Hi again, especially Mark,
I have some new observations and a patch regarding this problem, see below.
On 23. 3. 2013 Matěj Laitl wrote:
> following test code produces C code that fails to compile:
> > cdef class ExtensionType(object):
> > cdef public int dummy
> >
> > def __init__(self, n):
> > self.dummy = n
> >
> > cdef cfoo(self):
> > print self.dummy
> >
> > items = [ExtensionType(1), ExtensionType(2)]
> > cdef ExtensionType[:] view = np.array(items, dtype=ExtensionType)
> > view[0].cfoo()
>
> with gcc error and relevant C file lines:
> extension_type_memoryview.c:2604:94: error: ‘PyObject’ has no member named
> ‘__pyx_vtab’
>
> 2570: PyObject *__pyx_t_1 = NULL;
> (...)
> 2601: __pyx_t_1 = (PyObject *) *((struct
>
> :__pyx_obj_25extension_type_memoryview_ExtensionType * *) ( /* dim=0 */
> :
> : (__pyx_v_25extension_type_memoryview_view.data + __pyx_t_2 *
> : __pyx_v_25extension_type_memoryview_view.strides[0]) ));
>
> 2602: __Pyx_INCREF((PyObject*)__pyx_t_1);
> 2603: /* __pyx_t_4 allocated */
> 2604: __pyx_t_4 = ((struct
>
> : __pyx_vtabstruct_25extension_type_memoryview_ExtensionType *)__pyx_t_1
> :
> :->__pyx_vtab)->cfoo(__pyx_t_1); if (unlikely(!__pyx_t_4))
> :{__pyx_filename
> :
> : = __pyx_f[0]; __pyx_lineno = 69;
>
> It seems that generic PyObject* temporary for __pyx_t_1 is used here while
> typed ExtensionType* temporary should have been used instead (as suggested
> by excess casting on line 2601).
I've found this is caused by following check in
ExprNode.allocate_temp_result():
> if type.is_pyobject:
> type = PyrexTypes.py_object_type
Removing the check breaks everything else, so I suppose it is intentional
(what's its purpose?) and I've resorted to overriding allocate_temp_result()
in IndexNode and skipping the check in the very special case of memoryview
direct indexing.
This fixes the test-case and doesn't break other tests, but sounds a bit hacky
and may be actually completely incorrect.
The patch and test-case is here: https://github.com/cython/cython/pull/213
P.S.: Is this too late for 0.19?
Cheers,
Matěj
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