perf(core): don't re-publish step messages this invocation already published by pranaygp · Pull Request #4099 · vercel/workflow

pranaygp · 2026-09-11T08:23:28Z

Motivation (measured)

On a 32-branch fan-out (durabench, 2026-09-11, Datadog traces of 3 orchestrator invocations), the orchestrator invocation publishes the 29 queued steps' messages ~450-750 ms into the invocation, runs its 3 inline steps, then falls back into the replay loop, reloads the log, and its pending-step dispatch pass re-publishes 28 / 20 / 19 of those same steps ~400 ms after it first published them. VQS dedupes them by idempotency key, but the sends take 150-550 ms on the 8-connection HTTP/1.1 pool and hold the invocation open (one run acked at 1455 ms instead of ~1050 ms). Every redundant send came from the same invocation that had just published the step.

What changed

packages/core/src/runtime.ts: the queue-message handler now keeps an invocation-scoped set, publishedStepCorrelationIds, of the steps this delivery has already published a step-execution message for. It lives next to continuedHookIds (the closure that owns the replay loop), so it persists across replay passes within one delivery and dies with it. It is populated from:

suspensionResult.queuedStepCorrelationIds on every pass (the suspension handler's resilient publishes), and
every immediate step-execution enqueue the dispatch pass itself performs.

It is not populated by delayed backstop wakes (they target the run, not a step) or owned-recovery steps (executed in-process). On a later pass the dispatch pass skips the immediate re-enqueue of a pending step whose id is in the set, unless step.sawRetrying is true (a retry handoff is a new schedule). The check sits before the TTR hand-off so a skipped step never consumes the resume-timing measurement.

Skips are reported as a debug log (republishesSkipped, loopIteration) and a new span attribute workflow.dispatch.republish_skipped, set alongside the existing backstop_wakes_armed / owned_recovery_steps attributes.

Safety argument

Only invocation-local knowledge is used. A step_created in the log proves the step was created, not that its message was ever sent (the publisher may have crashed between the two), so the set is never derived from the log. A different invocation (crash-recovery redelivery, a concurrent wake) still re-enqueues unconditionally, exactly as before. Within one invocation, every publish that seeds the set is joined before the delivery can ack (the dispatch join and deferredBatchWork), so a publish that fails fails the delivery and the redelivery starts with an empty set. This is stated in a code comment on the set.

QuickJS engine

packages/core/src/runtime/quickjs-entrypoint.ts already has the equivalent: an invocation-scoped queuedStepIds set, seeded from dispatchPendingOps's queuedStepCids and its own overflow publishes, which the later pending-step requeue pass consults (if (queuedStepIds.has(step.correlationId)) continue;). It is unchanged. One small asymmetry worth knowing: that engine skips unconditionally, without the sawRetrying carve-out added here.

Tests

Three tests added to the workflowEntrypoint step-dispatch ack ordering suite in packages/core/src/runtime.test.ts, reusing its harness (one inline step, one queued step, a sleep, a stateful event log so the loop runs a second pass):

the post-inline replay pass publishes zero step messages for the already-published step (1 stepId send for the whole invocation; asserts events.list ran at least twice). Fails on main with 2 sends.
a step with a step_retrying observed since is still re-enqueued (2 sends, same correlation id).
with WORKFLOW_RESILIENT_STEP_DISPATCH=1 the suspension handler's own publish (carrying stepInput) counts as already published (1 send). Fails on main with 2 sends.

Command	Result
`pnpm vitest run src/runtime.test.ts` (ack-ordering suite)	8 passed
`cd packages/core && FORCE_COLOR=0 pnpm test`	112 files passed, 1 skipped; 2405 tests passed, 3 expected fail, 1 skipped
`tsc --noEmit` in `packages/core`	clean

