[v2] Cannot return 400 BadRequest as response to function runtime

Function App v2.0 (beta) nupkg v1.0.6+ (have tried .6, .7, and .8)

The following code:

[FunctionName(@"MyFunction")]
public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Function, @"post")]HttpRequestMessage req, TraceWriter log)
{
	return req.CreateErrorResponse(HttpStatusCode.BadRequest, "Error Message");
}

will result in an error from the function runtime that looks like:

[2/28/2018 11:16:34 PM] A ScriptHost error has occurred
[2/28/2018 11:16:34 PM] Exception while executing function: MyFunction. Autofac: The requested service 'System.Net.Http.Formatting.IContentNegotiator' has not been registered. To avoid this exception, either register a component to provide the service, check for service registration using IsRegistered(), or use the ResolveOptional() method to resolve an optional dependency.
[2/28/2018 11:16:34 PM] Exception while executing function: MyFunction
[2/28/2018 11:16:34 PM] Exception while executing function: MyFunction. Autofac: The requested service 'System.Net.Http.Formatting.IContentNegotiator' has not been registered. To avoid this exception, either register a component to provide the service, check for service registration using IsRegistered(), or use the ResolveOptional() method to resolve an optional dependency.
[2/28/2018 11:16:35 PM] Function completed (Failure, Id=6cf69e24-80aa-49a8-83b4-62819122aa1e, Duration=12084ms)

I’ve tried returning an Exception object (as the overload allows), and also a properly formatted JSON string (eg: { "errors" : "My error message" }) but with no success.

In Functions v1(.0.9 CLI) w/ nupkg v1.0.8, this same code runs successfully and gives back:

[2/28/2018 11:27:44 PM] Response details: {
[2/28/2018 11:27:44 PM]   "requestId": "4f759841-5832-4915-8ca7-75120e3870b6",
[2/28/2018 11:27:44 PM]   "status": "BadRequest"
[2/28/2018 11:27:44 PM] }

as we’d expect.

[fabiocav]

This should be resolved. Moving this to the next sprint for validation.

[fabiocav]

Closing as resolved.