[Numpy-discussion] bug in PyArray_GetCastFunc

[Geoffrey Irving]

When attempting to cast to a user defined type, PyArray_GetCast looks
up the cast function in the dictionary but doesn't check if the entry
exists.  This causes segfaults.  Here's a patch.

Geoffrey

diff --git a/numpy/core/src/multiarray/convert_datatype.c
b/numpy/core/src/multiarray/convert_datatype.c
index 818d558..4b8f38b 100644
--- a/numpy/core/src/multiarray/convert_datatype.c
+++ b/numpy/core/src/multiarray/convert_datatype.c
@@ -81,7 +81,7 @@ PyArray_GetCastFunc(PyArray_Descr *descr, int type_num)
             key = PyInt_FromLong(type_num);
             cobj = PyDict_GetItem(obj, key);
             Py_DECREF(key);
-            if (NpyCapsule_Check(cobj)) {
+            if (cobj && NpyCapsule_Check(cobj)) {
                 castfunc = NpyCapsule_AsVoidPtr(cobj);
             }
         }