🤖 Generated with Claude Code

…blished On a fan-out that runs some steps inline, the orchestrator invocation publishes the queued siblings' step-execution messages, runs its inline steps, falls back into the replay loop, reloads the log, and its pending-step dispatch pass publishes every one of those messages again (measured 19-28 re-sends per pass on a 32-branch fan-out, ~400 ms after the originals). The queue dedupes them by idempotency key, but the sends still cost round-trips on the shared connection pool and hold the invocation open past its useful work. Track, per delivery, the correlation ids this invocation has already published a step message for (the suspension handler's resilient publishes plus the dispatch pass's own immediate enqueues) and skip the immediate re-enqueue for those on later passes, unless a step_retrying has been observed since (a new schedule). The set is invocation-scoped and never derived from the log: a step_created does not prove the message was ever sent, so a different delivery still re-enqueues unconditionally. Reported as a debug log and the `workflow.dispatch.republish_skipped` span attribute. The QuickJS engine already keeps the equivalent invocation-scoped `queuedStepIds` set, so it is unchanged. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

changeset-bot · 2026-09-11T08:23:32Z

🦋 Changeset detected

Latest commit: a1d0ea6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 16 packages

Name	Type
@workflow/core	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	Patch
@workflow/web-shared	Patch
@workflow/web	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

vercel · 2026-09-11T08:23:34Z

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
example-nextjs-workflow-turbopack	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
example-nextjs-workflow-webpack	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
example-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-astro-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-express-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-fastify-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
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workbench-nestjs-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
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workbench-nuxt-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-python-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-sveltekit-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-tanstack-start-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workbench-vite-workflow	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workflow-docs	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
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workflow-tarballs	Ready	Preview, v0	Sep 11, 2026 8:26am UTC
workflow-web	Ready	Preview, v0	Sep 11, 2026 8:26am UTC

github-actions · 2026-09-11T08:23:46Z

📊 Workflow Benchmarks

commit a1d0ea6 · Fri, 11 Sep 2026 08:48:06 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	1249 (+67%) 🔻	1409 🔴 (+28%) 🔻	1443 🔴 (+25%) 🔻	1809 🔴 (+33%) 🔻	30
TTFS	stream	216 (-15%)	1565 🔴 (+46%) 🔻	1583 🔴 (+43%) 🔻	1620 🔴 (+44%) 🔻	30
TTFS	hook + stream	1294 (+50%) 🔻	1598 🔴 (+23%) 🔻	1627 🔴 (+19%) 🔻	1772 🔴 (-8.4%)	30
Fan-out TTFS	Promise.all(100 steps)	566 (-6.8%)	918 (+12%)	1029 (+23%) 🔻	2167 (+22%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	1738 (+9.7%)	4804 (+8.0%)	5488 (-17%) 💚	8980 (+4.4%)	10
STSO	1020 steps (inline)	73 (-36%) 💚	137 (+0.7%)	157 (+2.6%)	246 (+25%) 🔻	1019
WO	1020 steps	136535 (±0%)	136535 (±0%)	136535 (±0%)	136535 (±0%)	1
CRTT	first chunk (pooled)	63 (-16%) 💚	104 (-24%) 💚	154 (-42%) 💚	172 (-39%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	86.5 (-11%)	150 (-39%)	246 (-49%)	775 (+23%)	139 (-51%)	10
size sweep (100/s, 160B-12KB)	89.5 (-8%)	140 (-67%)	255 (-65%)	452 (-62%)	148 (-58%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	82 (-42%)	133 (-26%)	167 (-32%)	258 (-45%)	176 (-52%)	3
replay eve-gpt-5.6-sol-2000t (1x)	115 (+2%)	154 (-26%)	1496 (+242%)	4626 (+304%)	2298 (+302%)	2
replay eve-gpt-5.6-sol-2000t (2x)	83 (-39%)	183 (-62%)	260 (-61%)	481 (-46%)	331 (-29%)	3

📈 STSO distribution vs main (inline / queue-hop histograms)

1020 steps (inline)

Cumulative STSO time: main 136104ms → this run 136383ms (Δ +279ms, +0%)

 50-100 ms  ┃                         main   0  this   1    +1
100-150 ms  ███████████████████████┃  main 894  this 876   -18
150-200 ms  ██┃                       main 117  this 121    +4
200-250 ms  ┃                         main   8  this  13    +5
250-300 ms  ┃                         main   0  this   4    +4
300-350 ms  ┃                         main   0  this   1    +1
350-400 ms  ┃                         main   0  this   3    +3

