Singletons and dependency sets.

[vjpr]

my-foo depends on swc-loader which has a peer dependency on webpack and @swc/core.
my-bar depends on webpack.

webpack must be a singleton or I get an error of: The 'compilation' argument must be an instance of Compilation

But my-foo's webpack points to webpack+swc_core and my-bar's webpack points to webpack.

I have to add @swc/core to my-bar (even though it doesn't use it) in order for my-foo and my-bar to use the same singleton instance.

This can get out of hand quickly.

I think we need some tooling to help with the singleton use case. Something like a pnpm doctor duplicates command to guide your through fixing it.

The problem with the status-quo, is that even if you ensure that every package uses the exact same version of a dep, they can still be using multiple instances because of the dependency sets. And with hoist=true, a random version gets chosen which is even more problematic. I am using nohoist btw.