[Bug]: The builtin loaders should not pass meta to the next loader

[chenjiahan]

System Info

Rspack 1.0.3

Details

In webpack, the meta param of loader can only be passed to the next loader, and the bulitin loaders in Rspack should follow the same behavior.

https://webpack.js.org/api/loaders/#thiscallback

Example

For example, the css-loader and postcss-loader uses meta.ast to resue PostCSS AST, see:

• https://github.com/webpack-contrib/css-loader/blob/a7f5288cb9285f3309f67ce5d03b749d872d3970/src/index.js#L158
• https://github.com/webpack-contrib/postcss-loader/blob/638be98312f82e9d919bf8f5fa03a8fce8a61635/src/index.js#L103

When using Rspack's builtin:lightningcss-loader like this:

postcss-loader ---passing AST meta---> builtin:lightningcss-loader ---passing AST meta---> css-loader

The builtin:lightningcss-loader will not take any effect, because css-loader will read the AST meta from postcss-loader, and drop the transformation result of builtin:lightningcss-loader.

Reproduce link

web-infra-dev/rsbuild#3247

Reproduce Steps

See web-infra-dev/rsbuild#3247 for more details.

[h-a-n-a]

This is probably caused by the logic of the Rust loader implementations. On rust side, we does not expose an API to override the values at once (content, sourceMap, additionalData). In this case, it caused the additionalData being accidentally passed onto the next loader.