net/http: ErrWriteAfterFlush unused

[perillo]

The variable ErrWriteAfterFlush, defined in net/http/server.go, is never used.

After a bit of code archaeology with git, I found that the variable was introduced in https://github.com/golang/go/blob/e73acc1b35f3490f3d800b4bf49da79630e808fc/src/lib/http/server.go, but at some point it was no more used.

[perillo]

The unused tool, with the -export flag, also reports the following error variables to be unused:

• ErrHeaderTooLong
• ErrShortBody
• ErrNotSupported
• ErrMissingContentLength
• ErrNoCookie
• ErrLineTooLong

However I have not checked if they are obsolete as with ErrWriteAfterFlush.

[dominikh]

All of those are part of the public API and cannot be removed under the Go 1 compatibility guarantee. Also, most of these are defined in terms of their net/http/internal counterpart, are returned from internal and used by users of net/http.

As an aside, unused -exported is not at all useful for the standard library, except when checking internal packages. All exported identifiers in the stdlib are by their nature used by users of Go.

[perillo]

On Wed, Apr 6, 2016 at 12:34 PM, Dominik Honnef notifications@github.com
wrote:

All of those are part of the public API and cannot be removed under the Go
1 compatibility guarantee. Also, most of these are defined in terms of
their net/http/internal counterpart are returned from internal and used
by users of net/http.

At least ErrWriteAfterFLush seems to be obsolete. Of course it can not be
removed, but a comment can be added to explain that it is no more used.

IMHO, a variable without a comment and that appears to be never used, only
cause confusion for users (at least for me).

[gopherbot]

CL https://golang.org/cl/22658 mentions this issue.