# Code Review Workflow

## Overview

Code review is a systematic examination of source code intended to find bugs, improve code quality, and share knowledge among team members. It's a critical part of the software development process that helps maintain high standards and reduces technical debt.

## Code Review Process

### 1. Pre-Review Preparation

#### Author Responsibilities
- **Self-Review**: Review your own code before submitting
- **Clear Description**: Write a clear pull request description
- **Small Changes**: Keep changes focused and reasonably sized
- **Test Coverage**: Ensure adequate test coverage for changes
- **Documentation**: Update documentation as needed

#### Checklist Before Submitting
- [ ] Code compiles without errors or warnings
- [ ] All tests pass locally
- [ ] Code follows team coding standards
- [ ] Commit messages are clear and descriptive
- [ ] No debugging code or commented-out code
- [ ] No secrets or sensitive information committed

### 2. Review Assignment

#### Reviewer Selection
- **Expertise**: Choose reviewers with relevant domain knowledge
- **Availability**: Consider reviewer workload and availability
- **Learning**: Include junior developers for knowledge transfer
- **Coverage**: Ensure all critical areas are reviewed

#### Review Timeline
- **Response Time**: Acknowledge review requests within 24 hours
- **Review Time**: Complete reviews within 48 hours for normal changes
- **Urgent Changes**: Expedited process for critical fixes
- **Follow-up**: Timely responses to review feedback

### 3. Review Execution

#### What to Review

##### Functionality
- Does the code do what it's supposed to do?
- Are edge cases handled appropriately?
- Is error handling comprehensive and appropriate?
- Are there any logical errors or bugs?

##### Code Quality
- Is the code readable and well-structured?
- Are variable and function names descriptive?
- Is the code properly commented where necessary?
- Does the code follow established patterns and conventions?

##### Performance
- Are there any obvious performance issues?
- Is the algorithm choice appropriate?
- Are database queries optimized?
- Is memory usage reasonable?

##### Security
- Are there any security vulnerabilities?
- Is input validation adequate?
- Are authentication and authorization handled correctly?
- Is sensitive data protected appropriately?

##### Maintainability
- Is the code easy to understand and modify?
- Are functions and classes appropriately sized?
- Is there appropriate separation of concerns?
- Is the code well-tested?

#### Review Techniques

##### Line-by-Line Review
- Examine each line of changed code
- Look for syntax errors, typos, and logical issues
- Check for adherence to coding standards
- Verify proper use of language features

##### Architectural Review
- Assess how changes fit into overall system architecture
- Evaluate design patterns and architectural decisions
- Consider impact on system performance and scalability
- Review API design and interface contracts

##### Testing Review
- Verify test coverage for new functionality
- Check test quality and effectiveness
- Ensure tests are maintainable and readable
- Validate test data and scenarios

### 4. Providing Feedback

#### Feedback Categories

##### Must Fix (Blocking)
- Bugs or logical errors
- Security vulnerabilities
- Performance issues
- Violations of critical standards

##### Should Fix (Non-blocking)
- Code quality improvements
- Better naming or structure
- Missing documentation
- Minor performance optimizations

##### Suggestions (Optional)
- Alternative approaches
- Learning opportunities
- Style preferences
- Future improvements

#### Feedback Guidelines

##### Be Constructive
- Focus on the code, not the person
- Explain the reasoning behind suggestions
- Provide specific examples when possible
- Offer solutions, not just problems

##### Be Clear and Specific
- Point to specific lines or sections
- Use clear, unambiguous language
- Provide examples of preferred approaches
- Link to relevant documentation or standards

##### Be Respectful
- Use positive, professional language
- Acknowledge good work and improvements
- Ask questions to understand intent
- Assume positive intent from the author

### 5. Addressing Feedback

#### Author Response Process
- **Acknowledge**: Respond to all feedback promptly
- **Clarify**: Ask questions if feedback is unclear
- **Implement**: Make requested changes or provide justification
- **Update**: Push new commits addressing feedback
- **Communicate**: Explain changes made in response to feedback

#### Handling Disagreements
- **Discussion**: Engage in respectful technical discussion
- **Escalation**: Involve team lead or architect if needed
- **Documentation**: Document decisions for future reference
- **Compromise**: Find mutually acceptable solutions

### 6. Final Approval

#### Approval Criteria
- All blocking issues resolved
- Required number of approvals obtained
- All tests passing in CI/CD pipeline
- Documentation updated as needed
- No merge conflicts with target branch

#### Merge Process
- **Final Check**: Verify all criteria met before merging
- **Merge Strategy**: Use appropriate merge strategy for the change
- **Cleanup**: Delete feature branch after successful merge
- **Communication**: Notify relevant stakeholders of merge

## Review Tools and Automation

### Code Review Platforms
- **GitHub**: Pull requests with inline comments
- **GitLab**: Merge requests with discussion threads
- **Bitbucket**: Pull requests with approval workflows
- **Azure DevOps**: Pull requests with work item integration

### Automated Checks
- **Linting**: Automated code style checking
- **Testing**: Automated test execution
- **Security Scanning**: Automated vulnerability detection
- **Coverage**: Code coverage reporting
- **Performance**: Automated performance testing

### Review Metrics
- **Review Time**: Time from submission to approval
- **Defect Detection**: Bugs found during review vs. production
- **Review Coverage**: Percentage of code changes reviewed
- **Participation**: Team member participation in reviews

## Best Practices

### For Authors
- **Small PRs**: Keep changes small and focused
- **Clear Context**: Provide clear description and context
- **Self-Review**: Review your own code first
- **Responsive**: Respond to feedback promptly
- **Learning**: Use reviews as learning opportunities

### For Reviewers
- **Timely**: Provide feedback in a timely manner
- **Thorough**: Review code carefully and completely
- **Constructive**: Provide helpful, actionable feedback
- **Consistent**: Apply standards consistently across reviews
- **Mentoring**: Use reviews to mentor and share knowledge

### For Teams
- **Standards**: Establish clear coding and review standards
- **Training**: Provide training on effective code review
- **Culture**: Foster a positive review culture
- **Continuous Improvement**: Regularly assess and improve the process
- **Balance**: Balance thoroughness with development velocity

## Common Pitfalls

### Review Fatigue
- **Large Changes**: Avoid reviewing overly large changes
- **Frequency**: Don't overwhelm reviewers with too many requests
- **Quality**: Maintain review quality despite time pressure
- **Rotation**: Rotate review responsibilities among team members

### Inconsistent Standards
- **Documentation**: Clearly document coding standards
- **Training**: Ensure all team members understand standards
- **Tooling**: Use automated tools to enforce standards
- **Regular Updates**: Keep standards current and relevant

### Poor Communication
- **Clarity**: Ensure feedback is clear and actionable
- **Tone**: Maintain professional, respectful tone
- **Context**: Provide sufficient context for suggestions
- **Follow-up**: Follow up on unresolved discussions
