You type git push , hit Enter, and Git slaps you with a rejection. No warning. No obvious reason. Just an error that makes you stare at the screen wondering what you broke. You didn't break anything — but you do need to fix it. Here's how. What's Actually Going On When Git says your push was rejected due to a non-fast-forward error , it's telling you one specific thing: your local branch and the remote branch have diverged — they've each gone in different directions since their last shared point. In plain terms: someone (or something — maybe an automated CI commit) added a commit to the remote branch after you last pulled. Now your local branch has a commit the remote doesn't, and the remote has a commit you don't. Git's response? Refuse the push. Pushing would silently overwrite the remote's new commit, and Git will never let that happen without a fight.…