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Merge requests

Merge requests allow you to visualize and collaborate on the proposed changes to source code that exist as commits on a given Git branch.

Merge request view

Overview

A Merge Request (MR) is the basis of GitLab as a code collaboration and version control platform. It is as simple as the name implies: a request to merge one branch into another.

With GitLab merge requests, you can:

With GitLab Enterprise Edition, you can also:

Use cases

A. Consider you are a software developer working in a team:

  1. You checkout a new branch, and submit your changes through a merge request
  2. You gather feedback from your team
  3. You work on the implementation optimizing code with Code Quality reports (STARTER)
  4. You verify your changes with JUnit test reports in GitLab CI/CD
  5. You avoid using dependencies whose license is not compatible with your project with License Compliance reports (ULTIMATE)
  6. You request the approval from your manager
  7. Your manager pushes a commit with their final review, approves the merge request, and set it to merge when pipeline succeeds (Merge Request Approvals are available in GitLab Starter)
  8. Your changes get deployed to production with manual actions for GitLab CI/CD
  9. Your implementations were successfully shipped to your customer

B. Consider you're a web developer writing a webpage for your company's website:

  1. You checkout a new branch, and submit a new page through a merge request
  2. You gather feedback from your reviewers
  3. Your changes are previewed with Review Apps
  4. You request your web designers for their implementation
  5. You request the approval from your manager (STARTER)
  6. Once approved, your merge request is squashed and merged, and deployed to staging with GitLab Pages
  7. Your production team cherry picks the merge commit into production

Merge requests per project

View all the merge requests within a project by navigating to Project > Merge Requests.

When you access your project's merge requests, GitLab will present them in a list, and you can use the tabs available to quickly filter by open and closed. You can also search and filter the results.

Project merge requests list view

Merge requests per group

View merge requests in all projects in the group, including all projects of all descendant subgroups of the group. Navigate to Group > Merge Requests to view these merge requests. This view also has the open and closed merge requests tabs.

You can search and filter the results from here.

Group Issues list view

Deleting the source branch

When creating a merge request, select the "Delete source branch when merge request accepted" option and the source branch will be deleted when the merge request is merged.

This option is also visible in an existing merge request next to the merge request button and can be selected/deselected before merging. It's only visible to users with Maintainer permissions in the source project.

If the user viewing the merge request does not have the correct permissions to delete the source branch and the source branch is set for deletion, the merge request widget will show the "Deletes source branch" text.

Delete source branch status

Allow collaboration on merge requests across forks

When a user opens a merge request from a fork, they are given the option to allow upstream maintainers to collaborate with them on the source branch. This allows the maintainers of the upstream project to make small fixes or rebase branches before merging, reducing the back and forth of accepting community contributions.

Learn more about allowing upstream members to push to forks.

Authorization for merge requests

There are two main ways to have a merge request flow with GitLab:

  1. Working with protected branches in a single repository
  2. Working with forks of an authoritative project

Learn more about the authorization for merge requests.

Cherry-pick changes

Cherry-pick any commit in the UI by simply clicking the Cherry-pick button in a merged merge requests or a commit.

Learn more about cherry-picking changes.

Semi-linear history merge requests

A merge commit is created for every merge, but the branch is only merged if a fast-forward merge is possible. This ensures that if the merge request build succeeded, the target branch build will also succeed after merging.

Navigate to a project's settings, select the Merge commit with semi-linear history option under Merge Requests: Merge method and save your changes.

Fast-forward merge requests

If you prefer a linear Git history and a way to accept merge requests without creating merge commits, you can configure this on a per-project basis.

Read more about fast-forward merge requests.

Merge when pipeline succeeds

When reviewing a merge request that looks ready to merge but still has one or more CI jobs running, you can set it to be merged automatically when CI pipeline succeeds. This way, you don't have to wait for the pipeline to finish and remember to merge the request manually.

Learn more about merging when pipeline succeeds.

Resolve threads in merge requests reviews

Keep track of the progress during a code review with resolving comments. Resolving comments prevents you from forgetting to address feedback and lets you hide threads that are no longer relevant.

Read more about resolving threads in merge requests reviews.

Commenting on any file line in merge requests

Introduced in GitLab 11.5.

GitLab provides a way of leaving comments in any part of the file being changed in a Merge Request. To do so, click the ... button in the gutter of the Merge Request diff UI to expand the diff lines and leave a comment, just as you would for a changed line.

