[Cython] "relaxed_strides" test broken with NumPy 1.8

[mark florisson]

On 3 January 2014 18:22, Stefan Behnel <stefan_ml at behnel.de> wrote:
> Hi,
>
> I enabled the NumPy build for our Py3.3 test runs and while I was at it, I
> got it to use the latest NumPy release 1.8. This made one of the tests fail:
>
> """
>     Traceback (most recent call last):
>       File ".../doctest.py", line 1313, in __run
>         compileflags, 1), test.globs)
>       File "<doctest relaxed_strides.__test__.test_one_sized (line
> 29)[3]>", line 1, in <module>
>         test_one_sized(a)[0]
>       File "relaxed_strides.pyx", line 38, in
> relaxed_strides.test_one_sized (relaxed_strides.cpp:1414)
>       File "stringsource", line 622, in View.MemoryView.memoryview_cwrapper
> (relaxed_strides.cpp:7568)
>       File "stringsource", line 327, in
> View.MemoryView.memoryview.__cinit__ (relaxed_strides.cpp:3717)
>
>     ValueError: ndarray is not C-contiguous
> """
>
> https://sage.math.washington.edu:8091/hudson/job/cython-devel-tests/1787/ARCH=m64,BACKEND=cpp,PYVERSION=py33m/console
>
> According to the comments in the test file and the corresponding NumPy pull
> request, this seems to be somewhat expected.
>
> https://github.com/cython/cython/blob/master/tests/memoryview/relaxed_strides.pyx
>
> https://github.com/numpy/numpy/pull/3162
>
> Does someone know enough about this to figure out what to do?
>
> Stefan
> _______________________________________________
> cython-devel mailing list
> cython-devel at python.org
> https://mail.python.org/mailman/listinfo/cython-devel

Hey Stefan,

It seems to come from the call to __Pyx_GetBuffer, which is
PyObject_GetBuffer in python 3. Maybe this is Python 3 not checking
for an extent of 1, but instead only checking the stride (which is a
multiple of the itemsize)?

Maybe Nathaniel or Sebastien can shed more light on this matter.

Mark