Simplify Git commit fixes using fixup and auto-squash

Throughout a project I will typically make commits that could be categorised as fixes to previous commits. To help highlight such commits I would follow the pattern of starting the message with ‘fix: …’, making the final rebase step (before merging into master) easier. However, as time passed locating which ‘fix-commits’ related to other previous commits became harder to determine.

I would typically have to resort to reviewing these commits to work out the context, as fixes would not always occur in an chronological order.

One day a colleague noticed me doing this, and pointed me in the direction of a great feature available in Git (since 1.7). This feature allows you to make a commit which is conceptually ‘tagged’ as a fix to a previous commit. These commits all follow the ‘fixup! Subject commit message’ naming convention, and can be auto-squashed when performing an interactive rebase. The great benefit of doing this is it not only marks the commit as a ‘fixup’, but also reorders the commits allowing you to typically just apply the changes without any modification. Below is a contrived example showcasing the usage of this feature.

git add . # stage fixes for 9c8735
git commit --fixup=9c8735
git rebase -i --autosquash 9c8735~1 # one before the subject commit