I've been researching when I work in ASGI environments (single-threaded) whether it is safe to mutate singletons or global variables. I thought initially that it would be safe, but AI tells me it's not safe and I'm having a tough time believing it because I cannot reproduce it. Look at this code here. import asyncio import random counter = 0 async def increment(name: str): global counter await asyncio.sleep(random.uniform(0, 5)) # yield control to event loop counter = counter + 1 # write (based on possibly stale value) print(f"{name}: counter → {counter}") async def main(): await asyncio.gather(*[increment(f"{i}") for i in range(10000)]) print(f"Final counter (should be 10000): {counter}") if __name__ == "__main__": asyncio.run(main()) This retuns correctly at the end. Here is an example of the last lines of input: 7825: counter → 9995 8403: counter → 9996 6039: counter → 9997 5887: counter → 9998 9942: counter → 9999 8631: counter → 10000 Final counter (should be 10000): 10000 This is safe right ? Continue reading...
