tor-browser

commit 6fbded534bc2552052cdb178825ab2406cc38afc
parent 18d4db910547464c5b8ca8870b9f9b69b17779de
Author: André Bargull <andre.bargull@gmail.com>
Date:   Thu, 27 Nov 2025 10:03:37 +0000

Bug 1999316 - Part 3: Add CalendarHasMidYearEras. r=spidermonkey-reviewers,mgaudet

Rename `CalendarEraStartsAtYearBoundary` to `CalendarHasMidYearEras` to match
the spec.

Also rename `CalendarEraStartsAtYearBoundary` to `IsJapaneseEraName`.

Differential Revision: https://phabricator.services.mozilla.com/D272032

Diffstat:
M
js/src/builtin/temporal/Calendar.cpp
 | 
6
+++---
M
js/src/builtin/temporal/CalendarFields.cpp
 | 
5
++---
M
js/src/builtin/temporal/Era.h
 | 
53
+++++++++++++++++++++--------------------------------

3 files changed, 26 insertions(+), 38 deletions(-)
diff --git a/js/src/builtin/temporal/Calendar.cpp b/js/src/builtin/temporal/Calendar.cpp
@@ -962,7 +962,7 @@ static bool FirstYearOfJapaneseEra(JSContext* cx, CalendarId calendarId,
                                    const icu4x::capi::Calendar* calendar,
                                    EraCode era, int32_t* result) {
   MOZ_ASSERT(calendarId == CalendarId::Japanese);
-  MOZ_ASSERT(!CalendarEraStartsAtYearBoundary(calendarId, era));
+  MOZ_ASSERT(IsJapaneseEraName(era));
 
   // All supported Japanese eras last at least one year, so December 31 is
   // guaranteed to be in the first year of the era.
@@ -1141,7 +1141,7 @@ static UniqueICU4XDate CreateDateFromCodes(
       // or case 3. Handle a possible case 1 error first by mapping the era year
       // to a common era year and then re-try creating the date.
       if (calendarId == CalendarId::Japanese &&
-          !CalendarEraStartsAtYearBoundary(calendarId, eraYear.era)) {
+          IsJapaneseEraName(eraYear.era)) {
         EraYear commonEraYear;
         if (!JapaneseEraYearToCommonEraYear(cx, calendarId, calendar, eraYear,
                                             &commonEraYear)) {
@@ -1219,7 +1219,7 @@ static UniqueICU4XDate CreateDateFrom(JSContext* cx, CalendarId calendarId,
       if (!date) {
         return nullptr;
       }
-      MOZ_ASSERT_IF(CalendarEraStartsAtYearBoundary(calendarId),
+      MOZ_ASSERT_IF(!CalendarHasMidYearEras(calendarId),
                     OrdinalMonth(date.get()) == month);
       return date;
     }
diff --git a/js/src/builtin/temporal/CalendarFields.cpp b/js/src/builtin/temporal/CalendarFields.cpp
@@ -577,10 +577,9 @@ static auto NonISOFieldKeysToIgnore(CalendarId calendar,
     result += eraOrAnyYear;
   }
 
-  // If eras don't start at year boundaries, we have to ignore "era" and
+  // If eras can start in the middle of the year, we have to ignore "era" and
   // "eraYear" if any of "day", "month", or "monthCode" is present.
-  if (!CalendarEraStartsAtYearBoundary(calendar) &&
-      !(keys & dayOrAnyMonth).isEmpty()) {
+  if (CalendarHasMidYearEras(calendar) && !(keys & dayOrAnyMonth).isEmpty()) {
     result += eraOrEraYear;
   }
 
diff --git a/js/src/builtin/temporal/Era.h b/js/src/builtin/temporal/Era.h
@@ -206,41 +206,30 @@ constexpr auto CalendarEraName(CalendarId calendar, EraCode era) {
   return *names.begin();
 }
 
-constexpr bool CalendarEraStartsAtYearBoundary(CalendarId id) {
-  switch (id) {
-    // Calendar system which use a single era.
-    case CalendarId::ISO8601:
-    case CalendarId::Buddhist:
-    case CalendarId::Chinese:
-    case CalendarId::Coptic:
-    case CalendarId::Dangi:
-    case CalendarId::Ethiopian:
-    case CalendarId::EthiopianAmeteAlem:
-    case CalendarId::Hebrew:
-    case CalendarId::Indian:
-    case CalendarId::Persian:
-      return true;
-
-    // Calendar system which use multiple eras, but each era starts at a year
-    // boundary.
-    case CalendarId::Gregorian:
-    case CalendarId::IslamicCivil:
-    case CalendarId::IslamicTabular:
-    case CalendarId::IslamicUmmAlQura:
-    case CalendarId::ROC:
-      return true;
+/**
+ * CalendarHasMidYearEras ( calendar )
+ */
+constexpr bool CalendarHasMidYearEras(CalendarId calendar) {
+  // Steps 1-2.
+  //
+  // Japanese eras can start in the middle of the year. All other calendars
+  // start their eras at year boundaries. (Or don't have eras at all.)
+  return calendar == CalendarId::Japanese;
+}
 
-    // Calendar system which use multiple eras and eras can start within a year.
-    case CalendarId::Japanese:
+constexpr bool IsJapaneseEraName(EraCode era) {
+  switch (era) {
+    case EraCode::Standard:
+    case EraCode::Inverse:
       return false;
+    case EraCode::Meiji:
+    case EraCode::Taisho:
+    case EraCode::Showa:
+    case EraCode::Heisei:
+    case EraCode::Reiwa:
+      return true;
   }
-  MOZ_CRASH("invalid calendar id");
-}
-
-constexpr bool CalendarEraStartsAtYearBoundary(CalendarId id, EraCode era) {
-  MOZ_ASSERT_IF(id != CalendarId::Japanese,
-                CalendarEraStartsAtYearBoundary(id));
-  return era == EraCode::Standard || era == EraCode::Inverse;
+  MOZ_CRASH("invalid era");
 }
 
 struct EraYear {