fix(vite): rebuild workflows once per change, not per environment by alangenfeld · Pull Request #4370 · vercel/workflow

alangenfeld · 2026-09-24T18:29:41Z

Summary & Motivation

Vite calls hotUpdate once per environment (client, ssr, and any a framework adds) for a single file change, and the plugin rebuilt on each call — so one edit cost two to three full rebuilds, back to back, before any HMR update went out. The backlog leaked past dev.test.ts into the e2e suite, where a rebuild stalling a race workflow's 1s sleep made sleepWinsRaceWorkflow the most-retried test on main (12 retries in 9 of the last 30 runs, nearly all in the vite and tanstack-start dev lanes). In this vite dev lane, all 24 rebuilds came from dev.test.ts edits, took 2.5–17s each on the runner, and were still draining 1.5 minutes into e2e. Environment calls for one change share a timestamp, so the plugin now remembers each (timestamp, file) and skips the repeats.

Affects every integration using workflowHotUpdatePlugin: vite, nitro/tanstack-start, sveltekit, astro.

Test Plan

Unit tests added for the deduplication, including interleaved changes; verified locally against workbench/vite dev: one dev.test.ts run made 10 changes, each delivered to 3 environments, and rebuilds dropped from 21 to 8 with dev.test.ts still passing. Without the fix, 3 of the new tests fail.

vercel · 2026-09-24T18:29:43Z

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Project	Deployment	Actions	Updated
example-nextjs-workflow-turbopack	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
example-nextjs-workflow-webpack	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
example-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-astro-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-express-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-fastify-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-hono-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-nestjs-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-nitro-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-nuxt-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-python-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-sveltekit-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-tanstack-start-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workbench-vite-workflow	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workflow-docs	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workflow-swc-playground	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workflow-tarballs	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC
workflow-web	Ready	Preview, v0	Sep 24, 2026 7:49pm UTC

changeset-bot · 2026-09-24T18:29:53Z

🦋 Changeset detected

Latest commit: 0d2ab2f

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

This PR includes changesets to release 16 packages

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

github-actions · 2026-09-24T18:30:02Z

🧪 E2E Test Results

❌ Some tests failed

❌ Failed E2E Tests

▲ Vercel Production (62 failed)

python-node (62 failed):

promiseAllWorkflow | wrun_41M3AFAV4Q0GV9Y4NBTZMFMS8D | 🔍 observability
promiseRaceWorkflow | wrun_41M3AFAV4Q0GV9Y4NBTZMFMS8E | 🔍 observability
promiseAnyWorkflow | wrun_41M3AFAV4Q0GV9Y4NBTZMFMS8F | 🔍 observability
retainedInterleavingWorkflow | wrun_41M3AFB22G0GGGXB3SZNXKK5TE | 🔍 observability
hookWorkflow | wrun_41M3AFB5MM0GQZHRWWC1CSRX3T | 🔍 observability
hookWorkflow is not resumable via public webhook endpoint | wrun_41M3AFB6AZ0GJYF69MS6D3ZBPR | 🔍 observability
sleepingWorkflow | wrun_41M3AFBF8R0GPS0A6B31CF9W4M | 🔍 observability
parallelSleepWorkflow | wrun_41M3AFBFRV0GZAKJ9Y2CXPRC7Z | 🔍 observability
sleepWinsRaceWorkflow | wrun_41M3AFBN3H0GXHM5A6MY2EPWTN | 🔍 observability
stepWinsRaceWorkflow | wrun_41M3AFBNF60GK8GMA0WTS3HC3V | 🔍 observability
nullByteWorkflow | wrun_41M3AFBP1Q0GXA3PXGT74VX5AC | 🔍 observability
outputStreamWorkflow no startIndex (reads all chunks)
outputStreamWorkflow positive startIndex (skips first chunk)
outputStreamWorkflow negative startIndex (reads from end)
outputStreamWorkflow - getTailIndex and getChunks getTailIndex returns correct index after stream completes
outputStreamWorkflow - getTailIndex and getChunks getChunks returns same content as reading the stream
outputStreamInsideStepWorkflow - getWritable() called inside step functions | wrun_41M3AFCDDZ0GRNNMX5B1N8TER8 | 🔍 observability
utf8StreamWorkflow | wrun_41M3AFCDM80GW83GKEEREDJ49Z | 🔍 observability
writableForwardedFromWorkflowWorkflow | wrun_41M3AFCEQ60GWX3RG6GCMZ97MD | 🔍 observability
writableForwardedFromStepWorkflow | wrun_41M3AFCFEE0GKJZG9T59WDEQG6 | 🔍 observability
promiseRaceStressTestWorkflow | wrun_41M3AFCHJJ0GMWQ5GXW61810QV | 🔍 observability
error handling retry behavior regular Error retries until success
error handling retry behavior FatalError fails immediately without retries
error handling retry behavior RetryableError respects custom retryAfter delay
error handling retry behavior maxRetries=0 disables retries
error handling catchability FatalError can be caught and detected with FatalError.is()
error handling catchability step throw round-trips FatalError with cause chain to workflow catch
error handling catchability workflow throw round-trips FatalError + cause through run_failed event
error handling not registered StepNotRegisteredError fails the step but workflow can catch it
error handling not registered StepNotRegisteredError fails the run when not caught in workflow
hookCleanupTestWorkflow - hook token reuse after workflow completion | wrun_41M3AFE3590GG5B2WAMY5RD2FP | 🔍 observability
concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_41M3AFE1PM0GZTSTB06CWAB73M | 🔍 observability
hookGetConflictWorkflow - awaiting hook.getConflict() registers hook without payload | wrun_41M3AFE1AA0GTX9WWHSF6T6Q85 | 🔍 observability
'hookGetConflictWithPriorStepWorkflow' - hook.getConflict() does not block step execution | wrun_41M3AFE5R40GZEBNKZ8W79SDPF | 🔍 observability
'hookGetConflictWithParallelStepWorkfl…' - hook.getConflict() does not block step execution | wrun_41M3AFE77H0GNNFMNEVSXMEFN3 | 🔍 observability
hookGetConflictThenStepParallelWorkflow - hook.getConflict() continuation step runs alongside other steps | wrun_41M3AFE7PK0GR1FWBSSAXX8F85 | 🔍 observability
hookGetConflictWorkflow - hook.getConflict() resolves with the conflicting run when token is already registered | wrun_41M3AFED4H0GJ2J6VQ4959QFJJ | 🔍 observability
hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data | wrun_41M3AFEZZQ0GM88Y2AYHFGFY50 | 🔍 observability
hookAdoptOwnerResultWorkflow - duplicate adopts the owner result via conflict.returnValue | wrun_41M3AFENR40GXNFRSJ18PAGSCZ | 🔍 observability
hookSignalOwnerWorkflow - duplicate forwards its payload to the owner via resumeHook | wrun_41M3AFERN10GZDHJT3JVC7MXQJ | 🔍 observability
resume-or-start route pattern - resumeHook retried after start() reaches the new run | wrun_41M3AFFGVC0GG9C20F47TRHWWX | 🔍 observability
hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running | wrun_41M3AFFKXQ0GP362XVD3DPQGCS | 🔍 observability
hookTokenReuseLoopWorkflow - same run recreates a hook with the same token after dispose() | wrun_41M3AFFHQH0GNAJCD86JFJ9N2N | 🔍 observability
spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step | wrun_41M3AFG0550GP8RC9SVGVJAWSC | 🔍 observability
cancelRun - cancelling a running workflow | wrun_41M3AFGWX10GK437X7DCT1ZA9N | 🔍 observability
cancelRun via CLI - cancelling a running workflow | wrun_41M3AFH2FF0GJMKDSFCJS0GM0Y | 🔍 observability
hookWithSleepWorkflow - hook payloads delivered correctly with concurrent sleep | wrun_41M3AFH2HC0GJ1YGGFHYN0GN2J | 🔍 observability
hookWithSleepFinalStepWorkflow - step only on final payload | wrun_41M3AFH4K90GHEQN6DXV8HFB9A | 🔍 observability
sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_41M3AFH5NV0GQYQBXYWJ0TVXZB | 🔍 observability
sleepWithSequentialStepsWorkflow - sequential steps work with concurrent sleep (control) | wrun_41M3AFH6ZP0GX0R5K52YFV5G86 | 🔍 observability
AbortController abortTimeoutWorkflow: timeout cancels long-running step
AbortController abortParallelWorkflow: abort cancels all parallel steps
AbortController abortReasonWorkflow: abort reason preserved across boundaries
AbortController abortViaHookWorkflow: external hook triggers abort on in-flight step
metadataFromHelperWorkflow - getWorkflowMetadata/getStepMetadata work from module-level helper (#1577) | wrun_41M3AFHQ0M0GNW1F3344K623GV | 🔍 observability
resilient start: addTenWorkflow completes when run_created returns 500 | wrun_41M3AFHQBD0GXC3X3Z2G53CWPK | 🔍 observability
setAttributes start: initial attributes are seeded on run creation
setAttributes start: reserved-prefix initial attributes are seeded with allowReservedAttributes
setAttributes setAttributesWorkflow: workflow-body calls append native attr_set events and merge correctly
setAttributes setAttributesInsideStepWorkflow: step-body calls append attributed native events
setAttributes Promise.all of disjoint-key writes: every key lands
setAttributes workflow throws after awaited setAttributes: attribute still persists on the failed run

