http.ResponseWriter.Write() writes headers.

[AlekSi]

So should we.

Otherwise call to Write() followed by WriteHeader() will produce unexpected result.

[AlekSi]

@vishr poke

[vishr]

In what case I would call WriteHeader() after Write? For me this is a program error.

[AlekSi]

In what case I would call WriteHeader() after Write?

From middleware or error handler.
Consider this example: https://gist.github.com/AlekSi/5562d7eb06f4970161d1. Without my patch, error will be send mixed with data with HTTP code 200. With my patch error will be logged, but not send.

[AlekSi]

@vishr poke

[AlekSi]

@vishr May you please merge it to v1? We hit this issue quite often.

[vishr]

It is in.

[AlekSi]

Thanks. But you decided not to me merge unit test?

[vishr]

Just included it.