net/http: ServeContent does not send Content-Range in 416 errors

[anacrolix]

https://tools.ietf.org/html/rfc7233#section-4.4 says that if the range cannot be satisfied because it is beyond the length of the instance, Content-Range should be returned with a 416 containing the instance length. This does not occur with http.ServeContent.

[quentinmit]

/cc @bradfitz @adg

With anything HTTP... I defer to the experts to decide if we should follow the spec.

[adg]

Sure, seems like a failure mode we overlooked in the implementation. Also seems like low hanging fruit for anyone looking for something to do.

[gopherbot]

CL https://golang.org/cl/24212 mentions this issue.