Re: "git push" silently fails, says 'Everything up-to-date" when it's not.

From: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Date: May 28, 2012, 12:11 UTC
Message-ID: <vpqipfgec9k.fsf@bauges.imag.fr>
In-Reply-To: <1338206011.11518.115.camel@shinybook.infradead.org>

David Woodhouse <dwmw2@infradead.org> writes:

Show 7 quoted lines

> [dwmw2@shinybook mtd-2.6]$ git push
> Everything up-to-date
>
> But it lies. Only when I try to *pull* does it give me a hint:
>
> [dwmw2@shinybook mtd-2.6]$ git pull
> You are not currently on a branch, so I cannot use any

What does

  git config push.default

say?

You probably have push.default=matching, which is the default. In this mode, Git will push all your local branches to remote branches having the same name (regardless of which branch you currently have checked-out). The commits you just did were not on any branch, so they're not pushed.

> Why would it do this evil thing and start lying to me? When it told me
> 'Everything up-to-date', precisely *what* was it telling me was up to
> date? Did it ever push *anything*, *anywhere*, or was it just a complete
> fabrication?

It probably pushed your branches, but not commits done in detached HEAD.

> I don't quite know how I ended up "not currently on a branch" either.

Either you did "git checkout <some-commit-identifier>" (in which case you had a big fat warning), or you used one command that runs in detached HEAD like "git rebase" or "git bisect" without concluding the operation ("git bisect reset", "git rebase --continue" or so).

With a recent enough version of Git, each commit you did in detached head had this little reminder:

$ git commit -m foo
[detached HEAD acb1d5b] foo
 ^^^^^^^^^^^^^

As for the future, there's a patch serie in progress that will make "git status" warn a bit more loudly in these cases, and give you a clue about what to do next.

In Git 2.0, the push.default value will change to "simple", which errors out like this in your case:

$ git push fatal: You are not currently on a branch. To push the history leading to the current (detached HEAD) state now, use

    git push origin HEAD:<name-of-remote-branch>

If you can't wait to have this "simple" mode, you may want to set push.default=upstream (or current), which will push the current branch to its upstream (or to the one with the same name remotely).

I don't know what can be done to improve the case of detached HEAD with push.default=matching. Perhaps Git should warn when HEAD is not pushed (detached HEAD, or HEAD points to a branch that doesn't exist remotely)?

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/