HMR in Module Federation

[foxaltus]

In the module-federation example in the repo, HMR does not seem to work when modifying the remote. Is it a limitation or a bug?

Steps:

1. Run examples/module-federation/host (pnpm dev)
2. Run examples/modfule-federation/remote (pnpm dev)
3. Open the host at http://localhost:3000/
4. Modify Button.js at examples/module-federation/remote
5. Save

=> The button is not updated on the page

[chenjiahan]

Hi, you can refer to this issue: module-federation/core#2459

[foxaltus]

Im sorry but I need to challenge this a bit @chenjiahan. I see that the module-federation-interop for rspack has HMR working for Module Federation < 2 along with webpack, which is great for anyone looking to gradually migrate their MFEs.

What's stopping rsbuild to do the same? If nothing, please explain to modify the config in the rsbuild example. Else, why?

[chenjiahan]

I will resolve it

[chenjiahan]

Should be fixed by #2853 and #2852

[chenjiahan]

Hi, I just released https://github.com/web-infra-dev/rsbuild/releases/tag/v1.0.0-alpha.7 to fix the Module Federation HMR.

Now Rsbuild will set dev.client.port and tools.rspack.output.uniqueName to ensure HMR can work with remote modules.

[foxaltus]

Thank you for your support, HMR now works perfectly in the module-federation example 👍
I want to make more tests to check interop with webpack Module Federation, and will let you know if any issues.

[chenjiahan]

Thanks for the feedback ❤️

[foxaltus]

Hey @chenjiahan I confirm that HMR also works when the host is Rsbuild and the remote is webpack, and vice and versa. Now looks like we can have a gradual upgrade path to Rsbuild. Great work!

[sanjaykumar66]

HMR isn’t working in my setup. The host app uses the rolldown-vite bundler and loads remote apps through the @module-federation/runtime plugin. The remote app is built using Rsbuild, but HMR isn’t reflecting updates.

I can see the hot-update.js request in the network tab, but the latest code changes aren’t being applied or rendered in the UI.

I tried webpack bundler for remoteApp, in that case, HMR is working fine.