[http-server-csharp] Placeholder is generated

[ArcturusZhang]

For todoApp, there is another Placeholder generated:

        [HttpGet]
        [Route("/items/{itemId}/attachments")]
        [ProducesResponseType((int)HttpStatusCode.OK, Type = typeof(Placeholder))]
        public virtual async Task<IActionResult> List(long itemId)
        {
            var result = await AttachmentsOperationsImpl.ListAsync(itemId);
            return Ok(result);
        }

I think this is generated from:

  @list op list(...PaginationControls): WithStandardErrors<TodoPage>;

model TodoPage {
    /** The items in the page */
    @pageItems items: TodoItem[];

    /** The number of items returned in this page */
    pageSize: int32;

    /** The total number of items */
    totalSize: int32;

    ...PaginationControls;

    /** A link to the previous page, if it exists */
    @prevLink
    prevLink?: url;

    /** A link to the next page, if it exists */
    @nextLink
    nextLink?: url;
  }
alias WithStandardErrors<T> = T | Standard4XXResponse | Standard5XXResponse;

I am not sure where it goes wrong from the spec which looks nothing special comparing with others in this spec.

[ArcturusZhang]

Its corresponding interface is generating JsonNode as a return type as well. I think JsonNode should work like a placeholder as well (we even do not have a using statement for it)
This looks like the return type TodoPage is not properly handled and recognized.

[markcowl]

Cannot repro this issue. Appears to be fixed in my branch, at least

[ArcturusZhang]

the issue is still there: https://github.com/allenjzhang/typespec-e2e-demo/blob/2abc70f27d1e5344ce286462fa77ab887abbc228/todoApp/servers/aspnet/generated/controllers/AttachmentsOperationsControllerBase.cs#L25
on main branch of this project.

[ArcturusZhang]

Apparently, this Placeholder is written here:

typespec/packages/http-server-csharp/src/utils.ts

Line 426 in 5cfd1f7

if (name === undefined) return "Placeholder";

this line might be called every time it has an anonymous model - and in this project there happens to have one: https://github.com/allenjzhang/typespec-e2e-demo/blob/2abc70f27d1e5344ce286462fa77ab887abbc228/todoApp/servers/aspnet/generated/models/Model0.cs

[ArcturusZhang]

Cannot repro this issue. Appears to be fixed in my branch, at least

The reason you cannot reproduce might be you have the friendlyName decorator on the model - and it now has a name.
But in your latest change, the friendlyName is removed, therefore this issue pops up again.
I could add the decorator back, but this is still an issue to fix.

[markcowl]

Yeah, this was fixed in my branch when you filed this issue i. All fixes in this PR: #5417

Generated code here: allenjzhang/typespec-e2e-demo#47