Comment on any diff file line

Perform a Review (PREMIUM)

Start a review in order to create multiple comments on a diff and publish them once you're ready. Starting a review allows you to get all your thoughts in order and ensure you haven't missed anything before submitting all your comments.

Learn more about Merge Request Reviews

Squash and merge

GitLab allows you to squash all changes present in a merge request into a single commit when merging, to allow for a neater commit history.

Learn more about squash and merge.

Suggest changes

Introduced in GitLab 11.6.

As a reviewer, you can add suggestions to change the content in merge request threads, and users with appropriate permission can easily apply them to the codebase directly from the UI. Read through the documentation on Suggest changes to learn more.

Multiple assignees (STARTER)

Introduced in GitLab Starter 11.11.

Multiple people often review merge requests at the same time. GitLab allows you to have multiple assignees for merge requests to indicate everyone that is reviewing or accountable for it.

multiple assignees for merge requests sidebar

To assign multiple assignees to a merge request:

  1. From a merge request, expand the right sidebar and locate the Assignees section.
  2. Click on Edit and from the dropdown menu, select as many users as you want to assign the merge request to.

Similarly, assignees are removed by deselecting them from the same dropdown menu.

It's also possible to manage multiple assignees:

Resolve conflicts

When a merge request has conflicts, GitLab may provide the option to resolve those conflicts in the GitLab UI.

Learn more about resolving merge conflicts in the UI.

Create new merge requests by email

This feature needs incoming email to be configured by a GitLab administrator to be available for CE/EE users, and it's available on GitLab.com.

You can create a new merge request by sending an email to a user-specific email address. The address can be obtained on the merge requests page by clicking on a Email a new merge request to this project button. The subject will be used as the source branch name for the new merge request and the target branch will be the default branch for the project. The message body (if not empty) will be used as the merge request description. You need "Reply by email" enabled to use this feature. If it's not enabled to your instance, you may ask your GitLab administrator to do so.

This is a private email address, generated just for you. Keep it to yourself as anyone who gets ahold of it can create issues or merge requests as if they were you. You can add this address to your contact list for easy access.

Create new merge requests by email

In GitLab 11.7, we updated the format of the generated email address. However the older format is still supported, allowing existing aliases or contacts to continue working.

Adding patches when creating a merge request via e-mail

Introduced in GitLab 11.5.

You can add commits to the merge request being created by adding patches as attachments to the email. All attachments with a filename ending in .patch will be considered patches and they will be processed ordered by name.

The combined size of the patches can be 2MB.

If the source branch from the subject does not exist, it will be created from the repository's HEAD or the specified target branch to apply the patches. The target branch can be specified using the /target_branch quick action. If the source branch already exists, the patches will be applied on top of it.

Git push options

Introduced in GitLab 11.10.

NOTE: Note: Git push options are only available with Git 2.10 or newer. With Git older than 2.18 git push --push-option=... should be used instead of git push -o ....

GitLab supports using Git push options to perform the following actions against merge requests at the same time as pushing changes:

  • Create a new merge request for the pushed branch.
  • Set the target of the merge request to a particular branch.
  • Set the merge request to merge when its pipeline succeeds.
  • Set the merge request to remove the source branch when it's merged.
  • Set the title of the merge request to a particular title.
  • Set the description of the merge request to a particular description.

Create a new merge request using git push options

To create a new merge request for a branch, use the merge_request.create push option:

git push -o merge_request.create

Set the target branch of a merge request using git push options

To update an existing merge request's target branch, use the merge_request.target=<branch_name> push option:

git push -o merge_request.target=branch_name

You can also create a merge request and set its target branch at the same time using a -o flag per push option:

git push -o merge_request.create -o merge_request.target=branch_name

Set merge when pipeline succeeds using git push options

To set an existing merge request to merge when its pipeline succeeds, use the merge_request.merge_when_pipeline_succeeds push option:

git push -o merge_request.merge_when_pipeline_succeeds

You can also create a merge request and set it to merge when its pipeline succeeds at the same time using a -o flag per push option:

git push -o merge_request.create -o merge_request.merge_when_pipeline_succeeds

Set removing the source branch using git push options

Introduced in GitLab 12.2.

