Fix dangling stream readers, serialization bugs, and refactor abort reducer code

[karthikscale3]

Description

Follow-up to #1301 (AbortController/AbortSignal serialization).

What changed

Bug fixes:

• Dangling stream reader hang — reviveAbortController starts a stream reader that blocks indefinitely if no abort arrives, causing serverless function timeouts. Introduced an internal ABORT_READER_CANCEL controller that the step handler cancels after the step function returns, racing against the reader to prevent hangs.
• Request.signal serialization — The Request reducer now only serializes signals tagged with ABORT_STREAM_NAME, preventing plain native signals (e.g. from fetch timeouts) from creating unnecessary stream infrastructure.
• Missing is_system migration — Added the 0010_add_is_system.sql Drizzle migration and plumbed isSystem through suspension-handler, world-postgres, and world-local so system hooks are correctly persisted.
• WorkflowAPIError reference in suspension-handler — Replaced non-existent WorkflowAPIError.is(err) with EntityConflictError.is(err) || RunExpiredError.is(err), matching the pattern used everywhere else in the file (renamed in refactor: replace HTTP status code checks with semantic error types #1342).
• DurableAgent timeout in workflow VM — Adding AbortController to the workflow VM caused DurableAgent.stream() to enter its setTimeout-based timeout path, which the VM traps. Added typeof setTimeout === 'function' guard so the timeout is only set in contexts where timers are available.

Refactors:

• Deduplicated ~180 lines of reducer code — Extracted reduceAbortWithListener() and reduceAbortBySymbol() helpers, replacing 3x near-identical AbortController/AbortSignal reducer implementations across external, workflow, and step contexts.
• Replaced fragile string manipulation — Added getAbortStreamIdFromToken() to derive stream names from hook tokens with proper prefix validation, replacing manual replace('abrt_', '') + string concat in suspension-handler.
• Added onabort setter on WorkflowAbortSignal — Matches the native AbortSignal API contract.
• Signal-only revival path — Added reviveAbortSignal() that skips the abort() patching overhead. Stored ABORT_READER_CANCEL on signals too, fixing a latent bug where cancelAbortReaders couldn't clean up standalone signal readers.

Tests:

• Added test for abort stream reader propagation with targeted mock override.
• Added test for plain (non-workflow) Request.signal stripping.
• Updated step-handler.test.ts mock to include cancelAbortReaders.

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Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, Comment	Apr 7, 2026 9:55pm
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🧪 E2E Test Results

❌ Some tests failed

Summary

	Passed	Failed	Skipped	Total
✅ ▲ Vercel Production	1022	0	111	1133
✅ 💻 Local Development	1010	0	226	1236
✅ 📦 Local Production	1010	0	226	1236
✅ 🐘 Local Postgres	1010	0	226	1236
✅ 🪟 Windows	91	0	12	103
❌ 🌍 Community Worlds	16	73	12	101
✅ 📋 Other	255	0	54	309
Total	4414	73	867	5354

❌ Failed Tests

🌍 Community Worlds (73 failed)

mongodb-dev (1 failed):

• dev e2e should rebuild on imported step dependency change

redis-dev (1 failed):

• dev e2e should rebuild on imported step dependency change

turso-dev (1 failed):

• dev e2e should rebuild on imported step dependency change

turso (70 failed):

