Branches¶

A branch is a separate line of work. You can try something on a branch without affecting main, then merge it in when it works.

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gitGraph TB:
    commit id: "Add README"
    commit id: "Add parts list"
    branch add-sensors
    checkout add-sensors
    commit id: "Add sensor list"
    commit id: "Add wiring notes"
    checkout main
    merge add-sensors

On a team, main should always work. New features and fixes happen on branches.

Create and switch branches¶

cd ~/my-robot
git switch -c add-sensors     # create a branch and switch to it
git branch                    # list branches; * marks the current one

Make a commit on the branch:

nano sensors.md
git add sensors.md
git commit -m "Add sensor list"

Switch back to main:

git switch main
ls

sensors.md is gone. It exists only on the add-sensors branch. Switch back and it returns:

git switch add-sensors
ls

Commit before switching

If you have uncommitted changes, Git may refuse to switch branches. Commit them first.

Merge a branch¶

When the work is done, merge it into main:

git switch main
git merge add-sensors
git log --oneline

main now has the sensor commit. Delete the branch, since its work is in main:

git branch -d add-sensors
git push

Naming branches¶

Use short, descriptive names with hyphens, such as add-lidar-driver, fix-motor-direction or docs-wiring.

Exercise¶

Create a branch called add-goals.
Add a goals.md file and commit it.
Edit README.md on the same branch and commit again.
Merge it into main, delete the branch, and push.

On a team you usually don't merge into main on your own laptop. You open a pull request so someone can review first, which is the next lesson.