On Fri, Feb 26, 2021 at 2:42 PM Nathaniel Smith <njs@pobox.com> wrote:
On Fri, Feb 26, 2021 at 5:05 AM Irit Katriel <iritkatriel@googlemail.com> wrote:
> I'm not sure it's safe to assume that it is necessarily a programming error, and that the interpreter can essentially break the program in this case.
> Is this not allowed?
> try:
>     try:
>         obj.func()    # function that raises ExceptionGroups
>     except AttributeError:
>         logger.info("obj doesn't have a func")
> except *(AttributeError, SyntaxError):
>     logger.info("func had some problems")

I'd be fine with disallowing that. The intuition is that things will
be simplest if ExceptionGroup is kept as transparent and meaningless
as possible, i.e. ExceptionGroup(ValueError) and ValueError mean
exactly the same thing -- "some code inside this block raised
ValueError" -- and ideally should be processed in exactly the same

But they don't mean the same thing if this prints hello:

    raise ValueError()
except ValueError:

and this raises a RuntimeError:

    raise ExceptionGroup("", [ValueError()])
except ValueError:

What am I missing?