⚠️ 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.

no startIndex (reads all chunks) (astro · vercel-prod / vercel / quickjs / production)

🛠 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.

124 infra events

cold-start-warmup · suite warmup (python) · at 19:48:58Z · abandoned wrun_41M3AF9XPR0GXCAQV2YN6JYSDS · (+7 more)
run-pickup-stall · promiseAllWorkflow (python) · at 19:49:15Z · abandoned wrun_41M3AFDJMJ0GRNDHR895EDCZ5F
run-pickup-stall · retainedInterleavingWorkflow (python) · at 19:49:15Z · abandoned wrun_41M3AFDJMK0GKEAE4A0SH7DVPP
run-pickup-stall · hookWorkflow (python) · at 19:49:15Z · abandoned wrun_41M3AFDJMQ0GPXMFDAMX76X1VX
run-pickup-stall · promiseRaceWorkflow (python) · at 19:49:15Z · abandoned wrun_41M3AFDJMK0GKEAE4A0SH7DVPM
run-pickup-stall · promiseAnyWorkflow (python) · at 19:49:15Z · abandoned wrun_41M3AFDJMK0GKEAE4A0SH7DVPN
run-pickup-stall · retainedInterleavingWorkflow (python) · at 19:50:04Z · abandoned wrun_41M3AFF2V50GZXPSNR80YV8DNZ
run-pickup-stall · hookWorkflow (python) · at 19:50:04Z · abandoned wrun_41M3AFF2N50GJQS27WNPCWAXQ1
run-pickup-stall · promiseRaceWorkflow (python) · at 19:50:16Z · abandoned wrun_41M3AFFE4D0GYCFM00GM7ASZ2N
run-pickup-stall · promiseAllWorkflow (python) · at 19:50:16Z · abandoned wrun_41M3AFFE5H0GQ43ZWMHZX5Y223
run-pickup-stall · promiseAnyWorkflow (python) · at 19:50:16Z · abandoned wrun_41M3AFFE4J0GV1WKZ9C68WSBQ8
cold-start-warmup · suite warmup (tanstack-start) · at 19:50:43Z · abandoned wrun_01M3AFG7A1W0FNY2NW74CF3W3F
run-pickup-stall · hookWorkflow is not resumable via public webhook endpoint (python) · at 19:50:51Z · abandoned wrun_41M3AFGH0T0GKVTAZXQYEKEVGA
run-pickup-stall · sleepingWorkflow (python) · at 19:50:51Z · abandoned wrun_41M3AFGH5T0GWMTK3FQMD073C3
run-pickup-stall · sleepWinsRaceWorkflow (python) · at 19:51:20Z · abandoned wrun_41M3AFHA950GW14JAQ859EZN2S
run-pickup-stall · parallelSleepWorkflow (python) · at 19:51:20Z · abandoned wrun_41M3AFHA5S0GX0X7HTX43JDT2Y
run-pickup-stall · stepWinsRaceWorkflow (python) · at 19:51:21Z · abandoned wrun_41M3AFHAEE0GM3F757NJTZC20K
run-pickup-stall · hookWorkflow is not resumable via public webhook endpoint (python) · at 19:52:38Z · abandoned wrun_41M3AFK1000GYHR2E1XE2B2S2J
run-pickup-stall · sleepingWorkflow (python) · at 19:52:39Z · abandoned wrun_41M3AFK16Y0GXF1DK3X1DWQ926
run-pickup-stall · parallelSleepWorkflow (python) · at 19:52:53Z · abandoned wrun_41M3AFM22A0GXEJ7JBKN92PHZN
run-pickup-stall · sleepWinsRaceWorkflow (python) · at 19:52:53Z · abandoned wrun_41M3AFM25Q0GX55VD0RH43T5RF
run-pickup-stall · stepWinsRaceWorkflow (python) · at 19:52:53Z · abandoned wrun_41M3AFM2AY0GRN64G4FB88PESH
run-pickup-stall · nullByteWorkflow (python) · at 19:53:14Z · abandoned wrun_41M3AFMWAT0GGS9EKBQ8BQQ4CJ
run-pickup-stall · no startIndex (reads all chunks) (python) · at 19:53:14Z · abandoned wrun_41M3AFMWKA0GZ3FFZBXK0T1X42
run-pickup-stall · positive startIndex (skips first chunk) (python) · at 19:53:49Z · abandoned wrun_41M3AFNWNA0GT1G11P1MFD2PNZ
run-pickup-stall · negative startIndex (reads from end) (python) · at 19:53:49Z · abandoned wrun_41M3AFNWRQ0GJ0JN9CT8BCGVDA
run-pickup-stall · getTailIndex returns correct index after stream completes (python) · at 19:53:50Z · abandoned wrun_41M3AFNZG80GHNSNVK28CBP403
run-pickup-stall · getTailIndex returns -1 before any chunks are written (python) · at 19:54:14Z · abandoned wrun_41M3AFPPXT0GKJATQEP9SX3R7K
run-pickup-stall · getChunks returns same content as reading the stream (python) · at 19:54:14Z · abandoned wrun_41M3AFPQ6A0GYTKZ8E6EP4JQVM
run-pickup-stall · outputStreamInsideStepWorkflow - getWritable() called inside step functions (python) · at 19:54:31Z · abandoned wrun_41M3AFQ74X0GMBRH98Y7M4QHJH
run-pickup-stall · utf8StreamWorkflow (python) · at 19:54:47Z · abandoned wrun_41M3AFQQ8A0GVTH7N0QG099A6T
run-pickup-stall · nullByteWorkflow (python) · at 19:54:50Z · abandoned wrun_41M3AFQT380GWRX9P1RN1A813P
run-pickup-stall · no startIndex (reads all chunks) (python) · at 19:54:50Z · abandoned wrun_41M3AFQTJ80GKRXW7D276FRCZM
run-pickup-stall · positive startIndex (skips first chunk) (python) · at 19:55:14Z · abandoned wrun_41M3AFRHSA0GKTKXHRNCBZ2T6S
run-pickup-stall · negative startIndex (reads from end) (python) · at 19:55:31Z · abandoned wrun_41M3AFS2NY0GQDG21T43WBBEGF
run-pickup-stall · getTailIndex returns correct index after stream completes (python) · at 19:55:51Z · abandoned wrun_41M3AFSNNR0GTSZVJ340Q6FPF7
