git 2.39.0 change from relative to absolute submodule paths

[Adam Dinwoodie]

On Wed, May 17, 2023 at 06:26:38AM +0000, Fuchs, Thorsten via Cygwin wrote:
> Hello,
> 
> After submodule update with git 2.39.0 some of our sub modules got
> their worktree settings in the .git/modules/<submodul>/config fil set
> as absolute paths. See the attached config files as example. It seems
> that if the path is changed from relative. Not all submodules are
> effected. It happens also sporadically and not and very frequently.
>
> It is possible to carry on working Cygwin git. However, we are using
> Tortoise git with libgit2 and git for windows in parallel. Due to the
> absolute Cygwin paths this is not working anymore.
>
> We have not yet seen such a behavior in git for windows. Also we can't
> reproduce it at this point in time. We consider it a bug but nor sure
> about it.

This is odd.  I suspect rewriting the paths like this is something in
the upstream Git project, rather than anything Cygwin-specific (although
clearly the issues it's causing are Cygwin-specific).  I don't think
there's enough information here for me to investigate or report
upstream, unfortunately; what I really need is information about what
triggers the behaviour so I can reproduce the problem.

If you manage to work out how to reproduce this behaviour, rather than
just noticing it after the fact, that would be incredibly useful and I
can take things from there.

Adam