To set an existing merge request to remove the source branch when the merge request is merged, the merge_request.remove_source_branch push option can be used:

git push -o merge_request.remove_source_branch

You can also use this push option in addition to the merge_request.create push option.

Set merge request title using git push options

Introduced in GitLab 12.2.

To set the title of an existing merge request, use the merge_request.title push option:

git push -o merge_request.title="The title I want"

You can also use this push option in addition to the merge_request.create push option.

Set merge request description using git push options

Introduced in GitLab 12.2.

To set the description of an existing merge request, use the merge_request.description push option:

git push -o merge_request.description="The description I want"

You can also use this push option in addition to the merge_request.create push option.

Find the merge request that introduced a change

Introduced in GitLab 10.5.

When viewing the commit details page, GitLab will link to the merge request (or merge requests, if it's in more than one) containing that commit.

This only applies to commits that are in the most recent version of a merge request - if a commit was in a merge request, then rebased out of that merge request, they will not be linked.

Read more about merge request versions

Revert changes

GitLab implements Git's powerful feature to revert any commit with introducing a Revert button in merge requests and commit details.

Learn more about reverting changes in the UI

Merge requests versions

Every time you push to a branch that is tied to a merge request, a new version of merge request diff is created. When you visit a merge request that contains more than one pushes, you can select and compare the versions of those merge request diffs.

Read more about merge request versions

Work In Progress merge requests

To prevent merge requests from accidentally being accepted before they're completely ready, GitLab blocks the "Accept" button for merge requests that have been marked as a Work In Progress.

Learn more about setting a merge request as "Work In Progress".

Merge Requests for Confidential Issues

Create merge requests to resolve confidential issues for preventing leakage or early release of sentive data through regular merge requests.

Merge request approvals (STARTER)

Included in GitLab Starter.

If you want to make sure every merge request is approved by one or more people, you can enforce this workflow by using merge request approvals. Merge request approvals allow you to set the number of necessary approvals and predefine a list of approvers that will need to approve every merge request in a project.

Read more about merge request approvals.

Code Quality (STARTER)

Introduced in GitLab Starter 9.3.

If you are using GitLab CI, you can analyze your source code quality using the Code Climate analyzer Docker image. Going a step further, GitLab can show the Code Climate report right in the merge request widget area.

Read more about Code Quality reports.

Metrics Reports (PREMIUM)

Introduced in GitLab Premium 11.10. Requires GitLab Runner 11.10 and above.

If you are using GitLab CI, you can configure your job to output custom metrics and GitLab will display the Metrics Report on the merge request so that it's fast and easy to identify changes to important metrics.

Read more about Metrics Report.

Browser Performance Testing (PREMIUM)

Introduced in GitLab Premium 10.3.

If your application offers a web interface and you are using GitLab CI/CD, you can quickly determine the performance impact of pending code changes. GitLab uses Sitespeed.io, a free and open source tool for measuring the performance of web sites, to analyze the performance of specific pages.

GitLab runs the Sitespeed.io container and displays the difference in overall performance scores between the source and target branches.

Read more about Browser Performance Testing.

Cross-project Merge Request Dependencies (PREMIUM)

Introduced in GitLab Premium 12.2.

A single logical change may be split across several merge requests, across several projects. When this happens, the order in which MRs are merged is important.

GitLab allows you to specify that a merge request depends on other MRs. With this relationship in place, the merge request cannot be merged until all of its dependencies have also been merged, helping to maintain the consistency of a single logical change.

Read more about cross-project merge request dependencies.

Security reports (ULTIMATE)

GitLab can scan and report any vulnerabilities found in your project.

Read more about security reports.

JUnit test reports

Configure your CI jobs to use JUnit test reports, and let GitLab display a report on the merge request so that it’s easier and faster to identify the failure without having to check the entire job log.

Read more about JUnit test reports.

Merge request diff file navigation

When reviewing changes in the Changes tab the diff can be navigated using the file tree or file list. As you scroll through large diffs with many changes, you can quickly jump to any changed file using the file tree or file list.

Merge request diff file navigation

Incrementally expand merge request diffs

By default, the diff shows only the parts of a file which are changed. To view more unchanged lines above or below a change click on the Expand up or Expand down icons. You can also click on Show all lines to expand the entire file.

Incrementally expand merge request diffs

Ignore whitespace changes in Merge Request diff view

If you click the Hide whitespace changes button, you can see the diff without whitespace changes (if there are any). This is also working when on a specific commit page.

