BUG: Holiday(..) with both offset and observance raises

doc/source/whatsnew/v0.17.0.txt

@@ -38,6 +38,8 @@ Backwards incompatible API changes
 Other API Changes
 ^^^^^^^^^^^^^^^^^
 
+- ``Holiday`` now raises NotImplementedError if both offset and observance are used in constructor. (:issue:`102171`)
+
 .. _whatsnew_0170.deprecations:
 
 Deprecations

pandas/tests/test_tseries.py

@@ -9,6 +9,8 @@
 import pandas.lib as lib
 import pandas._period as period
 import pandas.algos as algos
+from pandas.tseries.holiday import Holiday, SA, next_monday
+from pandas import DateOffset
 
 
 class TestTseriesUtil(tm.TestCase):
@@ -737,6 +739,17 @@ def test_get_period_field_raises_on_out_of_range(self):
     def test_get_period_field_array_raises_on_out_of_range(self):
         self.assertRaises(ValueError, period.get_period_field_arr, -1, np.empty(1), 0)
 
+
+class TestHolidayConflictingArguments(tm.TestCase):
+
+    # GH 10217
+
+    def test_both_offset_observance_raises(self):
+
+        with self.assertRaises(NotImplementedError) as cm:
+            h = Holiday("Cyber Monday", month=11, day=1,
+                        offset=[DateOffset(weekday=SA(4))], observance=next_monday)
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=[__file__, '-vvs', '-x', '--pdb', '--pdb-failure'],

pandas/tseries/holiday.py

@@ -148,6 +148,9 @@ class from pandas.tseries.offsets
         >>> July3rd = Holiday('July 3rd', month=7, day=3,
                               days_of_week=(0, 1, 2, 3))
         """
+        if offset is not None and observance is not None:
+            raise NotImplementedError("Cannot use both offset and observance.")
+
         self.name = name
         self.year = year
         self.month = month