If you are leveraging git submodule for Hugo themes and you are accustomed to using
git diff to see what changes you made and totally forgot to commit, you will need to tweak your command for git submodules. By appending
--submodule=diff you will see diffs for submodules as well:
$ git diff --submodule=diff
You can run this command at your top level repo and see all changes in that repo plus submodule(s) or
cd into a specific submodule and see see the diffs for those changes only.