[Python-Dev] Non-stable pyc results on python 3.6 (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Thu Jul 27 11:08:53 EDT 2017

On 28 Jul 2017 00:54, "Nick Coghlan" <ncoghlan at gmail.com> wrote:

The fact that disorderfs makes a difference does make me a little suspicious, as there's an early exit from the FLAG_REF setting code related to objects having exactly one live reference. Courtesy of string interning and other immutable object caches, order of code compilation can affect how many live references there are to strings and other constants, and hence there may be cases where marshal won't flag an immutable object if only that particular code object has been compiled, but will flag it if some other code object has been created first. That check has been there since version 3 of the marshal format was defined, so if it is the culprit, then you'll see this misbehaviour with 3.4 as well.

It occurs to me that it would likely be easier for you to just test that theory directly: the check that now seems suspicious to me is the one that calls "Py_REFCNT" (and is the only reference to that API in the file), so if you comment that out, and the problem goes away, it is most likely the cause of the currently variable behaviour.

Cheers, Nick. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20170728/564f5522/attachment.html>

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