Bug report

If a bound method is used as the condition for BaseExceptionGroup.split the following exception is raised:

TypeError: expected a function, exception type or tuple of exception types

Consider the following example:

classHandleError:def__enter__(self):passdef__exit__(self,exc_type,exc_inst,exc_tb):ifexc_typeisNone:returnFalseifisinstance(exc_inst,ExceptionGroup):match,rest=exc_inst.split(self._log_and_ignore_error)ifmatchisNone:returnFalseelifrestisNone:returnTrueraiserestelse:returnself._log_and_ignore_error(exc_inst)def_log_and_ignore_error(self,e:BaseException)->bool:        ...returnTruewithHandleError():raiseExceptionGroup('foo', [ValueError('bar')])

If we replace the bound method with a lambda (lambda e: self._log_and_ignore_error(e)) then no exception is raised.

I think it would be useful to accept any callable here. I guess the code update would be simple too, just replacePyFunction_Check withPyCallable_Check in

if (PyFunction_Check(value)) {*type=EXCEPTION_GROUP_MATCH_BY_PREDICATE;return0;    }

Update the exception message to allow callables, and change the assert in

caseEXCEPTION_GROUP_MATCH_BY_PREDICATE: {assert(PyFunction_Check(matcher_value));PyObject*exc_matches=PyObject_CallOneArg(matcher_value,exc);

to callPyCallable_Check again.

Your environment

• CPython versions tested on: 3.11.2

The c code snippets are from origin/main.

Linked PRs

• gh-105730: support more callables in ExceptionGroup.split() and subgroup() #106035