How to remove all commit history from a Git branch and rebuild it

Sometimes you accidentally commit sensitive data and need to completely remove the commit history of a branch.
The safest way to do this is by recreating the branch as an orphan branch, which removes all previous commits while keeping the current files.

This approach works for any branch (main, bleeding-edge, legacy, etc.).

Steps

First, check out the branch you want to clean:

git checkout main

Create an orphan branch (no history, working tree unchanged):

git checkout --orphan main-clean

Commit the current state as the new starting point:

git add .
git commit -m "cleanup"

Replace the old branch and force-push it:

git branch -D main
git branch -m main-clean main
git push origin main --force

After this, the branch will contain only one commit, and the previous history will no longer be referenced by the branch.

Cheers.