BUG: stack_arrays fails for subdtypes

Again, fixed by not using descr

2 files changed, 34 insertions, 5 deletions

diff --git a/numpy/lib/recfunctions.py b/numpy/lib/recfunctions.py
index a0a070547..f66cfd32e 100644
--- a/numpy/lib/recfunctions.py
+++ b/numpy/lib/recfunctions.py
@@ -782,10 +782,10 @@ def stack_arrays(arrays, defaults=None, usemask=True, asrecarray=False,
     fldnames = [d.names for d in ndtype]
     #
     dtype_l = ndtype[0]
-    newdescr = dtype_l.descr
+    newdescr = get_fieldspec(dtype_l)
     names = [_[0] for _ in newdescr]
     for dtype_n in ndtype[1:]:
-        for descr in dtype_n.descr:
+        for descr in get_fieldspec(dtype_n):
             name = descr[0] or ''
             if name not in names:
                 newdescr.append(descr)
@@ -794,11 +794,11 @@ def stack_arrays(arrays, defaults=None, usemask=True, asrecarray=False,
                 nameidx = names.index(name)
                 current_descr = newdescr[nameidx]
                 if autoconvert:
-                    if np.dtype(descr[1]) > np.dtype(current_descr[-1]):
+                    if descr[1] > current_descr[1]:
                         current_descr = list(current_descr)
-                        current_descr[-1] = descr[1]
+                        current_descr[1] = descr[1]
                         newdescr[nameidx] = tuple(current_descr)
-                elif descr[1] != current_descr[-1]:
+                elif descr[1] != current_descr[1]:
                     raise TypeError("Incompatible type '%s' <> '%s'" %
                                     (dict(newdescr)[name], descr[1]))
     # Only one field: use concatenate
diff --git a/numpy/lib/tests/test_recfunctions.py b/numpy/lib/tests/test_recfunctions.py
index 50a85a08e..799d7cd8e 100644
--- a/numpy/lib/tests/test_recfunctions.py
+++ b/numpy/lib/tests/test_recfunctions.py
@@ -546,6 +546,35 @@ class TestStackArrays(TestCase):
         assert_equal(test, control)
         assert_equal(test.mask, control.mask)
 
+    def test_subdtype(self):
+        z = np.array([
+            ('A', 1), ('B', 2)
+        ], dtype=[('A', '|S3'), ('B', float, (1,))])
+        zz = np.array([
+            ('a', [10.], 100.), ('b', [20.], 200.), ('c', [30.], 300.)
+        ], dtype=[('A', '|S3'), ('B', float, (1,)), ('C', float)])
+
+        res = stack_arrays((z, zz))
+        expected = ma.array(
+            data=[
+                (b'A', [1.0], 0),
+                (b'B', [2.0], 0),
+                (b'a', [10.0], 100.0),
+                (b'b', [20.0], 200.0),
+                (b'c', [30.0], 300.0)],
+            mask=[
+                (False, [False],  True),
+                (False, [False],  True),
+                (False, [False], False),
+                (False, [False], False),
+                (False, [False], False)
+            ],
+            dtype=zz.dtype
+        )
+        assert_equal(res.dtype, expected.dtype)
+        assert_equal(res, expected)
+        assert_equal(res.mask, expected.mask)
+
 
 class TestJoinBy(TestCase):
     def setUp(self):