[TCGC] [LRO] lroMetadata.pollingStep.responseBody.usage is not correct when polling operation is defined in different namespace

[haolingdong-msft]

Issue

I believe this is an edge case. See below test case, PollResponse model in namespace Cadl.ServiceNamespace has usage === 0`, but it is actually used in polling operation.

import "@typespec/rest";
import "@azure-tools/typespec-client-generator-core";
import "@azure-tools/typespec-azure-core";


using TypeSpec.Rest;
using TypeSpec.Http;
using TypeSpec.Versioning;
using Azure.Core;
using Azure.Core.Traits;


@service({
  title: "ServiceNamespace",
})
@versioned(ApiVersions)
@route("/servicenamespace")
namespace Cadl.ServiceNamespace {
  enum ApiVersions {
    @useDependency(global.Azure.Core.Versions.v1_0_Preview_2)
    v2022_06_01_preview: "2022-06-01-preview",
  }

  model PollResponse {
    operationId: string;
    status: Azure.Core.Foundations.OperationState;
  }

  @pollingOperation(NonService.poll)
  @post
  @route("/post")
  op longRunning(): AcceptedResponse;

}

@useDependency(Azure.Core.Versions.v1_0_Preview_2, Cadl.ServiceNamespace.ApiVersions.v2022_06_01_preview)
namespace Cadl.NonService {
  @route("/poll")
  @get
  op poll(): Cadl.ServiceNamespace.PollResponse;
}

Solution

PollResponse should be public access + output usage.