git submodule of reference with no branch

Hello,

I use Gerrit as a code review platform, there are some events in which I would like to review a feature that touches two repositories, one is a submodule of the other.

The git module reference is set correctly, but since the change is under refs/changes/xxx and not under refs/heads/xxx, git cannot find this reference when trying to check out the repository.

I could not find any option to either have an explicit reference without a branch or somehow to tweak the configuration to search under refs/changes instead of refs/heads.

I understand the branch concept makes sense when updating as usually we are following a repository branch stream, however, I do not understand what purpose does the branch serve during checkout. The checkout should be possible based on the reference regardless of the branch.

Does anyone have an idea if it is possible to have a submodule with a reference only or tweak git to search a different hierarchy of refs?

Thanks, Alon