QUERY · ISSUE
Unexpected asyncio code exec between exc in task and call of global asyncio crash handler
bug
Port, board and/or hardware
unix and esp32
MicroPython version
MicroPython v1.23.0-preview.436.gc8021842c
Reproduction
import asyncio
class Loop():
async def run(self):
print("---", self.__class__.__name__, "---")
async def run_forever(self):
while True:
try:
await self.run()
await asyncio.sleep(0.1)
except Exception as exc:
print("EEE", exc)
raise
class Loop_1(Loop):
pass
class Loop_2(Loop):
async def run(self):
await super().run()
raise Exception("MOEP!")
class Loop_3(Loop):
pass
def async_crash_hdlr(loop, ctx):
# called when unhandled exceptions thrown in asyncio tasks.
# this function is called from within a task running in the mainloop.
print("Global asyncio exception handler called -> FREEZE")
while True:
pass
async def main():
asyncio.get_event_loop().set_exception_handler(async_crash_hdlr)
loop1 = Loop_1()
loop2 = Loop_2()
loop3 = Loop_3()
print("Starting loop1")
asyncio.create_task(loop1.run_forever())
print("Starting loop2")
asyncio.create_task(loop2.run_forever())
print("Starting loop3")
asyncio.create_task(loop3.run_forever())
while True:
print("--- MAINLOOP ---")
await asyncio.sleep(1)
print("Entering main program")
asyncio.run(main())
Expected behaviour
Expected the defined global asyncio exception handler (async_crash_hdlr) being called immediately.
Expected output from above code (as per CPython3):
Entering main program
Starting loop1
Starting loop2
Starting loop3
--- MAINLOOP ---
--- Loop_1 ---
--- Loop_2 ---
EEE MOEP!
Global asyncio exception handler called -> FREEZE
Observed behaviour
Unexpected to me, between the exception being raised in Loop2 and async_crash_hdlr() being called, there is still asyncio code being executed, despite no fruther await or alike in between.
In this very case (code from) Loop3 is being run:
Entering main program
Starting loop1
Starting loop2
Starting loop3
--- MAINLOOP ---
--- Loop_1 ---
--- Loop_2 ---
EEE MOEP!
--- Loop_3 --- # <<<<<-------------------------
Global asyncio exception handler called -> FREEZE
Additional Information
No, I've provided everything above.
Code of Conduct
Yes, I agree
CANDIDATE · ISSUE
asyncio: Calling .run() within a task does not behave as per CPython
bugextmod
Port, board and/or hardware
Unix build
MicroPython version
MicroPython v1.23.0-preview.72.g4a2e510a8.dirty on 2024-02-04; linux [GCC 11.4.0] version
Reproduction
import asyncio
async def foo(s):
while True:
print(f"Task {s}")
await asyncio.sleep(1)
async def main():
asyncio.create_task(foo(1))
await asyncio.sleep(2)
asyncio.run(foo(2)) # CPython throws a RuntimeError
await asyncio.sleep(2)
asyncio.create_task(foo(1))
await asyncio.sleep(5)
print("Done") # never happens in MP
asyncio.run(main())
Expected behaviour
On CPython issuing run() in a running task throws a RuntimeError:
Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import rats17
Task 1
Task 1
Task 1
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/adminpete/rats17.py", line 17, in <module>
asyncio.run(main())
File "/usr/lib/python3.10/asyncio/runners.py", line 44, in run
return loop.run_until_complete(main)
File "/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
return future.result()
File "/home/adminpete/rats17.py", line 11, in main
asyncio.run(foo(2)) # CPython throws a RuntimeError
File "/usr/lib/python3.10/asyncio/runners.py", line 33, in run
raise RuntimeError(
RuntimeError: asyncio.run() cannot be called from a running event loop
>>>
Observed behaviour
The run() command appears to work, starting the second foo instance. However main never terminates.
MicroPython v1.23.0-preview.72.g4a2e510a8.dirty on 2024-02-04; linux [GCC 11.4.0] version
Use Ctrl-D to exit, Ctrl-E for paste mode
>>> import rats17
Task 1
Task 1
Task 1
Task 2
Task 1
Task 2
Task 1
Task 2
Task 1
Task 2
... continues forever
Additional Information
This arose from this issue.
A possible fix to asyncio.core.py is
def run(coro):
if cur_task is None:
return run_until_complete(create_task(coro))
else:
raise RuntimeError("asyncio.run() cannot be called from a running event loop")
Code of Conduct
Yes, I agree