BUG: fix ticket #2029.

The fix is to disallow views of masked arrays if the element size
of the view is different than that of the original.

2 files changed, 39 insertions, 6 deletions

diff --git a/numpy/core/src/multiarray/getset.c b/numpy/core/src/multiarray/getset.c
index d3146dc5c..db107ed61 100644
--- a/numpy/core/src/multiarray/getset.c
+++ b/numpy/core/src/multiarray/getset.c
@@ -414,7 +414,6 @@ array_nbytes_get(PyArrayObject *self)
  * (contiguous or fortran) with compatibile dimensions The shape and strides
  * will be adjusted in that case as well.
  */
-
 static int
 array_descr_set(PyArrayObject *self, PyObject *arg)
 {
@@ -431,16 +430,24 @@ array_descr_set(PyArrayObject *self, PyObject *arg)
 
     if (!(PyArray_DescrConverter(arg, &newtype)) ||
         newtype == NULL) {
-        PyErr_SetString(PyExc_TypeError, "invalid data-type for array");
+        PyErr_SetString(PyExc_TypeError,
+                "invalid data-type for array");
+        return -1;
+    }
+
+    if (PyArray_HASMASKNA(self) &&
+            newtype->elsize != PyArray_DESCR(self)->elsize) {
+        PyErr_SetString(PyExc_TypeError,
+                "view cannot change element size of NA-masked array");
         return -1;
     }
+
     if (PyDataType_FLAGCHK(newtype, NPY_ITEM_HASOBJECT) ||
         PyDataType_FLAGCHK(newtype, NPY_ITEM_IS_POINTER) ||
         PyDataType_FLAGCHK(PyArray_DESCR(self), NPY_ITEM_HASOBJECT) ||
         PyDataType_FLAGCHK(PyArray_DESCR(self), NPY_ITEM_IS_POINTER)) {
-        PyErr_SetString(PyExc_TypeError,                      \
-                        "Cannot change data-type for object " \
-                        "array.");
+        PyErr_SetString(PyExc_TypeError,
+                "Cannot change data-type for object array.");
         Py_DECREF(newtype);
         return -1;
     }
@@ -457,7 +464,7 @@ array_descr_set(PyArrayObject *self, PyObject *arg)
         /* But no other flexible types */
         else {
             PyErr_SetString(PyExc_TypeError,
-                            "data-type must not be 0-sized");
+                    "data-type must not be 0-sized");
             Py_DECREF(newtype);
             return -1;
         }
diff --git a/numpy/core/tests/test_maskna.py b/numpy/core/tests/test_maskna.py
index 341ed0bc2..e17798db4 100644
--- a/numpy/core/tests/test_maskna.py
+++ b/numpy/core/tests/test_maskna.py
@@ -3,6 +3,7 @@ from numpy.compat import asbytes
 from numpy.testing import *
 import sys, warnings
 from numpy.testing.utils import WarningManager
+import itertools
 
 def test_array_maskna_flags():
     a = np.arange(3)
@@ -456,6 +457,31 @@ def test_array_maskna_view_function():
     assert_(c.flags.maskna)
     assert_(c.flags.ownmaskna)
 
+def test_array_maskna_view_dtype():
+    tcs = np.typecodes['AllFloat'] + \
+          np.typecodes['AllInteger'] + \
+          np.typecodes['Complex']
+
+    same_size = []
+    diff_size = []
+    for x in itertools.combinations(tcs, 2):
+        if np.dtype(x[0]).itemsize == np.dtype(x[1]).itemsize:
+            same_size.append(x)
+        else: diff_size.append(x)
+
+    for (from_type, to_type) in diff_size:
+        a = np.arange(10, dtype=from_type, maskna=True)
+
+        # Ensure that a view of a masked array cannot change to
+        # different sized dtype
+        assert_raises(TypeError, a.view, to_type)
+
+    for (from_type, to_type) in same_size:
+        a = np.arange(10, dtype=from_type, maskna=True)
+
+        # Ensure that a view of a masked array can change to
+        # same sized dtype
+        b = a.view(dtype=to_type)
 
 def test_array_maskna_array_function_1D():
     a = np.arange(10)