Discriminated unions seem broken for JS http client

[billoneil]

https://typespec.io/docs/standard-library/discriminated-types/#inject-discriminator-inline

It appears like discriminated unions don't work with the newer form with generating the js http client. Possibly related to https://github.com/microsoft/typespec/pull/6286/files?

Playground Link

This also causes issues.

@discriminated(#{envelope: "none"})
union Widget {
  heavy: WidgetBase,
  light: WidgetBase,
}

[MaryGao]

@billoneil Thanks for reporting this! Actually the @discriminated is not supported in client js yet, could you try the @discriminator instead as a workaround? It could express similar swagger payload I believe.

• default discriminated replacement playground
• envelope as none case replacement playground

[billoneil]

I see so the older implementation of @discriminated was also not fully supported in the js http client. Makes sense, appreciate the prompt response. Should I close this issue or leave it open to track the implementation?

[MaryGao]

Let's keep the issue to track the support effort @discriminated and we would review our bandwidth and consider the priority for that. Let us know if any urgency or blocking from your side.

[billoneil]

No urgency the options you provided should work, it just looks like a more convenient syntax.

Are there any example PRs showing how to modify the codegen or any specific patterns this should be solved with? I'd be open to trying to implement it myself if I have time.

[Kludgy4]

I believe this is the same issue so I'll add it here:
Generating a js client with discriminated doesn't seem to properly handle the deserialisation of the data model.

[Kludgy4]

I've created a PR to fix this #8077