[New-bugs-announce] [issue25612] nested try..excepts don't work correctly for generators

[Yury Selivanov]

New submission from Yury Selivanov:

Nested try..except statements with yields can loose reference to the current exception.

The following code:

    class MainError(Exception):
        pass

    class SubError(Exception):
        pass

    def main():
        try:
            raise MainError()
        except MainError:
            try:
                yield
            except SubError:
                print('got SubError')
            raise

    coro = main()
    coro.send(None)
    coro.throw(SubError())

prints:

    got SubError
    Traceback (most recent call last):
      File "t.py", line 19, in <module>
        coro.throw(SubError())
      File "t.py", line 15, in main
        raise
    RuntimeError: No active exception to reraise

----------
components: Interpreter Core
messages: 254557
nosy: benjamin.peterson, gvanrossum, haypo, larry, ncoghlan, yselivanov
priority: release blocker
severity: normal
status: open
title: nested try..excepts don't work correctly for generators
versions: Python 3.4, Python 3.5, Python 3.6

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue25612>
_______________________________________