cmd/go: add support for GitHub Enterprise import path

[matope]

For now, go get does not fetch packages hosted on GitHub Enterprise correctly without any workarounds.

$ go get -v ghe.in.my.company/user/repo/sub
Fetching ghe.in.my.company/user/repo/sub?go-get=1
Parsing meta tags from https://ghe.in.my.company/user/repo/sub?go-get=1 (status code 404)
package ghe.in.my.company/user/repo/sub: unrecognized import path "ghe.in.my.company/user/repo/sub" (parse https://ghe.in.my.company/user/repo/sub?go-get=1: no go-import meta tags)

When I execute go get, it issues an HTTP request to find go-import meta-tags.
But GHE does not return any meta-tag because ghe.in.my.company/user/repo/sub is 404 for GHE ( ghe.in.my.company/user/repo/tree/master/sub would work fine).

So, in order to use golang with GHE, we have to

• a) Use import path with .vcs. ex) ghe.in.my.company/user/repo.git/sub
• b) or use a redirect server that attach go-import meta-tags.

But, a) would be a error prone especially for newbies. Many people at first download repo into ghe.in.my.company/user/repo but, after that, go get would download it's sub packages into ghe.in.my.company/user.git/repo. I think this would make people confused.
b) This would work fine, but I think managing a server only for dependency resolution is not very efficient.

So, I think it would be great if cmd/go natively support GitHub Enterprise.

[matope]

My patch is here. Could anybody please review this?
https://go-review.googlesource.com/#/c/33171/

[gopherbot]

CL https://golang.org/cl/33171 mentions this issue.

[gopherbot]

CL https://golang.org/cl/37176 mentions this issue.

[matope]

Hi, @bradfitz. As go cmd had a major refactoring, I've abandoned the previous CL and created new one which is rebased on Go1.8 with some cleanup.

I'd appreciate you if you could review my new one.

[rsc]

It sounds like maybe the solution should be to support ?go-get=1 in the GHE 404 page, but we'd have to write down exactly what that would mean before approaching GitHub (or suggesting that their paying customers do that).

[blaskovicz]

Here is the Gitlab implementation, for reference. It seems that there was a similar issue with Golang subpackages for it as well.

[jijojv]

ok 1.9 is out and disappointed that it still doesn't work with GitHub Enterprise over ssh as-is.

git clone git@ghe.mycompany.com:org/repo.git does not create a .git directory but go decided not to allow any git url schemes and not to use the standard git cloning convention and create a directory with .git suffix which provides a confusing experience for everyone involved...

[ianlancetaylor]

@jijojv I encourage you to send a patch, so that this can be fixed for 1.10.