[issue23020] New matmul operator crashes modules compiled with CPython3.4

[Amaury Forgeot d'Arc]

New submission from Amaury Forgeot d'Arc:

When an extension module is compiled with CPython3.4, the nb_matrix_multiply slot is not filled, and no memory is allocated for it.
If the extension module is imported by CPython3.5, nb_matrix_multiply contains garbage and segfaults the interpreter.

In Python 2.7 there are flags like Py_TPFLAGS_HAVE_INDEX to gate the access  to recently added slots. I think Python3.5 should have a similar one.

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messages: 232372
nosy: amaury.forgeotdarc, benjamin.peterson
priority: normal
severity: normal
status: open
title: New matmul operator crashes modules compiled with CPython3.4
type: crash

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue23020>
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