When it comes to managing software development, there are many different approaches to choose from. One such approach is trunk-based development (TBD), which is becoming increasingly popular among development teams. TBD is an approach where all developers work on a single shared codebase, the “trunk”. In this approach, code changes are committed to the trunk frequently, and the trunk is always kept in a deployable state, i.e., TBD involves developers working on a shared codebase, with changes being committed directly to the main branch of the repository.  

Rather than working on separate branches for features or bug fixes, developers collaborate on the same codebase and integrate their changes directly into the trunk. It encourages continuous integration and reduces the risk of conflicts or integration issues that can arise when merging changes from separate branches. 

When should you choose trunk-based development (TBD)? 

Trunk-based development is best suited for teams with high collaboration and trust, as changes are committed directly to the main branch without any separate branch or pull request workflow. This means that developers must be comfortable working on a shared codebase and have confidence that their changes will not negatively impact the codebase as a whole. 

TBD is also well-suited for projects with a high stability level and a low risk of conflicting changes. TBD may not work with projects that have a high degree of instability or frequent changes. In such cases, it may be more appropriate to use feature branching or release branching to better manage the complexity of the codebase. For further clarity, let’s look at the pros and cons of the TBD approach. 

Pros of TBD: 

  • Faster feedback: With all developers working on a single branch, changes can be integrated and tested quickly, which allows for more rapid feedback and quicker detection of bugs. 
  • Rapid iteration: All changes developers make are integrated into the main codebase, and the code is regularly built and tested. It means that changes can be tested and deployed quickly, allowing teams to iterate rapidly on new features and improvements. 
  • Reduced merge conflicts: As all developers work on the same codebase, they merge their changes into the mainline, ensuring that any conflicts are discovered and resolved quickly rather than at the end of a long development cycle. The team can resolve conflicts with less effort, reducing the likelihood of larger problems arising later
  • Reduced complexity: TBD simplifies the development process by removing the need to manage multiple branches and merges, which can be time-consuming and error prone. 
  • Improved collaboration: Just like DevOps trunk-based development actively breaks down siloes. By working on a shared branch, developers are encouraged to collaborate and communicate more effectively, leading to better code quality and faster problem-solving. 

Cons of TBD: 

  • Risk of breaking changes: With all developers working on the same codebase, a mistake or bad code change can quickly propagate to everyone else and cause major problems. 
  • Lack of isolation: As the developers will be working on the same branch, isolating and testing specific features or changes will be challenging, making it harder to identify and debug issues. 
  • Limited flexibility: TBD can be restrictive for teams with more complex development needs or projects that require long-lived feature branches. 
  • Need for frequent integration: Developers must integrate their changes frequently to ensure the trunk remains stable. It can be challenging if developers work on extensive, complex features that require more development time. Trunk-based development and continuous integration need to go hand-in-hand to ensure that the changes are not breaking the codebase and that the trunk is always in a deployable state. 

There are several benefits to using TBD for the right projects and teams. By committing changes directly to the main branch, developers can avoid the need for separate branches, which can be time-consuming and lead to merge conflicts, ultimately leading to a more efficient development process and faster time-to-market. 

Benefits of using TBD include the following: 

  • Faster feedback and testing: Since all developers are working on the same codebase, changes can be integrated and tested quickly, allowing for faster feedback on code changes. 
  • Reduced merge conflicts: By avoiding separate long-lived feature branches, TBD minimizes the likelihood of merge conflicts arising when trying to merge separate branches. 
  • Increased collaboration: TBD encourages collaboration and communication between developers since they all work on the same codebase and can easily see each other’s changes. 
  • Easier to maintain: With all changes made directly to the trunk, there is no need to maintain multiple long-lived feature branches, making it easier to manage and maintain the codebase over time. 

Developers can reduce the overhead of managing branches and pull requests, promote better collaboration and communication between developers, and promote a continuous integration and deployment culture. Overall, trunk-based development promotes a more efficient, collaborative, and streamlined development process, which can ultimately lead to higher-quality software and faster delivery of new features.