Continuous Integration vs Feature Branch Workflow

Summary

In this video, Dave Farley explores the principles of continuous integration (CI) and the challenges of feature branching. He emphasizes the importance of integrating code frequently to avoid conflicts, reduce merge pain, and ensure the software is always in a releasable state. Farley discusses strategies like dark launching, branch by abstraction, and feature flags to deploy incomplete features safely. He highlights the significance of behavioral branching, where small, regular commits allow teams to test and evolve code more effectively. The video encourages developers to embrace CI for smoother collaboration and faster delivery.

Takeaways

• 😀 Continuous Integration (CI) is about integrating changes frequently and keeping code visible to teammates to avoid integration issues.
• 😀 Feature branching can conflict with CI principles since it isolates changes, which goes against the idea of continuous integration where all changes should be visible and integrated.
• 😀 The definition of CI emphasizes frequent integration, ideally at least daily, to ensure all changes are tested and validated together.
• 😀 In CI, merging changes frequently prevents merge conflicts and improves code quality and stability.
• 😀 Continuous integration is about making small, frequent changes, committing them often, and integrating them into the main branch without long-lived branches.
• 😀 Testing in CI should happen frequently, ideally as soon as changes are made, rather than waiting until a feature is complete or merged.
• 😀 A key strategy in CI is minimizing the duration of branches, and ideally, not using feature branches for long periods of time.
• 😀 Continuous Delivery (CD) takes CI further by ensuring software is always in a deployable state, even if it’s not fully released or visible to users.
• 😀 Dark launching, branch by abstraction, and feature flags are common strategies to release incomplete features without affecting users directly.
• 😀 Behavioral branching (via feature flags and other strategies) allows testing different code behaviors in parallel without causing merge conflicts, unlike traditional feature branches.

Q & A

What is Continuous Integration (CI) in software development?

Continuous Integration (CI) is a software development practice where developers integrate their changes into the shared repository frequently, ideally several times a day. This helps to detect integration problems early and ensures the system is always in a working state.

Why is frequent integration important in CI?

Frequent integration is crucial in CI because it minimizes the risk of conflicts and bugs. By integrating small changes regularly, developers can resolve issues quickly and avoid the large, time-consuming merge conflicts that occur with long-lived feature branches.

How does feature branching conflict with Continuous Integration?

Feature branching isolates changes in separate branches, which goes against the CI philosophy of making all changes visible to the team in real-time. This isolation can create conflicts and integration issues when the feature branch is eventually merged back into the main codebase.

What is the downside of testing on feature branches?

Testing on feature branches can lead to evaluating code versions that are unlikely to be the one deployed into production. This creates a discrepancy between the code being worked on and the actual version that will be integrated into the main codebase, wasting time and resources.

How does Continuous Integration improve team collaboration?

CI enhances team collaboration by ensuring that changes are frequently integrated, making them visible to everyone. This allows developers to understand how their changes interact with others' work and resolve issues earlier in the development cycle.

What are some common strategies in Continuous Delivery (CD) to manage incomplete features?

Common strategies in Continuous Delivery to manage incomplete features include dark launching (deploying code without it being visible to users), branch by abstraction (incrementally introducing changes by modifying the code's abstraction), and feature flags (hiding incomplete features behind a flag until ready for release).

What is the role of testing in Continuous Integration?

In Continuous Integration, testing is crucial to ensure that every change is safe to integrate. Tests should be run frequently, ideally after every commit, to ensure that each change works correctly and doesn’t introduce errors into the system.

What does the term 'shrinking branches' mean in CI?

Shrinking branches in CI refers to the practice of minimizing the duration for which branches are isolated. Instead of working on long-lived feature branches, developers make small, frequent commits to the main codebase, ensuring that the code is always close to the truth of the production code.

Why is it important to separate deployment from release in Continuous Delivery?

Separating deployment from release allows for deploying incomplete or untested features to production without making them available to end users. This gives teams the flexibility to continue working on features while ensuring that the production environment remains stable and deployable at all times.

What is the difference between traditional feature branching and CI strategies like behavioral branching?

Traditional feature branching isolates changes until the feature is complete, which can lead to integration conflicts. CI strategies like behavioral branching allow different versions of a feature to coexist in parallel, enabling developers to test and evaluate them together without affecting the live system.