Working with Yarn PnP

[Downchuck]

Related to the question of why there is a tsp install in the first place -- I am trying to boot up with a clean yarn pnp workspace - which is a bit of a challenge with the current typespec ecosystem as it seems to lean into using "node_modules" heavily for extensions.

For the vs code extension, in settings.json file can be pointed to an unplugged compiler, e.g.:

  "typespec.tsp-server.path": "${workspaceFolder}/sdk/.yarn/unplugged/@typespec-compiler-npm-0.60.1-b04a9a8287/node_modules/@typespec/compiler"

Overall though, simply running yarn tsp does not seem enough to maintain the pnp resolver:

> yarn tsp compile .        
(node:39488) [MODULE_NOT_FOUND] Error: @typespec/compiler tried to access source-map-support, but it isn't declared in its dependencies; this makes the require call ambiguous and unsound.
(Use `node --trace-warnings ...` to show where the warning was created)
TypeSpec compiler v0.60.1

Diagnostics were reported during compilation:

/sdk/main.tsp:1:1 - error import-not-found: Couldn't resolve import "@typespec/http"
> 1 | import "@typespec/http";

Note source-map-support is in the dev dependencies, so that may be a hint as to something going strange in the loader.

Similarly, or from a different strategy, we can quickly reproduce a sad time with yarn in:

yarn dlx -p  @typespec/compiler -p @typespec/http tsp compile .

That stated, this appears to work:

yarn pnpify tsp compile .

That's using @yarnpkg/pnpify and whether or not it's needed, I added to my .yarnrc.yml:

packageExtensions:
  "@typespec/compiler@*":
    dependencies:
      "source-map-support": "~0.5.21"
      "@typespec/http": "*"
      "@typespec/openapi": "*"
      "@typespec/openapi3": "*"
      "@typespec/json-schema": "*"

[timotheeguerin]

It tries to load source-map-support if it is present(e.g. development) but ignore if not. I have never seen this warning, which version of node are you using?

For the yarn pnp part I am not sure, I am not familiar at all with it, how does it work? Could you make a repo with a repro so we can investigate how to support that.