Python Code Review

This command invokes the python-reviewer agent for comprehensive Python-specific code review.

What This Command Does

1. Identify Python Changes: Find modified .py files via git diff
2. Run Static Analysis: Execute ruff, mypy, pylint, black --check
3. Security Scan: Check for SQL injection, command injection, unsafe deserialization
4. Type Safety Review: Analyze type hints and mypy errors
5. Pythonic Code Check: Verify code follows PEP 8 and Python best practices
6. Generate Report: Categorize issues by severity

When to Use

Use /python-review when:

• After writing or modifying Python code
• Before committing Python changes
• Reviewing pull requests with Python code
• Onboarding to a new Python codebase
• Learning Pythonic patterns and idioms

Review Categories

CRITICAL (Must Fix)

• SQL/Command injection vulnerabilities
• Unsafe eval/exec usage
• Pickle unsafe deserialization
• Hardcoded credentials
• YAML unsafe load
• Bare except clauses hiding errors

HIGH (Should Fix)

• Missing type hints on public functions
• Mutable default arguments
• Swallowing exceptions silently
• Not using context managers for resources
• C-style looping instead of comprehensions
• Using type() instead of isinstance()
• Race conditions without locks

MEDIUM (Consider)

• PEP 8 formatting violations
• Missing docstrings on public functions
• Print statements instead of logging
• Inefficient string operations
• Magic numbers without named constants
• Not using f-strings for formatting
• Unnecessary list creation

Automated Checks Run

# Type checking
mypy .

# Linting and formatting
ruff check .
black --check .
isort --check-only .

# Security scanning
bandit -r .

# Dependency audit
pip-audit
safety check

# Testing
pytest --cov=app --cov-report=term-missing

Example Usage

User: /python-review

Agent:
# Python Code Review Report

## Files Reviewed
- app/routes/user.py (modified)
- app/services/auth.py (modified)

## Static Analysis Results
✓ ruff: No issues
✓ mypy: No errors
⚠️ black: 2 files need reformatting
✓ bandit: No security issues

## Issues Found

[CRITICAL] SQL Injection vulnerability
File: app/routes/user.py:42
Issue: User input directly interpolated into SQL query
```python
query = f"SELECT * FROM users WHERE id = {user_id}"  # Bad

Fix: Use parameterized query

query = "SELECT * FROM users WHERE id = %s"  # Good
cursor.execute(query, (user_id,))

[HIGH] Mutable default argument File: app/services/auth.py:18 Issue: Mutable default argument causes shared state

def process_items(items=[]):  # Bad
    items.append("new")
    return items

Fix: Use None as default

def process_items(items=None):  # Good
    if items is None:
        items = []
    items.append("new")
    return items

[MEDIUM] Missing type hints File: app/services/auth.py:25 Issue: Public function without type annotations

def get_user(user_id):  # Bad
    return db.find(user_id)

Fix: Add type hints

def get_user(user_id: str) -> Optional[User]:  # Good
    return db.find(user_id)

[MEDIUM] Not using context manager File: app/routes/user.py:55 Issue: File not closed on exception

f = open("config.json")  # Bad
data = f.read()
f.close()

Fix: Use context manager

with open("config.json") as f:  # Good
    data = f.read()

Summary

• CRITICAL: 1
• HIGH: 1
• MEDIUM: 2

Recommendation: ❌ Block merge until CRITICAL issue is fixed

Formatting Required

Run: black app/routes/user.py app/services/auth.py

## Approval Criteria

| Status | Condition |
|--------|-----------|
| ✅ Approve | No CRITICAL or HIGH issues |
| ⚠️ Warning | Only MEDIUM issues (merge with caution) |
| ❌ Block | CRITICAL or HIGH issues found |

## Integration with Other Commands

- Use `/tdd` first to ensure tests pass
- Use `/code-review` for non-Python specific concerns
- Use `/python-review` before committing
- Use `/build-fix` if static analysis tools fail

## Framework-Specific Reviews

### Django Projects
The reviewer checks for:
- N+1 query issues (use `select_related` and `prefetch_related`)
- Missing migrations for model changes
- Raw SQL usage when ORM could work
- Missing `transaction.atomic()` for multi-step operations

### FastAPI Projects
The reviewer checks for:
- CORS misconfiguration
- Pydantic models for request validation
- Response models correctness
- Proper async/await usage
- Dependency injection patterns

### Flask Projects
The reviewer checks for:
- Context management (app context, request context)
- Proper error handling
- Blueprint organization
- Configuration management

## Related

- Agent: `agents/python-reviewer.md`
- Skills: `skills/python-patterns/`, `skills/python-testing/`

## Common Fixes

### Add Type Hints
```python
# Before
def calculate(x, y):
    return x + y

# After
from typing import Union

def calculate(x: Union[int, float], y: Union[int, float]) -> Union[int, float]:
    return x + y

Use Context Managers

# Before
f = open("file.txt")
data = f.read()
f.close()

# After
with open("file.txt") as f:
    data = f.read()

Use List Comprehensions

# Before
result = []
for item in items:
    if item.active:
        result.append(item.name)

# After
result = [item.name for item in items if item.active]

Fix Mutable Defaults

# Before
def append(value, items=[]):
    items.append(value)
    return items

# After
def append(value, items=None):
    if items is None:
        items = []
    items.append(value)
    return items

Use f-strings (Python 3.6+)

# Before
name = "Alice"
greeting = "Hello, " + name + "!"
greeting2 = "Hello, {}".format(name)

# After
greeting = f"Hello, {name}!"

Fix String Concatenation in Loops

# Before
result = ""
for item in items:
    result += str(item)

# After
result = "".join(str(item) for item in items)

Python Version Compatibility

The reviewer notes when code uses features from newer Python versions:

Feature	Minimum Python
Type hints	3.5+
f-strings	3.6+
Walrus operator (:=)	3.8+
Position-only parameters	3.8+
Match statements	3.10+
Type unions (`x | None`)	3.10+

Ensure your project's pyproject.toml or setup.py specifies the correct minimum Python version.