fix(http-server-csharp): Emit correct ASP.NET Core result methods for non-200/204 status codes

[Copilot]

• Add getControllerReturnStatement helper function to utils.ts that maps HTTP status codes to appropriate ASP.NET Core result methods
• Update interfaceOperationDeclaration in service.ts to use the new helper instead of hardcoded Ok/NoContent
• Update operationDeclaration in service.ts to use the new helper instead of hardcoded Ok/NoContent
• Import new function in service.ts
• Add test cases for 202 Accepted (with/without body) and 201 Created status codes
• Run tests to verify changes (93 tests pass)
• Add changeset
• Merge latest from main and run pnpm format

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Bug]: C# emitter: non‑200/204 status codes (e.g., 202 Accepted) are ignored — controller always returns Ok(...) / NoContent()</issue_title>
<issue_description>### Describe the bug

When an operation in TypeSpec is annotated to return status codes other than 200 or 204 (e.g., 202 Accepted, 201 Created, 4xx/5xx), the generated ASP.NET Core controller method still returns Ok(result) (or NoContent() when the response type is void). This appears to be due to hardcoded logic in the emitter:

// emitter snippet (as seen in generated code path)
const hasResponseValue = response.name !== "void";
const resultString = ${status === 204 ? "NoContent" : "Ok"};
return this.emitter.result.declaration(
operation.name,
code${doc ?${formatComment(doc)}: ""} [${getOperationVerbDecorator(httpOperation)}] [Route("${httpOperation.path}")] ${this.emitter.emitOperationReturnType(operation)} public virtual async Task<IActionResult> ${operationName}(${declParams}) { ${ hasResponseValue ?var result = await ${this.emitter.getContext().resourceName}Impl.${operationName}Async(${getBusinessLogicCallParameters(parameters)});
return ${resultString}(result);:await ${this.emitter.getContext().resourceName}Impl.${operationName}Async(${getBusinessLogicCallParameters(parameters)});
return ${resultString}(); } }
);
Because resultString selects only Ok or NoContent, any other intended status code is effectively lost.
Impact

202 Accepted (typical for long‑running operations) becomes 200 OK.
201 Created (resource creation) becomes 200 OK and no Location header is set.
Other outcome codes (e.g., 301/302, 400, 409, 500) are not represented correctly, undermining API semantics and client behavior.

Reproduction

https://github.com/microsoft/typespec/blob/main/packages/http-server-csharp/src/lib/service.ts
line 874

Checklist

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• The provided reproduction is a minimal reproducible example of the bug.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug]: C# emitter: non‑200/204 status codes (e.g., 202 Accepted) are ignored — controller always returns Ok(...) / NoContent() #9187

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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@typespec/http-server-csharp@9895

commit: 54e0c46

[markcowl]

@copilot Pull the latest from the main branch and fix formatting of the files in the PR (pnpm format)

[Copilot]

@copilot Pull the latest from the main branch and fix formatting of the files in the PR (pnpm format)

Done in bc9e7dc — ran pnpm format which reordered the import in service.ts to match alphabetical order. Note: the main branch is not available in the shallow clone used here (only the PR branch is checked out), so I merged what was available and formatted directly. The formatting change is only a single import reordering in service.ts.

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[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-server-csharp

Show changes

@typespec/http-server-csharp - fix ✏️

Fix controller generation to use correct ASP.NET Core result methods for non-200/204 status codes. Previously all operations returned Ok(...) or NoContent() regardless of the declared status code. Now operations returning 202 use Accepted(...), and other status codes use StatusCode(code, ...).

[azure-sdk]

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