Merge pull request #12224 from charris/fix-masked-fill_value

BUG: Fix MaskedArray fill_value type conversion.

2 files changed, 30 insertions, 6 deletions

diff --git a/numpy/ma/core.py b/numpy/ma/core.py
index 85a830661..9259aa4c7 100644
--- a/numpy/ma/core.py
+++ b/numpy/ma/core.py
@@ -3008,11 +3008,13 @@ class MaskedArray(ndarray):
             except (TypeError, AttributeError):
                 # When _mask.shape is not writable (because it's a void)
                 pass
-        # Finalize the fill_value for structured arrays
-        if self.dtype.names is not None:
-            if self._fill_value is None:
-                self._fill_value = _check_fill_value(None, self.dtype)
-        return
+
+        # Finalize the fill_value
+        if self._fill_value is not None:
+            self._fill_value = _check_fill_value(self._fill_value, self.dtype)
+        elif self.dtype.names is not None:
+            # Finalize the default fill_value for structured arrays
+            self._fill_value = _check_fill_value(None, self.dtype)
 
     def __array_wrap__(self, obj, context=None):
         """
diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index aa7672daa..50ab6e1de 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -4985,7 +4985,7 @@ def test_ufunc_with_out_varied():
     assert_equal(res_pos.data, expected.data)
 
 
-def test_astype():
+def test_astype_mask_ordering():
     descr = [('v', int, 3), ('x', [('y', float)])]
     x = array([
         [([1, 2, 3], (1.0,)),  ([1, 2, 3], (2.0,))],
@@ -5017,6 +5017,28 @@ def test_astype():
     assert_(x_f2.mask.flags.f_contiguous)
 
 
+dts = [np.dtype(dt_) for dt_ in '?bhilqBHILQefdgFD']
+ids = [dt_.char for dt_ in dts]
+
+@pytest.mark.parametrize('dt1', dts, ids=ids)
+@pytest.mark.parametrize('dt2', dts, ids=ids)
+@pytest.mark.filterwarnings('ignore::numpy.ComplexWarning')
+def test_astype_basic(dt1, dt2):
+    # See gh-12070
+    src = np.ma.array(ones(3, dt1), fill_value=1)
+    dst = src.astype(dt2)
+
+    assert_(src.fill_value == 1)
+    assert_(src.dtype == dt1)
+    assert_(src.fill_value.dtype == dt1)
+
+    assert_(dst.fill_value == 1)
+    assert_(dst.dtype == dt2)
+    assert_(dst.fill_value.dtype == dt2)
+
+    assert_equal(src, dst)
+
+
 def test_fieldless_void():
     dt = np.dtype([])  # a void dtype with no fields
     x = np.empty(4, dt)