run-pickup-stall · getChunks returns same content as reading the stream (python) · at 19:55:53Z · abandoned wrun_41M3AFSQZN0GM3MMR1AYVSE4DC
run-pickup-stall · outputStreamInsideStepWorkflow - getWritable() called inside step functions (python) · at 19:56:14Z · abandoned wrun_41M3AFTCCB0GRRWPSP47NKG3WK
run-pickup-stall · writableForwardedFromWorkflowWorkflow (python) · at 19:56:31Z · abandoned wrun_41M3AFTX8Z0GSGJ7Z66QZTR265
run-pickup-stall · writableForwardedFromStepWorkflow (python) · at 19:56:49Z · abandoned wrun_41M3AFVEX70GPDT7Q1VFRVPN92
run-pickup-stall · utf8StreamWorkflow (python) · at 19:56:51Z · abandoned wrun_41M3AFVG8Q0GTB1TWCTW0HM9A7
run-pickup-stall · promiseRaceStressTestWorkflow (python) · at 19:56:55Z · abandoned wrun_41M3AFVM4X0GQJKRMVA5R01PE5
run-pickup-stall · regular Error retries until success (python) · at 19:57:15Z · abandoned wrun_41M3AFW7Q40GXFZR1X0Y893FZ2
run-pickup-stall · FatalError fails immediately without retries (python) · at 19:57:55Z · abandoned wrun_41M3AFXEQY0GYJC7Q5B6KVBXQP
run-pickup-stall · RetryableError respects custom retryAfter delay (python) · at 19:58:15Z · abandoned wrun_41M3AFY2A50GXVXCVR0EW75G30
run-pickup-stall · maxRetries=0 disables retries (python) · at 19:58:31Z · abandoned wrun_41M3AFYJEZ0GNJ0QFH31ZN852D
run-pickup-stall · ChainableService.processWithThis - static step methods using this to reference the class (nextjs-webpack) · at 19:58:37Z · abandoned wrun_01M3AFYSA3PRXT5QECX4HX060Q
run-pickup-stall · FatalError can be caught and detected with FatalError.is() (python) · at 19:58:49Z · abandoned wrun_41M3AFZ4370GSM6N4R4QNHPYKW
run-pickup-stall · step throw round-trips FatalError with cause chain to workflow catch (python) · at 19:58:51Z · abandoned wrun_41M3AFZ5ER0GWZNC6NSCWXW8GY
run-pickup-stall · workflow throw round-trips FatalError + cause through run_failed event (python) · at 19:58:55Z · abandoned wrun_41M3AFZ9AX0GPD3ZX1SVK9CNBC
run-pickup-stall · StepNotRegisteredError fails the step but workflow can catch it (python) · at 19:59:15Z · abandoned wrun_41M3AFZWX50GN7RF9D982RFKKJ
run-pickup-stall · StepNotRegisteredError fails the run when not caught in workflow (python) · at 19:59:36Z · abandoned wrun_41M3AG0D1Z0GYKM2Z1RBTA8NVS
run-pickup-stall · promiseRaceStressTestWorkflow (python) · at 20:01:08Z · abandoned wrun_41M3AG28G50GSAYZDRWP08T4QG
run-pickup-stall · writableForwardedFromStepWorkflow (python) · at 20:01:13Z · abandoned wrun_41M3AG2VD90GVDWBRHC2ZBC0BA
run-pickup-stall · regular Error retries until success (python) · at 20:01:15Z · abandoned wrun_41M3AG2C9X0GTG1M7MR8MDW669
run-pickup-stall · writableForwardedFromWorkflowWorkflow (python) · at 20:01:15Z · abandoned wrun_41M3AG2CNS0GJ16EDJN4PG8M69
run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (python) · at 20:01:45Z · abandoned wrun_41M3AG3AB50GK6VKQDCBN3C0E4
run-pickup-stall · FatalError fails immediately without retries (python) · at 20:02:30Z · abandoned wrun_41M3AG43370GYP18PXYN384B7H
run-pickup-stall · RetryableError respects custom retryAfter delay (python) · at 20:02:36Z · abandoned wrun_41M3AG523A0GGC9R4AH9X8D4H9
run-pickup-stall · maxRetries=0 disables retries (python) · at 20:02:37Z · abandoned wrun_41M3AG54Y60GS4XR6FBKX30VRH
run-pickup-stall · FatalError can be caught and detected with FatalError.is() (python) · at 20:02:46Z · abandoned wrun_41M3AG5XP60GJMQDGW1MWY68QJ
run-pickup-stall · step throw round-trips FatalError with cause chain to workflow catch (python) · at 20:02:46Z · abandoned wrun_41M3AG61VR0GPQKG59KFZJDGTW
run-pickup-stall · workflow throw round-trips FatalError + cause through run_failed event (python) · at 20:02:54Z · abandoned wrun_41M3AG6GK90GMGHRXDV8Z4429F
run-pickup-stall · StepNotRegisteredError fails the step but workflow can catch it (python) · at 20:03:04Z · abandoned wrun_41M3AG6WPB0GQF6M98ETQBQ9QH
run-pickup-stall · StepNotRegisteredError fails the run when not caught in workflow (python) · at 20:03:09Z · abandoned wrun_41M3AG714P0GM59WFFQHNHXKDZ
run-pickup-stall · hookCleanupTestWorkflow - hook token reuse after workflow completion (python) · at 20:03:38Z · abandoned wrun_41M3AG7XXT0GM6JS0KB1R7KVW8
run-pickup-stall · hookGetConflictWorkflow - awaiting hook.getConflict() registers hook without payload (python) · at 20:03:52Z · abandoned wrun_41M3AG8B680GMR1FCXYCBR6DWA
run-pickup-stall · 'hookGetConflictWithPriorStepWorkflow' - hook.getConflict() does not block step execution (python) · at 20:04:04Z · abandoned wrun_41M3AG8Q9B0GGKCKKHS246YPHS
run-pickup-stall · 'hookGetConflictWithParallelStepWorkfl…' - hook.getConflict() does not block step execution (python) · at 20:04:10Z · abandoned wrun_41M3AG8XBV0GMV46XHN24170BV
