"erlang:send_after(50, self(), hello),
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receive hello -> erlang:monotonic_time() end")
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50)
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;; ── T2 — cancel_timer returns remaining ms; message never arrives ──
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;; Cancel immediately after scheduling: clock has not advanced, so the
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;; full duration (~1000ms) is reported as remaining.
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(er-sa-test
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"T2 cancel returns remaining ms"
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(sa-ev
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"Ref = erlang:send_after(1000, self(), late),
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erlang:cancel_timer(Ref)")
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1000)
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;; The cancelled timer never delivers — the receive falls through to
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;; its `after` clause and returns `none`.
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(er-sa-test
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"T2 cancelled message never arrives"
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(get
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(sa-ev
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"Ref = erlang:send_after(1000, self(), late),
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erlang:cancel_timer(Ref),
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receive late -> got after 50 -> none end")
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:name)
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"none")
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