fix-bugs

Bug Detection & Auto-Fix

Scan and fix issues in: $ARGUMENTS (default: changed files)

Detection Categories

1. Common Bugs

Null/Undefined Handling

# Bug: AttributeError if user is None
user.name  

# Fix: Safe navigation
user.name if user else None
# Or: getattr(user, 'name', None)

Off-by-One Errors

# Bug: Misses last element
for i in range(len(items) - 1):

# Fix: Include last element
for i in range(len(items)):

Resource Leaks

# Bug: File handle not closed on error
f = open('file.txt')
data = f.read()
f.close()

# Fix: Context manager
with open('file.txt') as f:
    data = f.read()

2. Async Issues

Missing await

# Bug: Returns coroutine, not result
async def get_user():
    return fetch_user(id)  # Missing await!

# Fix
async def get_user():
    return await fetch_user(id)

Blocking in async context

# Bug: Blocks event loop
async def process():
    time.sleep(1)  # Blocking!

# Fix: Use async sleep
async def process():
    await asyncio.sleep(1)

3. Logic Errors

Boolean Expression Bugs

# Bug: Always True
if x == 1 or 2:

# Fix
if x == 1 or x == 2:
# Or: if x in (1, 2):

Mutable Default Arguments

# Bug: Shared list across calls
def add_item(item, items=[]):
    items.append(item)
    return items

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

4. Type Issues

Type Coercion Problems

// Bug: String concatenation instead of addition
const total = "5" + 3;  // "53"

// Fix: Explicit conversion
const total = Number("5") + 3;  // 8

5. Security Issues

Injection Vulnerabilities

# Bug: SQL Injection
query = f"SELECT * FROM users WHERE id = {user_id}"

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

Execution Flow

Step 1: Identify Targets