run-pickup-stall · hookGetConflictThenStepParallelWorkflow - hook.getConflict() continuation step runs alongside other steps (python) · at 20:04:25Z · abandoned wrun_41M3AG9C0D0GGPW3BTJ0B725MZ
run-pickup-stall · hookGetConflictWorkflow - hook.getConflict() resolves with the conflicting run when token is already registered (python) · at 20:04:41Z · abandoned wrun_41M3AG9VA80GJH1E6MNDDF5ZXF
run-pickup-stall · hookGetConflictWorkflow - awaiting hook.getConflict() registers hook without payload (python) · at 20:04:55Z · abandoned wrun_41M3AGA6HQ0GGVEK9QC7B0DAM6
run-pickup-stall · 'hookGetConflictWithPriorStepWorkflow' - hook.getConflict() does not block step execution (python) · at 20:05:05Z · abandoned wrun_41M3AGAJNY0GZ27NS97H7380NG
run-pickup-stall · 'hookGetConflictWithParallelStepWorkfl…' - hook.getConflict() does not block step execution (python) · at 20:05:14Z · abandoned wrun_41M3AGARSB0GPFTS3M6N6R81VX
run-pickup-stall · hookGetConflictWorkflow - hook.getConflict() resolves with the conflicting run when token is already registered (python) · at 20:05:31Z · abandoned wrun_41M3AGBC5G0GJFM9DP1N4GRT20
run-pickup-stall · hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (python) · at 20:05:53Z · abandoned wrun_41M3AGC1XH0GM93R8N7TFR25RQ
run-pickup-stall · hookGetConflictThenStepParallelWorkflow - hook.getConflict() continuation step runs alongside other steps (python) · at 20:05:56Z · abandoned wrun_41M3AGC4N50GWS815KCW7RD7VD
run-pickup-stall · hookAdoptOwnerResultWorkflow - duplicate adopts the owner result via conflict.returnValue (python) · at 20:06:06Z · abandoned wrun_41M3AGCE1J0GXZ4W715Z1TYMDA
run-pickup-stall · hookSignalOwnerWorkflow - duplicate forwards its payload to the owner via resumeHook (python) · at 20:06:12Z · abandoned wrun_41M3AGCMAT0GXPKQ9TW3CR1F0Y
run-pickup-stall · resume-or-start route pattern - resumeHook retried after start() reaches the new run (python) · at 20:06:19Z · abandoned wrun_41M3AGCTRS0GRQFHKXE9WXRDG4
run-pickup-stall · hookClaimOnlyMutexWorkflow - hook works as a pure run mutex without payload data (python) · at 20:06:42Z · abandoned wrun_41M3AGDGC10GXX6PEMNVBQVT6C
run-pickup-stall · hookAdoptOwnerResultWorkflow - duplicate adopts the owner result via conflict.returnValue (python) · at 20:06:53Z · abandoned wrun_41M3AGDW470GHNM9KRD1BBRQSQ
run-pickup-stall · hookSignalOwnerWorkflow - duplicate forwards its payload to the owner via resumeHook (python) · at 20:07:00Z · abandoned wrun_41M3AGE2W00GQSF6CVW0HM2Q68
run-pickup-stall · resume-or-start route pattern - resumeHook retried after start() reaches the new run (python) · at 20:07:06Z · abandoned wrun_41M3AGE9C80GR54X57S0Z6MBTP
run-pickup-stall · hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (python) · at 20:07:27Z · abandoned wrun_41M3AGEXBR0GMD2068TKSQQF6M
run-pickup-stall · hookTokenReuseLoopWorkflow - same run recreates a hook with the same token after dispose() (python) · at 20:07:29Z · abandoned wrun_41M3AGEZVY0GG18S3F7K31WP4H
run-pickup-stall · spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step (python) · at 20:07:40Z · abandoned wrun_41M3AGFA000GNNYDQN9QJ6CQME
run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:07:51Z · abandoned wrun_41M3AGFMKG0GJNYP4K89ZK7E00
run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:07:54Z · abandoned wrun_41M3AGFQVY0GVRWVZ6KFQWGZGR
run-pickup-stall · hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running (python) · at 20:08:16Z · abandoned wrun_41M3AGGBE30GGWNF8DHGSXXFSE
run-pickup-stall · hookTokenReuseLoopWorkflow - same run recreates a hook with the same token after dispose() (python) · at 20:08:16Z · abandoned wrun_41M3AGGDQD0GP4Y21JP0MN8E3X
run-pickup-stall · cancelRun - cancelling a running workflow (python) · at 20:08:23Z · abandoned wrun_41M3AGGM680GQZKZWERXXYEE54
run-pickup-stall · cancelRun via CLI - cancelling a running workflow (python) · at 20:08:26Z · abandoned wrun_41M3AGGQ7T0GKR676QT3ATQTXD
run-pickup-stall · hookWithSleepWorkflow - hook payloads delivered correctly with concurrent sleep (python) · at 20:08:56Z · abandoned wrun_41M3AGHKP70GVNKJG31X30ZWK5
run-pickup-stall · hookWithSleepFinalStepWorkflow - step only on final payload (python) · at 20:08:58Z · abandoned wrun_41M3AGHPVE0GWKY8FCCXAFJHA8
run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:09:03Z · abandoned wrun_41M3AGHVFR0GY75CDSSMEB6KEY
