git: SSH config not respected

[uhthomas]

Expected Behaviour

jj git clone should respect the SSH config (~/.ssh/config).

Actual Behaviour

The SSH config is not respected, which may be problematic in some cases. In this case, ProxyCommand is to communicate with a private Git server.

Steps to Reproduce the Problem

1. Use an SSH environment which requires additional configuration via ~/.ssh/config to work.
2. Observe jj git clone hang.

Specifications

• Version: 0.2.0.r917.2916cb2-1
• Platform: Linux x86_64

[martinvonz]

Thanks for your report. I'll be away from my computer for about a week from now. If anyone feels like looking into this while I'm away, I think the right place to start is here.

[valpackett]

libgit2 uses libssh2, not OpenSSH, so of course it doesn't use OpenSSH's configuration. And unfortunately there is no support for proxying at all. See libgit2/libgit2#4872 (one linked PR does something in that direction)

the right place to start is here

Hopefully the hardcoded id_rsa won't remain the only supported key path for non-agent operation there for long… :)

[martinvonz]

By the way, Git has its "credential helpers", which may be what we should use. I don't know enough about it yet.

[bergkvist]

Is it possible to use OpenSSH instead of libssh2?

[martinvonz]

Is it possible to use OpenSSH instead of libssh2?

I was going to say that I think we'd have to ask for such support from libgit2 (or switch to gitoxide or something) but I see you've already asked there (thanks). I have no idea how feasible it is.

[arxanas]

@bergkvist One alternative is what I do: I never use jj git and simply use git for all clone/fetch/push operations, and use jj's colocated repo mode to use jj with the Git repository by running jj init --git-repo .. I had to do this at a previous job where they used a custom version of Git. (I'm assuming that your installation of Git uses OpenSSH instead of libssh2 in whatever way you require.)

[bergkvist]

@arxanas Do you have to rerun jj init --git-repo . every time you do a git pull? Or does it "keep in sync" after you do it once?

[yuja]

jj init --git-repo . is needed only once.

jj git fetch is basically the same as git fetch --prune && jj git import, and for "colocated" repo created by --git-repo ., jj git import runs implicitly every time you do jj <subcommand>.

[bergkvist]

@martinvonz: See libgit2/libgit2#6617

[martinvonz]

@martinvonz: See libgit2/libgit2#6617

Wow, that's great news! Thanks for the update. Will you get a chance to try it?

[bergkvist]

I tested it out now, but I'm getting a segfault when using a git remote like git@github.com:bergkvist/jj. (Building https://github.com/bergkvist/jj will in theory also allow you to reproduce the segfault).

$ git clone git@github.com:bergkvist/jj && cd jj
$ cargo install --path=.
$ ~/.cargo/bin/jj init --git-repo=.
$ ~/.cargo/bin/jj git fetch
Segmentation fault