Trunk-Based Development (TBD) is a software development model emphasizing frequent collaboration on a single branch called “trunk” or “main” (previously “master” in Git). This method prioritizes rapid, incremental changes over long-lived feature branches, maintaining stability and facilitating continuous integration and delivery.
Key Aspects of Trunk-Based Development
- Single Main Branch:
- Development occurs on a single branch, avoiding prolonged feature branches.
- Frequent Commits:
- Developers commit multiple times per day to ensure small, incremental changes.
- Small, Incremental Changes:
- Work is broken into manageable chunks that can be integrated quickly.
- Continuous Integration (CI):
- Each commit triggers automated builds and tests to ensure trunk stability.
- Feature Toggles:
- Feature flags hide incomplete code, allowing safe integration without disrupting production functionality.
- Short-Lived Feature Branches:
- Feature branches, if needed, are kept very short (typically less than a day) and merged quickly.
- Continuous Delivery/Deployment (CD):
- The trunk remains in a deployable state, allowing for frequent, easy releases.
- Collaborative Coding:
- Emphasis on teamwork, using techniques like pair programming and thorough code reviews.
- Automated Testing:
- Comprehensive tests maintain code quality, catching defects early.
- Rapid Feedback:
- The model enables fast integration and immediate feedback on changes.
Benefits of Trunk-Based Development
- Reduced Merge Conflicts: Avoids complex merge processes by limiting branch divergence.
- Faster Release Cycles: Code is always ready for deployment, enabling frequent releases.
- Improved Collaboration: Developers work in sync, reducing silos and improving code quality.
- Stable Codebase: Continuous integration and testing ensure the trunk remains reliable.
- Supports CI/CD: TBD aligns closely with modern agile and DevOps practices, facilitating automation and faster delivery.
Challenges of Trunk-Based Development
- Requires Discipline: Developers must be diligent with frequent commits and small changes.
- Tooling: Effective usage of feature toggles and automated CI/CD pipelines is essential.
- Scalability: Larger teams or complex projects need robust coordination and practices to avoid bottlenecks.
Industry Relevance
Many large tech companies adopt Trunk-Based Development due to its alignment with agile methodologies, DevOps, and CI/CD pipelines, helping to streamline software development and deployment processes.