📈 CRTT drill-down vs main (RTT distributions & profiles)

variant  RTT 1ms→5s+             avg         p50           p90           p99     n
control  ······▅█▂▁···  141.6 (-30%)  112 (-31%)    246 (-49%)    775 (+23%)  3000
sweep    ······▅█▁····  121.6 (-56%)  107 (-44%)    255 (-65%)    452 (-62%)  3000
gw 1x    ·····▁▇█▁····  110.9 (-26%)  107 (-21%)    167 (-32%)    258 (-45%)  5295
eve 1x   ·····▁██▁▁▁▁·  288.8 (+52%)  104 (-22%)  1496 (+242%)  4626 (+304%)  5186
eve 2x   ·····▁▃█▃▁···  152.7 (-43%)  135 (-37%)    260 (-61%)    481 (-46%)  7779

RTT over stream progress (avg per tenth of stream, bars scaled min→max):

control  ▂▂▅▇██▄▅▃▁  115–170ms
sweep    ▄▆▂▂▃█▅▁▂▂  100–161ms
gw 1x    ▂▂▂▁▃▄▄▂█▁  105–128ms
eve 1x   ▁▁▁▁▁█▃▁▁▁  95–1600ms
eve 2x   ▁▁▂▂▁▁▄█▁▂  133–234ms

RTT by chunk size (avg per log size bin, ~160B → ~12KB serialized, bars scaled min→max):

sweep  ▆█▅▆▃▁▁  120–124ms

Delivery jitter over stream progress (avg positive CDV per tenth of stream, bars scaled min→max):

control  ▂▂█▁▅▆▁▄▃▂  33–50ms
sweep    ▁▇▃▄█▇▅▃▁▃  38–63ms
gw 1x    ▅▆▅▁▅█▇▅▆▄  26–38ms
eve 1x   ▁▂▁▁▁█▃▁▂▂  19–71ms
eve 2x   ▆▅▅▂▅▁▅▂▂█  21–29ms

ℹ️ Metric definitions & methodology

_{Streams: first-chunk RTT (the stream-open path, before any buffering/backpressure), CRTT percentiles, and worst delivery stall (CDV max). Cells are medians across iterations; per-run values in the artifacts. No 🔴/🟢 marks until targets attach.}

_{The 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). █ = main, ┃ = this run, ░ = fill.}

_{The collapsed CRTT drill-down: per-variant RTT histograms (fixed log bins, · = empty) and mean RTT/positive-CDV profile lines over stream progress and chunk size. Histograms, avgs, and profiles merge exactly across runs; p50–p99 are percentile-of-percentiles. Per-index rows live in the artifacts.}

_{Best/P75/P90/P99 deltas compare against the most recent benchmark run on main at the time of this run. 🔻 flags a delta worse than +15%, 💚 one better than −15%.}

_{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) · CRTT: chunk round-trip time (per-chunk write → read latency, one clock domain: deployment → stream backend → same deployment) · CDV: chunk delay variation / delivery jitter (inter-arrival gap minus inter-write gap per seq-adjacent pair; skew-free; the row is each run's MAX positive value, so one stall moves it)}

_{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 · paced control (100/s, 60B): the control: 300 tiny (~60B) deltas metronome-paced at 100/s — zero workload structure, so it reads the transport floor and flush cadence, and disambiguates transport-wide vs workload-specific when a replay row moves · size sweep (100/s, 160B-12KB): same pacing as the control with deltas padded in rotation across seven log-spaced sizes (~160B–12KB) — rotation decouples size from stream position, so it isolates whether chunk size causes latency · replay gateway-gpt-5.4-nano-2000t (1x): raw provider SSE cadence captured at the AI gateway boundary (gpt-5.4-nano, the most popular gateway model; per-token deltas p50 208B = the modal production chunk size), replayed exactly as measured — the typical customer's workload; its CDV is the typical customer's real delivery jitter · replay eve-gpt-5.6-sol-2000t (1x): a captured eve turn (gpt-5.6-sol, the most-used demanding eve model; ~2000 output tokens = production p50 turn length) replayed exactly as measured — eve's envelope protocol re-ships the cumulative message so sizes ramp 142B→13KB; the demanding outlier tenant's reality · replay eve-gpt-5.6-sol-2000t (2x): the same eve capture at 2x — the headroom/stress row; real fast-tier models emit the same chunk sizes at proportionally higher rate, so time compression is a faithful speed model · first chunk (pooled): every run's seq-0 RTT pooled across all stream scenarios — the first chunk precedes any workload differentiation, so pooling samples one shared stream-open path with exact percentiles}

