[Bug]: `import.meta.webpackHot.accept` not called when `class` changes

[dartess]

Version

System:
    OS: macOS 15.3.1
    CPU: (10) arm64 Apple M1 Pro
    Memory: 3.04 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Browsers:
    Brave Browser: 134.1.76.73
    Chrome: 134.0.6998.44
    Chrome Canary: 136.0.7054.0
    Edge: 111.0.1661.54
    Safari: 18.3
    Safari Technology Preview: 18.4
  npmPackages:
    @rsbuild/core: ^1.2.15 => 1.2.15 
    @rsbuild/plugin-react: ^1.1.1 => 1.1.1

Details

I want to listen for changes in a file using "import.meta.webpackHot.accept" and react to the changes.

However, when changing in the class code, nothing happens, as if the file does not change.

note "a": there is a workaround to make the system react to changes. for this it is enough to export an empty function next to the class. now I have to place such a hack in each file with a class.

note "b": I tried to reproduce the problem with rspack and it doesn't seem to reproduce the problem.

Reproduce link

https://github.com/dartess/rsbuild-class-hmr

Reproduce Steps

1. npm i
2. npm run dev:rsbuild
3. open http://localhost:3000/
4. change value in src/Features.ts
   expected result: console.log: changed!
   actual result: nothing.

for note "a": uncomment // export function hmrHack() {} and try again — everything works fine with this workaround.

[GRAMMAC1]

It seems that Rsbuild cannot detect file changes when only exporting one class. Adding an additional export can temporarily solve this problem.

For example

export const VERSION = 1;
export class Features {
  public value = "123";
  public version = VERSION;
}

It works 😁

[GRAMMAC1]

disable fastRefresh of Rsbuild React Plugin then HMR works fine.

[GRAMMAC1]

In test case disable fast refresh HMR still works, the file is in

https://github.com/web-infra-dev/rsbuild/blob/main/e2e/cases/react/disable-fast-refresh/rsbuild.config.ts

so its just a normal behavior rather than a bug in this case? @chenjiahan

[chenjiahan]

@GRAMMAC1 Fast Refresh is designed for React component HMR. If Fast Refresh is disabled, HMR will still work, but will not be able to preserve the state of the React component.

For this issue, I think it should work whether React Refresh is enabled or disabled..