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[world-sim] Restore the slot-era check in in-flight-before-decision-counted - #4783
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…ounted #3544 removed the mint-ordered log and, with it, restored this scenario's pre-#3519 check that the count half of the fence rejected a write the watermark let through. That premise held when watermarks were milliseconds. With commit-time slots the hook lands above the caller's watermark, so the watermark half rejects the decision and the count at or below the watermark never grows. The check has failed on every main push since #3544, with the runtime trace identical to the passing one before it. Assert that the fence rejected the orchestrator's decision write instead, which is what #3519 meant by "the fence fires at all". Pinning it to the decision rather than any 412 matters: with the watermark half disarmed, the count half lets the decision through and rejects the settle step's step_completed after the branch has run, which the old check accepted. Add a store test for the count half, which no book scenario reaches now. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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Sim WorldSimulated world deterministic testing for races. Traces 🟢 world-sim scenario book — 0 fail of 42 total
Full trace: |
📊 Workflow Benchmarkscommit Backend:
📈 STSO distribution vs main (inline / queue-hop histograms)1020 steps (inline) Cumulative STSO time: main 105566ms → this run 133882ms (Δ +28316ms, +27%) ℹ️ Metric definitions & methodologyThe collapsed STSO distribution section above buckets every step gap, split inline (same warm process — pure framework overhead) vs queue-hop (fresh process — dispatch, reinit, replay). Best/P75/P90/P99 deltas compare against the most recent benchmark run on Metrics — TTFS: time to first step body (in-deployment start() → first step body) · Fan-out TTFS: fan-out time to first step (in-deployment start() → first of the parallel step bodies to complete) · Fan-out TTLS: fan-out time to last step (in-deployment start() → last of the parallel step bodies to complete, i.e. when the Promise.all resolves) · STSO: step-to-step overhead (gap between consecutive step bodies) · WO: workflow overhead (whole-run time outside step bodies, in-deployment anchored) Scenarios — step: one trivial no-op step, no stream; no hooks, so the run stays in turbo mode (in-process fast path) · stream: one streaming step; no hooks, so the run stays in turbo mode (in-process fast path) · hook + stream: registers a hook before one step, which exits turbo mode (dispatch path) · 1020 steps: 1020 trivial sequential steps; STSO is measured between consecutive steps in the given step ranges, and WO is the whole-run overhead outside step bodies · Promise.all(100 steps): 100 trivial no-op steps started together in a single Promise.all; Fan-out TTFS is the first of them to complete and Fan-out TTLS the last, both from the in-deployment clientStart, so their gap is the spread the runtime adds across the fan-out 🔴 marks a percentile over its target (within target is left unmarked). Targets (p75/p90/p99, ms) — TTFS 200/300/600 All timestamps are deployment-side; runs are triggered in-deployment, so the CI runner and api.vercel.com sit outside every measured window. TTFS = Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor. |
🧪 E2E Test Results✅ All tests passed