_{Replay cadences (semantic sha256) — eve-gpt-5.6-sol-2000t eaf22f5946e7c61f3c65c7006d550df180cfabd4e706254a09f22aec0cfb420d · gateway-gpt-5.4-nano-2000t 6f24ac518b6b83ff1d0e85a5fe78230db192716d66a7fc6b2fe022752001d041}

_{🔴 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 = start() → first step body (includes dispatch + any cold start); Fan-out TTFS/TTLS = first/last step completion of one Promise.all from the same anchor (the gap is the runtime’s fan-out spread); STSO/WO between step bodies; CRTT inside the workflow (excludes the api.vercel.com read path).}

_{Cold starts stay in the numbers (real bursty-workload latency, inflates P75+); Best is the warm floor.}

github-actions · 2026-09-11T08:23:47Z

🧪 E2E Test Results

✅ All tests passed

⚠️ Flaky E2E Tests (passed on retry)

These tests failed at least once and passed on a retry. A recurring entry here is a real race worth investigating.

cancelRun via CLI - cancelling a running workflow (nextjs-turbopack)
cancelRun via CLI - cancelling a running workflow (nextjs-webpack)
promiseAllWorkflow (express)
promiseRaceWorkflow (vite)

🛠 Infra Events (absorbed by the harness)

Platform anomalies the e2e harness detected and worked around (e.g. a run the queue never picked up, replaced by a fresh run). Clustered timestamps indicate a backend blip; a steady drip indicates a platform issue worth escalating.

cold-start-warmup · suite warmup (tanstack-start) · at 08:29:43Z · abandoned wrun_01M27SBN0QBQ8ZCNQ0WBSXM1QB

E2E Test Summary

Summary

	Passed	Skipped	Total
✅ ▲ Vercel Production	3662	685	4347
✅ 💻 Local Development	3922	586	4508
✅ 📦 Local Production	3922	586	4508
✅ 🐘 Local Postgres	3922	586	4508
✅ 🪟 Windows	320	2	322
✅ 🌐 Cross-language Conformance	68	74	142
✅ vercel-http-transport	823	143	966
✅ vercel-multi-region	27	0	27
✅ vercel-ws-transport	557	87	644
Total	17223	2749	19972

Details by Category

✅ ▲ Vercel Production

App	Passed	Skipped
✅ astro-node	133	28
✅ astro-quickjs	133	28
✅ example-node	133	28
✅ example-quickjs	133	28
✅ express-node	133	28
✅ express-quickjs	133	28
✅ fastify-node	133	28
✅ fastify-quickjs	133	28
✅ hono-node	133	28
✅ hono-quickjs	133	28
✅ nest-node	133	28
✅ nest-quickjs	133	28
✅ nextjs-turbopack-node	158	3
✅ nextjs-turbopack-quickjs	158	3
✅ nextjs-webpack-node	158	3
✅ nextjs-webpack-quickjs	158	3
✅ nitro-node	133	28
✅ nitro-quickjs	133	28
✅ nuxt-node	133	28
✅ nuxt-quickjs	133	28
✅ python-node	66	95
✅ sveltekit-node	152	9
✅ sveltekit-quickjs	152	9
✅ tanstack-start-node	133	28
✅ tanstack-start-quickjs	133	28
✅ vite-node	133	28
✅ vite-quickjs	133	28

✅ 💻 Local Development

App	Passed	Skipped
✅ astro-stable-node	134	27
✅ astro-stable-quickjs	134	27
✅ express-stable-node	134	27
✅ express-stable-quickjs	134	27
✅ fastify-stable-node	134	27
✅ fastify-stable-quickjs	134	27
✅ hono-stable-node	134	27
✅ hono-stable-quickjs	134	27
✅ nest-stable-node	134	27
✅ nest-stable-quickjs	134	27
✅ nextjs-turbopack-canary-node	141	20
✅ nextjs-turbopack-canary-quickjs	141	20
✅ nextjs-turbopack-stable-node	160	1
✅ nextjs-turbopack-stable-quickjs	160	1
✅ nextjs-webpack-canary-node	141	20
✅ nextjs-webpack-canary-quickjs	141	20
✅ nextjs-webpack-stable-node	160	1
✅ nextjs-webpack-stable-quickjs	160	1
✅ nitro-stable-node	134	27
✅ nitro-stable-quickjs	134	27
✅ nuxt-stable-node	134	27
✅ nuxt-stable-quickjs	134	27
✅ sveltekit-stable-node	153	8
✅ sveltekit-stable-quickjs	153	8
✅ tanstack-start-node	134	27
✅ tanstack-start-quickjs	134	27
✅ vite-stable-node	134	27
✅ vite-stable-quickjs	134	27

