Changes to vite.config.js build --watch mode is not reflected as mentioned in the docs

[shirotech]

Describe the bug

https://vitejs.dev/guide/build.html#rebuild-on-files-changes

With the --watch flag enabled, changes to the vite.config.js, as well as any files to be bundled, will trigger a rebuild.

The above statement is not the case, currently it only works on serve mode and not build mode.

Reproduction

https://stackblitz.com/edit/vitejs-vite-xqrbrg?file=vite.config.js&terminal=dev

Steps to reproduce

Make any changes to let count in vite.config.js, it doesn't work, but running in serve mode via vite command works fine.

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 16.14.2 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    vite: ^4.1.1 => 4.1.1

### Used Package Manager

npm

### Logs

_No response_

### Validations

- [X] Follow our [Code of Conduct](https://github.com/vitejs/vite/blob/main/CODE_OF_CONDUCT.md)
- [X] Read the [Contributing Guidelines](https://github.com/vitejs/vite/blob/main/CONTRIBUTING.md).
- [X] Read the [docs](https://vitejs.dev/guide).
- [X] Check that there isn't [already an issue](https://github.com/vitejs/vite/issues) that reports the same bug to avoid creating a duplicate.
- [X] Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to [vuejs/core](https://github.com/vuejs/core) instead.
- [X] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/vitejs/vite/discussions) or join our [Discord Chat Server](https://chat.vitejs.dev/).
- [X] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.

[fi3ework]

build.watch could not watch the config file now since rollup cannot watch a file outside the module graph. The documentation is misleading. We could either make the watch work or correct the doc. I'd like to develop a PR to implement the watch these days.

[shirotech]

build.watch could not watch the config file now since rollup cannot watch a file outside the module graph. The documentation is misleading. We could either make the watch work or correct the doc. I'd like to develop a PR to implement the watch these days.

It seems include is kind of like a whitelist rather, I thought this.addWatchFile is for adding additional files?

[fi3ework]

I thought this.addWatchFile is for adding additional files?

It might work, but when the config file is changed, we need to start a new rollup watcher with the new rollup config which might be changed. So we need to restart the build function, not only to adding a watched file to rollup.

[bluwy]

Since fixing this is a bit hard without changing the function return signature, let's fix the documentation for now.

[DamChtlv]

So if i understand this correctly: vite build --watch doesn't detect newly appended files but vite dev does?
I can also reproduce and quite sad that this doesn't work :/

[naumanahmed19]

Just tested we still have this issue.

[neochief]

Yeah, still relevant. In build with --watch mode, changes to vite.config.ts/js are not respected. Including the file explicitly also doesn't help.