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| Passed | Failed | Skipped | Total | |
|---|---|---|---|---|
| ✅ ▲ Vercel Production | 3982 | 0 | 878 | 4860 |
| ✅ 💻 Local Development | 4669 | 0 | 551 | 5220 |
| ✅ 📦 Local Production | 4669 | 0 | 551 | 5220 |
| ✅ 🐘 Local Postgres | 4669 | 0 | 551 | 5220 |
| ✅ 🪟 Windows | 348 | 0 | 12 | 360 |
| ✅ 🌐 Cross-language Conformance | 68 | 0 | 87 | 155 |
| ✅ dynamic-runs | 0 | 0 | 0 | 0 |
| ✅ vercel-http-transport | 897 | 0 | 183 | 1080 |
| ✅ vercel-multi-region | 27 | 0 | 0 | 27 |
| ✅ vercel-ws-transport | 607 | 0 | 113 | 720 |
| Total | 19936 | 0 | 2926 | 22862 |
Details by Category
✅ ▲ Vercel Production
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ astro-node | 145 | 0 | 35 |
| ✅ astro-quickjs | 145 | 0 | 35 |
| ✅ example-node | 145 | 0 | 35 |
| ✅ example-quickjs | 145 | 0 | 35 |
| ✅ express-node | 145 | 0 | 35 |
| ✅ express-quickjs | 145 | 0 | 35 |
| ✅ fastify-node | 145 | 0 | 35 |
| ✅ fastify-quickjs | 145 | 0 | 35 |
| ✅ hono-node | 145 | 0 | 35 |
| ✅ hono-quickjs | 145 | 0 | 35 |
| ✅ nest-node | 145 | 0 | 35 |
| ✅ nest-quickjs | 145 | 0 | 35 |
| ✅ nextjs-turbopack-node | 172 | 0 | 8 |
| ✅ nextjs-turbopack-quickjs | 172 | 0 | 8 |
| ✅ nextjs-webpack-node | 172 | 0 | 8 |
| ✅ nextjs-webpack-quickjs | 172 | 0 | 8 |
| ✅ nitro-node | 145 | 0 | 35 |
| ✅ nitro-quickjs | 145 | 0 | 35 |
| ✅ nuxt-node | 145 | 0 | 35 |
| ✅ nuxt-quickjs | 145 | 0 | 35 |
| ✅ python-node | 66 | 0 | 114 |
| ✅ sveltekit-node | 164 | 0 | 16 |
| ✅ sveltekit-quickjs | 164 | 0 | 16 |
| ✅ tanstack-start-node | 145 | 0 | 35 |
| ✅ tanstack-start-quickjs | 145 | 0 | 35 |
| ✅ vite-node | 145 | 0 | 35 |
| ✅ vite-quickjs | 145 | 0 | 35 |
✅ 💻 Local Development
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ astro-stable-node | 151 | 0 | 29 |
| ✅ astro-stable-quickjs | 151 | 0 | 29 |
| ✅ express-stable-node | 151 | 0 | 29 |
| ✅ express-stable-quickjs | 151 | 0 | 29 |
| ✅ fastify-stable-node | 151 | 0 | 29 |
| ✅ fastify-stable-quickjs | 151 | 0 | 29 |
| ✅ hono-stable-node | 151 | 0 | 29 |
| ✅ hono-stable-quickjs | 151 | 0 | 29 |
| ✅ nest-stable-node | 151 | 0 | 29 |
| ✅ nest-stable-quickjs | 151 | 0 | 29 |
| ✅ nextjs-turbopack-canary-node | 179 | 0 | 1 |
| ✅ nextjs-turbopack-canary-quickjs | 179 | 0 | 1 |
| ✅ nextjs-turbopack-quickjs-snapshot | 179 | 0 | 1 |
| ✅ nextjs-turbopack-stable-node | 179 | 0 | 1 |
| ✅ nextjs-turbopack-stable-quickjs | 179 | 0 | 1 |
| ✅ nextjs-webpack-canary-node | 179 | 0 | 1 |
| ✅ nextjs-webpack-canary-quickjs | 179 | 0 | 1 |
| ✅ nextjs-webpack-stable-node | 179 | 0 | 1 |
| ✅ nextjs-webpack-stable-quickjs | 179 | 0 | 1 |
| ✅ nitro-stable-node | 151 | 0 | 29 |
| ✅ nitro-stable-quickjs | 151 | 0 | 29 |
| ✅ nuxt-stable-node | 151 | 0 | 29 |
| ✅ nuxt-stable-quickjs | 151 | 0 | 29 |
| ✅ sveltekit-stable-node | 170 | 0 | 10 |
| ✅ sveltekit-stable-quickjs | 170 | 0 | 10 |
| ✅ tanstack-start-node | 151 | 0 | 29 |
| ✅ tanstack-start-quickjs | 151 | 0 | 29 |
| ✅ vite-stable-node | 151 | 0 | 29 |
| ✅ vite-stable-quickjs | 151 | 0 | 29 |
✅ 📦 Local Production
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ astro-stable-node | 151 | 0 | 29 |
| ✅ astro-stable-quickjs | 151 | 0 | 29 |
| ✅ express-stable-node | 151 | 0 | 29 |
| ✅ express-stable-quickjs | 151 | 0 | 29 |
| ✅ fastify-stable-node | 151 | 0 | 29 |
| ✅ fastify-stable-quickjs | 151 | 0 | 29 |
| ✅ hono-stable-node | 151 | 0 | 29 |
| ✅ hono-stable-quickjs | 151 | 0 | 29 |