✅ 📦 Local Production

App	Passed	Skipped
✅ astro-stable-node	134	27
✅ astro-stable-quickjs	134	27
✅ express-stable-node	134	27
✅ express-stable-quickjs	134	27
✅ fastify-stable-node	134	27
✅ fastify-stable-quickjs	134	27
✅ hono-stable-node	134	27
✅ hono-stable-quickjs	134	27
✅ nest-stable-node	134	27
✅ nest-stable-quickjs	134	27
✅ nextjs-turbopack-canary-node	141	20
✅ nextjs-turbopack-canary-quickjs	141	20
✅ nextjs-turbopack-stable-node	160	1
✅ nextjs-turbopack-stable-quickjs	160	1
✅ nextjs-webpack-canary-node	141	20
✅ nextjs-webpack-canary-quickjs	141	20
✅ nextjs-webpack-stable-node	160	1
✅ nextjs-webpack-stable-quickjs	160	1
✅ nitro-stable-node	134	27
✅ nitro-stable-quickjs	134	27
✅ nuxt-stable-node	134	27
✅ nuxt-stable-quickjs	134	27
✅ sveltekit-stable-node	153	8
✅ sveltekit-stable-quickjs	153	8
✅ tanstack-start-node	134	27
✅ tanstack-start-quickjs	134	27
✅ vite-stable-node	134	27
✅ vite-stable-quickjs	134	27

✅ 🐘 Local Postgres

App	Passed	Skipped
✅ astro-stable-node	134	27
✅ astro-stable-quickjs	134	27
✅ express-stable-node	134	27
✅ express-stable-quickjs	134	27
✅ fastify-stable-node	134	27
✅ fastify-stable-quickjs	134	27
✅ hono-stable-node	134	27
✅ hono-stable-quickjs	134	27
✅ nest-stable-node	134	27
✅ nest-stable-quickjs	134	27
✅ nextjs-turbopack-canary-node	141	20
✅ nextjs-turbopack-canary-quickjs	141	20
✅ nextjs-turbopack-stable-node	160	1
✅ nextjs-turbopack-stable-quickjs	160	1
✅ nextjs-webpack-canary-node	141	20
✅ nextjs-webpack-canary-quickjs	141	20
✅ nextjs-webpack-stable-node	160	1
✅ nextjs-webpack-stable-quickjs	160	1
✅ nitro-stable-node	134	27
✅ nitro-stable-quickjs	134	27
✅ nuxt-stable-node	134	27
✅ nuxt-stable-quickjs	134	27
✅ sveltekit-stable-node	153	8
✅ sveltekit-stable-quickjs	153	8
✅ tanstack-start-node	134	27
✅ tanstack-start-quickjs	134	27
✅ vite-stable-node	134	27
✅ vite-stable-quickjs	134	27

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	160	0	1
✅ nextjs-turbopack-quickjs	160	0	1

✅ 🌐 Cross-language Conformance

App	Passed	Failed	Skipped
✅ python	68	0	74

✅ vercel-http-transport

App	Passed	Skipped
✅ example	133	28
✅ express	133	28
✅ hono	133	28
✅ nextjs-turbopack	158	3
✅ nitro	133	28
✅ vite	133	28

✅ vercel-multi-region

App	Passed	Failed	Skipped
✅ nextjs-turbopack	27	0	0

✅ vercel-ws-transport

App	Passed	Skipped
✅ example	133	28
✅ express	133	28
✅ nextjs-turbopack	158	3
✅ vite	133	28

