How do I fix the metainformation on the first commit in git?

Question

This is a related question to How do I edit git’s history to correct an incorrect email address/name. Using git rebase -i <first commit>, git commit --amend --author "Foo <foo@example.com>", and git rebase --continue, I was able to fix the logs for all of the commits but the first one. How do I fix the first commit?

Answer 1

After much trial and error, the following recipe was found to work:

# tag the root-most commit so we can reference it
git tag root `git rev-list HEAD | tail -1`
# check it out on its own branch
git checkout -b new-root root
# amend the commit
git commit --amend
# now you've changed the commit message, so checkout the original branch again
git checkout @{-1}
# and rebase it onto your new root commit
git rebase --onto new-root root
# then nuke the temporary branch and tag we created
git branch -d new-root
git tag -d root

true credit should go to drizzd on #git for this answer.