Teams with many developers collaborating on shared repositories understand all too well the headaches that come with merging code, maintaining it, branching off, and rolling out releases. What they might not know is that a solid branching strategy can help reduce merge conflicts, improve code quality and time-to-market.
Today, we’re exploring the top two branching strategies of the last decade: Trunk-Based Development (TBD) and Git Flow. In the past few years, Trunk-Based Development has surged in popularity — largely due to its compatibility with CI/CD — and this shift has in turn contributed to a decline in the popularity of Git Flow. Although Git Flow still holds value for its rigorous management of development stages and clear workflows, it’s becoming less favored as more teams move towards more agile, DevOps-aligned methodologies.
We’ll break down the main characteristics of each strategy and assess which types of projects and teams they’re best suited for.
What is Branching in Version Control?
Branching is a powerful tool that gives your development teams a dedicated space to work on their code changes before merging them into a main branch. It enables features to be developed on separate branches, bug fixes to be addressed independently, and other tasks to be handled without disrupting the main branch. However, this process often leads to merge conflicts.
Merge conflicts are a common source of frustration for your developers and can significantly impact your team’s productivity and time to market. Luckily, a well-implemented branching strategy can reduce their occurrence, making this a crucial process to ensure successful and timely releases.
What is Trunk-Based Development?
TBD is a highly efficient source control branching model. It encourages developers to integrate small, frequent changes into a single trunk or master branch, ensuring a streamlined and efficient development process.
In Trunk-Based Development, all team members work on a single shared branch known as the trunk or mainline. There could be short-lived branches, but the emphasis is on frequent commits and maintaining shippable code at all times.
How does Trunk-Based Development Help Reduce Merge Conflicts?
TBD also helps minimize merge conflicts. For instance, if developers Alice and Bob are working on related features, they continuously merge their small, isolated changes into the trunk. This frequent integration helps detect and resolve conflicts early, preventing large, complex issues that arise from long-lived branches. Automated tests and continuous integration pipelines further ensure that each integration maintains the trunk’s stability, keeping it always ready for deployment.
What are the pillars of Trunk-Based Development?
Let’s discuss some core pillars that form the foundation of Trunk-Based Development. These are also essential and guide the development process.
- The trunk is the main branch, also known as the mainline or trunk, and is the single source of truth. All changes need to propagate to this at frequent intervals.
- Code Review is the backbone of TBD. With changes being committed frequently, a robust review process is essential.
- TBD encourages devs to push small, frequent commits. This process ensures that code is committed regularly – even multiple times throughout the day – significantly reducing the likelihood of merge conflicts. By keeping these conflicts limited to very small chunks of code, they also become easier to review and fix.
- Continuous Integration: As code is committed, an automatic build process gets triggered, which then kicks off an automated test to check for quality. This process ensures that any failures are addressed immediately and automatically.
- Feature Flags: For users needing more flexibility, feature flags (or toggles) can merge new code directly into the main branch without immediately exposing these changes to all users. This approach allows for testing new features in production environments under real conditions. Once tested, the feature can be turned off without deploying new code.
- Releasable State & Monitoring: In Trunk-Based Development, the mainline failures are immediately attended to, and the mainline is always in a ‘releasable state’. This means it has gone through a series of reviews, validation, and testing, and is ready for deployment. Continuous monitoring is also crucial, where the feedback is continuous, which helps with the overall code quality.
Who Should Adopt Trunk-Based Development and Why?
Trunk-Based Development has proven successful for many teams and organizations across different industries, stages of development and priorities. Below are some of the key reasons why certain teams have found success with TBD.
- Agile Development teams: Agile is a natural companion for Trunk-Based Development. It can speed up feedback loops, decrease integration issues, and streamline bug detection and fixing. These benefits translate into enhanced collaboration, accelerated delivery, and improved customer satisfaction, making it an ideal choice for Agile teams.
- Microservices Architecture-based Teams: Microservices architecture is a business approach in which a single application is composed of many smaller, independent services, each responsible for a specific function. This makes these teams highly dependent on good communication and integration processes. A robust CI/CD driven by TBD is necessary for microservices teams to succeed as it reduces the complexity of integration and rollbacks.
