game · 2 min
Spot the Block
Click the line that freezes the asyncio event loop. 6 puzzles of increasing subtlety, each a real anti-pattern from production async Python.
A code-reading game tied to the asyncio in production post. Each round shows a short async function with one line that blocks the event loop. Click the offender.
The rule the puzzles teach: every function call inside an async def is either async-aware (returns a coroutine, you await it) or blocking (sync work that freezes the loop). The puzzles cover the common offenders: requests, time.sleep, sync DB drivers, CPU work, subprocess.run, file I/O.