Fixes #663: fixed dtype alignment for array of structs in case of converting from tuple descr

2 files changed, 22 insertions, 4 deletions

diff --git a/numpy/core/src/multiarray/descriptor.c b/numpy/core/src/multiarray/descriptor.c
index 8d983ffc9..c1c1ce568 100644
--- a/numpy/core/src/multiarray/descriptor.c
+++ b/numpy/core/src/multiarray/descriptor.c
@@ -243,7 +243,7 @@ is_datetime_typestr(char *type, Py_ssize_t len)
 }
 
 static PyArray_Descr *
-_convert_from_tuple(PyObject *obj)
+_convert_from_tuple(PyObject *obj, int align)
 {
     PyArray_Descr *type, *res;
     PyObject *val;
@@ -252,9 +252,16 @@ _convert_from_tuple(PyObject *obj)
     if (PyTuple_GET_SIZE(obj) != 2) {
         return NULL;
     }
-    if (!PyArray_DescrConverter(PyTuple_GET_ITEM(obj,0), &type)) {
-        return NULL;
+    if (align) {
+        if (!PyArray_DescrAlignConverter(PyTuple_GET_ITEM(obj, 0), &type)) {
+            return NULL;
+        }
     }
+    else {
+        if (!PyArray_DescrConverter(PyTuple_GET_ITEM(obj, 0), &type)) {
+            return NULL;
+        }
+    }    
     val = PyTuple_GET_ITEM(obj,1);
     /* try to interpret next item as a type */
     res = _use_inherit(type, val, &errflag);
@@ -1547,7 +1554,7 @@ PyArray_DescrConverter(PyObject *obj, PyArray_Descr **at)
     }
     else if (PyTuple_Check(obj)) {
         /* or a tuple */
-        *at = _convert_from_tuple(obj);
+        *at = _convert_from_tuple(obj, 0);
         if (*at == NULL){
             if (PyErr_Occurred()) {
                 return NPY_FAIL;
@@ -2928,6 +2935,9 @@ PyArray_DescrAlignConverter(PyObject *obj, PyArray_Descr **at)
         *at = _convert_from_commastring(tmp, 1);
         Py_DECREF(tmp);
     }
+    else if (PyTuple_Check(obj)) {
+        *at = _convert_from_tuple(obj, 1);
+    }
     else if (PyList_Check(obj)) {
         *at = _convert_from_array_descr(obj, 1);
     }
diff --git a/numpy/core/tests/test_dtype.py b/numpy/core/tests/test_dtype.py
index 35b8f6868..27fbb10d5 100644
--- a/numpy/core/tests/test_dtype.py
+++ b/numpy/core/tests/test_dtype.py
@@ -205,6 +205,14 @@ class TestRecord(object):
         assert_equal(dt3.itemsize, 11)
         assert_equal(dt1, dt2)
         assert_equal(dt2, dt3)
+        # Array of subtype should preserve alignment
+        dt1 = np.dtype([('a', '|i1'),
+                        ('b', [('f0', '<i2'),
+                        ('f1', '<f4')], 2)], align=True)
+        assert_equal(dt1.descr, [('a', '|i1'), ('', '|V3'),
+                                 ('b', [('f0', '<i2'), ('', '|V2'),
+                                 ('f1', '<f4')], (2,))])
+        
 
     def test_union_struct(self):
         # Should be able to create union dtypes