Cause a conflict on purpose and resolve it

kind: drill

In a shared practice repository, two people change the same line of the same file on two branches. Merge both into main and resolve the conflict.

Solution

The first merge is a fast-forward or a clean merge; the second reports the conflict. Resolve by reading both versions and deciding what the code should do — often the answer is a third version containing both intentions. Then git add, git commit, and run the build before you push.

Produce a diverged branch and repair it

kind: drill

Commit locally, then commit something else to main through the web interface, then try to push.

Solution

The push is rejected. git status reports "diverged". git pull creates a merge commit joining both lines, then the push works. Note what you did not do: --force, which would have deleted the web commit.

Recover a commit made on main by mistake

kind: drill

Commit directly to main, then move that commit onto a branch and restore main.

Solution 
git switch -c fix/oops        # branch now contains the commit
git switch main
git reset --hard origin/main  # main back to the remote state

reset --hard discards local changes on main — safe here precisely because the commit is already saved on the new branch. Check with git log on both before you reset.

Establish the team routine

kind: project

Agree in your team on when everyone pulls, how conflicts are resolved and who merges, and write it into the project README.