[Python] Why is my asyncio task not executing immediately after `asyncio.create_task()`?

import asyncio

async def worker():
print("worker start")
await asyncio.sleep(1)
print("worker done")

async def main():
# Schedule the coroutine
asyncio.create_task(worker())
# Give control back to the event loop for a moment
await asyncio.sleep(0.1)
print("main exiting")

asyncio.run(main())


Expected behavior

I thought calling asyncio.create_task(worker()) would start worker() right away, so I expected to see:

worker start
main exiting
worker done


Actual behavior

Instead, nothing from worker() is printed until after main() finishes:

main exiting
worker start
worker done


What I’ve tried

• Increasing the await asyncio.sleep(0.1) delay
• Replacing asyncio.create_task with await worker()
• Running on Python 3.11 and 3.12 (same outcome)

Questions

1. Why doesn’t the task begin execution immediately after create_task()?
2. Is there a recommended pattern to ensure the task gets a chance to run before main() exits (without awaiting it directly)?

Environment

• Python 3.12.2
• macOS 14.4 (Sonoma)

Any insights appreciated!

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