[Feature]: Support for webpack-assets-manifest

[ramon-villain]

What problem does this feature solve?

Background

Shakapacker is a popular library for handling JS bundling in Rails apps. It's the successor to rails/webpacker and uses webpack-assets-manifest as a core component. There's ongoing discussion about adding Rspack as a bundler option for Shakapacker (see issue #476), but the lack of support for webpack-assets-manifest in Rspack is a significant roadblock.

Current Progress

I've forked the original webpack-assets-manifest plugin and started adapting it for Rspack. Most of the test coverage is passing, but there are still some issues. You can see the current state of the refactor here: rspack-assets-manifest test results.

To complete the port, Rspack needs to support or provide alternatives for the following webpack features:

1. codeGenerationResults: Used in the original plugin to gather asset information.
2. assetsInfo: Used to store and retrieve additional information about assets.

We could either:

1. Add similar properties or methods to Rspack's compilation object.
2. Provide alternative APIs that serve the same purpose but fit better with Rspack's architecture.
3. Think about workarounds or patterns to achieve the same results without these specific properties.

Benefits

1. Enable easier migration from webpack to Rspack for projects using Shakapacker.
2. Increase Rspack's compatibility with existing webpack ecosystems. (as the lib itself has >600k downloads/week)
3. Potentially benefit other projects that rely on webpack-assets-manifest.

I'm willing to contribute to this feature's implementation, but I would need some direction on Rspack's internal architecture and best practices for adding these or equivalent features.

What does the proposed API of configuration look like?

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[LingyuCoder]

You can try to use rspack-manifest-plugin instead, it is forked from webpack-manifest-plugin and seems do the same thing with webpack-assets-manifest.

The assetsInfo can be got by compilation.getAsset()[].info. If you need to override it, you can use compilation.updateAsset(), but currently it does not support custom field (the rawRequest is not supported but the sourceFilename is supported).

Seems there is no method to get the code generation data of asset modules. But the assets of these modules will always be emitted through compilation.emitAsset and can be got from compilation.getAssets(). They have sourceFilename in their infos. You can also get all modules by compilation.modules so I think you can gather asset information by combining sourceFilename and module.userRequest/rawRequest.

[KalachevDev]

I tried to replace webpack-assets-manifest with rspack-manifest-plugin, but it doesn't support entrypoints as I see. According to this page rspack is compatible with webpack-assets-manifest, however compilation fails because rspack.Compilation does not have codeGenerationResults property

[jdb8]

Just ran into this after bumping webpack-assets-manifest to 5.2.1 (previous versions were erroring on TypeError: The 'compilation' argument must be an instance of Compilation during plugin instantiation).

I don't have much familiarity with codeGenerationResults - is this something that's likely to be ported to rspack, or is there a recommended workaround for plugins relying on this? @LingyuCoder is your approach above expected to be equivalent or are there missing pieces that would have to be implemented on the rspack side?

If anyone has a working patch for webpack-assets-manifest that would also be very useful :)

[stale[bot]]

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[agneym]

Found that a mapping is possible using rspack-manifest-plugin even though it doesn't support entrypoints natively.

You can see a sample of this on rsbuild manifest plugin: https://github.com/web-infra-dev/rsbuild/blob/main/packages/core/src/plugins/manifest.ts

[bpinto]

It would indeed be nice if webpack-assets-manifest were supported since it's a maintained package and, from what I understand, is a superset of webpack-manifest-plugin.

As it is however I fear that without some work from someone that understands the inner code of rspack a lot of projects won't be able to migrate to rspack.