code-review-excellence

卓越的代码审查

通过建设性的反馈、系统化分析和协作改进，将代码审查从把关转变为知识分享。

何时使用此技能

• 审查拉取请求和代码变更
• 为团队制定代码审查标准
• 通过审查指导初级开发者
• 进行架构审查
• 制定审查清单和指南
• 改进团队协作
• 缩短代码审查周期
• 维护代码质量标准

核心原则

1. 审查心态

代码审查的目标：

• 发现 Bug 和边界情况
• 确保代码易于维护
• 在团队中分享知识
• 落实编码标准
• 改进设计和架构
• 建设团队文化

非目标：

• 炫耀知识
• 吹毛求疵地纠结格式（使用代码检查工具）
• 不必要地阻碍进度
• 按照自己的偏好重写代码

2. 有效反馈

良好的反馈应当：

• 具体且可执行
• 具有教育意义，而非评判
• 聚焦于代码，而非个人
• 保持平衡（也要赞扬优秀的工作）
• 按优先级排序（关键问题与可改进项）

❌ Bad: "This is wrong."
✅ Good: "This could cause a race condition when multiple users
         access simultaneously. Consider using a mutex here."

❌ Bad: "Why didn't you use X pattern?"
✅ Good: "Have you considered the Repository pattern? It would
         make this easier to test. Here's an example: [link]"

❌ Bad: "Rename this variable."
✅ Good: "[nit] Consider `userCount` instead of `uc` for
         clarity. Not blocking if you prefer to keep it."

3. 审查范围

需要审查的内容：

• 逻辑正确性和边界情况
• 安全漏洞
• 性能影响
• 测试覆盖率和质量
• 错误处理
• 文档和注释
• API 设计和命名
• 架构适配性

无需手动审查的内容：

• 代码格式（使用 Prettier、Black 等工具）
• 导入项的组织
• 代码检查违规项
• 简单的拼写错误

审查流程

阶段 1：收集上下文（2-3 分钟）

Before diving into code, understand:

1. Read PR description and linked issue
2. Check PR size (>400 lines? Ask to split)
3. Review CI/CD status (tests passing?)
4. Understand the business requirement
5. Note any relevant architectural decisions

阶段 2：高层审查（5-10 分钟）

1. **Architecture & Design**
   - Does the solution fit the problem?
   - Are there simpler approaches?
   - Is it consistent with existing patterns?
   - Will it scale?

2. **File Organization**
   - Are new files in the right places?
   - Is code grouped logically?
   - Are there duplicate files?

3. **Testing Strategy**
   - Are there tests?
   - Do tests cover edge cases?
   - Are tests readable?

阶段 3：逐行审查（10-20 分钟）

For each file:

1. **Logic & Correctness**
   - Edge cases handled?
   - Off-by-one errors?
   - Null/undefined checks?
   - Race conditions?

2. **Security**
   - Input validation?
   - SQL injection risks?
   - XSS vulnerabilities?
   - Sensitive data exposure?

3. **Performance**
   - N+1 queries?
   - Unnecessary loops?
   - Memory leaks?
   - Blocking operations?

4. **Maintainability**
   - Clear variable names?
   - Functions doing one thing?
   - Complex code commented?
   - Magic numbers extracted?

阶段 4：总结并做出决定（2-3 分钟）

1. Summarize key concerns
2. Highlight what you liked
3. Make clear decision:
   - ✅ Approve
   - 💬 Comment (minor suggestions)
   - 🔄 Request Changes (must address)
4. Offer to pair if complex

审查技巧

技巧 1：清单法

## Security Checklist
- [ ] User input validated and sanitized
- [ ] SQL queries use parameterization
- [ ] Authentication/authorization checked
- [ ] Secrets not hardcoded
- [ ] Error messages don't leak info

## Performance Checklist
- [ ] No N+1 queries
- [ ] Database queries indexed
- [ ] Large lists paginated
- [ ] Expensive operations cached
- [ ] No blocking I/O in hot paths

## Testing Checklist
- [ ] Happy path tested
- [ ] Edge cases covered
- [ ] Error cases tested
- [ ] Test names are descriptive
- [ ] Tests are deterministic

技巧 2：提问法

不要直接指出问题，而是通过提问鼓励对方思考：

❌ "This will fail if the list is empty."
✅ "What happens if `items` is an empty array?"

