fix(miniflare): Fix Durable Object RPC calls from Node.js blocking the event loop by NuroDev · Pull Request #11663 · cloudflare/workers-sdk

NuroDev · 2025-12-16T12:53:05Z

This fixes Durable Object RPC calls from Node.js blocking the event loop, preventing Promise.race() and timeouts from working correctly.

Tests
- Tests included/updated
- Tests not necessary because:
Public documentation
- Cloudflare docs PR(s):
- Documentation not necessary because: It is already documented that RPC stubs should always be async.
Wrangler V3 Backport
- Wrangler PR: V3 backport #11663 - Fix Durable Object RPC calls from Node.js blocking the event loop #11664
- Not necessary because:

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changeset-bot · 2025-12-16T12:53:10Z

🦋 Changeset detected

Latest commit: ab328ee

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

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claude · 2025-12-16T12:53:29Z

Claude finished @NuroDev's task in 36s —— View job

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Read changeset guidelines from .changeset/README.md
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✅ Changeset looks good!

Validation Details

Version Type: ✅ patch for miniflare

Correctly identified as a patch (bug fix)
No major version bump for wrangler (forbidden rule not violated)

Changelog Quality: ✅ Good

Clear title describing the symptom: "Fix Durable Object RPC calls from Node.js blocking the event loop"
Well-written body that:
- Describes the problem (blocking event loop, preventing Promise.race() and timeouts)
- Explains the previous behavior
- Explains what the fix does
Appropriate level of detail for a bug fix

Markdown Headers: ✅ None used

No h1/h2/h3 headers that would break changelog formatting

Package Coverage: ✅ Correct

Only miniflare is affected, which is correctly specified

The changeset follows all guidelines and provides sufficient context for users to understand the bug fix.

pkg-pr-new · 2025-12-16T12:57:09Z

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@11663

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@11663

miniflare

npm i https://pkg.pr.new/miniflare@11663

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@11663

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@11663

@cloudflare/vite-plugin

npm i https://pkg.pr.new/@cloudflare/vite-plugin@11663

@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@11663

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@11663

@cloudflare/workers-utils

npm i https://pkg.pr.new/@cloudflare/workers-utils@11663

wrangler

npm i https://pkg.pr.new/wrangler@11663

commit: ab328ee

packages/miniflare/test/plugins/do/index.spec.ts

petebacondarwin

Don't merge this unless someone else also approves, as this is a hairy bit of the code base - but LGTM!

packages/miniflare/test/plugins/do/index.spec.ts

Co-authored-by: Pete Bacon Darwin <pete@bacondarwin.com>

ascorbic

For the same reason as Pete I won't give this a final approval as I don't know that part of the codebase at all, but the code itself looks good.

packages/miniflare/src/workers/core/constants.ts

packages/miniflare/src/workers/core/proxy.worker.ts

packages/miniflare/test/plugins/do/index.spec.ts

Co-authored-by: Dario Piotrowicz <dario@cloudflare.com>

dario-piotrowicz

Lol I've reviewed the changes but I'm in the same boat as Pete and Matt 😅

If this works locally anyways and passes all the tests I think it'd be safe to merge 🙂

…ng the event loop (#11664) * Add Miniflare logic to mark DO stubs as async * Added tests to check for blocking DO stubs * Added changeset * Updated backport tests * Updated changeset description

NuroDev added 3 commits December 16, 2025 12:45

Add Miniflare logic to mark DO stubs as async

f9f56bf

Added tests to check for blocking DO stubs

48449cc

Added changeset

166b1e5

NuroDev self-assigned this Dec 16, 2025

NuroDev added the miniflare Relating to Miniflare label Dec 16, 2025

workers-devprod added this to workers-sdk Dec 16, 2025

github-project-automation bot moved this to Untriaged in workers-sdk Dec 16, 2025

NuroDev mentioned this pull request Dec 16, 2025

V3 backport #11663 - Fix Durable Object RPC calls from Node.js blocking the event loop #11664

Merged

petebacondarwin reviewed Dec 16, 2025

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packages/miniflare/test/plugins/do/index.spec.ts Outdated Show resolved Hide resolved

petebacondarwin reviewed Dec 16, 2025

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packages/miniflare/test/plugins/do/index.spec.ts Outdated Show resolved Hide resolved

packages/miniflare/test/plugins/do/index.spec.ts Outdated Show resolved Hide resolved

NuroDev and others added 8 commits December 16, 2025 14:02

Minor blockedOn RPC method refactoring

35096f7

Co-authored-by: Pete Bacon Darwin <pete@bacondarwin.com>

Merge branch 'main' into fix/miniflare-do-stub-blocking

b64bb23

Improved DO "complete when unblocked" RPC tests timeouts

feb8d7f

Fixed DO RPC calls timeout test

ec9abfa

Minor DO RPC calls timeout test tweaks

1028a64

Updated release method to be synchronous

3e8aa52

Updated changset description

05b8cb4

Merge branch 'main' into fix/miniflare-do-stub-blocking

ed0d2e1

NuroDev marked this pull request as ready for review December 16, 2025 19:41

NuroDev requested a review from a team as a code owner December 16, 2025 19:41

NuroDev added 2 commits December 17, 2025 10:49

Merge branch 'main' into fix/miniflare-do-stub-blocking

ca091a3

Merge branch 'main' into fix/miniflare-do-stub-blocking

7957fa3

ascorbic reviewed Dec 17, 2025

View reviewed changes

dario-piotrowicz reviewed Dec 17, 2025

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packages/miniflare/src/workers/core/constants.ts Outdated Show resolved Hide resolved

packages/miniflare/src/workers/core/proxy.worker.ts Show resolved Hide resolved

packages/miniflare/test/plugins/do/index.spec.ts Show resolved Hide resolved

Shorten commit sha links

ab328ee

Co-authored-by: Dario Piotrowicz <dario@cloudflare.com>

dario-piotrowicz approved these changes Dec 17, 2025

View reviewed changes

github-project-automation bot moved this from Untriaged to Approved in workers-sdk Dec 17, 2025

NuroDev merged commit 737c0f4 into main Dec 17, 2025
52 of 54 checks passed

NuroDev deleted the fix/miniflare-do-stub-blocking branch December 17, 2025 13:20

github-project-automation bot moved this from Approved to Done in workers-sdk Dec 17, 2025

workers-devprod mentioned this pull request Dec 17, 2025

Version Packages #11666

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fix(miniflare): Fix Durable Object RPC calls from Node.js blocking the event loop#11663

fix(miniflare): Fix Durable Object RPC calls from Node.js blocking the event loop#11663
NuroDev merged 14 commits intomainfrom
fix/miniflare-do-stub-blocking

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