- Organizations Driving Quality First: Organizations that prioritize high-quality software above all tend to implement extensive automation early in the development process. TBD aligns perfectly with these goals by promoting frequent, small commits. Coupled with continuous integration and testing, each small code change can be automatically tested and validated for the highest quality.
- Startups: For startups, the ability to pivot, release rapidly, and adapt swiftly to changes is crucial. Complex branching methodologies can slow down these efforts, potentially leading to failure. TBD, on the other hand, is an ideal match for startups. It accelerates the release cycle, improves time to market, and fosters a culture of embracing changes, all of which are vital for startup success.
Git Flow
If TBD encourages short-term branching, Git flow revolves around multiple and typically long-lived branches. Git Flow is a Git branching strategy that sets up a clear workflow for teams planning regular releases.
It uses two main branches: ‘master’ for your live production releases and ‘develop’ for day-to-day development work. When you’re adding new features, you branch off from ‘develop’ into ‘feature’ branches. Once you’re ready to roll out a release, you spin up a ‘release’ branch to fine-tune everything. If something breaks in production, you quickly fix it in a ‘hotfix’ branch.
What Are the Pillars of Git Flow?
- Branch Organization: Git Flow organizes its branches into two main types: long-lived and short-lived branches. The long-lived branches include ‘master’ for production releases and ‘develop’ for ongoing development. Short-lived branches are created for features (‘feature’ branches), releases (‘release’ branches), and urgent fixes (‘hotfix’ branches).
- Clear Workflow: This model defines a clear and predictable workflow for managing features, releases, and fixes. By clearly separating development efforts (on ‘develop’ and ‘feature’ branches), release preparations (on ‘release’ branches), and emergency corrections (on ‘hotfix’ branches), Git Flow helps manage complexity and maintains stability in production.
- Parallel development: Git Flow empowers developers by providing robust support for managing various versions of production releases with parallel development. Each branch is focused on a different goal, reducing dependencies and making it a breeze to track and manage different versions of your software.
- Release Management: One of the strengths of Git Flow is its strong emphasis on release management. The use of dedicated ‘release’ branches allows for pre-release adjustments like bug fixes, documentation generation, and other release-specific tasks without disrupting ongoing development on the ‘develop’ branch.
- Hotfixes: The ability to address issues in production without disrupting the flow of ongoing development work is facilitated by hotfix branches. These branches allow critical fixes to be applied directly to the production environment (‘master’ branch) and then merged back into the development line (‘develop’), ensuring all subsequent releases include these fixes.
- Standardization and Discipline: Git Flow enforces a disciplined approach to source code management, which is particularly useful in team environments and larger projects. It standardizes the development process so that team members know exactly where to branch off and merge, reducing the chances of conflicts and confusion.
TLDR;
Git Flow and Trunk-Based Development (TBD) both offer unique advantages tailored to different development needs and team structures:
Git Flow is perfect for teams that need structured, sequential releases. It is particularly effective for larger teams and projects that require thorough staging and testing before deployment. The model’s use of multiple branch types allows for detailed management of features and fixes, ensuring that each release is stable and vetted. That is why Git Flow is ideal for complex projects with stability requirements or those that must comply with strict regulatory standards.
On the other hand, Trunk-Based Development is best suited for teams prioritizing rapid iteration and continuous integration. TBD encourages all developers to work collaboratively on a single branch (the trunk), minimizing the complexity and overhead of managing multiple branches. This approach supports a faster cycle of feedback and deployment, making it ideal for agile teams that aim for frequent and incremental updates. TBD is particularly effective in reducing merge conflicts and aligning closely with DevOps practices, promoting a more streamlined and dynamic development process.
In short, Git Flow is the go-to for teams needing rigorous release management and stability, while Trunk-Based Development shines in fast-paced environments that value quick releases and collaborative development. Each method has its strengths, and the choice between them should be based on the specific needs and goals of your project and team.
