[Bug]: TCGC getClientNameOverride returns an object (instead of string or null)

[weidongxu-microsoft]

Describe the bug

export declare function getClientNameOverride(context: TCGCContext, entity: Type): string | undefined;

but it returns an object when the issue happens

Reproduction

loadtesting
https://github.com/Azure/azure-rest-api-specs-pr/blob/c4b80c74909bf593825e29ce7ff459decba35efd/specification/loadtestservice/LoadTestService/tspconfig.yaml

PR https://github.com/Azure/azure-rest-api-specs-pr/pull/17749

operation is

createOrUpdateTest is StandardResourceOperations.ResourceCreateOrUpdate<Test>;

they also have a

@@clientName(Azure.Core.Foundations.ResourceBody.resource, "body");

in routes.tsp, not sure if related.

call to getClientNameOverride is on the ModelProperty of the Test model.

Checklist

• Follow our Code of Conduct
• Check that this issue is about the Azure libraries for typespec. For bug in the typespec language or core libraries file it in the TypeSpec repo
• Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
• The provided reproduction is a minimal reproducible example of the bug.

[mitsha-microsoft]

Hi @weidongxu-microsoft ,
I am from the load testing team. Is this bug present in the version we install via npm as well, as I am not able to generate C# SDKs for my APIs

[weidongxu-microsoft]

@mitsha-microsoft

It likely present in the csharp emitter as well. But you may want to contact csharp dev on this, as it may not be the only cause.
(you can try comment out the @@clientName(Azure.Core.Foundations.ResourceBody.resource, "body"); -- TCGC dev and me both think this line is suspicious -- if emitter works without this line in routes.tsp, likely this is the cause)

I'm Java and this is the only problem on Java emitter.

[tadelesh]

I could not reproduce locally. You mean call getClientNameOverride for the body parameter will return object?

[tadelesh]

@timotheeguerin in tcgc, the decorator function could not get string value, but a decorator object (minimum tsp case here). i'm wondering if it is a tsp bug?

[timotheeguerin]

Is this only happening in that specific case? I was trying with the @doc decorator instead and that seems to work fine with the playground you shared.

@tadelesh can try you make a unit test reproing in Tcgc but without using azure core and I'll debug

[tadelesh]

@timotheeguerin i could repro with this tsp.

[timotheeguerin]

ok so the trigger is augmenting a templated type with @clientName but what is weird is it doesn't apply to other decorators

[timotheeguerin]

hhm actually happens to @extension as well. So seems like maybe the compiler decorators work for some reason but libraries don't