Bugs

Python Async/Await Mistakes: What Goes Wrong

Forgetting an await, blocking the event loop, or mixing sync and async incorrectly are extremely common mistakes even for experienced developers.


❌ Missing await Keyword

async def fetch_data(url):
    async with aiohttp.ClientSession() as session:
        response = session.get(url)  # Bug: missing await!
        return response.json()  # Returns coroutine, not data

✅ Correctly Awaited

async def fetch_data(url):
    async with aiohttp.ClientSession() as session:
        response = await session.get(url)
        return await response.json()
💡

Pro tip: Never call time.sleep(), requests.get(), or file I/O inside async functions. Use asyncio.sleep(), aiohttp, and aiofiles instead.

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