Understanding Pull Request
A pull request, called a merge request on GitLab and Bitbucket, is the mechanism most teams use to propose, review, and merge code changes. Instead of pushing directly to a shared branch, a developer pushes their work to a separate branch and opens a request asking that it be merged into a target branch, typically main. The pull request bundles the diff, a description of the change, a discussion thread, and the status of any automated checks into a single reviewable unit.
How It Works
A developer creates a branch, for example with git checkout -b fix/login-timeout, commits their changes, and runs git push origin fix/login-timeout. On GitHub, GitLab, or Bitbucket, they open a pull request against main, write a description of what changed and why, and request review from a teammate. The platform automatically triggers CI checks, lint, tests, build, security scans, and displays their pass or fail status directly on the pull request. Reviewers leave inline comments on specific lines, the author pushes follow-up commits addressing feedback, and once the required approvals and checks are satisfied, the branch is merged, often as a single squashed commit to keep the trunk’s history clean.
Pull Requests vs. CI
A pull request is the review and merge workflow; Continuous Integration is the automated verification that typically runs on every pull request. They work together, CI provides the automated pass or fail signal, and the pull request provides the human review, discussion, and merge decision layered on top of that signal.
Why Teams Use Pull Requests
- Peer review catches design issues, logic errors, and security concerns that automated checks miss.
- Every change has an audit trail: who wrote it, who approved it, and what discussion happened before it merged.
- They act as a natural gate for automated checks such as static analysis, tests, and dependency scanning.
- Reviewing each other’s code spreads knowledge of the codebase across the team rather than leaving it siloed.
Trade-offs and Limitations
Pull requests can become a bottleneck if reviewers are slow to respond, stalling work in progress. Large pull requests, hundreds or thousands of lines, are notoriously hard to review well; reviewers tend to rubber-stamp them rather than catch real issues. There is also tension with trunk-based development: if branches live for days waiting on review, they work against the goal of frequent, small integration that CI depends on.
Best Practices
- Keep pull requests small, ideally under a few hundred lines changed, so they can be reviewed thoroughly and quickly.
- Write a clear description that explains the why, not just the what, and link the related issue or ticket.
- Require at least one approval and a passing CI status before allowing a merge, enforced through branch protection rules.
- Use draft pull requests to get early feedback on an approach before the implementation is finished.
- Let automated linting and static analysis handle style nitpicks so human reviewers can focus on logic and design.
- Set a team norm or SLA for review turnaround so pull requests do not sit unreviewed for days.
Frequently Asked Questions
What is Pull Request?
A pull request is a version-control workflow for proposing code changes from one branch into another, giving teammates a place to review the diff, run automated checks, and discuss the change before it merges.
How does Pull Request work?
Pull Request works by combining the components described in the sections above. The main page walks through the architecture, the typical use cases, and the trade-offs to weigh before adopting it.
Why does Pull Request matter?
Teams adopt Pull Request to ship faster, run more reliably, and reduce the cognitive load on engineers. The benefits, limits, and adjacent tools are covered in the body above.
When should you use Pull Request?
Use Pull Request when the problems it solves match what your team is hitting today. The page above outlines the signals that mean you should adopt it now, and the cases where a simpler approach is fine.