📋 View full workflow run

github-actions · 2026-09-11T08:27:26Z

Sim World

Simulated world deterministic testing for races. Traces

🟠 world-sim scenario book — 1 fail of 41 total

fence=per-spec

scenario	outcome	events	virt	replay
✅ `smoke-no-steps`	completed	3	0ms	ok
✅ `smoke-one-step`	completed	6	0ms	ok
✅ `hook-at-step-started`	completed	12	0ms	ok
✅ `hook-at-step-completed`	completed	12	0ms	ok
✅ `hook-at-hook-created`	completed	12	0ms	ok
✅ `deadline-hook-wins`	completed	7	1.0h	ok
✅ `deadline-expires`	completed	7	1.0h	ok
✅ `long-sleep`	completed	11	30.0d	ok
✅ `hook-never-arrives`	stalled	3	0ms	skipped
✅ `step-retries-twice`	completed	10	2.0s	ok
✅ `parallel-steps`	completed	9	0ms	ok
✅ `hook-on-execution-state`	completed	12	0ms	ok
✅ `peek-hook-before-branch`	completed	12	0ms	ok
✅ `peek-hook-after-branch`	completed	12	0ms	ok
✅ `peek-hook-at-registration`	completed	12	0ms	ok
✅ `race-hook-before-probe`	completed	12	0ms	ok
✅ `race-hook-after-probe`	completed	12	0ms	ok
✅ `race-duplicate-delivery`	completed	13	0ms	ok
✅ `attr-hook-before-step`	completed	11	0ms	ok
✅ `attr-hook-after-step`	completed	11	0ms	ok
✅ `attr-from-step-body`	completed	13	0ms	ok
✅ `fork-hook-after-timeout`	completed	14	1.0m	ok
✅ `fork-hook-before-timeout`	completed	14	1.0m	ok
✅ `count-hook-after-timeout`	completed	17	1.0m	ok
✅ `count-hook-before-timeout`	completed	20	1.0m	ok
✅ `stale-read-step-count-fork`	completed	20	1.0m	ok
✅ `stale-read-equal-step-counts`	completed	14	1.0m	ok
✅ `step-vs-step-fork`	completed	12	0ms	ok
✅ `step-vs-step-fork-fenced`	completed	12	0ms	ok
✅ `fence-catches-benign-direction`	completed	12	5ms	ok
✅ `in-flight-before-decision`	completed	17	1.0m	ok
❌ `in-flight-before-decision-counted`	completed	17	1.0m	ok
✅ `in-flight-after-decision`	completed	19	2.0m	ok
✅ `stale-read-step-count-fork-fenced`	completed	20	1.0m	ok
✅ `fork-hook-wins`	completed	13	1.0m	ok
✅ `fork-timeout-wins`	completed	13	1.0m	ok
✅ `unclaimed-payload-under-fork`	completed	17	1.0m	ok
✅ `claimed-payload-under-fork`	completed	17	1.0m	ok
✅ `writers-independent-step-bodies`	completed	12	0ms	ok
✅ `writers-scripted-tempo`	completed	12	0ms	ok
✅ `cancel-mid-step`	cancelled	7	0ms	skipped

Full trace: world-sim.txt

github-actions · 2026-09-11T08:28:07Z

Framework	Flow route	Step reg.	Framework output
hono	201.6 KiB (±0)	42.3 KiB (±0)	1.79 MiB (+357 B)
nextjs-turbopack	207.8 KiB (±0)	439 B (±0)	779.6 KiB (+157 B)

About these numbers

Sizes are gzip; parentheses show the change against main.
Flow route and Step reg. gate this job, on raw bytes rather than the gzip shown, at max(2%, 50.0 KiB). Framework output is informational.

a1d0ea6 · run

Copilot

🟡 Changes recommended

Resilient step publishes can be duplicated on early-exit paths because their IDs are seeded too late.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Improves workflow performance by preventing duplicate step-message publishes during replay passes.

Changes:

Tracks invocation-scoped step publishes and skips redundant dispatches.
Adds telemetry and regression tests.
Adds a core patch changeset.

File summaries

File	Summary
`packages/core/src/telemetry/semantic-conventions.ts`	Adds republish-suppression telemetry.
`packages/core/src/runtime.ts`	Implements publish tracking and deduplication.
`packages/core/src/runtime.test.ts`	Tests replay, retry, and resilient dispatch behavior.
`.changeset/dispatch-skip-republished.md`	Declares the core patch release.

