[New-bugs-announce] [issue8305] memoview[0] creates an invalid view if ndim != 1

[STINNER Victor]

New submission from STINNER Victor <victor.stinner at haypocalc.com>:

memory_item() function creates a new memoryview object if ndim is different than 1. Example with numpy:

   from numpy import array
   y=array([ 0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11])
   y.shape = 3,4
   view=memoryview(y)
   view2 = view[0]
   print type(view2)

Result: <type 'memoryview'>. (Without the shape, ndim equals 1, and view2 is a standard str object.)

The problem is that view attribute of the view2 (PyMemoryViewObject) is not initialized. Extract of memory_item():

        /* Return a new memory-view object */
        Py_buffer newview;
        memset(&newview, 0, sizeof(newview));
        /* XXX:  This needs to be fixed so it actually returns a sub-view */
        return PyMemoryView_FromBuffer(&newview);

"This needs to be fixed" :-/

--

view2 is not initialized and so view2.tolist() does crash.

----------
messages: 102270
nosy: haypo
severity: normal
status: open
title: memoview[0] creates an invalid view if ndim != 1
versions: Python 2.7, Python 3.1, Python 3.2

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue8305>
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