Support pnpm-style directory layout

[Toxaris]

napi-postinstall expects to require.resolve the optional dependencies of another package, but in a pnpm-style directory layout, a package can only require.resolve its own dependencies.

Details:

We are using a pnpm-style directory layout in a build sandbox that doesn't have internet access, and as part of updating Jest we run into an issue with the use of napi-postinstall in unrs-resolver.

The platform is linux-x64-gnu so we need the @unrs/resolver-binding-linux-x64-gnu package. We checked the build sandbox and see that this package is indeed installed as an optional dependency of unrs-resolver.

However, due to the pnpm-style directory-layout, it is not visible to the require.resolve in line 331 of src/index.ts.

That is, we have the following directory structure in our build sandbox:

• a/node_modules/unrs-resolver contains the unrs-resolver package
• a/node_modules/@unrs/resolver-binding-linux-x64-gnu is a symlink to b/node_modules/@unrs-resolver-binding-linux-x64-gnu
• a/node_modules/napi-postinstall is a symlink to c/node_modules/napi-postinstall
• b/node_modules/@unrs/resolver-binding-linux-x64-gnu contains the @unrs/resolver-binding-linux-x64-gnu package
• c/node_modules/napi-postinstall contains the napi-postinstall package

So the optional dependency has been correctly installed into a/node_modules, but the require.resolve is in a file below c/node_nodules and cannot see it. The fallback to download the package also fails due to the missing Internet access in the build sandbox (rightly so, because we don't want to download random files during the build).

We are creating the pnpm-style directory layout with our own tooling, but it should be possible to also reproduce this with pnpm by setting hoist to false.

[JounQin]

pnpm supports optional dependencies perfectly, so you can use pnpm approve-builds to disable postinstall for unrs-resolver or oxc-resolver, etc.

And I haven't met such issue for pnpm, could you provide a minimal reproduction?

[Toxaris]

Thanks for the hint regarding disabling postinstall, we ended up patching unrs-resolver to remove the postinstall script (using the pnpm support for patches), which resolved our immediate problem.

I haven't met such issue for pnpm, could you provide a minimal reproduction?

Didn't find the time so far, sorry.

Background: Our setup is mixed between rush+pnpm with hoist=true where we don't see the problem; and our own implementation of a pnpm-style directory layout simulating hoist=false where we do see the problem. So I guess but did not confirm that the problem can be reproduced by pnpm with hoist=false. Note that hoist=true is the default, so a default pnpm setup would not be affected anyway.