• addTenWorkflow | wrun_01KNN14X8HYW55Q7JNMGSS3XAG
• addTenWorkflow | wrun_01KNN14X8HYW55Q7JNMGSS3XAG
• wellKnownAgentWorkflow (.well-known/agent) | wrun_01KNMZ3021RED3M5F64YHYAAYD
• should work with react rendering in step
• promiseAllWorkflow | wrun_01KNN158EY06F76QG200P0BVK0
• promiseRaceWorkflow | wrun_01KNN15CR7MABGMH1NRW96P52V
• promiseAnyWorkflow | wrun_01KNN15H0A3EHBQCJ0SC37G5V1
• importedStepOnlyWorkflow | wrun_01KNMZ3CF3AC9148VDX0C2QWKB
• hookWorkflow | wrun_01KNN15WPDVW8DXBG5ZD2R9T9E
• hookWorkflow is not resumable via public webhook endpoint | wrun_01KNN1688G6ZDP2WM963WBW3CN
• webhookWorkflow | wrun_01KNN16GX3T390Q1SCV0ZH84CK
• sleepingWorkflow | wrun_01KNN16QYDF2EK7H718J5MG2QN
• parallelSleepWorkflow | wrun_01KNN1746V5HZY9SDMWKD29653
• nullByteWorkflow | wrun_01KNN17819WFQQNNND2JYH232Y
• workflowAndStepMetadataWorkflow | wrun_01KNN17A1MDYW25516KW8XD0JS
• fetchWorkflow | wrun_01KNN1A4C618A3C95BQBQT6EXJ
• promiseRaceStressTestWorkflow | wrun_01KNN1A7MH7STJYAGFN1SSRQTE
• error handling error propagation workflow errors nested function calls preserve message and stack trace
• error handling error propagation workflow errors cross-file imports preserve message and stack trace
• error handling error propagation step errors basic step error preserves message and stack trace
• error handling error propagation step errors cross-file step error preserves message and function names in stack
• 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 not registered WorkflowNotRegisteredError fails the run when workflow does not exist
• 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_01KNN1DP70CB5RBCXFZQW9CZ6Z
• concurrent hook token conflict - two workflows cannot use the same hook token simultaneously | wrun_01KNN1EAMD40GR6M88TCB8YXA4
• hookDisposeTestWorkflow - hook token reuse after explicit disposal while workflow still running | wrun_01KNN1EZW5WJ8ZAZ4852WF258C
• stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars) | wrun_01KNN1FK8ECY387NNCHRY1760B
• stepFunctionWithClosureWorkflow - step function with closure variables passed as argument | wrun_01KNN1FW3RC2AN8PRR4RWPMNE2
• closureVariableWorkflow - nested step functions with closure variables | wrun_01KNN1G1DFXN8Y27KEVZPJ2VQC
• spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step | wrun_01KNN1G3EDC6NWA6RCH97E5Q3H
• health check (queue-based) - workflow and step endpoints respond to health check messages
• pathsAliasWorkflow - TypeScript path aliases resolve correctly | wrun_01KNN1GHD9K9A9D4QR22H6PABB
• Calculator.calculate - static workflow method using static step methods from another class | wrun_01KNN1GPSV1FJ62GF2YX3D4T8S
• AllInOneService.processNumber - static workflow method using sibling static step methods | wrun_01KNN1GXA5E4A15ZDSKM84BK9R
• ChainableService.processWithThis - static step methods using this to reference the class | wrun_01KNN1H4TQ7JSH0KCDVGNY0FRV
• thisSerializationWorkflow - step function invoked with .call() and .apply() | wrun_01KNN1HB9S55KD2076044CF891
• customSerializationWorkflow - custom class serialization with WORKFLOW_SERIALIZE/WORKFLOW_DESERIALIZE | wrun_01KNN1HHJ3HQRSSNS98A8P8680
• instanceMethodStepWorkflow - instance methods with "use step" directive | wrun_01KNN1HQYG2NDA9EPAXDW9YRC6
• crossContextSerdeWorkflow - classes defined in step code are deserializable in workflow context | wrun_01KNN1J5G99NPTFX5BSXMB57KD
• stepFunctionAsStartArgWorkflow - step function reference passed as start() argument | wrun_01KNN1JE33S87EK0G831R2GD62
• cancelRun - cancelling a running workflow | wrun_01KNN1JP5HH29G3W14XMDAXDRB
• cancelRun via CLI - cancelling a running workflow | wrun_01KNN1JZDTY0QBW9G426YGDPB9
• pages router addTenWorkflow via pages router
• pages router promiseAllWorkflow via pages router
• pages router sleepingWorkflow via pages router
• hookWithSleepWorkflow - hook payloads delivered correctly with concurrent sleep | wrun_01KNN1KBA52SDFSP6DRJTW7EBF
• sleepInLoopWorkflow - sleep inside loop with steps actually delays each iteration | wrun_01KNN1M05YH7ZZZBBZ26TXMYF5
• sleepWithSequentialStepsWorkflow - sequential steps work with concurrent sleep (control) | wrun_01KNN1MANHE1VFN2J9KTGK9E9J
• AbortController abortTimeoutWorkflow: timeout cancels long-running step
• AbortController abortParallelWorkflow: abort cancels all parallel steps
• AbortController abortFromStepWorkflow: step calls abort(), workflow sees aborted state
• AbortController abortAlreadyAbortedWorkflow: pre-aborted signal seen by step
• AbortController abortReasonWorkflow: abort reason preserved across boundaries
• AbortController abortAfterCompletionWorkflow: abort after step completes is a no-op
• AbortController abortViaHookWorkflow: external hook triggers abort on in-flight step
• AbortController abortExternalSignalWorkflow: signal passed as workflow input
• AbortController abortSurvivesReplayWorkflow: controller state consistent across replay
• AbortController abortThrowIfAbortedWorkflow: throwIfAborted causes FatalError, no retries
• AbortController abortReasonTypesWorkflow: various abort reason types propagate correctly
• AbortController abortFetchUncaughtWorkflow: uncaught fetch AbortError is FatalError, no retries
• AbortController abortDeterministicBranchWorkflow: if-check takes same path on first-run and replay
• importMetaUrlWorkflow - import.meta.url is available in step bundles | wrun_01KNN1PEGDZFA72CDGQJ4W6G9K
• metadataFromHelperWorkflow - getWorkflowMetadata/getStepMetadata work from module-level helper (#1577) | wrun_01KNN1PHMVD8XADQ36275ZTER7
• resilient start: addTenWorkflow completes when run_created returns 500 | wrun_01KNN1PMHQNJEP1TZZBM6V7765

