Squashing Commits for Clean History

Squashing Commits for Clean History

Squashing commits is a powerful technique to maintain a clean and organized Git history. This guide will show you how to effectively squash commits before merging your changes.

What You’ll Learn

• What is commit squashing
• When to squash commits
• How to squash using interactive rebase
• Best practices for squashing
• Handling merge conflicts

Implementation Steps

1. Interactive Rebase

   # Start interactive rebase
   git rebase -i HEAD~3
   

   • Opens editor with commit list
   • Commits in reverse chronological order
   • Choose squash or fixup
   • Edit final commit message

2. Squash Commands

   pick   abc1234 First commit
   squash def5678 Second commit
   squash ghi9012 Third commit
   

   • pick: Keep commit as is
   • squash: Combine with previous
   • fixup: Combine and discard message
   • edit: Stop for amending

3. Commit Message

   # Final commit message
   
   Feature: Add user authentication
   
   - Add login functionality
   - Implement password reset
   - Add session management
   

   • Write clear summary
   • List key changes
   • Reference issues
   • Follow conventions

4. Pushing Changes

   # Force push after squash
   git push --force-with-lease origin feature-branch
   

   • Use force with lease
   • Update remote branch
   • Maintain history
   • Avoid conflicts

Best Practices

1. When to Squash

   • Before merging PRs
   • After feature completion
   • Before sharing branches
   • When cleaning history

2. Squash Strategy

   • Keep related changes together
   • Maintain logical grouping
   • Preserve important context
   • Follow team standards

3. Commit Messages

   • Write clear summaries
   • List key changes
   • Reference issues
   • Follow conventions

4. Safety Measures

   • Create backup branch
   • Use force with lease
   • Test after squashing
   • Communicate with team

Common Use Cases

1. Feature Development

   # Squash feature commits
   git rebase -i main
   
   # Edit commit messages
   git commit --amend
   
   # Push changes
   git push --force-with-lease
   

2. Bug Fixes

   # Squash fix commits
   git rebase -i HEAD~2
   
   # Combine related fixes
   # Update commit message
   git push --force-with-lease
   

3. Cleanup History

   # Squash old commits
   git rebase -i HEAD~5
   
   # Organize history
   # Update messages
   git push --force-with-lease
   

4. PR Preparation

   # Squash before PR
   git rebase -i main
   
   # Clean up history
   # Update messages
   git push --force-with-lease
   

Advanced Usage

1. Partial Squashing

   # Squash specific commits
   git rebase -i HEAD~5
   
   # Keep some commits
   # Squash others
   git push --force-with-lease
   

2. Squash with Conflicts

   # Resolve conflicts
   git add resolved-files
   git rebase --continue
   
   # Complete squash
   git push --force-with-lease
   

3. Squash with Reflog

   # Recover from mistakes
   git reflog
   git reset --hard HEAD@{1}
   
   # Try squash again
   git rebase -i HEAD~3
   

4. Squash with Hooks

   # Pre-push hook
   #!/bin/sh
   if git rev-parse --verify HEAD >/dev/null 2>&1
   then
     against=HEAD
   else
     against=$(git hash-object -t tree /dev/null)
   fi
   

Common Issues and Solutions

1. Merge Conflicts

   # Resolve conflicts
   git add resolved-files
   git rebase --continue
   
   # Complete squash
   git push --force-with-lease
   

2. Lost Commits

   # Find lost commits
   git reflog
   
   # Restore commits
   git reset --hard HEAD@{1}
   

3. Wrong Squash

   # Abort rebase
   git rebase --abort
   
   # Start over
   git rebase -i HEAD~3
   

Conclusion

Squashing commits helps maintain a clean Git history. Remember to:

• Squash before merging
• Write clear messages
• Use force with lease
• Test after squashing
• Follow team standards

Next Steps

After mastering commit squashing, you might want to:

• Learn about Git workflows
• Explore Git hooks
• Study Git internals
• Understand Git objects