BUG: masked array division should ignore all FPEs in mask calculation (numpy#26135)

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

* STY: Remove unnecessary brackets

Closes numpygh-25810

---------

Co-authored-by: Sebastian Berg <[email protected]>

Author: carlosilva10260

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 +2581,13 @@ 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):
+        x = np.arange(0, 3, 0.1)
+        X = np.ma.array(x)
+        with np.errstate(under="raise"):
+            X2 = X/2.0
+            np.testing.assert_array_equal(X2, x/2)
+
 class TestMaskedArrayInPlaceArithmetic:
     # Test MaskedArray Arithmetic