run-pickup-stall · sleepWithSequentialStepsWorkflow - sequential steps work with concurrent sleep (control) (python) · at 20:09:03Z · abandoned wrun_41M3AGHVJA0GNBVY7A61ND97YV
run-pickup-stall · spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step (python) · at 20:09:41Z · abandoned wrun_41M3AGJZZM0GHEXTFWGRXXQ64G
run-pickup-stall · hookWithSleepWorkflow - hook payloads delivered correctly with concurrent sleep (python) · at 20:09:43Z · abandoned wrun_41M3AGK2CM0GXBHFNFKD2D1Z9H
run-pickup-stall · hookWithSleepFinalStepWorkflow - step only on final payload (python) · at 20:09:46Z · abandoned wrun_41M3AGK50W0GT43YTQZMSY4PT3
run-pickup-stall · sleepWithSequentialStepsWorkflow - sequential steps work with concurrent sleep (control) (python) · at 20:10:04Z · abandoned wrun_41M3AGKPZK0GV9QWTG4SX9AAD2
run-pickup-stall · sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration (python) · at 20:10:04Z · abandoned wrun_41M3AGKQ0R0GJSF6QFSV3E96GS
run-pickup-stall · abortTimeoutWorkflow: timeout cancels long-running step (python) · at 20:10:43Z · abandoned wrun_41M3AGMPS10GXEZ2HHBBR4S7MJ
run-pickup-stall · abortParallelWorkflow: abort cancels all parallel steps (python) · at 20:10:44Z · abandoned wrun_41M3AGMRA30GVDHXMAHCYDSVQA
run-pickup-stall · abortReasonWorkflow: abort reason preserved across boundaries (python) · at 20:11:38Z · abandoned wrun_41M3AGNHJM0GW0056BVS7FP6RE
run-pickup-stall · metadataFromHelperWorkflow - getWorkflowMetadata/getStepMetadata work from module-level helper (Vercel World Regression: getWorkflowMetadata() fully breaking runs #1577) (python) · at 20:11:38Z · abandoned wrun_41M3AGNHKR0GWRZPB13QH0S90K
run-pickup-stall · abortViaHookWorkflow: external hook triggers abort on in-flight step (python) · at 20:12:33Z · abandoned wrun_41M3AGPJX30GKGF703Z2T08KKY
run-pickup-stall · abortTimeoutWorkflow: timeout cancels long-running step (python) · at 20:12:56Z · abandoned wrun_41M3AGR9F40GK7Y64RXMMQDGC6
run-pickup-stall · abortParallelWorkflow: abort cancels all parallel steps (python) · at 20:12:56Z · abandoned wrun_41M3AGRDG20GRZ1W0KSGTC5124
run-pickup-stall · start: initial attributes are seeded on run creation (python) · at 20:13:12Z · abandoned wrun_41M3AGRY3P0GRDBWH674ZD99CC
run-pickup-stall · start: reserved-prefix initial attributes are seeded with allowReservedAttributes (python) · at 20:13:17Z · abandoned wrun_41M3AGS6SR0GW89HZ6656J194P
run-pickup-stall · setAttributesWorkflow: workflow-body calls append native attr_set events and merge correctly (python) · at 20:13:20Z · abandoned wrun_41M3AGSE0S0GYVPGGFB2EE1BG0
run-pickup-stall · setAttributesInsideStepWorkflow: step-body calls append attributed native events (python) · at 20:13:28Z · abandoned wrun_41M3AGSVD50GH7KT754ADR9BAJ
run-pickup-stall · abortReasonWorkflow: abort reason preserved across boundaries (python) · at 20:13:36Z · abandoned wrun_41M3AGT4380GW77PAYFG92XEVW
run-pickup-stall · metadataFromHelperWorkflow - getWorkflowMetadata/getStepMetadata work from module-level helper (Vercel World Regression: getWorkflowMetadata() fully breaking runs #1577) (python) · at 20:13:37Z · abandoned wrun_41M3AGT4240GVSJ7C1ZPH4FETC
run-pickup-stall · abortViaHookWorkflow: external hook triggers abort on in-flight step (python) · at 20:13:41Z · abandoned wrun_41M3AGT9R20GVNGJ738WVXSF7M
run-pickup-stall · Promise.all of disjoint-key writes: every key lands (python) · at 20:13:43Z · abandoned wrun_41M3AGTD5F0GGF54WR7R4WPEF0
run-pickup-stall · start: initial attributes are seeded on run creation (python) · at 20:14:09Z · abandoned wrun_41M3AGV6800GZPJX3KVZ0K3W0T
run-pickup-stall · start: reserved-prefix initial attributes are seeded with allowReservedAttributes (python) · at 20:14:14Z · abandoned wrun_41M3AGVB590GK4S14GQVGAKEDQ
run-pickup-stall · setAttributesWorkflow: workflow-body calls append native attr_set events and merge correctly (python) · at 20:14:27Z · abandoned wrun_41M3AGVR9E0GV285PTC4A0HX13
run-pickup-stall · setAttributesInsideStepWorkflow: step-body calls append attributed native events (python) · at 20:14:34Z · abandoned wrun_41M3AGVYP80GVDDWM4G3X8HPAA
run-pickup-stall · Promise.all of disjoint-key writes: every key lands (python) · at 20:14:37Z · abandoned wrun_41M3AGW1T90GXT3DP3N5HA9QV4
run-pickup-stall · workflow throws after awaited setAttributes: attribute still persists on the failed run (python) · at 20:14:40Z · abandoned wrun_41M3AGW4AK0GSR8NEAVSR7ZY7H
run-pickup-stall · workflow throws after awaited setAttributes: attribute still persists on the failed run (python) · at 20:15:11Z · abandoned wrun_41M3AGX2CW0GZTAP11X62PTDNT

