Don't checkout master locally

It’s common to use short-lived branches to organize your work into individual features, instead of committing directly onto persistent “mainline” branches like master. This:

• Ensures you have an easy way of getting back to a known good state that’s not in the middle of some new feature
• Logically groups individual features/bug fixes
• Makes it easy to manage multiple concurrent changes

But even if you don’t commit directly onto a local master branch, you still often need to refer to the remote master branch to do things like:

• Start new feature branches off of master.
• Take changes that have been made to master and pull them into a feature branch.
• Do diffs against master.

You don’t need to have a locally checked out master branch to do any of that: git already allows you to refer to remote branches directly, via remote tracking branches, like origin/master.

• Need to do a diff against master? git diff origin/master
• Need to pull in changes from master? git merge origin/master (usually after a git fetch origin; or just do git pull origin master in one step)
• Need to start a new branch based on master? git branch my-new-branch origin/master

Sometimes you need more direct access to the content at master. E.g., maybe you want to just do a build at master, without necessarily starting a new topic branch.

You can do this using detached heads. In addition to checking out branches, git lets you check out arbitrary commits. So you can just checkout a remote tracking branch directly, with git checkout origin/master.

Why not just checkout master? Because it’s simpler not to: If you checkout master locally, you now need to mentally deal with your local view of the remote master (origin/master) and your local copy of master (master), which can diverge.

E.g., without a local master branch, bringing in changes from master is git pull origin master. If you have a local copy of master (and you don’t want it to become stale), you’d instead need to:

# starting with a feature branch checked out
git checkout master
git pull origin master
git checkout -
git merge master

↩   January 22, 2019