git_sparse_checkout using a branch tag

[jedwards4b]

If I try to use a branch tag in the git_sparse_checkout script I get an error in the checkout step:
error: pathspec 'branch_tag_name' did not match any file(s) known to git

I found that if I use the branch instead of the branchtag and then add additional commands:
git -C /path/to/submodule fetch -t -depth=1
git -C /path/to/submodule checkout branchtag

It will do what I need it to do, however I think that the fetch command could be improved to get less.

[jedwards4b]

This didn't work for a submodule that was referenced by hash instead of branchtag.
However I found that replacing both the additional commands with
git restore submodulename
gives what I want to happen.