Re: git push

[John Tapsell <johnflux@gmail.com>]

2009/3/5 Andreas Ericsson <ae@op5.se>:
> Finn Arne Gangstad wrote:
>>
>> Sorry to people receiving this mail twice, the list ate my first reply
>> since it managed to hit the spam-filter (maybe I should take a hint... :)
>>
>> On Tue, Feb 24, 2009 at 11:01:38PM -0800, Junio C Hamano wrote:
>>>
>>> [...]
>>>
>>> But if you are talking about changing the default when "git push" is run
>>> without any parameter, I have to say it is a terrible idea, for two
>>> reasons, and one is too obvious to state so I wouldn't repeat it and talk
>>> only about the other one.
>>
>> The current default behaviour of git push is very annoying for us at
>> least. The current behaviour is _dangerous_ and leads to serious
>> problems. It is too easy for someone to write "git push". They hit
>> enter too soon, or they write it expecting to get usage
>> information. They do not necessarily expect to overwrite random
>> branches in a remote repository.
>>
>> Most git commands are not destructive with no arguments at all, and
>> push is the _only_ command that really can screw things up for others,
>> so this command in particular should refrain from destructive default
>> behaviour.
>>
>> An example of random branch overwriting:
>> $ mkdir a
>> $ cd a
>> $ git init
>> $ echo contents > file
>> $ git add file
>> $ git commit -m message
>> $ cd ..
>> $ git clone a b
>> $ cd b
>> $ git checkout -b gif-support
>> $ echo foo > somefile
>> $ git add somefile
>> $ git commit -m message
>> $ ( cd ../a && git branch gif-support) # Assume done by someone else
>> $ git checkout master
>> $ # <hack away, maybe commit a bit>
>> $ git push  # <-- OOOPS! pushes gif-support!
>>
>> Notice that what branches git push ends up pushing is out of your
>> control, since new branches can appear in the remote repository at any
>> time. This is very unfriendly in our setup with a shared incoming repo.
>>
>> If developer A creates "gif-support", shares it with developer B, who
>> does an additional commit on it to make it print more debug info (but
>> has no intent of pushing it anywhere), and A pushes it to the "incoming"
>> repo, developer B risks overwriting that with his debug version.
>>
>
> git push will never overwrite changes in the remote repo unless you
> specify --force. If anyone *blindly* uses --force, they really shouldn't
> have write-access to anything so precious as your code repositories.

It's seems a very likely scenario to me.

I work on a remote branch with one other person, to make some new
feature.  Once we are done, I rebase and get rid of the cruft from the
history, then "git push --force" to update the branch.  Whoops, I've
just unknowingly wiped out a completely different branch.

>
> Worst-case scenario, you commits that were never intended for publication
> enter your public wateringhole and needs a revert later on. Big deal.
>
>> It is not realistic to believe that in a big project with many
>> developers, no one will ever do the mistake of typing "git push".  It
>> is also not realistic to believe that everyone will know how to (or
>> remember to) configure this away.
>>
>
> But it *is* realistic to not assume that they will also use --force
> while doing so.
>
>>> If you shoot for the least damage for such people, the sanest default for
>>> "git push" would be to do nothing.  You *always* say what to push where,
>>> then there is no risk of pushing something you did not intend to.
>>>  Perhaps
>>> "push.default = never" configuration may not be such a bad idea?
>>
>> If "git push" could do nothing at all without configuring anything, that
>> would be a big improvement to us.
>>
>
> I can buy this, I guess. I always type the remote-name I want to push to
> anyways. A sane no-op default would probably be to list the pre-configured
> remotes along with a short usage message. I still don't quite see the point
> of it.

If people don't agree on changing 'git push' to affect only the
current branch, I would also go for making 'git push' a noop.

John

>
> --
> Andreas Ericsson                   andreas.ericsson@op5.se
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