[Numpy-discussion] Segfault with python 3.2 structured array non-existent field

[Christoph Gohlke]

On 3/13/2011 11:29 AM, Matthew Brett wrote:
> Hi
>
> On Sun, Mar 13, 2011 at 9:54 AM, Christoph Gohlke<cgohlke at uci.edu>  wrote:
>> On 3/13/2011 1:57 AM, Matthew Brett wrote:
>>> Hi,
>>> I have this on my OSX 10.6 system and numpy 1.5.1 and current numpy
>>> head (30ee1d352):
>>>
>>> $ python3.2
>>> Python 3.2 (r32:88452, Feb 20 2011, 11:12:31)
>>> [GCC 4.2.1 (Apple Inc. build 5664)] on darwin
>>> Type "help", "copyright", "credits" or "license" for more information.
>>>>>> import numpy as np
>>>>>> a = np.zeros((1,), dtype=[('f1', 'f')])
>>>>>> a['f1'] = 1
>>>>>> a['f2'] = 1
>>> Segmentation fault
>>>
>>> All tests pass with np.test()
>>>
>>> Expected behavior with same code on python2.6:
>>>
>>>>>> a['f2'] = 1
>>> Traceback (most recent call last):
>>>     File "<stdin>", line 1, in<module>
>>> ValueError: field named f2 not found.
>>>
>>> Cheers,
>>>
>>> Matthew
>>
>> Confirmed on Windows. The crash is in line 816 of mapping.c:
>>
>>          PyErr_Format(PyExc_ValueError,
>>                       "field named %s not found.",
>>                       PyString_AsString(index));
>>
>> This works with Python 3.x:
>>
>>          PyErr_Format(PyExc_ValueError,
>>                       "field named %S not found.",
>>                       index);
>
> Sure enough, in python3.2:
>
>>>> a[b'f2'] = 1
> Traceback (most recent call last):
>    File "<stdin>", line 1, in<module>
> ValueError: field named f2 not found.
>
> That is - it is specifically passing a python 3 string that causes the
> segmentation fault.
>
> Is this a release blocker?  I'm afraid I don't know the code well
> enough to be confident of the right fix.  Is there something I can do
> to help?

Please open a ticket at <http://projects.scipy.org/numpy> and refer to 
this discussion and proposed fix.

diff --git a/numpy/core/src/multiarray/mapping.c 
b/numpy/core/src/multiarray/mapping.c
index 8db85bf..3a72811 100644
--- a/numpy/core/src/multiarray/mapping.c
+++ b/numpy/core/src/multiarray/mapping.c
@@ -812,10 +812,16 @@ array_ass_sub(PyArrayObject *self, PyObject 
*index, PyObject *op)
                  }
              }
          }
-
+#if defined(NPY_PY3K)
+        PyErr_Format(PyExc_ValueError,
+                     "field named %S not found.",
+                     index);
+#else
          PyErr_Format(PyExc_ValueError,
                       "field named %s not found.",
                       PyString_AsString(index));
+#endif
+
          return -1;
      }


Christoph

>
> Cheers,
>
> Matthew
>
>