Produce both kinds of merge on purpose

kind: drill

In a test repository, produce first a fast-forward merge and then a merge commit. Show with git log --graph --oneline that the histories differ.

Solution

Fast-forward: branch off, commit only on the branch, merge — the graph stays a line. Merge commit: branch off, commit on the branch and on main, then merge — the graph forks and joins, and git log shows a commit with two parents. You can force the second form with git merge --no-ff when you want the record even though a fast-forward would be possible.

Recover a deleted branch

kind: drill

Create a branch with two commits, switch away, delete it with git branch -D, then get it back.

Solution 
git reflog                      # find the hash of the branch tip
git switch -c feature/x <hash>

The commits were never deleted — only the pointer was. Unreferenced commits are removed eventually by garbage collection, but not immediately, which is what makes this recovery possible.

Name five branches for real work

kind: drill

Write branch names for: exporting attendance to CSV, fixing a crash on an empty list, updating the README, trying out a new database schema, preparing the milestone presentation.

Solution

For example feature/attendance-csv-export, fix/empty-list-crash, docs/readme-setup, spike/schema-v2, docs/milestone-1-slides. What matters is that the name says what the branch is for — felix and test2 do not.