[Cython] "relaxed_strides" test broken with NumPy 1.8

[Stefan Behnel]

mark florisson, 03.01.2014 23:28:
> On 3 January 2014 18:22, Stefan Behnel wrote:
>> 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?
> 
> 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)?

No, Py3 doesn't do any validation here, it does a straight call into the
object's slot function, i.e. into the NumPy array itself.

So, the question is: who's wrong here? The test or NumPy?

Hmm, or maybe just me. I didn't define the NPY_RELAXED_STRIDES_CHECKING
environment variable for the NumPy build. Let's try that first.

http://docs.scipy.org/doc/numpy/release.html#npy-relaxed-strides-checking

Stefan