Enhance Web Worker federation runtime support

Summary

• ensure async entrypoints such as Web Workers receive dedicated runtime chunks with the required federation helpers
• harden remote runtime initialization so dynamically created runtimes do not crash when helpers are missing
• document the worker demo updates and sync related tests, samples, and release notes

Verification

• gh pr checks (2025-10-21)
• reporter confirmed the canary build from this branch resolves issue #4085 on 2025-10-20

Resolves #4085.

🦋 Changeset detected

Latest commit: 823e3016206500337f165a851d9760a7d4a2ef89

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

This PR includes changesets to release 41 packages

Name	Type
@module-federation/enhanced	Patch
@module-federation/modern-js-v3	Patch
@module-federation/modern-js	Patch
@module-federation/nextjs-mf	Patch
@module-federation/node	Patch
@module-federation/rsbuild-plugin	Patch
@module-federation/rspress-plugin	Patch
@module-federation/storybook-addon	Patch
shared-tree-shaking-no-server-host	Patch
shared-tree-shaking-no-server-provider	Patch
shared-tree-shaking-with-server-host	Patch
shared-tree-shaking-with-server-provider	Patch
remote5	Patch
remote6	Patch
website-new	Patch
@module-federation/runtime	Patch
@module-federation/rspack	Patch
@module-federation/webpack-bundler-runtime	Patch
@module-federation/sdk	Patch
@module-federation/runtime-tools	Patch
@module-federation/managers	Patch
@module-federation/manifest	Patch
@module-federation/dts-plugin	Patch
@module-federation/third-party-dts-extractor	Patch
@module-federation/devtools	Patch
@module-federation/bridge-react	Patch
@module-federation/bridge-vue3	Patch
@module-federation/bridge-shared	Patch
@module-federation/bridge-react-webpack-plugin	Patch
@module-federation/retry-plugin	Patch
@module-federation/data-prefetch	Patch
@module-federation/error-codes	Patch
@module-federation/inject-external-runtime-core-plugin	Patch
@module-federation/runtime-core	Patch
create-module-federation	Patch
@module-federation/cli	Patch
@module-federation/metro	Patch
@module-federation/metro-plugin-rnef	Patch
@module-federation/metro-plugin-rnc-cli	Patch
@module-federation/esbuild	Patch
@module-federation/utilities	Patch

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@codex harshly review the changes here. not completly happy with the solutions applied here. do lots of research and give review comments

Summary

• Added REVIEW.md capturing three blocking concerns: the async runtime detection still ignores manually shared runtimes, runtime naming becomes non-deterministic for anonymous workers, and the remote loader now silently no-ops without the bundler runtime. REVIEW.mdL5-L12
• Noted the remaining duplication TODO in the worker runtime test suite so it doesn’t get locked in as the expected behaviour. REVIEW.mdL14-L16

Testing

• ⚠️ not run (review-only change)

View task →

@codex harshly review pr

Summary

• Added REVIEW.md outlining three blocking regressions introduced by the worker runtime changes (manual shared runtimes still break, anonymous runtime naming is non-deterministic, and remote loading now silently no-ops without the bundler runtime) plus a reminder to address the duplicated worker test fixture. REVIEW.mdL1-L17

Testing

• ⚠️ not run (documentation-only change)

View task →

@ScriptedAlchemy this will fix any references to modules via new URL(..., import.meta.url) syntax?

I'm asked because we use custom Worker constructor :/

Any chance you can send a PR or branch and modify one of our apps in /apps to replicate your needs so I can run against that app within this monorepo

@ogonkov i updated the pr to include what i think is your use case. can you check

@codex include changesets for this

@codex review pr

Codex Review: Didn't find any major issues. Nice work!

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Summary

• Taught the federation runtime plugin to skip cloning async runtimes when an entrypoint already specifies a runtime name and to generate deterministic identifiers for anonymous worker chunks. packages/enhanced/src/lib/container/runtime/FederationRuntimePlugin.tsL398-L513
• Added compiler and unit regression tests that assert manual shared runtimes remain intact and that anonymous workers receive stable runtime names. packages/enhanced/test/compiler-unit/container/FederationRuntimePluginAsyncEntrypoint.test.tsL236-L344 packages/enhanced/test/unit/container/runtime/FederationRuntimePlugin.ensureAsyncEntrypoints.test.tsL119-L157
• Updated the worker runtime changeset description to capture the new safeguards for explicit runtimes and deterministic naming. .changeset/steady-workers-remotes.mdL1-L6

Testing

• ⚠️ NODE_OPTIONS=--experimental-vm-modules pnpm --filter @module-federation/enhanced exec jest packages/enhanced/test/unit/container/runtime/FederationRuntimePlugin.ensureAsyncEntrypoints.test.ts packages/enhanced/test/compiler-unit/container/FederationRuntimePluginAsyncEntrypoint.test.ts --runInBand (fails because isolated Jest execution cannot resolve @module-federation/sdk/normalize-webpack-path)

View task →

@ScriptedAlchemy i preparing new demo

@ScriptedAlchemy can you publish some test package from this branch? I will try it in out project

@codex review pr deeply

Codex Review: Didn't find any major issues. :+1:

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• Mark a draft as ready
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@ScriptedAlchemy we've tried test package in production for some time, it seems work well, do you have plans to finish this PR?

Hi @ScriptedAlchemy,

I'm reaching out to ask about the status and next steps for merging this PR. Our project relies on the Web Worker fixes in this PR, so we're eager to see it land in main.

From my read of the PR and comments: - It looks like it solves the core issue (#4085) and has been tested successfully in production (as mentioned by @ogonkov). - The REVIEW.md file lists a few blocking items (async runtime detection, runtime naming, remote loader behavior). - The Codex review didn't flag major issues.

Could you share: - What’s needed to resolve the remaining REVIEW.md items? - Is there a rough timeline or milestone for merging this? - Can we help with testing, documentation, or specific changes to move this forward?

It would be great to prioritize this, as it unblocks projects using federation with Web Workers. Let us know how we can help.

Thanks for your work on this!

This feature is important for us too. If there’s anything we can do to help move it forward (testing, reviews, changes), we’d be happy to assist.

Bundle Size Report

4 package(s) changed, 32 unchanged.

Package	Total dist	Delta	ESM gzip	Delta
webpack-bundler-runtime	76.5 kB	+2.5 kB (+3.3%)	5.9 kB	+49 B (+0.8%)
enhanced	1.29 MB	+937 B (+0.1%)	744 B	no change
managers	39.3 kB	+482 B (+1.2%)	3.4 kB	+28 B (+0.8%)
runtime	15.6 kB	+196 B (+1.2%)	769 B	+11 B (+1.5%)

Total dist: 4.96 MB (+4.0 kB (+0.1%)) Total ESM gzip: 154.7 kB (+88 B (+0.1%))