BUG: #29049 make holiday support offsets of offsets (#57938)

* support offsets of offsets in holiday creation * update whatsnew * add type annotations * update type annotation * make types compatible * update docstring * don't accept, only raise with more informative exception * add attribute type hint * change array to list in docstring Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com> * broaden if check; specify error message * update test raises message --------- Co-authored-by: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>

Author: dontgoto

pandas/tests/tseries/holiday/test_holiday.py

@@ -271,6 +271,25 @@ def test_both_offset_observance_raises():
  )
 
 
+def test_list_of_list_of_offsets_raises():
+ # see gh-29049
+ # Test that the offsets of offsets are forbidden
+ holiday1 = Holiday(
+ "Holiday1",
+ month=USThanksgivingDay.month,
+ day=USThanksgivingDay.day,
+ offset=[USThanksgivingDay.offset, DateOffset(1)],
+ )
+ msg = "Only BaseOffsets and flat lists of them are supported for offset."
+ with pytest.raises(ValueError, match=msg):
+ Holiday(
+ "Holiday2",
+ month=holiday1.month,
+ day=holiday1.day,
+ offset=[holiday1.offset, DateOffset(3)],
+ )
+
+
 def test_half_open_interval_with_observance():
  # Prompted by GH 49075
  # Check for holidays that have a half-open date interval where

pandas/tseries/holiday.py

@@ -4,6 +4,7 @@
  datetime,
  timedelta,
 )
+from typing import Callable
 import warnings
 
 from dateutil.relativedelta import (
@@ -17,6 +18,7 @@
 )
 import numpy as np
 
+from pandas._libs.tslibs.offsets import BaseOffset
 from pandas.errors import PerformanceWarning
 
 from pandas import (
@@ -159,24 +161,34 @@ def __init__(
  year=None,
  month=None,
  day=None,
- offset=None,
- observance=None,
+ offset: BaseOffset | list[BaseOffset] | None = None,
+ observance: Callable | None = None,
  start_date=None,
  end_date=None,
- days_of_week=None,
+ days_of_week: tuple | None = None,
  ) -> None:
  """
  Parameters
  ----------
  name : str
  Name of the holiday , defaults to class name
- offset : array of pandas.tseries.offsets or
- class from pandas.tseries.offsets
- computes offset from date
- observance: function
- computes when holiday is given a pandas Timestamp
- days_of_week:
- provide a tuple of days e.g (0,1,2,3,) for Monday Through Thursday
+ year : int, default None
+ Year of the holiday
+ month : int, default None
+ Month of the holiday
+ day : int, default None
+ Day of the holiday
+ offset : list of pandas.tseries.offsets or
+ class from pandas.tseries.offsets, default None
+ Computes offset from date
+ observance : function, default None
+ Computes when holiday is given a pandas Timestamp
+ start_date : datetime-like, default None
+ First date the holiday is observed
+ end_date : datetime-like, default None
+ Last date the holiday is observed
+ days_of_week : tuple of int or dateutil.relativedelta weekday strs, default None
+ Provide a tuple of days e.g (0,1,2,3,) for Monday Through Thursday
  Monday=0,..,Sunday=6
 
  Examples
@@ -216,8 +228,19 @@ class from pandas.tseries.offsets
  >>> July3rd
  Holiday: July 3rd (month=7, day=3, )
  """
- if offset is not None and observance is not None:
- raise NotImplementedError("Cannot use both offset and observance.")
+ if offset is not None:
+ if observance is not None:
+ raise NotImplementedError("Cannot use both offset and observance.")
+ if not (
+ isinstance(offset, BaseOffset)
+ or (
+ isinstance(offset, list)
+ and all(isinstance(off, BaseOffset) for off in offset)
+ )
+ ):
+ raise ValueError(
+ "Only BaseOffsets and flat lists of them are supported for offset."
+ )
 
  self.name = name
  self.year = year