BUG: Fix _binop for operators for serials which has more than one returns (divmod/rdivmod).

doc/source/whatsnew/v0.24.2.rst

@@ -31,6 +31,7 @@ Fixed Regressions
 - Fixed regression in ``IntervalDtype`` construction where passing an incorrect string with 'Interval' as a prefix could result in a ``RecursionError``. (:issue:`25338`)
 - Fixed regression in :class:`Categorical`, where constructing it from a categorical ``Series`` and an explicit ``categories=`` that differed from that in the ``Series`` created an invalid object which could trigger segfaults. (:issue:`25318`)
 - Fixed pip installing from source into an environment without NumPy (:issue:`25193`)
+- Fixed bug in :meth:`Series.divmod` and :meth:`Series.rdivmod` (:issue:`25557`)
 
 .. _whatsnew_0242.enhancements:
 

pandas/core/ops.py

@@ -1494,18 +1494,20 @@ def _construct_result(left, result, index, name, dtype=None):
     not be enough; we still need to override the name attribute.
     """
     out = left._constructor(result, index=index, dtype=dtype)
-
-    out.name = name
+    out.__finalize__(left)
+    if name is None:
+        out.name = name
     return out
 
 
 def _construct_divmod_result(left, result, index, name, dtype=None):
     """divmod returns a tuple of like indexed series instead of a single series.
     """
-    constructor = left._constructor
     return (
-        constructor(result[0], index=index, name=name, dtype=dtype),
-        constructor(result[1], index=index, name=name, dtype=dtype),
+        _construct_result(left, result[0], index=index, name=name,
+                          dtype=dtype),
+        _construct_result(left, result[1], index=index, name=name,
+                          dtype=dtype),
     )
 
 

pandas/core/series.py

@@ -2502,6 +2502,7 @@ def _binop(self, other, func, level=None, fill_value=None):
         -------
         Series
         """
+
         if not isinstance(other, Series):
             raise AssertionError('Other operand must be Series')
 
@@ -2518,13 +2519,13 @@ def _binop(self, other, func, level=None, fill_value=None):
 
         with np.errstate(all='ignore'):
             result = func(this_vals, other_vals)
+
         name = ops.get_op_result_name(self, other)
-        result = self._constructor(result, index=new_index, name=name)
-        result = result.__finalize__(self)
-        if name is None:
-            # When name is None, __finalize__ overwrites current name
-            result.name = None
-        return result
+        if func.__name__ in ['divmod', 'rdivmod']:
+            ret = ops._construct_divmod_result(self, result, new_index, name)
+        else:
+            ret = ops._construct_result(self, result, new_index, name)
+        return ret
 
     def combine(self, other, func, fill_value=None):
         """

pandas/tests/series/test_operators.py

@@ -741,6 +741,21 @@ def test_op_duplicate_index(self):
         expected = pd.Series([11, 12, np.nan], index=[1, 1, 2])
         assert_series_equal(result, expected)
 
+    def test_divmod(self):
+        # GH25557
+        a = Series([1, 1, 1, np.nan], index=['a', 'b', 'c', 'd'])
+        b = Series([2, np.nan, 1, np.nan], index=['a', 'b', 'd', 'e'])
+
+        r1 = divmod(a, b)
+        r2 = a.divmod(b)
+        assert_series_equal(r1[0], r2[0])
+        assert_series_equal(r1[1], r2[1])
+
+        r3 = divmod(b, a)
+        r4 = a.rdivmod(b)
+        assert_series_equal(r3[0], r4[0])
+        assert_series_equal(r3[1], r4[1])
+
 
 class TestSeriesUnaryOps(object):
     # __neg__, __pos__, __inv__