feature: yarn-path to resolve paths.

[jdalton]

Do you want to request a feature or report a bug?

feature

What is the current behavior?

The current behavior passes the yarn-path value as-is to child.fork and child.spawn.

What is the wanted behavior?

For yarn to resolve paths so that users could specify a dev dependency like yarn-path "custom-yarn" and yarn would resolve the path to custom-yarn package.

[arcanis]

What's the underlying use case?

The way I see it, a custom Yarn has to be cloned/downloaded separately, not installed as a devDependency, since in order to run a devDependency you first need to run an install, which you couldn't do without the custom Yarn 🤔

[jdalton]

@arcanis

The use case I had in mind would be for wrapping yarn by way of child.spawn to customize flags, params, etc.

yarn-path: "esm/yarn"