Details by Category

✅ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro	92	0	11
✅ example	92	0	11
✅ express	92	0	11
✅ fastify	92	0	11
✅ hono	92	0	11
✅ nextjs-turbopack	97	0	6
✅ nextjs-webpack	97	0	6
✅ nitro	92	0	11
✅ nuxt	92	0	11
✅ sveltekit	92	0	11
✅ vite	92	0	11

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable	85	0	18
✅ express-stable	85	0	18
✅ fastify-stable	85	0	18
✅ hono-stable	85	0	18
✅ nextjs-turbopack-canary	74	0	29
✅ nextjs-turbopack-stable	91	0	12
✅ nextjs-webpack-canary	74	0	29
✅ nextjs-webpack-stable	91	0	12
✅ nitro-stable	85	0	18
✅ nuxt-stable	85	0	18
✅ sveltekit-stable	85	0	18
✅ vite-stable	85	0	18

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable	85	0	18
✅ express-stable	85	0	18
✅ fastify-stable	85	0	18
✅ hono-stable	85	0	18
✅ nextjs-turbopack-canary	74	0	29
✅ nextjs-turbopack-stable	91	0	12
✅ nextjs-webpack-canary	74	0	29
✅ nextjs-webpack-stable	91	0	12
✅ nitro-stable	85	0	18
✅ nuxt-stable	85	0	18
✅ sveltekit-stable	85	0	18
✅ vite-stable	85	0	18

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable	85	0	18
✅ express-stable	85	0	18
✅ fastify-stable	85	0	18
✅ hono-stable	85	0	18
✅ nextjs-turbopack-canary	74	0	29
✅ nextjs-turbopack-stable	91	0	12
✅ nextjs-webpack-canary	74	0	29
✅ nextjs-webpack-stable	91	0	12
✅ nitro-stable	85	0	18
✅ nuxt-stable	85	0	18
✅ sveltekit-stable	85	0	18
✅ vite-stable	85	0	18

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack	91	0	12

❌ 🌍 Community Worlds

App	Passed	Failed	Skipped
❌ mongodb-dev	4	1	0
❌ redis-dev	4	1	0
❌ turso-dev	4	1	0
❌ turso	4	70	12

✅ 📋 Other

App	Passed	Failed	Skipped
✅ e2e-local-dev-nest-stable	85	0	18
✅ e2e-local-postgres-nest-stable	85	0	18
✅ e2e-local-prod-nest-stable	85	0	18

---

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