How to use the command 'glab mr' (with examples)

The ‘glab mr’ command is a powerful tool for managing merge requests in GitLab efficiently. By using the command-line interface provided by glab, developers can streamline their workflow by handling merge requests directly from their terminal without needing to switch to a web browser. This agile approach ensures that developers can focus more on coding and less on navigating through graphical user interfaces. ‘glab mr’ supports various subcommands, allowing users to create, checkout, view, approve, merge, and update merge requests with ease. Each function serves a purpose in the lifecycle of a merge request, which typically involves code review and approval workflows in collaborative projects.

Create a merge request

Code:

glab mr create

Motivation:
Creating a merge request is often one of the first steps in any new feature or bug fix workflow. After pushing changes to a GitLab repository, developers need to create a merge request to initiate code review and collaboration. The glab mr create command allows developers to do this directly from the command line, simplifying the workflow by removing the need to switch context to a web interface.

Explanation:

• glab: This is the command-line tool for GitLab, similar to Git but focused on GitLab functionalities.
• mr: Short for merge request, this part of the command tells glab that we are performing actions related to merge requests.
• create: This subcommand specifies that the action to be performed is the creation of a new merge request.

Example output:
When a merge request is successfully created, the output will typically confirm the creation and may provide a merge request ID or a URL to view it in the web interface.

Merge request created: #1234 (https://gitlab.example.com/my-repo/-/merge_requests/1234)

Check out a specific merge request locally

Code:

glab mr checkout mr_number

Motivation:
Checking out a specific merge request locally is crucial for reviewing and testing changes in a personal environment. It enables developers to closely inspect the changes made in a merge request, run tests, or manually verify functionality before approving or merging these changes into the main branch.

Explanation:

• glab: The command-line helper tool interacting with GitLab.
• mr: Focuses on merge requests within the GitLab project.
• checkout: This subcommand lets you pull down the changes associated with a specified merge request into your local environment.
• mr_number: This argument represents the ID of the merge request to check out, allowing glab to locate and download the correct changes.

Example output:
Upon successful checkout of the merge request, the response informs the user of the new local branch created.

Switched to a new branch 'mr-1234'
Branch 'mr-1234' set up to track remote branch 'mr-1234' from 'origin'.

View the changes made in the merge request

Code:

glab mr diff

Motivation:
Before approving or merging a merge request, understanding the changes proposed is imperative. By using glab mr diff, a developer can clearly see all the code modifications, additions, or deletions made in a specific merge request, which aids in performing code reviews directly from the terminal.

Explanation:

• glab: The GitLab command-line tool.
• mr: Indicates that the operation concerns merge requests.
• diff: This subcommand outputs a diff of the changes made in the merge request, similar to running git diff.

Example output:
The output will be a list of code changes similar to a git diff, highlighting what lines of code were added or removed.

diff --git a/file1.txt b/file1.txt
index 83db48f..e22e34b 100644
--- a/file1.txt
+++ b/file1.txt
@@ -1,3 +1,3 @@
-Old line
+New line
 Another unchanged line

Approve the merge request for the current branch

Code:

glab mr approve

Motivation:
Approval is an essential part of code review processes, especially in collaborative settings. It signifies that the proposed changes have been reviewed and deemed fit for merging. By approving through the command line, developers save time and maintain their workflow without leaving the terminal.

Explanation:

• glab: Indicates the usage of the GitLab CLI.
• mr: Specifying operations related to merge requests.
• approve: This subcommand is used to approve the merge request linked to your current branch.

Example output:
Once the merge request approval is successful, you might get confirmation that your approval has been recorded.

Merge request approved: #1234

Merge the merge request associated with the current branch interactively

Code:

glab mr merge

Motivation:
Merging a pull request is the final step in integrating changes into the main branch. Using glab mr merge interactively provides an efficient means of finalizing this process by performing the merge operation directly from the terminal once all approvals and tests are satisfied.

Explanation:

• glab: The tool allowing CLI-based interactions with GitLab.
• mr: Denotes that we are dealing with merge requests.
• merge: This subcommand indicates that the current operation is to merge the merge request into the target branch.

Example output:
The output will confirm the merge action, providing information like the branch onto which the merge request has been merged.

Merge request #1234 has been merged into master branch.

Edit a merge request interactively

Code:

glab mr update

Motivation:
Sometimes, updates or corrections are required for an open merge request—for example, updating details, adding more reviewers, or modifying description/titles based on feedback. Employing glab mr update allows developers to edit merge request properties without using the GitLab web interface.

Explanation:

• glab: Refers to the GitLab command-line interface.
• mr: Asserts that the command involves merge requests.
• update: This subcommand prompts an interactive mode where various attributes of the merge request can be modified.

Example output:
After updating, you may see a confirmation about the applied changes, although specific output will vary.

Merge request #1234 updated successfully.

Edit the target branch of a merge request

Code:

glab mr update --target-branch branch_name

Motivation:
Changing the target branch of a merge request might be necessary if initial branch changes or if there’s a need to merge changes into a different branch than originally intended. This command makes this possible directly via the CLI.

Explanation:

• glab: The utility for interacting with GitLab from the terminal.
• mr: Directs the action towards merge requests.
• update: The subcommand which enables modifications on a merge request.
• --target-branch: A specific flag to change the branch where the merge request is currently aimed.
• branch_name: Represents the new target branch you wish the merge request to point to.

Example output:
The command’s output confirms the update in the target branch for the specified merge request.

Target branch of merge request #1234 changed to 'develop'.

Conclusion:

The glab mr command and its associated subcommands provide developers with robust functionality to manage merge requests efficiently without relying on the web interface. These command-line operations expedite actions like creating, reviewing, approving, merging, and updating merge requests, thereby supporting smoother continuous integration and collaborative workflows in software development environments. Each use case serves a specific purpose and enhances productivity by allowing developers to execute tasks directly from their preferred working environment— the terminal.