| ✅ nest-stable-node | 151 | 0 | 29 |
| ✅ nest-stable-quickjs | 151 | 0 | 29 |
| ✅ nextjs-turbopack-canary-node | 179 | 0 | 1 |
| ✅ nextjs-turbopack-canary-quickjs | 179 | 0 | 1 |
| ✅ nextjs-turbopack-quickjs-snapshot | 179 | 0 | 1 |
| ✅ nextjs-turbopack-stable-node | 179 | 0 | 1 |
| ✅ nextjs-turbopack-stable-quickjs | 179 | 0 | 1 |
| ✅ nextjs-webpack-canary-node | 179 | 0 | 1 |
| ✅ nextjs-webpack-canary-quickjs | 179 | 0 | 1 |
| ✅ nextjs-webpack-stable-node | 179 | 0 | 1 |
| ✅ nextjs-webpack-stable-quickjs | 179 | 0 | 1 |
| ✅ nitro-stable-node | 151 | 0 | 29 |
| ✅ nitro-stable-quickjs | 151 | 0 | 29 |
| ✅ nuxt-stable-node | 151 | 0 | 29 |
| ✅ nuxt-stable-quickjs | 151 | 0 | 29 |
| ✅ sveltekit-stable-node | 170 | 0 | 10 |
| ✅ sveltekit-stable-quickjs | 170 | 0 | 10 |
| ✅ tanstack-start-node | 151 | 0 | 29 |
| ✅ tanstack-start-quickjs | 151 | 0 | 29 |
| ✅ vite-stable-node | 151 | 0 | 29 |
| ✅ vite-stable-quickjs | 151 | 0 | 29 |
✅ 🐘 Local Postgres
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ astro-stable-node | 151 | 0 | 29 |
| ✅ astro-stable-quickjs | 151 | 0 | 29 |
| ✅ express-stable-node | 151 | 0 | 29 |
| ✅ express-stable-quickjs | 151 | 0 | 29 |
| ✅ fastify-stable-node | 151 | 0 | 29 |
| ✅ fastify-stable-quickjs | 151 | 0 | 29 |
| ✅ hono-stable-node | 151 | 0 | 29 |
| ✅ hono-stable-quickjs | 151 | 0 | 29 |
| ✅ nest-stable-node | 151 | 0 | 29 |
| ✅ nest-stable-quickjs | 151 | 0 | 29 |
| ✅ nextjs-turbopack-canary-node | 179 | 0 | 1 |
| ✅ nextjs-turbopack-canary-quickjs | 179 | 0 | 1 |
| ✅ nextjs-turbopack-quickjs-snapshot | 179 | 0 | 1 |
| ✅ nextjs-turbopack-stable-node | 179 | 0 | 1 |
| ✅ nextjs-turbopack-stable-quickjs | 179 | 0 | 1 |
| ✅ nextjs-webpack-canary-node | 179 | 0 | 1 |
| ✅ nextjs-webpack-canary-quickjs | 179 | 0 | 1 |
| ✅ nextjs-webpack-stable-node | 179 | 0 | 1 |
| ✅ nextjs-webpack-stable-quickjs | 179 | 0 | 1 |
| ✅ nitro-stable-node | 151 | 0 | 29 |
| ✅ nitro-stable-quickjs | 151 | 0 | 29 |
| ✅ nuxt-stable-node | 151 | 0 | 29 |
| ✅ nuxt-stable-quickjs | 151 | 0 | 29 |
| ✅ sveltekit-stable-node | 170 | 0 | 10 |
| ✅ sveltekit-stable-quickjs | 170 | 0 | 10 |
| ✅ tanstack-start-node | 151 | 0 | 29 |
| ✅ tanstack-start-quickjs | 151 | 0 | 29 |
| ✅ vite-stable-node | 151 | 0 | 29 |
| ✅ vite-stable-quickjs | 151 | 0 | 29 |
✅ 🪟 Windows
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ nextjs-turbopack-node | 174 | 0 | 6 |
| ✅ nextjs-turbopack-quickjs | 174 | 0 | 6 |
✅ 🌐 Cross-language Conformance
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ python | 68 | 0 | 87 |
✅ dynamic-runs
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ astro-vercel | 0 | 0 | 0 |
| ✅ example-vercel | 0 | 0 | 0 |
| ✅ express-vercel | 0 | 0 | 0 |
| ✅ fastify-vercel | 0 | 0 | 0 |
| ✅ hono-vercel | 0 | 0 | 0 |
| ✅ nest-vercel | 0 | 0 | 0 |
| ✅ nextjs-turbopack-vercel | 0 | 0 | 0 |
| ✅ nextjs-webpack-vercel | 0 | 0 | 0 |
| ✅ nitro-vercel | 0 | 0 | 0 |
| ✅ nuxt-vercel | 0 | 0 | 0 |
| ✅ sveltekit-vercel | 0 | 0 | 0 |
| ✅ tanstack-start-vercel | 0 | 0 | 0 |
| ✅ vite-vercel | 0 | 0 | 0 |
✅ vercel-http-transport
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ example | 145 | 0 | 35 |
| ✅ express | 145 | 0 | 35 |
| ✅ hono | 145 | 0 | 35 |
| ✅ nextjs-turbopack | 172 | 0 | 8 |
| ✅ nitro | 145 | 0 | 35 |
| ✅ vite | 145 | 0 | 35 |
✅ vercel-multi-region
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ nextjs-turbopack | 27 | 0 | 0 |
✅ vercel-ws-transport
