GitLab: Repositories, Branches & Merge Requests

GitLab is a complete DevSecOps platform — combining Git hosting, CI/CD, issue tracking, container registry, and security scanning in one application. Available as SaaS (gitlab.com) or self-managed.

Repository Basics

# Clone via HTTPS or SSH
git clone https://gitlab.com/group/project.git
git clone git@gitlab.com:group/project.git

# GitLab CLI
glab auth login
glab repo clone group/project

# Protected branches — set in Settings → Repository → Protected Branches
# Main/master: typically locked to Maintainers for push, Developers for merge

Branch Strategy

• GitLab Flow: feature branches → main → production (add environment branches like staging)

• Trunk-based development: short-lived feature branches, merge daily, use feature flags

• Protected branches: prevent force-push, require approvals before merge

• Default branch: configurable per project (Settings → Repository → Default branch)

• Branch naming convention: feature/, fix/, chore/ prefixes recommended

Merge Requests (MRs)

Merge Requests in GitLab are equivalent to GitHub Pull Requests. They are the primary unit of code review.

# Create MR via CLI
glab mr create --title "Add payment flow" --description "Implements Stripe checkout" --target-branch main

# List open MRs
glab mr list

# Check out MR locally
glab mr checkout 42

# Approve and merge
glab mr approve 42
glab mr merge 42

MR Settings & Best Practices

• Draft MRs: prefix title with "Draft:" to prevent accidental merge while WIP

• Assignee: the person responsible for merging; Reviewer: person doing the code review

• Approvals: configure required approvals in Settings → Merge Requests → Approval rules

• Squash commits: enabled per MR or as project default — keeps main branch history clean

• Delete source branch: check "Delete source branch when merge request is accepted"

• Rebase on merge: keeps linear history without merge commits

• Merge trains: queue MRs that pipeline-test against each other before merging

Code Review Features

• Inline comments: click the diff gutter to add a comment on a specific line

• Suggestions: click the "Insert suggestion" icon to propose a code change inline — author can apply with one click

• Threads: group related comments into a thread; resolve when addressed

• Review summary: submit all comments at once instead of notifying per comment

• MR dependencies: block an MR from merging until another MR is merged first

• Reviewers can filter by file, diff type (inline/side-by-side), or whitespace

Forks & Contributions

• Fork: copies the project to your namespace — use for open-source contributions

• Fork sync: GitLab can sync forks automatically with the upstream project

• Contribution limits: project owners can set who can create branches and MRs

• Merge request from fork: create MR targeting upstream repository directly