net/http: Response.Write includes Content-Length header on 204s

[bradfitz]

Apparently we send a Content-Length header on a 204 response:

https://play.golang.org/p/bxy_rEBy-s

A 204 can't have a body anyway, so the Content-Length is useless and misleading. (It might be a protocol violation? Haven't checked.)

[freeformz]

https://tools.ietf.org/html/rfc7230#section-3.3.2

...
 A server MUST NOT send a Content-Length header field in any response
   with a status code of 1xx (Informational) or 204 (No Content).
...

[bradfitz]

Oh, we're fine actually. This is a bug in Response.Write. It's correct on the network:

https://play.golang.org/p/ettdRyiOtn

[0xmohit]

Athough this appears to be specifically about 204, an existing test expects Content-Length with a status code of 1xx.

[bradfitz]

@0xmohit, that test can be changed.

[gopherbot]

CL https://golang.org/cl/28351 mentions this issue.