Migrate South Korea holidays to ObservedHolidayBase (#1560)

holidays/countries/south_korea.py

@@ -13,32 +13,22 @@
 from datetime import date
 from datetime import timedelta as td
 from gettext import gettext as tr
+from typing import Dict, Set
 
 from holidays.calendars import _CustomChineseHolidays
-from holidays.calendars.gregorian import (
-    JAN,
-    FEB,
-    MAR,
-    APR,
-    MAY,
-    JUN,
-    JUL,
-    AUG,
-    SEP,
-    OCT,
-    NOV,
-    DEC,
-    SAT,
-    SUN,
-)
+from holidays.calendars.gregorian import JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC
 from holidays.constants import BANK, PUBLIC
 from holidays.groups import (
     ChineseCalendarHolidays,
     ChristianHolidays,
     InternationalHolidays,
     StaticHolidays,
 )
-from holidays.observed_holiday_base import ObservedHolidayBase, SAT_SUN_TO_NEXT_MON
+from holidays.observed_holiday_base import (
+    ObservedHolidayBase,
+    SAT_SUN_TO_NEXT_WORKDAY,
+    SUN_TO_NEXT_WORKDAY,
+)
 
 
 class SouthKorea(
@@ -95,66 +85,48 @@ def __init__(self, *args, **kwargs):
         ChristianHolidays.__init__(self)
         InternationalHolidays.__init__(self)
         StaticHolidays.__init__(self, cls=SouthKoreaStaticHolidays)
-        kwargs.setdefault("observed_rule", SAT_SUN_TO_NEXT_MON)
+        kwargs.setdefault("observed_rule", SAT_SUN_TO_NEXT_WORKDAY)
+        kwargs.setdefault("observed_since", 2014)
         super().__init__(*args, **kwargs)
 
-    def _add_alt_holiday(
-        self, dt: date, name: str = "", since: int = 2014, include_sat: bool = True
-    ) -> None:
-        """
-        Add alternative holiday on first day from the date provided
-        that's not already a another holiday nor a weekend.
-
-        :param dt:
-           The date of the holiday.
-
-        :param name:
-           The name of the holiday.
-
-        :param since:
-           Year starting from which alt holiday should be added
-
-        :param include_sat:
-           Whether Saturday is to be considered a weekend in addition to
-           Sunday.
-        """
-        if not self.observed:
-            return None
-
-        target_weekday = {SUN}
-        if include_sat:
-            target_weekday.add(SAT)
-        if (dt.weekday() in target_weekday or len(self.get_list(dt)) > 1) and dt.year >= since:
-            obs_date = dt + td(days=+1)
-            while obs_date.weekday() in target_weekday or obs_date in self:
-                obs_date += td(days=+1)
-            for name in (name,) if name else self.get_list(dt):
-                if "Alternative holiday" not in name:
-                    self._add_holiday(self.tr(self.observed_label) % self.tr(name), obs_date)
-
-    def _add_three_day_holiday(self, dt: date, name: str) -> None:
-        """
-        Add holiday for the date before and after the given holiday date.
-
-        :param dt:
-           The date of the holiday.
-
-        :param name:
-           The name of the holiday.
-        """
-        for dt_alt in (
-            # The day preceding %s.
-            self._add_holiday(self.tr("%s 전날") % self.tr(name), dt + td(days=-1)),
-            dt,
-            # The second day of %s.
-            self._add_holiday(self.tr("%s 다음날") % self.tr(name), dt + td(days=+1)),
-        ):
-            self._add_alt_holiday(dt_alt, name=name, include_sat=False)  # type: ignore[arg-type]
+    def _populate_observed(self, dts: Set[date], three_day_holidays: Dict[date, str]) -> None:
+        for dt in sorted(dts.union(three_day_holidays.keys())):
+            if not self._is_observed(dt):
+                continue
+            dt_observed = self._get_observed_date(
+                dt, SUN_TO_NEXT_WORKDAY if dt in three_day_holidays else SAT_SUN_TO_NEXT_WORKDAY
+            )
+            if dt_observed != dt or len(self.get_list(dt)) > 1:
+                if dt_observed == dt:
+                    dt_observed = self._get_next_workday(dt)
+                names = (
+                    (three_day_holidays[dt],) if dt in three_day_holidays else self.get_list(dt)
+                )
+                for name in names:
+                    self._add_holiday(self.tr(self.observed_label) % self.tr(name), dt_observed)
 
     def _populate_public_holidays(self):
+        def append_observed(dt: date, since: int):
+            if self._year >= since:
+                dts_observed.add(dt)
+
+        def add_three_day_holiday(dt: date, name: str):
+            name = self.tr(name)
+            for dt_alt in (
+                # The day preceding %s.
+                self._add_holiday(self.tr("%s 전날") % name, dt + td(days=-1)),
+                dt,
+                # The second day of %s.
+                self._add_holiday(self.tr("%s 다음날") % name, dt + td(days=+1)),
+            ):
+                three_days_holidays[dt_alt] = name
+
         if self._year <= 1947:
             return None
 
+        dts_observed = set()
+        three_days_holidays = {}
+
         # Fixed Date Holidays.
 