E2E Test Summary

Summary

	Passed	Failed	Skipped	Total
❌ ▲ Vercel Production	3816	62	739	4617
✅ 💻 Local Development	4068	0	549	4617
✅ 📦 Local Production	4238	0	550	4788
✅ 🐘 Local Postgres	4238	0	550	4788
✅ 🪟 Windows	340	0	2	342
✅ vercel-http-transport	873	0	153	1026
✅ vercel-multi-region	27	0	0	27
✅ vercel-ws-transport	591	0	93	684
Total	18191	62	2636	20889

Details by Category

❌ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro-node	141	0	30
✅ astro-quickjs	141	0	30
✅ example-node	141	0	30
✅ example-quickjs	141	0	30
✅ express-node	141	0	30
✅ express-quickjs	141	0	30
✅ fastify-node	141	0	30
✅ fastify-quickjs	141	0	30
✅ hono-node	141	0	30
✅ hono-quickjs	141	0	30
✅ nest-node	141	0	30
✅ nest-quickjs	141	0	30
✅ nextjs-turbopack-node	168	0	3
✅ nextjs-turbopack-quickjs	168	0	3
✅ nextjs-webpack-node	168	0	3
✅ nextjs-webpack-quickjs	168	0	3
✅ nitro-node	141	0	30
✅ nitro-quickjs	141	0	30
✅ nuxt-node	141	0	30
✅ nuxt-quickjs	141	0	30
❌ python-node	4	62	105
✅ sveltekit-node	160	0	11
✅ sveltekit-quickjs	160	0	11
✅ tanstack-start-node	141	0	30
✅ tanstack-start-quickjs	141	0	30
✅ vite-node	141	0	30
✅ vite-quickjs	141	0	30

✅ 💻 Local Development

App	Passed	Skipped
✅ astro-stable-node	142	29
✅ astro-stable-quickjs	142	29
✅ express-stable-node	142	29
✅ express-stable-quickjs	142	29
✅ fastify-stable-node	142	29
✅ fastify-stable-quickjs	142	29
✅ hono-stable-node	142	29
✅ hono-stable-quickjs	142	29
✅ nest-stable-node	142	29
✅ nest-stable-quickjs	142	29
✅ nextjs-turbopack-canary-node	170	1
✅ nextjs-turbopack-canary-quickjs	170	1
✅ nextjs-turbopack-stable-node	170	1
✅ nextjs-turbopack-stable-quickjs	170	1
✅ nextjs-webpack-canary-quickjs	170	1
✅ nextjs-webpack-stable-node	170	1
✅ nextjs-webpack-stable-quickjs	170	1
✅ nitro-stable-node	142	29
✅ nitro-stable-quickjs	142	29
✅ nuxt-stable-node	142	29
✅ nuxt-stable-quickjs	142	29
✅ sveltekit-stable-node	161	10
✅ sveltekit-stable-quickjs	161	10
✅ tanstack-start-node	142	29
✅ tanstack-start-quickjs	142	29
✅ vite-stable-node	142	29
✅ vite-stable-quickjs	142	29

✅ 📦 Local Production

App	Passed	Skipped
✅ astro-stable-node	142	29
✅ astro-stable-quickjs	142	29
✅ express-stable-node	142	29
✅ express-stable-quickjs	142	29
✅ fastify-stable-node	142	29
✅ fastify-stable-quickjs	142	29
✅ hono-stable-node	142	29
✅ hono-stable-quickjs	142	29
✅ nest-stable-node	142	29
✅ nest-stable-quickjs	142	29
✅ nextjs-turbopack-canary-node	170	1
✅ nextjs-turbopack-canary-quickjs	170	1
✅ nextjs-turbopack-stable-node	170	1
✅ nextjs-turbopack-stable-quickjs	170	1
✅ nextjs-webpack-canary-node	170	1
✅ nextjs-webpack-canary-quickjs	170	1
✅ nextjs-webpack-stable-node	170	1
✅ nextjs-webpack-stable-quickjs	170	1
✅ nitro-stable-node	142	29
✅ nitro-stable-quickjs	142	29
✅ nuxt-stable-node	142	29
✅ nuxt-stable-quickjs	142	29
✅ sveltekit-stable-node	161	10
✅ sveltekit-stable-quickjs	161	10
✅ tanstack-start-node	142	29
✅ tanstack-start-quickjs	142	29
✅ vite-stable-node	142	29
✅ vite-stable-quickjs	142	29

