Pull Request Automation

Pull Request Automation

Table of Contents

• Overview
• When to Use
• Quick Start
• Reference Guides
• Best Practices

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

Quick Start

Minimal working example:

# .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
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

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

Bors: Merge Automation Configuration

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

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

Code Coverage Requirement

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

GitHub Actions: Auto Merge on Approval

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'
              });
            }

GitHub Actions: Auto Review Assignment

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
              });
            }

GitLab Merge Request Automation

GitLab Merge Request Automation

# .gitlab/merge_request_templates/default.md

PR Title Validation Workflow

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'
              );
            }