Pull Request Automation

Pull Request Automation

Overview

Implement pull request automation to streamline code review processes, enforce quality standards, and reduce manual overhead through templated workflows and intelligent assignment rules.

When to Use

• Code review standardization
• Quality gate enforcement
• Contributor guidance
• Review assignment automation
• Merge automation
• PR labeling and organization

Implementation Examples

1. GitHub Pull Request Template

# .github/pull_request_template.md

## Description
Briefly describe the changes made in this PR.

## Type of Change
- [ ] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)
- [ ] Documentation update

## Related Issues
Closes #(issue number)

## Changes Made
- Change 1
- Change 2

## Testing
- [ ] Unit tests added/updated
- [ ] Integration tests pass
- [ ] Manual testing completed

## Checklist
- [ ] Code follows style guidelines
- [ ] Self-review completed
- [ ] Comments added for complex logic
- [ ] Documentation updated
- [ ] No new warnings generated
- [ ] Tests pass locally

## Screenshots (if applicable)
Add screenshots for UI changes

## Performance Impact
- [ ] No performance impact
- [ ] Performance improved
- [ ] Potential performance implications (describe)

## Dependencies
List any new dependencies or version changes

2. GitHub Actions: Auto Review Assignment

# .github/workflows/auto-assign.yml
name: Auto Assign PR

on:
  pull_request:
    types: [opened, reopened]

jobs:
  assign:
    runs-on: ubuntu-latest
    steps:
      - name: Assign reviewers
        uses: actions/github-script@v7
        with:
          script: |
            const pr = context.payload.pull_request;
            const reviewers = ['reviewer1', 'reviewer2', 'reviewer3'];

            // Select random reviewers
            const selected = reviewers.sort(() => 0.5 - Math.random()).slice(0, 2);

            await github.rest.pulls.requestReviewers({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: pr.number,
              reviewers: selected
            });

      - name: Add labels
        uses: actions/github-script@v7
        with:
          script: |
            const pr = context.payload.pull_request;
            const labels = [];

            if (pr.title.startsWith('feat:')) labels.push('feature');
            if (pr.title.startsWith('fix:')) labels.push('bugfix');
            if (pr.title.startsWith('docs:')) labels.push('documentation');

            if (labels.length > 0) {
              await github.rest.issues.addLabels({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: pr.number,
                labels: labels
              });
            }

3. GitHub Actions: Auto Merge on Approval

# .github/workflows/auto-merge.yml
name: Auto Merge PR

on:
  pull_request_review:
    types: [submitted]
  check_suite:
    types: [completed]

jobs:
  auto-merge:
    runs-on: ubuntu-latest
    if: github.event.review.state == 'approved'
    steps:
      - name: Check PR status
        uses: actions/github-script@v7
        with:
          script: |
            const pr = await github.rest.pulls.get({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.issue.number
            });

            // Check if all required checks passed
            const checkRuns = await github.rest.checks.listForRef({
              owner: context.repo.owner,
              repo: context.repo.repo,
              ref: pr.data.head.ref
            });

            const allPassed = checkRuns.data.check_runs.every(
              run => run.status === 'completed' && run.conclusion === 'success'
            );

            if (allPassed && pr.data.approved_reviews_count >= 2) {
              // Auto merge with squash strategy
              await github.rest.pulls.merge({
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: context.issue.number,
                merge_method: 'squash'
              });
            }

4. GitLab Merge Request Automation

# .gitlab/merge_request_templates/default.md
## Description
<!-- Briefly describe what this MR does -->

## Related Issue
Closes #(issue number)

## Checklist
- [ ] Tests added/updated
- [ ] Documentation updated
- [ ] Code review self-check completed
- [ ] No new console errors/warnings

## Type of Change
- [ ] Bug fix
- [ ] Feature
- [ ] Breaking change
- [ ] Documentation

5. Bors: Merge Automation Configuration

# bors.toml
status = [
  "continuous-integration/travis-ci/pr",
  "continuous-integration/circleci",
  "codecov/project/overall"
]

# Reviewers
reviewers = ["reviewer1", "reviewer2"]

# Block merge if status checks fail
block_labels = ["blocked", "no-merge"]

# Automatically merge if all checks pass
timeout_sec = 3600

# Delete branch after merge
delete_merged_branches = true

# Squash commits on merge
squash_commits = true

6. Conventional Commit Validation

#!/bin/bash
# commit-msg validation script

COMMIT_MSG=$(<"$1")

# Pattern: type(scope): subject
PATTERN="^(feat|fix|docs|style|refactor|test|chore)(\([a-z\-]+\))?: .{1,50}$"

if ! [[ $COMMIT_MSG =~ $PATTERN ]]; then
    echo "❌ Commit message does not follow Conventional Commits format"
    echo "Format: type(scope): subject"
    echo "Types: feat, fix, docs, style, refactor, test, chore"
    exit 1
fi

echo "✅ Commit message format is valid"
exit 0

7. PR Title Validation Workflow

# .github/workflows/validate-pr-title.yml
name: Validate PR Title

on:
  pull_request:
    types: [opened, reopened, edited]

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - name: Validate PR title format
        uses: actions/github-script@v7
        with:
          script: |
            const pr = context.payload.pull_request;
            const title = pr.title;

            // Pattern: type: description
            const pattern = /^(feat|fix|docs|style|refactor|test|chore|perf)(\(.+\))?: .{1,80}$/;

            if (!pattern.test(title)) {
              core.setFailed(
                'PR title must follow: type: description\n' +
                'Types: feat, fix, docs, style, refactor, test, chore, perf'
              );
            }

8. Code Coverage Requirement

# .github/workflows/coverage-check.yml
name: Coverage Check

on: [pull_request]

jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: '18'

      - name: Run tests with coverage
        run: npm run test:coverage

      - name: Upload coverage
        uses: codecov/codecov-action@v3
        with:
          token: ${{ secrets.CODECOV_TOKEN }}
          files: ./coverage/lcov.info
          fail_ci_if_error: true
          minimum-coverage: 80

Best Practices

✅ DO

• Use PR templates for consistency
• Require code reviews before merge
• Enforce CI/CD checks pass
• Auto-assign reviewers based on code ownership
• Label PRs for organization
• Validate commit messages
• Use squash commits for cleaner history
• Set minimum coverage requirements
• Provide detailed PR descriptions

❌ DON'T

• Approve without reviewing code
• Merge failing CI checks
• Use vague PR titles
• Skip automated checks
• Merge to protected branches without review
• Ignore code coverage drops
• Force push to shared branches
• Merge directly without PR

CODEOWNERS Configuration

# .github/CODEOWNERS

# Global owners
* @owner1 @owner2

# Documentation
/docs/ @doc-owner
*.md @doc-owner

# Backend
/backend/ @backend-lead @backend-team
/src/api/ @api-team

# Frontend
/frontend/ @frontend-lead @frontend-team
/src/components/ @component-team

# DevOps
/infra/ @devops-team
/.github/workflows/ @devops-team

Resources

• GitHub PR Templates
• GitLab Merge Request Templates
• Conventional Commits
• Bors: Merge Bot