Merge strategy when using trunk based development

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Summary

When using trunk-based development, managing merge strategies between branches is crucial for maintaining a clean and linear commit history. The question revolves around the best approach to merge a development branch into the main branch, considering the implications of rebase, squash, and merge commit strategies.

Root Cause

The root cause of the issue lies in the understanding and application of different merge strategies in Git, specifically:

  • Rebase: Rewrites the commit history, creating new hashes, which can lead to duplicate commits in subsequent pull requests.
  • Squash: Creates a new commit that combines all changes, also resulting in new commits appearing in future pull requests.
  • Merge commit: Preserves the commit history but breaks the linear progression, which is often discouraged.

Why This Happens in Real Systems

This happens in real systems due to:

  • Misunderstanding of Git merge strategies and their implications.
  • Desire for a linear commit history.
  • Need for a clean and manageable codebase.
  • Balancing the preservation of commit history with the simplicity of the main branch.

Real-World Impact

The real-world impact includes:

  • Complexity in debugging: Non-linear commit histories can make it harder to identify and debug issues.
  • Commit history clutter: Duplicate or unnecessary commits can clutter the history, making it less informative.
  • Team confusion: Inconsistent merge strategies can lead to confusion among team members about the project’s history and current state.

Example or Code (if necessary and relevant)

# Example of a rebase operation
git checkout development
git pull --rebase origin development

# Example of a squash operation
git checkout development
git merge --squash main

# Example of a merge commit operation
git checkout main
git merge development

How Senior Engineers Fix It

Senior engineers fix this by:

  • Understanding the project’s requirements: Deciding whether a linear history or preserving all commits is more important.
  • Choosing the right merge strategy: Based on the project’s needs, selecting rebase, squash, or merge commit.
  • Consistency: Ensuring that the chosen strategy is applied consistently across the team.
  • Education: Teaching junior engineers about the implications of different merge strategies.

Why Juniors Miss It

Juniors might miss the best merge strategy due to:

  • Lack of experience: Limited exposure to different project requirements and Git workflows.
  • Insufficient training: Not receiving comprehensive training on Git and its strategies.
  • Complexity of Git: Git’s flexibility and the numerous options available can be overwhelming.
  • Prioritization of short-term goals: Focusing on completing tasks quickly rather than considering long-term codebase management.