GitLab Merge Train - How It Differs from Merge
Merge Train Features
Automated Merging Process
- Sequential merging of multiple merge requests (MRs)
- Automatic rebasing before merging
- Ensures the target branch remains up to date
- Reduces merge conflicts by merging MRs in a defined order
CI/CD Pipeline Efficiency
- Runs pipelines in a queue before merging
- Ensures each MR passes tests before integration
- Avoids redundant CI runs for multiple MRs
- Enhances pipeline efficiency and stability
Improved Collaboration
- MRs are added to the train automatically
- Developers donοΏ½t need to manually rebase MRs
- Ensures a predictable merge sequence
- Reduces bottlenecks in collaborative projects
Conflict Prevention & Resolution
- Detects conflicts before merging
- Allows developers to resolve conflicts before final integration
- Maintains clean and stable main branches
- Reduces the risk of last-minute merge failures
Parallel Execution & Queuing
- Supports multiple merge trains per target branch
- Runs tests for different MRs in parallel when possible
- Manages queued MRs efficiently
- Improves overall team productivity
Standard Merge Features
Manual Merge Process
- Developers merge MRs manually
- Requires rebasing or resolving conflicts individually
- Higher risk of introducing conflicts into the main branch
CI/CD Pipeline Execution
- Runs pipelines after merging into the target branch
- Does not guarantee stability before merging
- Might introduce errors if not tested properly before merging
Flexibility & Control
- Developers decide when and how to merge
- No predefined order for merging MRs
- More control over the process but requires manual intervention
Conflict Handling
- Conflicts are resolved before or after merging
- May cause delays if multiple developers work on the same branch
- Increases chances of main branch instability
Key Differences Between Merge Train & Standard Merge
| Feature | Merge Train | Standard Merge |
|---|---|---|
| Merging Approach | Automated, sequential merging | Manual merging |
| CI/CD Execution | Runs pipelines before merging | Runs pipelines after merging |
| Conflict Detection | Pre-merge conflict detection | Post-merge conflict resolution |
| Rebasing | Automatic rebasing before merging | Requires manual rebasing |
| Branch Stability | Ensures stable target branch | Might introduce instabilities |
| Merge Order | Predefined and managed automatically | Unstructured and manual |
| Developer Effort | Reduced manual intervention | Requires manual handling |
For more details, refer to the GitLab documentation.