Treat `KeyboardInterrupt` or `SystemExit` the same on program exit even if they are inside exception groups

Feature or enhancement

Proposal:

A KeyboardInterrupt or SystemExit inside a BaseExceptionGroup should be treated like a bare KeyboardInterrupt or SystemExit.

PS C:\...> python x.py
  + Exception Group Traceback (most recent call last):
  |   File "C:\...\x.py", line 1, in <module>
  |     raise BaseExceptionGroup("ki in an exception group", [KeyboardInterrupt()])
  | BaseExceptionGroup: ki in an exception group (1 sub-exception)
  +-+---------------- 1 ----------------
    | KeyboardInterrupt
    +------------------------------------
PS C:\...> $LastExitCode
1


PS C:\...> python x.py
Traceback (most recent call last):
  File "C:\...\x.py", line 1, in <module>
    raise KeyboardInterrupt()
KeyboardInterrupt
PS C:\...> $LastExitCode
-1073741510

Looking at the CPython source code, I believe _Py_HandleSystemExitAndKeyboardInterrupt is the relevant function.

Points for it:

• less pitfalls for a 3rd party using exception groups
• see any other failures (as exceptions) upon shutdown (ATM the workaround requires discarding the other exceptions)

Points against:

• SystemExit in an exception group prints out the stack trace, unlike when it's not in an exception group
  • we could make them consistent (filter out SystemExit and print the exception group then)

I volunteer to implement this if this is fine.

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

EDIT: I have now made a post. See https://discuss.python.org/t/keyboardinterrupt-and-systemexit-in-exception-groups-should-be-considered-for-pythons-exit-code/82816

Links to previous discussion of this feature:

I have tried some basic keyword searches as well as some digging in blame, but I can't find any previous discussion.

Bắt đầu với _Py_HandleSystemExitAndKeyboardInterrupt của CPython, được issue xác định là entry point liên quan, và tái hiện hai ví dụ về mã thoát bằng một script phát sinh một exception đơn lẻ và một script bên trong một BaseExceptionGroup. Đọc thảo luận được liên kết trước khi quyết định nên xử lý đầu ra của SystemExit như thế nào; hoàn tất khi KeyboardInterrupt và SystemExit được nhóm tuân theo hành vi thoát độc lập dự kiến.