Bug report

Python 3.12.0a7 (at least as of commitd65ed69) can fail to catch exceptions when an iterator is involved. The following code works on Python 3.11 but theValueError is uncaught on Python 3.12:

#!/usr/bin/env pythondefdo_work():yieldraiseValueError()defmain():try:for_indo_work():ifTrueisFalse:returnexceptValueError:passif__name__=='__main__':main()

With this code inrepro.py the following traceback is shown on Python 3.12:

Traceback (most recent call last):  File "//repro.py", line 18, in <module>    main()  File "//repro.py", line 12, in main    return  File "//repro.py", line 5, in do_work    raise ValueError()ValueError

No error or output occurs under Python 3.11.

Your environment

Tested on Ubuntu 20.04.5 using the deadsnakes nightly build: python3.12 - 3.12.0~a7-98-gd65ed693a8-1+focal1

Linked PRs

• GH-103488: Use return-offset, not yield-offset. #103502