Merge requests

We welcome merge requests with fixes and improvements to GitLab code, tests, and/or documentation. The issues that are specifically suitable for community contributions are listed with the Accepting merge requests label, but you are free to contribute to any other issue you want.

Please note that if an issue is marked for the current milestone either before or while you are working on it, a team member may take over the merge request in order to ensure the work is finished before the release date.

If you want to add a new feature that is not labeled it is best to first create a feedback issue (if there isn't one already) and leave a comment asking for it to be marked as Accepting Merge Requests. Please include screenshots or wireframes if the feature will also change the UI.

Merge requests should be opened at

If you are new to GitLab development (or web development in general), see the I want to contribute! section to get you started with some potentially easy issues.

To start with GitLab development download the GitLab Development Kit and see the Development section for some guidelines.

Merge request guidelines

If you can, please submit a merge request with the fix or improvements including tests. If you don't know how to fix the issue but can write a test that exposes the issue we will accept that as well. In general bug fixes that include a regression test are merged quickly while new features without proper tests are least likely to receive timely feedback. The workflow to make a merge request is as follows:

  1. Fork the project into your personal space on
  2. Create a feature branch, branch away from master
  3. Write tests and code
  4. Generate a changelog entry with bin/changelog
  5. If you are writing documentation, make sure to follow the documentation guidelines
  6. If you have multiple commits please combine them into a few logically organized commits by squashing them
  7. Push the commit(s) to your fork
  8. Submit a merge request (MR) to the master branch
    1. Your merge request needs at least 1 approval but feel free to require more. For instance if you're touching backend and frontend code, it's a good idea to require 2 approvals: 1 from a backend maintainer and 1 from a frontend maintainer
    2. You don't have to select any approvers, but you can if you really want specific people to approve your merge request
  9. The MR title should describe the change you want to make
  10. The MR description should give a motive for your change and the method you used to achieve it.
    1. If you are contributing code, fill in the template already provided in the "Description" field.
    2. If you are contributing documentation, choose Documentation from the "Choose a template" menu and fill in the template.
    3. Mention the issue(s) your merge request solves, using the Solves #XXX or Closes #XXX syntax to auto-close the issue(s) once the merge request will be merged.
  11. If you're allowed to, set a relevant milestone and labels
  12. If the MR changes the UI it should include Before and After screenshots
  13. If the MR changes CSS classes please include the list of affected pages, grep css-class ./app -R
  14. Be prepared to answer questions and incorporate feedback even if requests for this arrive weeks or months after your MR submission
    1. If a discussion has been addressed, select the "Resolve discussion" button beneath it to mark it resolved.
  15. If your MR touches code that executes shell commands, reads or opens files or handles paths to files on disk, make sure it adheres to the shell command guidelines
  16. If your code creates new files on disk please read the shared files guidelines.
  17. When writing commit messages please follow these guidelines.
  18. If your merge request adds one or more migrations, make sure to execute all migrations on a fresh database before the MR is reviewed. If the review leads to large changes in the MR, do this again once the review is complete.
  19. For more complex migrations, write tests.
  20. Merge requests must adhere to the merge request performance guidelines.
  21. For tests that use Capybara or PhantomJS, see this article on how to write reliable asynchronous tests.

Please keep the change in a single MR as small as possible. If you want to contribute a large feature think very hard what the minimum viable change is. Can you split the functionality? Can you only submit the backend/API code? Can you start with a very simple UI? Can you do part of the refactor? The increased reviewability of small MRs that leads to higher code quality is more important to us than having a minimal commit log. The smaller an MR is the more likely it is it will be merged (quickly). After that you can send more MRs to enhance it. The 'How to get faster PR reviews' document of Kubernetes also has some great points regarding this.

For examples of feedback on merge requests please look at already closed merge requests. If you would like quick feedback on your merge request feel free to mention someone from the [core team] or one of the Merge request coaches. Please ensure that your merge request meets the contribution acceptance criteria.

When having your code reviewed and when reviewing merge requests please take the code review guidelines into account.

Contribution acceptance criteria

  1. The change is as small as possible
  2. Include proper tests and make all tests pass (unless it contains a test exposing a bug in existing code). Every new class should have corresponding unit tests, even if the class is exercised at a higher level, such as a feature test.
  3. If you suspect a failing CI build is unrelated to your contribution, you may try and restart the failing CI job or ask a developer to fix the aforementioned failing test
  4. Your MR initially contains a single commit (please use git rebase -i to squash commits)
  5. Your changes can merge without problems (if not please rebase if you're the only one working on your feature branch, otherwise, merge master)
  6. Does not break any existing functionality
  7. Fixes one specific issue or implements one specific feature (do not combine things, send separate merge requests if needed)
  8. Migrations should do only one thing (e.g., either create a table, move data to a new table or remove an old table) to aid retrying on failure
  9. Keeps the GitLab code base clean and well structured
  10. Contains functionality we think other users will benefit from too
  11. Doesn't add configuration options or settings options since they complicate making and testing future changes
  12. Changes do not adversely degrade performance.
    • Avoid repeated polling of endpoints that require a significant amount of overhead
    • Check for N+1 queries via the SQL log or QueryRecorder
    • Avoid repeated access of filesystem
  13. If you need polling to support real-time features, please use polling with ETag caching.
  14. Changes after submitting the merge request should be in separate commits (no squashing).
  15. It conforms to the style guides and the following:
    • If your change touches a line that does not follow the style, modify the entire line to follow it. This prevents linting tools from generating warnings.
    • Don't touch neighbouring lines. As an exception, automatic mass refactoring modifications may leave style non-compliant.
  16. If the merge request adds any new libraries (gems, JavaScript libraries, etc.), they should conform to our Licensing guidelines. See the instructions in that document for help if your MR fails the "license-finder" test with a "Dependencies that need approval" error.
  17. The merge request meets the definition of done.

Definition of done

If you contribute to GitLab please know that changes involve more than just code. We have the following definition of done. Please ensure you support the feature you contribute through all of these steps.

  1. Description explaining the relevancy (see following item)
  2. Working and clean code that is commented where needed
  3. Unit, integration, and system tests that pass on the CI server
  4. Performance/scalability implications have been considered, addressed, and tested
  5. Documented in the /doc directory
  6. Changelog entry added, if necessary
  7. Reviewed by UX/FE/BE and any concerns are addressed
  8. Merged by a project maintainer
  9. Added to the release blog article, if relevant
  10. Added to the website, if relevant
  11. Community questions answered
  12. Answers to questions radiated (in docs/wiki/support etc.)
  13. Black-box tests/end-to-end tests added if required. Please contact the quality team with any questions

If you add a dependency in GitLab (such as an operating system package) please consider updating the following and note the applicability of each in your merge request:

  1. Note the addition in the release blog post (create one if it doesn't exist yet)
  2. Upgrade guide, for example
  3. Installation guide
  4. GitLab Development Kit
  5. Test suite
  6. Omnibus package creator

Return to Contributing documentation