Re: inside the git folder

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Chris,

as mentioned by Stefan (who is a respected, active core Git contributor,
if you need any more arguments to listen to him), it is inappropriate to
copy the contents of the .git/ directory wholesale to another user's
machine.

For one, it would horribly break in case the user overrode `user.email` in
`.git/config`. That's one setting that should not be copied *anywhere*.
And that's just one, there are *plenty* more examples. Just think of
absolute paths referring to files that probably do not even exist on
another machine! Like, worktrees, etc.

Of course, you could start a list of exceptions (files, config keys, etc)
that should not be copied. But that's very fragile a solution.

So no, copying the .git/ directory is always the wrong thing to do, as
Stefan pointed out.

I could imagine that a much better idea is to identify a *positive* list
of things you want to copy over. The output of `git rev-parse
--symbolic-full-name HEAD`? Sure. Maybe even the output of `git rev-parse
--symbolic-full-name HEAD@{u}`? And then the URL of the corresponding
remote? Sure. `.git/objects/alternates/`? Absolutely not.

It is tedious, alright, but you simply cannot copy the contents of .git/
to another machine and expect that to work.

Ciao,
Johannes

On Thu, 4 Oct 2018, Chris Jeschke wrote:

> Hi Stefan,
> 
> thanks for your answer.
> 
> The Goal after sending the files is to have a copy on the remote site.
> This includes that the working directory is the same (what we already
> guarantee with our tool) and that git is at the same 'state' (that
> means that we have the same history and that we checkout at the same
> branch/commit).
> My idea:
> Send the working directory with our  tool
> Initialize a Git directory on the remote side
> Send the 'objects','refs', 'HEAD' and the 'gitignore' with our tool
> 
> Is there anything else I should take care of?
> 
> Am Mi., 3. Okt. 2018 um 20:51 Uhr schrieb Stefan Beller <sbeller@google.com>:
> >
> > On Wed, Oct 3, 2018 at 5:26 AM Chris Jeschke
> > <chrisjberlin@googlemail.com> wrote:
> > >
> > > Hey git-team,
> > > I am working on a plug-in for a distributed pair programming tool. To
> > > skip the details: I was thinking about sending parts of the git folder
> > > as a zip folder with our own Bytestream instead of using the git API.
> > > Is there a common sense about what should and what shouldn't be done
> > > when working with the files inside the git folder?
> >
> > This contradicts the security model of git.
> > Locally I can do things like:
> >     git config alias.co "rm -rf ~"
> >     echo "rm -rf ~" >.git/hooks/{...}
> > and I would experience bad things, but that is ok,
> > as I configured it locally (supposedly I know what
> > I am doing); but if I have the ability to send these
> > tricks to my beloved coworkers, hilarity might ensue.
> >
> > What stuff do you need to send around?
> >
> > objects? Fine, as the receive could check they are
> > good using fsck.
> >
> > refs/ ? Sure. It may be confusing to users,
> > but I am sure you'll figure UX out.
> >
> > local config, hooks ? I would not.
> >
> > Not sure what else you'd think of sending around.
> >
> > Cheers,
> > Stefan
>