Re: Bug in git rev-parse @{push}?

From: Jeff King <peff@peff.net>
Date: Nov 3, 2016, 15:14 UTC
Message-ID: <20161103151422.nhrgzivapy5tisr4@sigill.intra.peff.net>
In-Reply-To: <CAJUoZVYF=ZCBUX6jztwhJX3BZdq4JEfrSRbi4cFPwn+7yA=VjA@mail.gmail.com>

On Thu, Nov 03, 2016 at 02:53:44PM +0000, Chris Purcell wrote:

Show 11 quoted lines

> I think I have discovered a bug in rev-parse's handling of @{push}:
> 
> $ git push
> Everything up-to-date
> $ git rev-parse @{push}
> fatal: cannot resolve 'simple' push to a single destination
> 
> The documentation for rev-parse says that "the suffix @{push} reports
> the branch 'where we would push to' if git push were run while
> branchname was checked out", so I would not expect this to error
> unless git push does.

I'm not too surprised if there's a bug there. IIRC, the way the code is structured, some of the logic had to be reimplemented for @{push} rather than re-used, so there may be corner cases where they do not agree.

Show 14 quoted lines

> The relevant parts of my configuration are:
> 
> [push]
>     default = simple
> [remote]
>     pushdefault = origin
> [branch "foo"]
>     remote = origin
>     merge = refs/heads/develop
> 
> The code in branch_get_push_1 (remote.c) in the PUSH_DEFAULT_SIMPLE
> case is calling both branch_get_upstream and tracking_for_push_dest
> and erroring if they don't return the same result, which I assume is
> incorrect for a triangular workflow?

I assume you have branch "foo" checked out?

With this config I don't see how "git push" would work. Because you're using "simple", it should complain that "develop" and "foo" are not the same name.

Can you give a more full reproduction recipe? If I try:

  git init tmp && cd tmp
  git config push.default simple
  git commit -m foo --allow-empty ;# just to have some commit to push

  git init --bare dst.git
  git remote add origin dst.git
  git push origin master:refs/heads/develop

  git checkout -b foo origin/develop

  # pushdefault of "origin" is already the default. checkout will have
  # set up branch.foo.* as you specified. So let's try our push.
  git push

Then I get:

  fatal: The upstream branch of your current branch does not match
  the name of your current branch.  To push to the upstream branch
  on the remote, use

      git push origin HEAD:develop

  To push to the branch of the same name on the remote, use

      git push origin foo

which makes sense.

If you _don't_ get that same message with "git push", then my next question is: might you have any aliases or other systems like "hub" that are munging the arguments to "git push"? Running with "GIT_TRACE=1" in the environment might be enlightening there.

> Please let me know if I've missed out important information by
> mistake. I'm happy to work on a patch if given guidance, but this is
> definitely outside my comfort zone for an unfamiliar codebase
> otherwise! e.g. I can't find the test suite.

The tests are in the "t" directory; see t/README for details. You can run them all with "make test" from the top-level directory.

-Peff