[Bug]: use `__webpack_require__` in source code will be inject runtime codes

[sylingd]

Version

OS: Windows 11 10.0.26200

    devDependencies:
      '@rslib/core':
        specifier: ^0.19.1
        version: 0.19.1(typescript@5.9.3)
      '@types/node':
        specifier: ^24.10.4
        version: 24.10.4
      typescript:
        specifier: ^5.9.3
        version: 5.9.3

Details

在源码中使用__webpack_require__会被注入相关运行时代码，无法获取原本希望获取的外部运行时代码。使用FAQ中的define只能解决其他的，不能解决__webpack_require__的问题。

Using __webpack_require__ in the source code will inject related runtime code, preventing you from retrieving the external runtime code expect. Using define in the FAQ only solves other issues, but not work with __webpack_require__.

例如：

declare const WEBPACK_REQUIRE: any;

export const squared = () => {
  console.log(WEBPACK_REQUIRE);
}

产物：

import { __webpack_require__ } from "./rslib-runtime.js";
const squared = ()=>{
    console.log(__webpack_require__);
};
export { squared };

配置：

import { defineConfig } from '@rslib/core';

export default defineConfig({
  source: {
    define: {
      WEBPACK_REQUIRE: '__webpack_require__',
    }
  },
  lib: [
    {
      format: 'esm',
      syntax: ['node 18'],
      dts: true,
      shims: {
        cjs: {
          'import.meta.url': false,
        },
        esm: {
          __dirname: false,
          __filename: false,
          require: false,
        }
      }
    },
    {
      format: 'cjs',
      syntax: ['node 18'],
      shims: {
        cjs: {
          'import.meta.url': false,
        },
        esm: {
          __dirname: false,
          __filename: false,
          require: false,
        }
      }
    },
  ],
});

Reproduce Steps

example.zip

• unzip
• run build command

[JSerFeng]

We really do not recommend to do this. And there is very likely to go wrong.

Think about this: We can __webpack_require__ during rslib build the Require1, and __webpack_require__ in web build the Require2

import foo from 'lib'

use(WEBPACK_REQUIRE)

The output is like

import {__webpack_require__} from 'lib'
const __foo = __webpack_require__('lib')

use(__webpack_require__)

The __webpack_require__ is still Require1, and if you don't have any dependencies, that becomes Require2.

The behavior depends on whether your module contains any runtime

[Timeless0911]

Webpack provide a global variable __webpack_global__ to access runtime in current compilation, see webpack/webpack#20170.

It's best to avoid using __webpack_require__ directly in source code to access the runtime based on the example above.

If you need to maintain compatibility with previous versions of webpack, you can write __WEBPACK_REQUIRE__ in your source code and then replace it accordingly in process assets stage.

e.g.

import { defineConfig, type RsbuildPlugin } from '@rslib/core';

const preserveWebpackRequirePlugin: RsbuildPlugin = {
  name: 'preserve-webpack-require',
  setup(api) {
    api.processAssets(
      { stage: 'report' },
      ({ assets, compilation, compiler }) => {
        for (const [assetName, assetSource] of Object.entries(assets)) {
          const newSource = assetSource
            .source()
            .toString()
            .replace(/__WEBPACK_REQUIRE__/g, '__webpack_require__');
          compilation.updateAsset(
            assetName,
            new compiler.webpack.sources.RawSource(newSource)
          );
        }
      }
    );
  },
};

export default defineConfig({
  lib: [
    {
      format: 'esm',
    },
  ],
  plugins: [preserveWebpackRequirePlugin],
});

[sylingd]

Webpack provide a global variable __webpack_global__ to access runtime in current compilation

看起来rspack暂未支持__webpack_global__，目前在 rslib 下只能自己写插件 updateAsset 解决。

[Timeless0911]

Can you provide a demo project to show how you use Rslib output with __webpack_require__ in Rspack?

[sylingd]

Can you provide a demo project to show how you use Rslib output with __webpack_require__ in Rspack?

I try to migrate this package from modern-lib to rslib but failed because of this problem.

https://github.com/web-infra-dev/modern.js/blob/v3.0.0-alpha.1/packages/runtime/render/src/server/rsc/rsc.tsx

[Timeless0911]

For this case, Rspack 2.0 will provide a new way to get runtime in RSC scene. You can migrate this package later in the future or use the workaround temporarily.