MR diff

Tip: You can append ?w=1 while on the diffs page of a merge request to ignore any whitespace changes.

Live preview with Review Apps

If you configured Review Apps for your project, you can preview the changes submitted to a feature-branch through a merge request in a per-branch basis. No need to checkout the branch, install and preview locally; all your changes will be available to preview by anyone with the Review Apps link.

With GitLab's Route Maps set, the merge request widget takes you directly to the pages changed, making it easier and faster to preview proposed modifications.

Read more about Review Apps.

Pipelines for merge requests

When a developer updates a merge request, a pipeline should quickly report back its result to the developer, but often pipelines take long time to complete because general branch pipelines contain unnecessary jobs from the merge request standpoint. You can customize a specific pipeline structure for merge requests in order to speed the cycle up by running only important jobs.

Learn more about pipelines for merge requests.

Pipeline status in merge requests

If you've set up GitLab CI/CD in your project, you will be able to see:

  • Both pre and post-merge pipelines and the environment information if any.
  • Which deployments are in progress.

If there's an environment and the application is successfully deployed to it, the deployed environment and the link to the Review App will be shown as well.

Post-merge pipeline status

When a merge request is merged, you can see the post-merge pipeline status of the branch the merge request was merged into. For example, when a merge request is merged into the master branch and then triggers a deployment to the staging environment.

Deployments that are ongoing will be shown, as well as the deploying/deployed state for environments. If it's the first time the branch is deployed, the link will return a 404 error until done. During the deployment, the stop button will be disabled. If the pipeline fails to deploy, the deployment info will be hidden.

Merge request pipeline

For more information, read about pipelines.

Bulk editing merge requests

Find out about bulk editing merge requests.

Troubleshooting

Sometimes things don't go as expected in a merge request, here are some troubleshooting steps.

Merge request cannot retrieve the pipeline status

This can occur for one of two reasons:

  • Sidekiq doesn't pick up the changes fast enough
  • Because of the bug described in #41545

Sidekiq

Sidekiq didn't process the CI state change fast enough. Please wait a few seconds and the status will update automatically.

Bug

Merge Request pipeline statuses can't be retrieved when the following occurs:

  1. A Merge Request is created
  2. The Merge Request is closed
  3. Changes are made in the project
  4. The Merge Request is reopened

To enable the pipeline status to be properly retrieved, close and reopen the Merge Request again.

Tips

Here are some tips that will help you be more efficient with merge requests in the command line.

Note: This section might move in its own document in the future.

Checkout merge requests locally

A merge request contains all the history from a repository, plus the additional commits added to the branch associated with the merge request. Here's a few tricks to checkout a merge request locally.

Please note that you can checkout a merge request locally even if the source project is a fork (even a private fork) of the target project.

Checkout locally by adding a git alias

Add the following alias to your ~/.gitconfig:

[alias]
    mr = !sh -c 'git fetch $1 merge-requests/$2/head:mr-$1-$2 && git checkout mr-$1-$2' -

Now you can check out a particular merge request from any repository and any remote. For example, to check out the merge request with ID 5 as shown in GitLab from the origin remote, do:

git mr origin 5

This will fetch the merge request into a local mr-origin-5 branch and check it out.

Checkout locally by modifying .git/config for a given repository

Locate the section for your GitLab remote in the .git/config file. It looks like this:

[remote "origin"]
  url = https://gitlab.com/gitlab-org/gitlab-ce.git
  fetch = +refs/heads/*:refs/remotes/origin/*

You can open the file with:

git config -e

Now add the following line to the above section:

fetch = +refs/merge-requests/*/head:refs/remotes/origin/merge-requests/*

In the end, it should look like this:

[remote "origin"]
  url = https://gitlab.com/gitlab-org/gitlab-ce.git
  fetch = +refs/heads/*:refs/remotes/origin/*
  fetch = +refs/merge-requests/*/head:refs/remotes/origin/merge-requests/*

Now you can fetch all the merge requests:

git fetch origin

...
From https://gitlab.com/gitlab-org/gitlab-ce.git
 * [new ref]         refs/merge-requests/1/head -> origin/merge-requests/1
 * [new ref]         refs/merge-requests/2/head -> origin/merge-requests/2
...

And to check out a particular merge request:

git checkout origin/merge-requests/1

all the above can be done with git-mr script.