❌ "You need error handling here."
✅ "How should this behave if the API call fails?"

❌ "This is inefficient."
✅ "I see this loops through all users. Have we considered
    the performance impact with 100k users?"

技巧 3：提出建议，而非发号施令

## Use Collaborative Language

❌ "You must change this to use async/await"
✅ "Suggestion: async/await might make this more readable:
    ```typescript
    async function fetchUser(id: string) {
        const user = await db.query('SELECT * FROM users WHERE id = ?', id);
        return user;
    }
    ```
    What do you think?"

❌ "Extract this into a function"
✅ "This logic appears in 3 places. Would it make sense to
    extract it into a shared utility function?"

技巧 4：区分严重程度

Use labels to indicate priority:

🔴 [blocking] - Must fix before merge
🟡 [important] - Should fix, discuss if disagree
🟢 [nit] - Nice to have, not blocking
💡 [suggestion] - Alternative approach to consider
📚 [learning] - Educational comment, no action needed
🎉 [praise] - Good work, keep it up!

Example:
"🔴 [blocking] This SQL query is vulnerable to injection.
 Please use parameterized queries."

"🟢 [nit] Consider renaming `data` to `userData` for clarity."

"🎉 [praise] Excellent test coverage! This will catch edge cases."

特定语言的模式

Python 代码审查

# Check for Python-specific issues

# ❌ Mutable default arguments
def add_item(item, items=[]):  # Bug! Shared across calls
    items.append(item)
    return items

# ✅ Use None as default
def add_item(item, items=None):
    if items is None:
        items = []
    items.append(item)
    return items

# ❌ Catching too broad
try:
    result = risky_operation()
except:  # Catches everything, even KeyboardInterrupt!
    pass

# ✅ Catch specific exceptions
try:
    result = risky_operation()
except ValueError as e:
    logger.error(f"Invalid value: {e}")
    raise

# ❌ Using mutable class attributes
class User:
    permissions = []  # Shared across all instances!

# ✅ Initialize in __init__
class User:
    def __init__(self):
        self.permissions = []

TypeScript/JavaScript 代码审查

// Check for TypeScript-specific issues

// ❌ Using any defeats type safety
function processData(data: any) {  // Avoid any
    return data.value;
}

// ✅ Use proper types
interface DataPayload {
    value: string;
}
function processData(data: DataPayload) {
    return data.value;
}

// ❌ Not handling async errors
async function fetchUser(id: string) {
    const response = await fetch(`/api/users/${id}`);
    return response.json();  // What if network fails?
}

// ✅ Handle errors properly
async function fetchUser(id: string): Promise<User> {
    try {
        const response = await fetch(`/api/users/${id}`);
        if (!response.ok) {
            throw new Error(`HTTP ${response.status}`);
        }
        return await response.json();
    } catch (error) {
        console.error('Failed to fetch user:', error);
        throw error;
    }
}

// ❌ Mutation of props
function UserProfile({ user }: Props) {
    user.lastViewed = new Date();  // Mutating prop!
    return <div>{user.name}</div>;
}

// ✅ Don't mutate props
function UserProfile({ user, onView }: Props) {
    useEffect(() => {
        onView(user.id);  // Notify parent to update
    }, [user.id]);
    return <div>{user.name}</div>;
}

高级审查模式

模式 1：架构审查

When reviewing significant changes:

1. **Design Document First**
   - For large features, request design doc before code
   - Review design with team before implementation
   - Agree on approach to avoid rework

2. **Review in Stages**
   - First PR: Core abstractions and interfaces
   - Second PR: Implementation
   - Third PR: Integration and tests
   - Easier to review, faster to iterate

3. **Consider Alternatives**
   - "Have we considered using [pattern/library]?"
   - "What's the tradeoff vs. the simpler approach?"
   - "How will this evolve as requirements change?"