         # New Year's Day.
@@ -175,12 +147,12 @@ def _populate_public_holidays(self):
             )
             korean_new_year = self._add_chinese_new_years_day(name)
             if self._year >= 1989:
-                self._add_three_day_holiday(korean_new_year, name)
+                add_three_day_holiday(korean_new_year, name)
 
         # Independence Movement Day.
         mar_1 = self._add_holiday_mar_1(tr("삼일절"))
         # mar_1 is used later for Presidential Election Day.
-        self._add_alt_holiday(mar_1, since=2022)
+        append_observed(mar_1, 2022)
 
         if 1949 <= self._year <= 2005 and self._year != 1960:
             # Tree Planting Day.
@@ -194,34 +166,34 @@ def _populate_public_holidays(self):
                 # Buddha's Birthday.
                 else tr("석가탄신일")
             )
-            self._add_alt_holiday(self._add_chinese_birthday_of_buddha(name), since=2023)
+            append_observed(self._add_chinese_birthday_of_buddha(name), 2023)
 
         if self._year >= 1975:
             # Children's Day.
-            self._add_alt_holiday(self._add_holiday_may_5(tr("어린이날")), since=2015)
+            append_observed(self._add_holiday_may_5(tr("어린이날")), 2015)
 
         if self._year >= 1956:
             # Memorial Day.
             jun_6 = self._add_holiday_jun_6(tr("현충일"))
-            # jun_6 is  used later for Local Election Day.
+            # jun_6 is used later for Local Election Day.
 
         if self._year <= 2007:
             # Constitution Day.
             self._add_holiday_jul_17(tr("제헌절"))
 
         # Liberation Day.
-        self._add_alt_holiday(self._add_holiday_aug_15(tr("광복절")), since=2021)
+        append_observed(self._add_holiday_aug_15(tr("광복절")), 2021)
 
         if 1976 <= self._year <= 1990:
             # Armed Forces Day.
             self._add_holiday_oct_1(tr("국군의 날"))
 
         # National Foundation Day.
-        self._add_alt_holiday(self._add_holiday_oct_3(tr("개천절")), since=2021)
+        append_observed(self._add_holiday_oct_3(tr("개천절")), 2021)
 
         if self._year <= 1990 or self._year >= 2013:
             # Hangul Day.
-            self._add_alt_holiday(self._add_holiday_oct_9(tr("한글날")), since=2021)
+            append_observed(self._add_holiday_oct_9(tr("한글날")), 2021)
 
         if 1950 <= self._year <= 1975:
             # United Nations Day.
@@ -233,10 +205,10 @@ def _populate_public_holidays(self):
         if 1986 <= self._year <= 1988:
             self._add_mid_autumn_festival_day_two(self.tr("%s 다음날") % self.tr(name))
         elif self._year >= 1989:
-            self._add_three_day_holiday(chuseok, name)
+            add_three_day_holiday(chuseok, name)
 
         # Christmas Day.
-        self._add_alt_holiday(self._add_christmas_day(tr("기독탄신일")), since=2023)
+        append_observed(self._add_christmas_day(tr("기독탄신일")), 2023)
 
         # Election Days since Sep 2006; excluding the 2017 Special Presidential Election Day.
 
@@ -292,6 +264,9 @@ def _populate_public_holidays(self):
             else:
                 self._add_holiday_1st_wed_of_jun(name)
 
+        if self.observed:
+            self._populate_observed(dts_observed, three_days_holidays)
+
     def _populate_bank_holidays(self):
         if self._year <= 1947:
             return None

holidays/observed_holiday_base.py

@@ -105,16 +105,20 @@ def __init__(self, observed_rule: ObservedRule, observed_since: int = None, *arg
     def _is_observed(self, *args, **kwargs) -> bool:
         return self._observed_since is None or self._year >= self._observed_since
 
+    def _get_next_workday(self, dt: date, delta: int = +1) -> date:
+        dt_work = dt + td(days=delta)
+        while dt_work.year == self._year:
+            if dt_work in self or self._is_weekend(dt_work):  # type: ignore[operator]
+                dt_work += td(days=delta)
+            else:
+                return dt_work
+        return dt
+
     def _get_observed_date(self, dt: date, rule: ObservedRule) -> date:
         delta = rule.get(dt.weekday(), 0)
         if delta != 0:
             if abs(delta) == 7:
-                delta //= 7
-                dt += td(days=delta)
-                while dt.year == self._year and (
-                    dt in self or self._is_weekend(dt)  # type: ignore[operator]
-                ):
-                    dt += td(days=delta)
+                dt = self._get_next_workday(dt, delta // 7)
             else:
                 dt += td(days=delta)
         return dt

snapshots/countries/KR.json

@@ -1513,8 +1513,8 @@
     "2036-04-09": "National Assembly Election Day",
     "2036-05-01": "Workers' Day",
     "2036-05-03": "Buddha's Birthday",
-    "2036-05-05": "Alternative holiday for Buddha's Birthday; Children's Day",
-    "2036-05-06": "Alternative holiday for Children's Day",
+    "2036-05-05": "Children's Day",
+    "2036-05-06": "Alternative holiday for Buddha's Birthday",
     "2036-06-06": "Memorial Day",
     "2036-08-15": "Liberation Day",
     "2036-10-03": "National Foundation Day; The day preceding Chuseok",