Hybrid Code Review Service: Combining CHANGE and Merge Request in Ctrip's GitLab Platform

Author Introduction Su Ling – 5 years of software configuration management and 7 years of continuous integration experience, former senior configuration management engineer at Suzhou Keda Technology and Dianping, now head of Ctrip Code Center. Li Haitao – senior development engineer at Ctrip Code Center, responsible for implementing GitLab sharding and hybrid code‑review services.

1. Overview Since 2013, Ctrip has used both Gerrit and GitLab for code review. Gerrit offers a pre‑commit review model, while GitLab provides post‑commit review via Merge Requests (MR). To unify the platform, Ctrip introduced a hybrid service on GitLab that supports both Gerrit‑style CHANGE and GitLab MR.

2. Terminology CHANGE: each local commit automatically creates a change; unreviewed changes cannot enter the shared Git repository. MR: each review involves creating two branches and submitting a Merge Request.

3. Gerrit vs. GitLab Comparison The article presents a dialogue between “Mr. Gerrit” and “Mr. GitLab” highlighting strengths such as pre‑commit protection, automatic review request on push, linear history, and branch‑level review. A summary table (translated) shows which platform wins for each advantage.

Specific Advantage

Is Advantage?

Gerrit

GitLab

Conclusion

Unreviewed code cannot enter repository

Yes

Yes

Yes (requires fork)

Gerrit wins

Push automatically creates review request

Yes

Yes

No

Gerrit wins

Review at branch level instead of each commit

Yes (in some cases)

No

Yes

GitLab wins

Review single commit for quality

Yes (in some cases)

Yes

No

Gerrit wins

Support linear history

Yes

Yes

Yes

Tie

4. Scenarios Particularly Suited for CHANGE Scenario 1: Projects that develop directly on the trunk branch. Scenario 2: Teams that place a strong emphasis on code quality and avoid forks. Scenario 3: Teams with many junior developers who need every change reviewed before it reaches the repository.

5. Using CHANGE and MR Together When both are used, junior developers push to refs/for/Feature‑A , reviewers approve the CHANGE, and later a Merge Request merges the feature branch into master, eliminating extra branch creation and MR steps.

6. Hybrid Service Implementation The hybrid service retains Gerrit‑style local operations (e.g., git push origin HEAD:refs/for/ ) and adds GitLab‑style clone URLs and UI support for both CHANGE and MR.

7. Review Mode Types and Applicable Scenarios Four modes are defined: CHANGE only, CHANGE+MR, MR only, and no code review. Each mode is matched with conditions such as product quality requirements, trunk‑based development, and the skill level of developers.

8. Conclusion The hybrid code‑review service provides flexibility for companies with diverse branching strategies, allowing them to benefit from both pre‑commit protection and the convenience of Merge Requests, and signals Ctrip’s move to fully replace Gerrit with GitLab.