✅ 🐘 Local Postgres

App	Passed	Skipped
✅ astro-stable-node	142	29
✅ astro-stable-quickjs	142	29
✅ express-stable-node	142	29
✅ express-stable-quickjs	142	29
✅ fastify-stable-node	142	29
✅ fastify-stable-quickjs	142	29
✅ hono-stable-node	142	29
✅ hono-stable-quickjs	142	29
✅ nest-stable-node	142	29
✅ nest-stable-quickjs	142	29
✅ nextjs-turbopack-canary-node	170	1
✅ nextjs-turbopack-canary-quickjs	170	1
✅ nextjs-turbopack-stable-node	170	1
✅ nextjs-turbopack-stable-quickjs	170	1
✅ nextjs-webpack-canary-node	170	1
✅ nextjs-webpack-canary-quickjs	170	1
✅ nextjs-webpack-stable-node	170	1
✅ nextjs-webpack-stable-quickjs	170	1
✅ nitro-stable-node	142	29
✅ nitro-stable-quickjs	142	29
✅ nuxt-stable-node	142	29
✅ nuxt-stable-quickjs	142	29
✅ sveltekit-stable-node	161	10
✅ sveltekit-stable-quickjs	161	10
✅ tanstack-start-node	142	29
✅ tanstack-start-quickjs	142	29
✅ vite-stable-node	142	29
✅ vite-stable-quickjs	142	29

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack-node	170	0	1
✅ nextjs-turbopack-quickjs	170	0	1

✅ vercel-http-transport

App	Passed	Skipped
✅ example	141	30
✅ express	141	30
✅ hono	141	30
✅ nextjs-turbopack	168	3
✅ nitro	141	30
✅ vite	141	30

✅ vercel-multi-region

App	Passed	Failed	Skipped
✅ nextjs-turbopack	27	0	0

✅ vercel-ws-transport

App	Passed	Skipped
✅ example	141	30
✅ express	141	30
✅ nextjs-turbopack	168	3
✅ vite	141	30

📋 View full workflow run

github-actions · 2026-09-24T18:31:10Z

📊 Workflow Benchmarks

commit 0d2ab2f · Thu, 24 Sep 2026 20:04:38 GMT · run logs

Backend: vercel · app: nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	273 (-84%) 💚	2236 🔴 (+14%)	2300 🔴 (+15%) 🔻	2741 🔴 (+21%) 🔻	30
TTFS	stream	159 (-28%) 💚	2140 🔴 (+12%)	2198 🔴 (+13%)	2209 🔴 (+7.4%)	30
TTFS	hook + stream	2036 (+193%) 🔻	2472 🔴 (+9.3%)	2542 🔴 (+11%)	2862 🔴 (+17%) 🔻	30
Fan-out TTFS	Promise.all(100 steps)	498 (+16%) 🔻	653 (+2.5%)	681 (-68%) 💚	2632 (+20%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	1947 (+52%) 🔻	3361 (+4.1%)	5183 (-5.0%)	10142 (+7.3%)	10
STSO	1020 steps (inline)	133 (+3.1%)	152 (+2.7%)	167 (+0.6%)	222 (±0%)	1019
WO	1020 steps	153396 (+2.7%)	153396 (+2.7%)	153396 (+2.7%)	153396 (+2.7%)	1
CRTT	first chunk (pooled)	61 (±0%)	97 (-6.7%)	105 (-25%) 💚	132 (-10%)	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	83.5 (-10%)	130 (-3%)	178 (-29%)	456 (-25%)	104 (-14%)	10
size sweep (100/s, 160B-12KB)	80 (-13%)	140 (-24%)	272 (-32%)	601 (-22%)	159 (-16%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	103 (-20%)	119 (-18%)	144 (-34%)	277 (-49%)	239 (-36%)	3
replay eve-gpt-5.6-sol-2000t (1x)	97.5 (+16%)	127 (-30%)	155 (-43%)	484 (-23%)	436 (+14%)	2
replay eve-gpt-5.6-sol-2000t (2x)	79 (-13%)	154 (-13%)	199 (-18%)	747 (+29%)	295 (-4%)	3

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

1020 steps (inline)

Cumulative STSO time: main 149218ms → this run 153183ms (Δ +3965ms, +3%)

100-150 ms  █████████████████████┃██  main 778  this 702   -76
150-200 ms  ███████░┃                 main 215  this 302   +87
200-250 ms  ┃                         main  19  this  13    -6
250-300 ms  ┃                         main   4  this   1    -3
300-350 ms  ┃                         main   3  this   1    -2

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

variant  RTT 1ms→5s+             avg        p50         p90         p99     n
control  ······▆█▁····   113.8 (-7%)  106 (±0%)  178 (-29%)  456 (-25%)  3000
sweep    ······▆█▁▁···  124.3 (-15%)  111 (-3%)  272 (-32%)  601 (-22%)  3000
gw 1x    ·····▁▇█▁····  107.4 (-16%)  103 (-9%)  144 (-34%)  277 (-49%)  5295
eve 1x   ·····▁██▁▁···  108.8 (-24%)  96 (-16%)  155 (-43%)  484 (-23%)  5186
eve 2x   ·····▁▄█▁▁···   134.2 (-3%)  123 (+4%)  199 (-18%)  747 (+29%)  7779

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

control  ▄▇█▇▁▁▇▁▅▄  105–122ms
sweep    ▃▇█▃▁▃▁▂▂▂  107–163ms
gw 1x    ▆▃▃▃▆▄▃▂█▁  97–122ms
eve 1x   ▂▄▂▂▇▂▅▆█▁  96–127ms
eve 2x   ▁█▂▂▂▂▄█▄▃  112–177ms

