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

David Woodhouse [off-list ref] writes:

[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/