Misleading error message when creating a PR on an empty repo

Summary

Unable to create a PR within a repository which while it's main(forked) repository is an empty repository.

Steps to Reproduce

1. Create an empty repository
2. Fork the empty repository
3. Add changes and branches on the Fork repository
4. Navigate to Pull Request page to create PR
5. Change the destination repository to the current repository (not the main(forked) repository)
6. Click Create Pull Request

Expected Results

Being able to create a pull request to the upstream repository regardless if its empty or not

Actual Results

After clicking on Create pull request, a "something went wrong" error shows up.

Workaround

Add at least a commit in the upstream repository