BUG: masked array division broken with np.seterr(under=raise) #25810

numpy/ma/core.py

@@ -877,7 +877,7 @@ def __call__(self, a, b):
             self.tolerance = np.finfo(float).tiny
         # don't call ma ufuncs from __array_wrap__ which would fail for scalars
         a, b = np.asarray(a), np.asarray(b)
-        with np.errstate(invalid='ignore'):
+        with np.errstate(all='ignore'):
             return umath.absolute(a) * self.tolerance >= umath.absolute(b)
 
 

numpy/ma/tests/test_core.py

@@ -2581,6 +2581,14 @@ def test_no_masked_nan_warnings(self):
             # also check that allclose uses ma ufuncs, to avoid warning
             allclose(m, 0.5)
 
+    def test_masked_array_underflow(self):
+        with(np.errstate(under="raise")):
+            x = np.arange(0, 3, 0.1)
+            X = np.ma.array(x)
+            x2 = x/2.0  # <- works
+            X2 = X/2.0
+            assert(X2.all() == X.all() / 2.0)
+
 class TestMaskedArrayInPlaceArithmetic:
     # Test MaskedArray Arithmetic