Backport #2059: feat(core): support passing parent WritableStream to child workflow via start()#2070
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Backport #2059: feat(core): support passing parent WritableStream to child workflow via start()#2070github-actions[bot] wants to merge 2 commits into
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…ia start() (#2059) * test(e2e): cover WritableStream passed as start() argument Adds an e2e workflow + test where a parent workflow gets a WritableStream via getWritable(), forwards it through start() to a child workflow, and the child step writes raw bytes to it. Asserts the external reader on the parent's stream observes the exact bytes the child wrote. * fix(core): avoid double-framing when WritableStream is forwarded via start() When a workflow's getWritable() handle is passed across start() to a child workflow, the parent step's reviver wraps it in a serialize transform that pipes into a workflow server stream. Until now, getExternalReducers.WritableStream then installed a second serialize transform on top of that — so every chunk the child step wrote got devalue-framed twice but only deframed once on the reader side, and external consumers saw the inner frame instead of the original bytes. Fix: tag every user-visible writable that's already backed by a workflow server stream with its (runId, name). When the external reducer recognizes those tags during dehydration, it bridges bytes straight from the new child-side server stream to the original server stream instead of piping through the user's writable. That leaves the producer-side serialize transform (installed once by the child's step reviver) as the only framing layer in the chain. * fix(core): forward (runId, name) when a tagged WritableStream crosses start() Replaces the previous in-process bridge with first-class writable forwarding at the descriptor level. When a parent workflow's getWritable() handle is passed as an argument to a child workflow, the dehydrated descriptor now carries the original (runId, name). The child run's step-side reviver opens the writable against the parent's server stream directly and resolves the parent run's encryption key (encrypt-only) via getEncryptionKeyForRun. This removes the architectural limitation that the bridge could only stay alive for the duration of the parent step process — on Vercel that capped forwarding at ~15 minutes regardless of the child run's lifetime, dropping any writes the child made after the parent step process exited. importKey() now accepts a usages parameter, defaulting to ['encrypt', 'decrypt']. The cross-run forwarding path imports with ['encrypt'] only so a compromised child run cannot decrypt any existing data on the parent's stream — only contribute new writes. * test: rename writable-forwarded workflows and cover step-context getWritable() Addresses PR review: - Rename writableForwardedToChildChildWorkflow → writableForwardedChildWorkflow (drops the duplicated 'Child' segment). - Split writableForwardedToChildWorkflow into two variants covered by a test.each: writableForwardedFromWorkflowWorkflow (workflow-context getWritable, the original test) and writableForwardedFromStepWorkflow (step-context getWritable passed directly into start() from the same step that called getWritable()). - Terser changeset description. Signed-off-by: Nathan Rajlich <n@n8.io>
🦋 Changeset detectedLatest commit: 75cdb77 The changes in this PR will be included in the next version bump. This PR includes changesets to release 17 packages
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🧪 E2E Test Results❌ Some tests failed Summary
❌ Failed Tests▲ Vercel Production (2 failed)astro (1 failed):
example (1 failed):
🌍 Community Worlds (71 failed)mongodb-dev (1 failed):
redis-dev (1 failed):
turso-dev (1 failed):
turso (68 failed):
Details by Category❌ ▲ Vercel Production
✅ 💻 Local Development
✅ 📦 Local Production
✅ 🐘 Local Postgres
✅ 🪟 Windows
❌ 🌍 Community Worlds
✅ 📋 Other
❌ Some E2E test jobs failed:
Check the workflow run for details. |
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Automated backport of #2059 to
stable(backport job run).AI recommendation: This commit fixes two real bugs in existing functionality that exists on
stable— forwarding a parent'sWritableStream(fromgetWritable()) to a child workflow viastart(). Onstablethis pattern silently drops child writes after the parent step process exits (notably on Vercel after ~15 minutes) and double-frames every chunk so external consumers see the inner devalue frame instead of raw bytes. The affected files (encryption.ts,serialization.ts,step/writable-stream.ts,symbols.ts,99_e2e.ts) all exist onstable, and the change is self-contained without dependencies onmain-only APIs.Merge conflicts were resolved by AI (opencode with
anthropic/claude-opus-4.7). Please review the conflict resolution carefully before merging.