[issue39689] struct and memoryview tests rely on undefined behavior (as revealed by clang 9)

[Stefan Krah]

Stefan Krah <stefan at bytereef.org> added the comment:

memoryview only supports the native format, so I've disabled the
(wrong) test that casts arrays with arbitrary values to _Bool. So
memoryview is done.


IMO the problem in _struct is that it swaps the x->unpack function
for the native one, which does not seem right for _Bool:

        /* Scan through the native table, find a matching
           entry in the endian table and swap in the
           native implementations whenever possible
           (64-bit platforms may not have "standard" sizes) */

If one disables that swap, the tests pass here.

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39689>
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