Re: How to checkout a revision that contains a deleted submodule?

[Luke Diamand <luke@diamand.org>]

On Sun, 20 Sep 2020 at 19:02, Kaartic Sivaraam
<kaartic.sivaraam@gmail.com> wrote:
>
> On 20/09/20 3:14 pm, Luke Diamand wrote:
> > On Sat, 19 Sep 2020 at 10:03, Luke Diamand <luke@diamand.org> wrote:
> >>
> >> Maybe this is a FAQ, but I couldn't figure it out!
> >>
> >> I have a repo which has a couple of submodules.
> >>
> >> At some point in the past I deleted one of those submodules:
> >>
> >>      git rm sub2
> >>      git add -u
> >>      git commit -m 'Deleting sub2'
> >>      git push origin
> >>      ...
> >>      ... more commits and pushes...
> >>
> >> Now I go and clone the head revision. This gives me a clone which has
> >> nothing present in .git/modules/sub2.
> >>      login on some other machine
> >>      git clone git@my.repo:thing
> >>      cd thing
> >>      ls .git/modules
> >>      <sub2 not present>
> >>
> >> So when I go and checkout an old revision where sub2 is still around I get:
> >>      git checkout oldrevision
> >>      fatal: not a git repository: sub2/../.git/modules/sub2
> >>
> >> What am I doing wrong?
> >> What set of commands do I need to use to ensure that this will always
> >> do the right thing?
> >>
> >> Thanks
> >> Luke
> >
> > Replying to myself, adding Jens who added the section below.
> >
> > This is a known bug:
> >
> > https://git-scm.com/docs/git-rm
> >
> >> BUGS
> >> ----
> >> Each time a superproject update removes a populated submodule
> >> (e.g. when switching between commits before and after the removal) a
> >> stale submodule checkout will remain in the old location. Removing the
> >> old directory is only safe when it uses a gitfile, as otherwise the
> >> history of the submodule will be deleted too. This step will be
> >> obsolete when recursive submodule update has been implemented.
> >
>
> I don't think that part of the documentation applies to your case. So,
> I also don't think this is a known bug. As a matter of fact, I couldn't
> reproduce this with the following:
>
>
>  git init checkout-removed-submodule &&
>  cd checkout-removed-submodule/ &&
>  echo "Hello, world" >foo &&
>  git add foo && git commit -m "Initial commit" &&
>  git init ../submodule &&
>  cd ../submodule/ &&
>  echo "Foo bar" >foobar.txt &&
>  git add foobar.txt && git commit -m "Foo bar baz" &&
>  cd ../checkout-removed-submodule/ &&
>  git submodule add ../submodule/ foobar &&
>  git commit -m "Add foobar submodule" &&
>  git rm foobar/ &&
>  git commit -m "Remove foobar submodule" &&
>  git checkout HEAD~ # Checking out the "Add foobar submodule" commit
>
> I get:
>
>  HEAD is now at 25270d8 Add foobar submodule
>
>
> I also tried with a cloned version of that repository as follows:
>  git clone /me/checkout-removed-submodule/ cloned-repo &&
>  cd cloned-repo &&
>  git co HEAD~
>
> I get:
>
>  HEAD is now at 25270d8 Add foobar submodule
>
> So, I don't get any errors when I checkout a revision where the deleted
> submodule is still around. There might other factors in play such as,
>
> - the version of Git being used
> - whether `--recurse-submodules` was passed to checkout
> - the configuration of the submodule in .gitmodules
>
> It would be great if you could share these and possibly other useful
> information to help us identify why you get an error when checking out
> the revision.

Thanks for taking the time to answer!

I will see if I can come up with a test case.

Luke