TypeSpec C#: @@include can't override inherited @@internal

[trrwilson]

We're using the @internal decorator (applied in a client.tsp file via @@) to hide a long-running operation route from the public surface of our client libraries, as we'd like to wrap the presentation of it with custom code.

This works well and produces the desired effect of directing the emission of the C# method and its response model hierarchy to be internal instead of public. It also applies to the options model used for the operation -- and that's the one thing we'd still like to retain in the public surface for reuse.

We tried to use the @include decorator for the options model in conjunction with the @internal used on the route that consumes that options model, but it unfortunately doesn't appear that @include can override the serialization change effected by @internal.

Issue/request: conditionalize model emission visibility to retain public if @include is used, even if the parsing hierarchy has been made @internal.

Example client.tsp body (where @internal works, but @include doesn't take effect in .NET):

// Azure-specific long-running operations should be treated as implementation details
@@internal(Azure.OpenAI.startGenerateImage);

// Some models from client-internal LROs are still desired for custom public surface
@@include(Azure.OpenAI.ImageGenerationOptions)

Edit: adding link for our original impacted .tsp:

• https://github.com/Azure/azure-rest-api-specs/blob/main/specification/cognitiveservices/OpenAI.Inference/client.tsp

This is intended to make the long-running operations internal while still preserving the public visibility of the options and response payload models involved (as those are then wrapped in a custom implementation).

[chunyu3]

Hello @trrwilson would you please provide the typespec files you uses and we want to check how you conjunction @include and @internal?

And do you mean that the model will be used in more than one operations, one is decorated with @internal, the other is not?

[tadelesh]

When a model is internal but include, we should not treat it as internal model.

I think this should be done in TCGC. When doing transitive closure detection for internal models, we should not label one model with internal if it has @include decoration.

@iscai-msft what do you think?