模式 2：测试质量审查

// ❌ Poor test: Implementation detail testing
test('increments counter variable', () => {
    const component = render(<Counter />);
    const button = component.getByRole('button');
    fireEvent.click(button);
    expect(component.state.counter).toBe(1);  // Testing internal state
});

// ✅ Good test: Behavior testing
test('displays incremented count when clicked', () => {
    render(<Counter />);
    const button = screen.getByRole('button', { name: /increment/i });
    fireEvent.click(button);
    expect(screen.getByText('Count: 1')).toBeInTheDocument();
});

// Review questions for tests:
// - Do tests describe behavior, not implementation?
// - Are test names clear and descriptive?
// - Do tests cover edge cases?
// - Are tests independent (no shared state)?
// - Can tests run in any order?

模式 3：安全审查

## Security Review Checklist

### Authentication & Authorization
- [ ] Is authentication required where needed?
- [ ] Are authorization checks before every action?
- [ ] Is JWT validation proper (signature, expiry)?
- [ ] Are API keys/secrets properly secured?

### Input Validation
- [ ] All user inputs validated?
- [ ] File uploads restricted (size, type)?
- [ ] SQL queries parameterized?
- [ ] XSS protection (escape output)?

### Data Protection
- [ ] Passwords hashed (bcrypt/argon2)?
- [ ] Sensitive data encrypted at rest?
- [ ] HTTPS enforced for sensitive data?
- [ ] PII handled according to regulations?

### Common Vulnerabilities
- [ ] No eval() or similar dynamic execution?
- [ ] No hardcoded secrets?
- [ ] CSRF protection for state-changing operations?
- [ ] Rate limiting on public endpoints?

提出棘手的反馈

模式：三明治法（改良版）

Traditional: Praise + Criticism + Praise (feels fake)

Better: Context + Specific Issue + Helpful Solution

Example:
"I noticed the payment processing logic is inline in the
controller. This makes it harder to test and reuse.

[Specific Issue]
The calculateTotal() function mixes tax calculation,
discount logic, and database queries, making it difficult
to unit test and reason about.

[Helpful Solution]
Could we extract this into a PaymentService class? That
would make it testable and reusable. I can pair with you
on this if helpful."

处理分歧

When author disagrees with your feedback:

1. **Seek to Understand**
   "Help me understand your approach. What led you to
    choose this pattern?"

2. **Acknowledge Valid Points**
   "That's a good point about X. I hadn't considered that."

3. **Provide Data**
   "I'm concerned about performance. Can we add a benchmark
    to validate the approach?"

4. **Escalate if Needed**
   "Let's get [architect/senior dev] to weigh in on this."

5. **Know When to Let Go**
   If it's working and not a critical issue, approve it.
   Perfection is the enemy of progress.

最佳实践

1. 及时审查：在 24 小时内完成，最好当天完成
2. 控制 PR 规模：为确保审查有效，每个 PR 最多 200-400 行
3. 分时段审查：每次最多 60 分钟，并适当休息
4. 使用审查工具：GitHub、GitLab 或专用工具
5. 尽可能自动化：代码检查工具、格式化工具、安全扫描
6. 建立融洽关系：表情符号、赞扬和同理心都很重要
7. 随时提供帮助：对于复杂问题，主动提出结对处理
8. 向他人学习：审阅其他人的审查意见

常见陷阱

• 完美主义：因为细微的风格偏好而阻止 PR
• 范围蔓延：“既然你正在处理，能不能也……”
• 标准不一：对不同的人采用不同标准
• 延迟审查：让 PR 搁置数日
• 失联：要求对方修改后便不再回应
• 走过场式批准：未实际审查就批准
• 纠结琐事：长时间争论无关紧要的细节

模板

PR 审查评论模板

## Summary
[Brief overview of what was reviewed]

## Strengths
- [What was done well]
- [Good patterns or approaches]

## Required Changes
🔴 [Blocking issue 1]
🔴 [Blocking issue 2]

## Suggestions
💡 [Improvement 1]
💡 [Improvement 2]

## Questions
❓ [Clarification needed on X]
❓ [Alternative approach consideration]

## Verdict
✅ Approve after addressing required changes

资源

• references/code-review-best-practices.md：全面的审查指南
• references/common-bugs-checklist.md：需要留意的特定语言 Bug
• references/security-review-guide.md：以安全为重点的审查清单
• assets/pr-review-template.md：标准审查评论模板
• assets/review-checklist.md：快速参考清单
• scripts/pr-analyzer.py：分析 PR 复杂度并推荐审查者