Could not access submodule when pulling recursively with git 2.21

Could not access submodule when pulling recursively with git 2.21

[Moritz Winter]

Hi,

I've recently upgraded to git from 2.20.1 to 2.21 and now my projects
with submodules show a access error when pulling recursively.

I have a couple of projects on gitlab.com that use two or more
submodules. The .gitmodules file is slightly changed for gitlab.com
compatibility. The paths are relative as described in:

https://docs.gitlab.com/ee/ci/git_submodules.html

Before updating git I could pull the submodules recursively within the
main repository. Now I get a "Could not access submodule 'foo'" error.

Example:

$ git -v
git version 2.20.1

$ git pull --recurse-submodules=true
Fetching submodule 'foo'
Fetching submodule 'bar'
Already up to date.

$ git -v
git version 2.21.0

$ git pull --recurse-submodules=true
Fetching submodule 'foo'
Fetching submodule 'bar'
Could not access submodule 'foo'
Could not access submodule 'bar'

This only happens in projects with two or more submodules. A project
with one submodule does work as expected. Additionally I have a
password protected ssh key if this is relevant.

$ uname -a
Linux box 4.19.28-1-MANJARO #1 SMP PREEMPT Sun Mar 10 08:32:42 UTC
2019 x86_64 GNU/Linux

Is this a regression in git or is there a error on my end/gitlab.com?
My workaround currently is to downgrade to git v 2.20.

I've already filed a bug with gitlab.com:

https://gitlab.com/gitlab-org/gitlab-ce/issues/58891

Thanks & best regards

Moritz