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

sweep  █▇▄▃▁▁▄  122–128ms

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

control  ▁▂█▃▁▂▅▃▆▃  31–38ms
sweep    ▃█▆▅▄▂▁▅█▂  44–57ms
gw 1x    █▄▃▁▇▇▅▃▅▂  29–36ms
eve 1x   ▂▃▁▂▆▄▆▅█▄  19–28ms
eve 2x   ▄█▁▃▆▄▅▃▅█  18–27ms

📜 Previous results (1)

`c832ffd`

Thu, 24 Sep 2026 18:48:42 GMT · run logs

vercel / nextjs-turbopack

Metric	Scenario	Best (ms)	P75 (ms)	P90 (ms)	P99 (ms)	Samples
TTFS	step	2137 (+193%) 🔻	2693 🔴 (+147%) 🔻	2708 🔴 (+143%) 🔻	2774 🔴 (+130%) 🔻	30
TTFS	stream	380 (+73%) 🔻	2626 🔴 (+150%) 🔻	2683 🔴 (+145%) 🔻	2823 🔴 (+98%) 🔻	30
TTFS	hook + stream	736 (-16%) 💚	3069 🔴 (+131%) 🔻	3118 🔴 (+122%) 🔻	3284 🔴 (+110%) 🔻	30
Fan-out TTFS	Promise.all(100 steps)	468 (-46%) 💚	581 (-66%) 💚	877 (-51%) 💚	3191 (+70%) 🔻	10
Fan-out TTLS	Promise.all(100 steps)	1822 (-21%) 💚	3570 (-1.7%)	5791 (+53%) 🔻	10548 (+46%) 🔻	10
STSO	1020 steps (inline)	99 (-1.0%)	132 (+1.5%)	144 (-6.5%)	183 (-9.9%)	1019
WO	1020 steps	130731 (-0.8%)	130731 (-0.8%)	130731 (-0.8%)	130731 (-0.8%)	1
CRTT	first chunk (pooled)	63 (-13%)	100 (-30%) 💚	128 (-40%) 💚	162 (-54%) 💚	28

Streams

Scenario	CRTT 1st	p75	p90	p99	CDV max	iters
paced control (100/s, 60B)	87.5 (-11%)	122 (-36%)	141 (-53%)	304 (-38%)	82 (-63%)	10
size sweep (100/s, 160B-12KB)	87.5 (-15%)	122 (-46%)	147 (-58%)	239 (-62%)	94.5 (-55%)	10
replay gateway-gpt-5.4-nano-2000t (1x)	100 (-27%)	119 (-37%)	137 (-57%)	247 (-57%)	214 (-51%)	3
replay eve-gpt-5.6-sol-2000t (1x)	90 (-14%)	122 (-38%)	149 (-51%)	257 (-53%)	169 (-63%)	2
replay eve-gpt-5.6-sol-2000t (2x)	78 (-45%)	137 (-58%)	161 (-67%)	279 (-70%)	272 (-42%)	3

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 · 2026-09-24T18:32:40Z

Sim World

Simulated world deterministic testing for races. Traces

🟠 world-sim scenario book — 1 fail of 42 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
✅ `step-vs-timer-early-settlement`	completed	8	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 · 2026-09-24T18:34:22Z

Framework	Flow route	Step reg.	Framework output
hono	252.0 KiB (±0)	94.9 KiB (±0)	1.91 MiB (±0)
nextjs-turbopack	259.3 KiB (±0)	426 B (±0)	907.5 KiB (±0)

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.

0d2ab2f · run

Vite calls hotUpdate once per environment (client, ssr, and any a framework adds, such as Nitro's) for each file change. The plugin rebuilt every workflow on each call, so a single edit cost two to three full rebuilds, run back to back before Vite sent any HMR update. Remember each change by (timestamp, file), which Vite shares across a change's environment calls, and skip the repeats. Signed-off-by: Alex Langenfeld <alex.langenfeld@vercel.com>

) Vite calls hotUpdate once per environment (client, ssr, and any a framework adds, such as Nitro's) for each file change. The plugin rebuilt every workflow on each call, so a single edit cost two to three full rebuilds, run back to back before Vite sent any HMR update. Remember each change by (timestamp, file), which Vite shares across a change's environment calls, and skip the repeats. Signed-off-by: Alex Langenfeld <alex.langenfeld@vercel.com>

github-actions · 2026-09-24T20:36:18Z

Backport PR opened against stable: #4385. Merge conflicts were resolved by AI — please review carefully. (backport job run)

… environment (#4385) Vite calls hotUpdate once per environment (client, ssr, and any a framework adds, such as Nitro's) for each file change. The plugin rebuilt every workflow on each call, so a single edit cost two to three full rebuilds, run back to back before Vite sent any HMR update. Signed-off-by: Alex Langenfeld <alex.langenfeld@vercel.com> Co-authored-by: Alex Langenfeld <alex.langenfeld@vercel.com> Co-authored-by: Peter Wielander <mittgfu@gmail.com> Co-authored-by: Peter Wielander <peter.wielander@vercel.com>

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alangenfeld force-pushed the alangenfeld/vite-dev-rebuild-storm branch from c832ffd to 0d2ab2f Compare September 24, 2026 19:45

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alangenfeld merged commit 38b5709 into main Sep 24, 2026
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alangenfeld deleted the alangenfeld/vite-dev-rebuild-storm branch September 24, 2026 20:34

github-actions Bot mentioned this pull request Sep 24, 2026

Version Packages (beta) #4345

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Version Packages #4540

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fix(vite): rebuild workflows once per change, not per environment - #4370

fix(vite): rebuild workflows once per change, not per environment#4370
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Summary & Motivation

Test Plan

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🧪 E2E Test Results

❌ Failed E2E Tests

⚠️ Flaky E2E Tests (passed on retry)

🛠 Infra Events (absorbed by the harness)

E2E Test Summary

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📊 Workflow Benchmarks

c832ffd

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Sim World

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