Remove Hijri<AstronomicalSimulation> logic (#7301)

This reduces the code size of `date_try_from_fields.wasm` from 47kB to
19kB.

We still include 250 years of hardcoded data, and fall back to the
tabular algorithm outside that range.

This calendar specifically documents that we can change the range of the
astronomical calculations (which are incorrect *anyway*).

This is not the size increase observed in
#7201, as Temporal excludes
this calendar.

Author: robertbastian

components/calendar/src/cal/hijri.rs

@@ -13,9 +13,6 @@ use crate::types::DateFields;
 use crate::types::Month;
 use crate::{types, Calendar, Date};
 use crate::{AsCalendar, RangeError};
-use calendrical_calculations::islamic::{
-    ISLAMIC_EPOCH_FRIDAY, ISLAMIC_EPOCH_THURSDAY, WELL_BEHAVED_ASTRONOMICAL_RANGE,
-};
 use calendrical_calculations::rata_die::RataDie;
 use core::fmt::Debug;
 use icu_locale_core::preferences::extensions::unicode::keywords::{
@@ -166,96 +163,21 @@ impl Rules for AstronomicalSimulation {
     fn year(&self, extended_year: i32) -> HijriYear {
         if let Some(data) = HijriYear::lookup(
             extended_year,
-            simulated_mecca_data::STARTING_YEAR,
-            simulated_mecca_data::DATA,
+            match self.location {
+                SimulatedLocation::Mecca => simulated_mecca_data::STARTING_YEAR,
+            },
+            match self.location {
+                SimulatedLocation::Mecca => simulated_mecca_data::DATA,
+            },
         ) {
-            return data;
-        }
-
-        let location = match self.location {
-            SimulatedLocation::Mecca => calendrical_calculations::islamic::MECCA,
-        };
-
-        let start_day = calendrical_calculations::islamic::fixed_from_observational_islamic(
-            extended_year,
-            1,
-            1,
-            location,
-        );
-        let next_start_day = calendrical_calculations::islamic::fixed_from_observational_islamic(
-            extended_year + 1,
-            1,
-            1,
-            location,
-        );
-        match (next_start_day - start_day) as u16 {
-            355 | 354 => (),
-            353 => {
-                icu_provider::log::trace!(
-                    "({}) Found year {extended_year} AH with length {}. See <https://github.com/unicode-org/icu4x/issues/4930>",
-                    self.debug_name(),
-                    next_start_day - start_day
-                );
-            }
-            other => {
-                debug_assert!(
-                    !WELL_BEHAVED_ASTRONOMICAL_RANGE.contains(&start_day),
-                    "({}) Found year {extended_year} AH with length {}!",
-                    self.debug_name(),
-                    other
-                )
+            data
+        } else {
+            TabularAlgorithm {
+                leap_years: TabularAlgorithmLeapYears::TypeII,
+                epoch: TabularAlgorithmEpoch::Friday,
             }
+            .year(extended_year)
         }
-
-        let month_lengths = {
-            let mut excess_days = 0;
-            let mut month_lengths = core::array::from_fn(|month_idx| {
-                let days_in_month =
-                    calendrical_calculations::islamic::observational_islamic_month_days(
-                        extended_year,
-                        month_idx as u8 + 1,
-                        location,
-                    );
-                match days_in_month {
-                    29 => false,
-                    30 => true,
-                    31 => {
-                        icu_provider::log::trace!(
-                            "({}) Found year {extended_year} AH with month length {days_in_month} for month {}.",
-                            self.debug_name(),
-                            month_idx + 1
-                        );
-                        excess_days += 1;
-                        true
-                    }
-                    _ => {
-                        debug_assert!(
-                            !WELL_BEHAVED_ASTRONOMICAL_RANGE.contains(&start_day),
-                            "({}) Found year {extended_year} AH with month length {days_in_month} for month {}!",
-                            self.debug_name(),
-                            month_idx + 1
-                        );
-                        false
-                    }
-                }
-            });
-            // To maintain invariants for calendar arithmetic, if astronomy finds
-            // a 31-day month, "move" the day to the first 29-day month in the
-            // same year to maintain all months at 29 or 30 days.
-            if excess_days != 0 {
-                debug_assert!(
-                    excess_days == 1 || !WELL_BEHAVED_ASTRONOMICAL_RANGE.contains(&start_day),
-                    "({}) Found year {extended_year} AH with more than one excess day!",
-                    self.debug_name()
-                );
-                if let Some(l) = month_lengths.iter_mut().find(|l| !(**l)) {
-                    *l = true;
-                }
-            }
-            month_lengths
-        };
-        HijriYear::try_new(extended_year, start_day, month_lengths)
-            .unwrap_or_else(|| UmmAlQura.year(extended_year))
     }
 }
 
@@ -498,8 +420,8 @@ pub enum TabularAlgorithmEpoch {
 impl TabularAlgorithmEpoch {
     fn rata_die(self) -> RataDie {
         match self {
-            Self::Thursday => ISLAMIC_EPOCH_THURSDAY,
-            Self::Friday => ISLAMIC_EPOCH_FRIDAY,
+            Self::Thursday => calendrical_calculations::islamic::ISLAMIC_EPOCH_THURSDAY,
+            Self::Friday => calendrical_calculations::islamic::ISLAMIC_EPOCH_FRIDAY,
         }
     }
 }
@@ -1275,27 +1197,27 @@ mod test {
         DateCase {
             year: -1245,
             month: 12,
-            day: 10,
+            day: 9,
         },
         DateCase {
             year: -813,
             month: 2,
-            day: 25,
+            day: 23,
         },
         DateCase {
             year: -568,
             month: 4,
-            day: 2,
+            day: 1,
         },
         DateCase {
             year: -501,
             month: 4,
-            day: 7,
+            day: 6,
         },
         DateCase {
             year: -157,
             month: 10,
-            day: 18,
+            day: 17,
         },
         DateCase {
             year: -47,
@@ -1330,7 +1252,7 @@ mod test {
         DateCase {
             year: 687,
             month: 2,
-            day: 21,
+            day: 20,
         },
         DateCase {
             year: 697,
@@ -1339,8 +1261,8 @@ mod test {
         },
         DateCase {
             year: 793,
-            month: 6,
-            day: 29,
+            month: 7,
+            day: 1,
         },
         DateCase {
             year: 839,
@@ -1350,7 +1272,7 @@ mod test {
         DateCase {
             year: 897,
             month: 6,
-            day: 2,
+            day: 1,
         },
         DateCase {
             year: 960,
@@ -1370,7 +1292,7 @@ mod test {
         DateCase {
             year: 1091,
             month: 6,
-            day: 3,
+            day: 2,
         },
         DateCase {
             year: 1128,
@@ -1380,7 +1302,7 @@ mod test {
         DateCase {
             year: 1182,
             month: 2,
-            day: 4,
+            day: 3,
         },
         DateCase {
             year: 1234,