[issue37269] Python 3.8b1 miscompiles conditional expressions containing __debug__

[Marius Gedminas]

New submission from Marius Gedminas <marius at gedmin.as>:

Python 3.8 miscompiles the following code:

    $ cat /tmp/wat.py
    enable_debug = False

    if not enable_debug or not __debug__:
        print("you shall not pass!")

    $ python3.7 /tmp/wat.py
    you shall not pass!

    $ python3.8 /tmp/wat.py

(no output is produced.)

This is a distilled example from zope.traversing's codebase (https://github.com/zopefoundation/zope.traversing/issues/13).

----------
components: Interpreter Core
messages: 345533
nosy: mgedmin
priority: normal
severity: normal
status: open
title: Python 3.8b1 miscompiles conditional expressions containing __debug__
versions: Python 3.8, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue37269>
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