Python 3.9 asyncio: Task cancel() throws asyncio.exceptions.CancelledError instead of asyncio.CancelledError

[Chris Angelico]

On Sat, 1 Apr 2023 at 10:05, Clint Olsen <clint.olsen at gmail.com> wrote:
>
> On Friday, March 31, 2023 at 3:23:24 PM UTC-7, Chris Angelico wrote:
> > On Sat, 1 Apr 2023 at 09:19, Clint Olsen <xxx... at gmail.com> wrote:
> > > Attempting to catch asyncio.CancelledError or asyncio.CancelledError does not work. The function in question looks like:
> > >>> asyncio.exceptions.CancelledError is asyncio.CancelledError
> > True
> >
> > Does that answer the question?
>
> No, I couldn't catch either exception even though they are the same.
>

Okay, so that deals with the part from the subject line, leaving a
slightly different problem: The caught exception is not of the same
type as you were expecting. First question: Can you reproduce the
issue on command? If so, I would recommend trying this:

except BaseException as e:
    print("Got an exception!", type(e))
    print(id(type(e)))
    print(id(asyncio.CancelledError)
except:
    print("Weird things are happening")
    import sys
    print(sys.exc_info())
    print(id(sys.exc_info()[0]))
    print(id(asyncio.CancelledError))

Basically, I want to know whether (a) BaseException has changed, which
would be a nightmare; and (b) whether asyncio.CancelledError has
changed.

This is the kind of bizarre behaviour that can happen if a module is
reloaded, or if there are multiple versions loaded for some reason.
But if that ISN'T what's happening, there'll have to be some other
explanation.

ChrisA