Merge pull request #7894 from charris/fixup-7790

fixup-7790, BUG: construct ma.array from np.array which contains padding

2 files changed, 56 insertions, 15 deletions

diff --git a/numpy/ma/core.py b/numpy/ma/core.py
index 29b818c06..37836a0a0 100644
--- a/numpy/ma/core.py
+++ b/numpy/ma/core.py
@@ -371,24 +371,61 @@ def maximum_fill_value(obj):
         raise TypeError(errmsg)
 
 
-def _recursive_set_default_fill_value(dtypedescr):
+def _recursive_set_default_fill_value(dt):
+    """
+    Create the default fill value for a structured dtype.
+
+    Parameters
+    ----------
+    dt: dtype
+        The structured dtype for which to create the fill value.
+
+    Returns
+    -------
+    val: tuple
+        A tuple of values corresponding to the default structured fill value.
+
+    """
     deflist = []
-    for currentdescr in dtypedescr:
-        currenttype = currentdescr[1]
-        if isinstance(currenttype, list):
+    for name in dt.names:
+        currenttype = dt[name]
+        if currenttype.subdtype:
+            currenttype = currenttype.subdtype[0]
+
+        if currenttype.names:
             deflist.append(
                 tuple(_recursive_set_default_fill_value(currenttype)))
         else:
-            deflist.append(default_fill_value(np.dtype(currenttype)))
+            deflist.append(default_fill_value(currenttype))
     return tuple(deflist)
 
 
-def _recursive_set_fill_value(fillvalue, dtypedescr):
-    fillvalue = np.resize(fillvalue, len(dtypedescr))
+def _recursive_set_fill_value(fillvalue, dt):
+    """
+    Create a fill value for a structured dtype.
+
+    Parameters
+    ----------
+    fillvalue: scalar or array_like
+        Scalar or array representing the fill value. If it is of shorter
+        length than the number of fields in dt, it will be resized.
+    dt: dtype
+        The structured dtype for which to create the fill value.
+
+    Returns
+    -------
+    val: tuple
+        A tuple of values corresponding to the structured fill value.
+
+    """
+    fillvalue = np.resize(fillvalue, len(dt.names))
     output_value = []
-    for (fval, descr) in zip(fillvalue, dtypedescr):
-        cdtype = descr[1]
-        if isinstance(cdtype, list):
+    for (fval, name) in zip(fillvalue, dt.names):
+        cdtype = dt[name]
+        if cdtype.subdtype:
+            cdtype = cdtype.subdtype[0]
+
+        if cdtype.names:
             output_value.append(tuple(_recursive_set_fill_value(fval, cdtype)))
         else:
             output_value.append(np.array(fval, dtype=cdtype).item())
@@ -411,9 +448,8 @@ def _check_fill_value(fill_value, ndtype):
     fields = ndtype.fields
     if fill_value is None:
         if fields:
-            descr = ndtype.descr
-            fill_value = np.array(_recursive_set_default_fill_value(descr),
-                                  dtype=ndtype,)
+            fill_value = np.array(_recursive_set_default_fill_value(ndtype),
+                                  dtype=ndtype)
         else:
             fill_value = default_fill_value(ndtype)
     elif fields:
@@ -425,9 +461,8 @@ def _check_fill_value(fill_value, ndtype):
                 err_msg = "Unable to transform %s to dtype %s"
                 raise ValueError(err_msg % (fill_value, fdtype))
         else:
-            descr = ndtype.descr
             fill_value = np.asarray(fill_value, dtype=object)
-            fill_value = np.array(_recursive_set_fill_value(fill_value, descr),
+            fill_value = np.array(_recursive_set_fill_value(fill_value, ndtype),
                                   dtype=ndtype)
     else:
         if isinstance(fill_value, basestring) and (ndtype.char not in 'OSVU'):
diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index 5c7ae4356..b3965000d 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -212,6 +212,12 @@ class TestMaskedArray(TestCase):
         assert_equal(data, [[0, 1, 2, 3, 4], [4, 3, 2, 1, 0]])
         self.assertTrue(data.mask is nomask)
 
+    def test_creation_from_ndarray_with_padding(self):
+        x = np.array([('A', 0)], dtype={'names':['f0','f1'],
+                                        'formats':['S4','i8'],
+                                        'offsets':[0,8]})
+        data = array(x) # used to fail due to 'V' padding field in x.dtype.descr
+
     def test_asarray(self):
         (x, y, a10, m1, m2, xm, ym, z, zm, xf) = self.d
         xm.fill_value = -9999