Review details

Suppressed comments (2)

packages/core/src/runtime.ts:4006

This set is keyed only by correlationId, but step-dispatch identity intentionally includes stepName because a stale-snapshot restart can re-derive the same correlation ID for a different step (packages/core/src/runtime/helpers.ts:1158-1173). publishedStepCorrelationIds survives restartReplayInProcess, so if an earlier pass published step A and a corrected replay maps that ID to step B, this condition skips B's legitimate enqueue; the old A message can then be rejected by the step-name fence and B never runs. Track the same correlation-id/step-name identity when seeding and checking this set.

                            publishedStepCorrelationIds.has(
                              step.correlationId
                            ) &&
                            step.sawRetrying !== true

packages/core/src/runtime.ts:4006

step.sawRetrying is a sticky flag: step.ts sets it on the first step_retrying and never clears it. After this invocation performs the first re-enqueue allowed by the carve-out, every later replay pass still sees sawRetrying === true, so this condition keeps publishing the same step message and defeats the invocation-local deduplication for multi-pass retry flows. Track/consume the retry handoff separately from the permanent ownership flag so only a new retry schedule bypasses the skip.

                          if (
                            publishedStepCorrelationIds.has(
                              step.correlationId
                            ) &&
                            step.sawRetrying !== true

Files reviewed: 4/4 changed files
Comments generated: 1
Review effort level: Lite

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pranaygp · 2026-09-11T20:47:13Z

+                        for (const correlationId of suspensionResult.queuedStepCorrelationIds) {
+                          publishedStepCorrelationIds.add(correlationId);
+                        }


Good catch, this is real: the set was only seeded at the dispatch pass, so a pass that exited early via the hook-conflict, attribute-event or serialization-failure branch forgot the handler's resilient publishes and the next pass re-sent them. Fixed in #4128 by seeding immediately after handleSuspension returns, before any early exit, with a test that drives a hook_conflict pass and asserts one send (it sends twice without the fix).

github-actions · 2026-09-11T20:08:01Z

No backport to stable for 788d4fb (AI decision).

This is a performance optimization (perf(core)), not a defect fix: the redundant step-execution publishes it eliminates are already deduped by the queue's idempotency key, so current behavior is correct, just slower and holding the invocation open longer. It also adds new observable surface (the workflow.dispatch.republish_skipped span attribute) and new invocation-scoped dispatch state in the replay loop, which is exactly the kind of behavioral risk a maintenance line exists to avoid. Latency on a 32-branch fan-out is not a stability problem on stable, so this should stay on main.

To override, re-run the Backport to stable workflow manually via workflow_dispatch and paste this commit SHA into the ref input:

788d4fbc261655b1dd7d049c334d21afac3edd81

…eturns Follow-up to #4099. The invocation-scoped set of step correlation ids this delivery already published was seeded from the suspension handler's `queuedStepCorrelationIds` only at the dispatch pass, which runs after the hook-conflict, attribute-event and serialization-failure branches `continue` the replay loop in-process. The handler's resilient publishes on such a pass were therefore forgotten: on the next pass the step already existed, the handler no longer reported it, and the dispatch pass published its message a second time. Move the seeding to immediately after `handleSuspension` returns, before any early exit, and drop the dispatch-pass-only placement. Adds a test that drives a hook_conflict pass with resilient dispatch on and asserts the queued step's message is sent exactly once across the invocation (it sends twice without the fix). Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

pranaygp requested a review from a team as a code owner September 11, 2026 08:23

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pranaygp merged commit 788d4fb into main Sep 11, 2026
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pranaygp deleted the pgp/dispatch-skip-republished branch September 11, 2026 20:07

This was referenced Sep 11, 2026

Version Packages (beta) #4071

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Version Packages ben-vargas/workflow#104

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pranaygp mentioned this pull request Sep 11, 2026

perf(core): seed the published-step set as soon as handleSuspension returns #4128

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github-actions Bot mentioned this pull request Sep 11, 2026

Version Packages (beta) Jokacar10/jkworkflow#548

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perf(core): don't re-publish step messages this invocation already published - #4099

perf(core): don't re-publish step messages this invocation already published#4099
pranaygp merged 1 commit into
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pranaygp commented Sep 11, 2026

Motivation (measured)

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Safety argument

QuickJS engine

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🧪 E2E Test Results

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