Reviewing Code

Code Review Excellence

Transform code reviews from gatekeeping to knowledge sharing through constructive feedback, systematic analysis, and collaborative improvement.

When to Use This Skill

• Reviewing pull requests and code changes
• Establishing code review standards for teams
• Mentoring junior developers through reviews
• Conducting architecture reviews
• Creating review checklists and guidelines

Workflow

1. Context Gathering (2-3 mins): Read PR description, check CI status, understand requirements.
2. High-Level Review (5-10 mins): Verify architecture, file organization, and testing strategy.
3. Line-by-Line Review (10-20 mins): Check logic, security, performance, and maintainability.
4. Summary & Decision (2-3 mins): Summarize findings, decision (Approve/Change Request), and offer pairing.

Instructions

1. The Review Mindset

Goals: Catch bugs, ensure maintainability, share knowledge, enforce standards. Anti-Goals: Show off, nitpick formatting (use linters), block unnecessarily.

2. Effective Feedback

• Specific & Actionable: Instead of "This is wrong", say "This could cause a race condition... consider a mutex."
• Educational: "Have you considered the Repository pattern? It helps with testing."
• Non-blocking (Nits): "[nit] Consider userCount for clarity."

3. Review Scope Checklist

Logic & Correctness:

• Edge cases handled?
• Off-by-one errors?
• Null/undefined checks?
• Race conditions?

Security:

• Input validation?
• SQL injection / XSS risks?
• Sensitive data exposure?

Performance:

• N+1 queries?
• Unnecessary loops?
• Memory leaks?

Maintainability:

• Clear naming?
• Single responsibility functions?
• No magic numbers?

4. Code Review Templates

PR Review Comment Template:

## Summary
[Brief overview]

## Strengths
- [Good patterns]

## Required Changes
🔴 [Blocking issue]

## Suggestions
💡 [Improvement idea]

## Questions
❓ [Clarification needed]

## Verdict
✅ Approve / 🔄 Request Changes

5. Language-Specific Patterns

Python:

• Avoid mutable default args (def foo(items=[])).
• Be specific with exceptions (except ValueError, not except:).
• Initialize mutable class attributes in __init__.

TypeScript/JavaScript:

• Avoid any.
• Handle async errors properly (try/catch).
• React: Don't mutate props directly methods.

Resources

• references/common-bugs-checklist.md
• references/security-review-guide.md