Trunk-based development in Git: What it is and when to use it

Ever feel like Git workflows can get a bit overwhelming? With all the branching, merging, and potential for conflicts, it's easy to lose track of where your code fits in.

That's where trunk-based development comes in. It's a simpler approach that keeps everyone on the same page and the codebase clean. Let's dive into what trunk-based development is all about and see how it stacks up against feature branching.

Understanding trunk-based development in Git

Trunk-based development is a Git workflow that revolves around a single trunk or mainline branch. This central branch is where all developers integrate their changes frequently—often daily. By committing directly to the trunk, teams promote continuous integration and maintain a stable, release-ready codebase.

In this setup, developers work on small, incremental changes and commit them straight to the trunk. This approach minimizes the risk of merge conflicts and ensures the codebase stays in a consistently deployable state. By integrating changes frequently, teams can spot and fix issues early, reducing the chances of prolonged integration problems.

To make trunk-based development flow smoothly, teams often use feature toggles or feature flags. These tools let developers introduce new features without disrupting the main codebase. By toggling features on or off, teams can control the visibility and availability of specific functionalities without needing long-lived feature branches.

While trunk-based development offers benefits like faster integration and reduced merge complexity, it does require a high level of discipline and collaboration among team members. Developers need to ensure their changes are thoroughly tested and don't introduce instability to the trunk. Robust automated testing and continuous integration practices are crucial to keep the codebase healthy.

At Statsig, we've seen how trunk-based development can streamline workflows and enhance team collaboration. By adopting this approach, teams can focus on delivering value rather than managing complex Git histories.

Trunk-based development vs. feature branching

So how does trunk-based development stack up against feature branching? Trunk-based development uses a single mainline, while feature branching employs multiple isolated branches. In trunk-based development, developers commit directly to the trunk, which fosters collaboration and reduces merge conflicts through frequent integration. Feature branches, on the other hand, allow developers to work independently on separate branches, sometimes for extended periods.

Long-lived feature branches can lead to divergence from the mainline, resulting in complex merges and potentially hindering team cohesion. Trunk-based development mitigates these risks by promoting small, incremental changes and continuous integration. By keeping the trunk as the single source of truth, this approach streamlines the development process and ensures a more stable codebase.

However, feature branching isn't without its merits—especially when managing large-scale changes or experimental features. It provides a controlled environment for development and testing before merging into the mainline. The key is to keep feature branches short-lived and regularly sync with the trunk to minimize divergence.

Ultimately, choosing between trunk-based development and feature branching depends on your team's size, project complexity, and release cadence. Smaller teams and projects with frequent releases might benefit from trunk-based development's simplicity and collaboration-friendly approach. Larger teams or projects with longer release cycles might find feature branching more suitable for managing parallel development efforts.

Regardless of the path you choose, adopting continuous integration practices and maintaining a disciplined merging strategy are crucial for success. By automating builds, tests, and deployments, you can catch integration issues early and keep your codebase in top shape.

Advantages of trunk-based development

One of the biggest perks of trunk-based development is how it enhances collaboration through shared responsibility and collective code ownership. When everyone works on a single branch, developers are more likely to communicate and coordinate their efforts. This fosters a culture of teamwork and mutual support, with everyone invested in maintaining a stable and functional codebase.

Trunk-based development also supports continuous integration and continuous delivery (CI/CD) by ensuring the mainline is always in a deployable state. With frequent commits and automated testing, issues can be identified and resolved quickly. This enables teams to deliver value to users more rapidly and reliably, as the software is constantly evolving and improving.

Another advantage is simplified branch management. By reducing the number of long-lived branches, teams can avoid the challenges associated with complex merging and integrating changes. This streamlined approach lets developers focus on writing code and delivering features, rather than navigating a tangled web of branches.

Additionally, trunk-based development encourages breaking down work into smaller, more manageable chunks. By committing code frequently and integrating it with the mainline, developers can receive timely feedback and catch potential issues early on. This iterative approach helps maintain code quality and reduces the risk of introducing bugs or conflicts.

Lastly, feature flags are a powerful tool in the trunk-based development arsenal. They allow developers to toggle features on and off without the need for separate branches. This enables teams to test and validate new functionality in a controlled manner, gather user feedback, and make data-driven decisions before fully releasing a feature. Tools like Statsig's feature management platform can help teams implement feature flags effectively.

When to use trunk-based development

Trunk-based development is ideal for teams practicing continuous delivery and needing rapid, frequent releases. It's best suited for projects requiring high collaboration and minimal merge conflicts. However, it requires disciplined testing and automation to ensure code stability.

Teams embracing trunk-based development should be comfortable with a fast-paced, highly collaborative environment. They need robust continuous integration practices to catch issues early, and automated testing is crucial to maintain code quality.

This approach works well for projects with a single, stable production version. It's less suitable for managing multiple versions or long-term support branches. In those cases, feature branching or even more structured workflows like GitFlow might be more appropriate.

Before jumping into trunk-based development, assess your team's readiness and project requirements. Make sure you have the necessary infrastructure and processes in place. With the right setup, trunk-based development can streamline your workflow and accelerate delivery.

Closing thoughts

Trunk-based development offers a streamlined and collaborative approach to Git workflows. By focusing on a single mainline and integrating changes frequently, teams can reduce merge conflicts and deliver features faster. It's all about keeping the codebase stable and everyone moving in the same direction.

If you're curious to learn more, check out resources from Statsig or dive into articles on continuous integration practices. Embracing trunk-based development might just be the boost your team needs. Hope you found this useful!