[Bug Report]: Externals exclusion only works on direct matches

[ScriptedAlchemy]

System Info

System:
OS: macOS 13.2.1
CPU: (20) x64 Apple M1 Ultra
Memory: 354.18 MB / 64.00 GB
Shell: 5.8.1 - /bin/zsh
Binaries:
Node: 14.21.2 - ~/.nvm/versions/node/v14.21.2/bin/node
Yarn: 1.22.19 - ~/.nvm/versions/node/v14.21.2/bin/yarn
npm: 6.14.17 - ~/.nvm/versions/node/v14.21.2/bin/npm
Browsers:
Brave Browser: 107.1.45.118
Chrome: 111.0.5563.64
Safari: 16.3
npmPackages:
@rspack/cli: ^0.1.1 => 0.1.1
@rspack/core: ^0.1.1 => 0.1.1

Details

I am using rspack to compile my lambda handlers / custom server that sits ontop of next.js

As such i want to exclude next.js from being bundled.

This works if i set externals to next: next and require('next')

however, rspack does not externalize something like this:
const NextServer = require("next/dist/server/next-server").default;

I can workaround the issue to some extent with:

const NextServer = __non_webpack_require__("next/dist/server/next-server").default;
const nextConfig = __non_webpack_require__("../../next.config");
const serverConfig = Object.assign({}, defaultConfig, nextConfig);

Reasoning:
Externals should allow regex matching expressions like /next/ or /next/$ as well as externals should exclude a string that startsWith a string.

If i make react an external, in webpack we do not need to also include react/jsx-runtime or any other possible files that could be required.

Reproduce link

https://github.com/ScriptedAlchemy/next-rspack-custom-server

Reproduce Steps

1. yarn install
2. yarn build-server

Look in server.js, currently this server is not hooked up to dev command, so i am purely testing if i can get dist/server.js to emit successfully before i attempt to leverage a bundled server file.

[hardfist]

@ScriptedAlchemy try this version @rspack/cli@0.0.0-canary-d95be9e

[ScriptedAlchemy]

@hardfist I'll test tomorrow morning. Thank you for such fast resolution!

[ScriptedAlchemy]

@hardfist, there is still some over explicit condition matches.

  externals: [
    /next\/dist/,
    /@swc/,
    /@vercel/,
    /@next/,
    /uglify-js/,
    /esbuild/,
    {
     '../next.config.js': 'next.config.js', // doesn't work
      '../next.config': 'next.config.js', //works
    }
  ]

it looks like rspack interparates string extenrals literally, so if i require without .js on the end, it will attempt to bundle it.
require('../next.config') vs next.config.js
We might want to allow for matching without extension when using string.

If i use regex to exclude file, that now works!

but i can get parse errors with

/next.config/

which returns error:

error[javascript]: JavaScript parsing error
   ┌─ main.js:48:18
   │
48 │ module.exports = ../next.config.js},
   │                  ^ Expression expected

[hardfist]

i check the behavior of webpack and it seems it doesn't work for webpack neither

  externals: [
    {
     '../next.config.js': 'next.config.js', // doesn't work
      '../next.config': 'next.config.js', //works
    }
  ]

I think this is by design otherwise we need to wait for resolve result to decide whether the module need to be external which may cause resolve failure.
when you use regex to match id the id keep in the require it also aligns with webpack's current behavior

[ScriptedAlchemy]

yeah this is something ive encountered before with webpack too, but hard to know exactly why. I think its because the package.json in next doesn't have a type so it doesn't know how to resolve or if its supposed to?

I usually use the function for resolving externals, when i need to handle various module formats.

Whats strange too is if i put commonjs ../next.config.js it will just emit that string as well.

A dirty workaround ive used in webpack in for rspack was to make the external be require('../next.config') so it just passes through the string.

If webpack behaves the same way, then i dont think its a bug :)