git remote add project-a path/to/project-a
git fetch project-a
git merge --allow-unrelated-histories project-a/master # or whichever branch you want to merge
git remote remove project-a
On the git merge command, the --allow-unrelated-histories failed.
So then I tried it without the flag
I have merge conflicts now. Ideally anything within RepoB/master (what's being pulled into RepoA/whatever) will override any merge conflicts.
I would do a PR Mitt, but this needs to be a repeatable process. Something that I can do with many many branches.