fix RecursionError when logging re-raised Exception from an ExceptionGroup

[leiyi2000]

Summary

Fixed a RecursionError when logging re-raised exceptions from an ExceptionGroup in Python 3.11 and above (#726). The fix adds a version check and detects when the exception cause is an ExceptionGroup, preventing further recursive traversal of the exception chain, which previously led to infinite recursion.

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[hynek]

@sscherfke 😇

[sscherfke]

lgtm :)

[sscherfke]

Maybe we could create a _compat module with constants for Python versions like I did here. Would make it easier to find these occurances and remove them when a Python versions gets unsupported.

[leiyi2000]

Maybe we could create a _compat module with constants for Python versions like I did here. Would make it easier to find these occurances and remove them when a Python versions gets unsupported.

I've reviewed the implementation in _compat module , but checking Python version ranges (e.g., ensuring the version is between 3.9 and 3.11) becomes quite cumbersome with this approach.

[leiyi2000]

Perhaps all we need is just a constant to indicate whether the current Python version supports ExceptionGroup.

[hynek]

The problem with all these constants instead of straight version checks is – last time I checked – that they're not supported by Mypy and you'll get weird errors about undefined symbols etc. Not sure if that changed?

[sscherfke]

Then let's keep the PR as it is.

The "python version checking" issue is unrelated to the issue that this PR addresses.

[hynek]

hopefully fixed by #739 with credit to you – sorry for the delays