| App | Passed | Failed | Skipped |
|---|---|---|---|
| ✅ example | 145 | 0 | 35 |
| ✅ express | 145 | 0 | 35 |
| ✅ nextjs-turbopack | 172 | 0 | 8 |
| ✅ vite | 145 | 0 | 35 |
About these numbersSizes are gzip; parentheses show the change against
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No backport to This commit only touches To override, re-run the Backport to stable workflow manually via |
Summary
Sim World has reported
in-flight-before-decision-countedas the book's one red on every PR, docs-only ones included. The cause is a stale expectation, not a runtime regression. This PR restores the check #3519 wrote for slot ids and adds a unit test for the count half of the fence, which no scenario reaches anymore.Where it started
It started at ec709ba (#3544, Aug 17), not in the #4772–#4782 range. It has failed on every
mainpush since then:ok check: the fence rejected the write.the count guard fenced the write the watermark let through.pnpm sim in-flight-before-decision-counted, with--append-onlyon the parent). The runtime trace is identical at both commits: the orchestrator'sstep_starteddecision is rejected withPreconditionFailedError: … changed out of band since the caller's snapshot, it reloads, and it completes with replay ok. Only the check changed.While removing the mint-ordered log, #3544 put back the scenario's pre-#3519 check, which matches the count half's own message (
at or below the caller). #3519 had replaced it on purpose. Watermarks used to be milliseconds, so the hook and the timeout compared equal and only the count could separate them. A slot watermark is strictly ordered.Why the expectation is stale, not the runtime
With commit-time slots, the in-flight hook commits at slot 8, above the caller's watermark of 7. The watermark half rejects the decision, and it is evaluated first. The old check can't pass even if the count half is reached: I disabled the watermark half locally, and at the decision write
recorded == loaded(7 == 7), so the count half lets it through. The count half fires only later, on the settle step'sstep_completed, after the branch has run.That makes the old check worse than unsatisfiable. With the watermark half broken it passes, because it accepts that late rejection. The runtime does the right thing here: it fences the decision, reloads, and settles on the branch the log implies, with 0 violations.
Changes
in-flight-before-decision-counted: assert that the fence rejected the orchestrator'sstep_starteddecision (PreconditionFailedError, writerorchestrator). Matching any 412 would also accept the late step-body rejection above. The description now matches what happens.store.test.ts: a test for the count half, a snapshot missing an event below its own watermark, rejected only withcountGuard. I mutation-checked it: loosening the predicate torecorded > count + 1makes it fail.No changeset.
@workflow/world-simand the workbench are private, and nothing outside tests and scenarios changed.Verification
pnpm sim: 42 passed, 0 failed, 0 violations (🟢 0 fail of 42).pnpm sim --no-fence: only this scenario fails, by design, with 0 violations. This is whatrun.tsand the README document.vitest run src/store.test.tsinpackages/world-sim: 25 passed.tsc --noEmitis clean.Follow-up (not in this PR)
packages/world-sim/DESIGN.mdstill describes the mint-ordered model #3544 removed: "The three" table,appendOnlyLog, and "6 → 8" violations.🤖 Generated with Claude Code