How to Run Merge Request Pipelines in GitLab CI/CD

A merge request pipeline runs in the MR context and exposes MR variables, which branch pipelines do not.

Add rules:if: $CI_PIPELINE_SOURCE == "merge_request_event" so the job runs in MR pipelines, and avoid duplicate branch-plus-MR pipelines by structuring rules carefully.

Steps

• Add a rule matching $CI_PIPELINE_SOURCE == "merge_request_event".
• Read MR context via $CI_MERGE_REQUEST_* variables.
• Add a branch rule too if you also want branch pipelines, avoiding duplicates.

Pipeline

test:
  script: npm test
  rules:
    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
    - if: '$CI_COMMIT_BRANCH == "main"'

Gotchas

• Without an MR rule, a job never runs in merge request pipelines and $CI_MERGE_REQUEST_* stays empty.
• Matching both branch and MR sources can create duplicate pipelines; use workflow:rules to pick one.

Related guides