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Chez concurrency pt.3: async agents (per-agent serialized dispatch)

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Replace the Janet synchronous agent shim (agent = atom, send applies inline) with
JVM-style async agents: send/send-off enqueue an action and a single worker thread
per agent applies them in order; deref reads the current (maybe not-yet-updated)
state without blocking; await blocks until the queue drains. A validator rejection
or a thrown action puts the agent in an error state (agent-error) and halts the
queue; restart-agent clears it. send and send-off share one serialized worker (a
superset of the JVM's fixed/cached pool split). Native versions re-asserted in
post-prelude over the overlay; await/restart-agent are new.

Corpus: the two "send/send-off applies" cases do (send a f) (deref a) with no
await, so they now read state before the action runs — diverging like the JVM
(the suite was literally "synchronous shim"). Allowlisted on both gates; floors
-2 (zero-Janet 2569->2567, prelude 2559->2557). cli-test covers async agents via
await (ordered 100-send dispatch, error capture) — 49/49. Janet gate + JVM cert
green; 0 new divergences on either corpus.

jolt-byjr
This commit is contained in:
Yogthos 2026-06-20 14:22:37 -04:00
parent 48ed72974f
commit c719e54543
5 changed files with 120 additions and 7 deletions
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11
test/chez/run-corpus-prelude.janet
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@ -102,7 +102,12 @@
# usually loses -> false), like the JVM; the Janet :expected relies on its
# cooperative scheduler. Flaky/divergent.
"cancel an in-flight future returns true" true
"future-cancelled? after cancel" true})
"future-cancelled? after cancel" true
# agents are async on Chez (per-agent serialized dispatch) = JVM, not Janet's
# synchronous shim: (send a f) (deref a) reads state before the action runs, so
# these sync-shim cases diverge like the JVM. Per jvm-parity-north-star.
"send applies" true
"send-off applies" true})
# Cases that BLOCK forever on a shared-heap / JVM host (profile.edn :bucket
# :timeout) — skip, like :throws, so a hung per-case process can't stall the gate.
@ -305,8 +310,10 @@
# 2280->2295, 0 new divergences.
# jolt-byjr (real-thread futures/pmap on Chez): future-call resolves, so the
# future/deref/pmap cases run instead of crashing. 2534->2559, 0 new divergences.
# Then -2 when agents went async (the two "send/send-off applies" sync-shim cases
# match the JVM's async raciness and are allowlisted) -> 2557.
# Strided runs scale down.
(def base-floor (scan-number (or (os/getenv "JOLT_CHEZ_PRELUDE_FLOOR") "2559")))
(def base-floor (scan-number (or (os/getenv "JOLT_CHEZ_PRELUDE_FLOOR") "2557")))
(def floor (if (os/getenv "JOLT_CORPUS_LIMIT") 0 base-floor))
(when (or (> (length diverged) 0) (< pass floor))
(printf "REGRESSION: pass %d < floor %d or %d new divergence(s)" pass floor (length diverged)))