dependency-extraction-webpack-plugin breaks when using optimizations.runtimeChunk = 'single'

[stefanfisk]

Describe the bug

@wordpress/dependency-extraction-webpack-plugin breaks in two ways when using optimizations.runtimeChunk = 'single'.

1. The asset files are named based on the runtime chunk's name, i.e. runtime.asset.php.
2. All asset files are added to the runtime chunk.

The first issue results in only the last entrypoint's asset being saved (as it overwrites the previous ones').

The second issue makes it impossible to correlate an asset file with its entrypoint.

To reproduce

I've created an example project here: https://github.com/stefanfisk/wordpress-dependency-extraction-webpack-plugin-runtimechunk-single-bug

Expected behavior

The asset files should be named according to the entrypoint names, and only be added to the entrypoint chunks.

Preferably it should be possible to configure the asset file names. For example it would be nice if using hashes in output.filename did not result in the asset filename containing a hash.

Plugin version:

• @wordpress/dependency-extraction-webpack-plugin 2.8.0
• webpack 4.44.1

[stefanfisk]

I've got a quick and dirty fix going here: https://github.com/stefanfisk/gutenberg/tree/fix/24352-dependency-extraction-runtimechunk-single

Since I don't quite grok the internals of Webpack It's probably broken in ways I cannot fathom, so I'm refraining from opening a PR for now.

[gziolo]

@sirreal, any chances you could have a look at this issue?

[sirreal]

@stefanfisk if you have a working change would you like to open a PR? It would be nice to have something to start from.

I don't have much bandwidth to dedicate to this myself, but I'll support with guidance and reviews as much as possible.

[slightlyfaulty]

Actually, this breaks when any entrypoints share a runtime, e.g. when using dependOn. Because runtimeChunk is used to determine the output filename instead of entrypointChunk, the output filenames clash and get overridden.

I've tested @stefanfisk's PR and it works great. Would be amazing if we could finally get it merged.

Maybe it's just me, but I don't see how efficient code-splitting has ever been possible while this issue exists??

[gziolo]

I've tested @stefanfisk's PR and it works great. Would be amazing if we could finally get it merged.

Thank you for the reminder and for testing the patch proposed. Let's see what we can do to move it forward 👍🏻