Refactoring Git Branches with Interactive Rebase and Autosquash in Android Studio

For most developers, Git is the go-to version control system for their software projects. At PSPDFKit, we host all our projects on GitHub, and many of them inside our monorepo, which currently counts about 50 active contributors. Our teams pride themselves on a clean commit history — not only on our main branch, but also inside the working branches maintained by individuals.

One particularly useful tool for keeping a clean commit history on a working branch is Git’s --interactive rebase option. Building on top of Git’s regular git rebase command, interactive rebasing allows users to modify single commits of the rebased branch by applying transformations such as commit renaming, reordering of all commits, removal of unwanted commits, merging of two or more commits into one, and more.

As an Android developer who likes to stay inside my preferred IDE as much as possible, I’m happy that Android Studio offers an easy-to-use integration of interactive rebasing that serves all my needs for commit housekeeping. Let’s look at how it works!

Whoops! A Typpo.

fun List<String>.fuzzyMatc(filterQuery: String): List<String> {
  // Fuzzy stuff in here.
}

git add .
git commit -m "Add fuzzy matcher method"
git push

git add .
git commit -m "Fix typo in method name"

❯ git log --format=oneline
6c1356e (HEAD -> fuzzy-feature) Fix typo in method name
e28d2e3 Add fuzzy matcher method

Let’s (Re)Write History

The mindful Git user probably noticed that the demonstrated fix could have been done using git commit --amend as well. However, using interactive rebase, it’s possible to fix up much older commits too — rather than only the previously committed one — by simply dragging the fixup commit right after the target to fix up.

Sasquatch? Autosquash!

While not as renowned as Bigfoot, --autosquash is a very real Git option for rebasing — one that autoconfigures the interactive rebase dialog when using specific Git commit naming conventions.

Consider the previous example: With autosquash, instead of manually marking a commit as a fixup for another commit, it’s sufficient to start the fixup commit message with !fixup, followed by the message of the commit to fix up. For example:

git commit -m "fixup! Add fuzzy matcher method"

Here’s how our commit log would look now:

❯ git log --format=oneline
bcc8e09 (HEAD -> fuzzy-feature) fixup! Add fuzzy matcher method
e28d2e3 Add fuzzy matcher method

After running git rebase --interactive --autosquash, Git will configure the rebase dialog the same way we did it manually before.

But how does this work within Android Studio? It gets even simpler. Instead of committing the fixup changes manually — either from the command line, or even from within Android Studio — all you need to do is right-click the fixup target commit inside Android Studio’s Git tool window, and then select Fixup… You can then commit the changes as suggested by Android Studio, which will automatically use the correct commit message:

After that, you continue with interactive rebasing, as explained before.

Piecing It Together

git config --global rebase.autosquash true

It’s safe to enable this option, since Git will only ever autoconfigure your interactive rebase if there are commits prefixed with !fixup, !squash, or similar commands. (Check out Git’s --autosquash reference docs for the extensive list of commands.)

Is There More?

As Martin Fowler once said: “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” In my opinion, the same applies to Git commit histories. So, to become better programmers, let’s rewrite history together!