Detect Bun tool when using bun.lock and yarn.lock

[jbarrieault]

Summary

Resolves #212

The build task incorrectly detect yarn as the JS tool when using Bun's text-based lockfile (bun.lock) if a yarn.lock is also present. The text-based lockfile was introduced in Bun v1.1.39.

Why would bun.lock and yarn.lock both exist?

Bun supports generating a yarn.lock file in addition to its own lockfile. Producing the yarn.lock file can be useful for integrating with tools that only know (how) to parse yarn.lock files, such as dependency report generators.

The fix

This checks for bun.lock ahead of yarn.lock to ensure Bun is detected as the tool.

Add additional control?

The is adjacent to rails/cssbundling-rails#169.

Perhaps a config that allows setting & differentiating the package manager and bundler would be reasonable. On the other hand, it should already be possible to achieve that by monkey-patching Jsbundling::Tasks.

[dhh]

Do bring this to cssbundling-rails too.

[navidemad]

@dhh I made this one with a bit of refactor also:

rails/cssbundling-rails#171