Import of CCTZ from GitHub.

PiperOrigin-RevId: 467950116
Change-Id: Iccb0c80c93f1064a82a5537d4519b041609cddd6

absl/time/internal/cctz/src/cctz_benchmark.cc

@@ -554,6 +554,7 @@ const char* const kTimeZoneNames[] = {"Africa/Abidjan",
                                       "Europe/Kaliningrad",
                                       "Europe/Kiev",
                                       "Europe/Kirov",
+                                      "Europe/Kyiv",
                                       "Europe/Lisbon",
                                       "Europe/Ljubljana",
                                       "Europe/London",
@@ -593,6 +594,7 @@ const char* const kTimeZoneNames[] = {"Africa/Abidjan",
                                       "Europe/Zagreb",
                                       "Europe/Zaporozhye",
                                       "Europe/Zurich",
+                                      "Factory",
                                       "GB",
                                       "GB-Eire",
                                       "GMT",

absl/time/internal/cctz/src/time_zone_info.cc

@@ -134,6 +134,21 @@ std::int_fast64_t Decode64(const char* cp) {
   return static_cast<std::int_fast64_t>(v - s64maxU - 1) - s64max - 1;
 }
 
+// Does the rule for future transitions call for year-round daylight time?
+// See tz/zic.c:stringzone() for the details on how such rules are encoded.
+bool AllYearDST(const PosixTimeZone& posix) {
+  if (posix.dst_start.date.fmt != PosixTransition::N) return false;
+  if (posix.dst_start.date.n.day != 0) return false;
+  if (posix.dst_start.time.offset != 0) return false;
+
+  if (posix.dst_end.date.fmt != PosixTransition::J) return false;
+  if (posix.dst_end.date.j.day != kDaysPerYear[0]) return false;
+  const auto offset = posix.std_offset - posix.dst_offset;
+  if (posix.dst_end.time.offset + offset != kSecsPerDay) return false;
+
+  return true;
+}
+
 // Generate a year-relative offset for a PosixTransition.
 std::int_fast64_t TransOffset(bool leap_year, int jan1_weekday,
                               const PosixTransition& pt) {
@@ -334,6 +349,7 @@ bool TimeZoneInfo::ExtendTransitions() {
 
   PosixTimeZone posix;
   if (!ParsePosixSpec(future_spec_, &posix)) return false;
+  if (AllYearDST(posix)) return true;  // last transition still prevails
 
   // Find transition type for the future std specification.
   std::uint_least8_t std_ti;

absl/time/internal/cctz/src/time_zone_lookup_test.cc

@@ -489,6 +489,7 @@ const char* const kTimeZoneNames[] = {"Africa/Abidjan",
                                       "Europe/Kaliningrad",
                                       "Europe/Kiev",
                                       "Europe/Kirov",
+                                      "Europe/Kyiv",
                                       "Europe/Lisbon",
                                       "Europe/Ljubljana",
                                       "Europe/London",
@@ -528,6 +529,7 @@ const char* const kTimeZoneNames[] = {"Africa/Abidjan",
                                       "Europe/Zagreb",
                                       "Europe/Zaporozhye",
                                       "Europe/Zurich",
+                                      "Factory",
                                       "GB",
                                       "GB-Eire",
                                       "GMT",
@@ -1188,11 +1190,12 @@ TEST(PrevTransition, AmericaNewYork) {
 
 TEST(NextTransition, Scan) {
   for (const char* const* np = kTimeZoneNames; *np != nullptr; ++np) {
+    SCOPED_TRACE(testing::Message() << "In " << *np);
     time_zone tz;
+    // EXPECT_TRUE(load_time_zone(*np, &tz));
     if (!load_time_zone(*np, &tz)) {
       continue;  // tolerate kTimeZoneNames/zoneinfo skew
     }
-    SCOPED_TRACE(testing::Message() << "In " << *np);
 
     auto tp = time_point<absl::time_internal::cctz::seconds>::min();
     time_zone::civil_transition trans;

absl/time/internal/cctz/testdata/README.zoneinfo

@@ -13,12 +13,7 @@ New versions can be generated using the following shell script.
   trap "rm -fr ${DESTDIR}" 0 2 15
   (
     cd ${DESTDIR}
-    if [ -n "${USE_GLOBAL_TZ}" ]
-    then
-      git clone -b global-tz https://github.com/JodaOrg/global-tz.git tz
-    else
     git clone https://github.com/eggert/tz.git
-    fi
     make --directory=tz \
         install DESTDIR=${DESTDIR} \
                 DATAFORM=vanguard \
@@ -26,6 +21,7 @@ New versions can be generated using the following shell script.
                 REDO=posix_only \
                 LOCALTIME=Factory \
                 TZDATA_TEXT= \
+                PACKRATDATA=backzone PACKRATLIST=zone.tab \
                 ZONETABLES=zone1970.tab
     tar --create --dereference --hard-dereference --file tzfile.tar \
         --directory=tz tzfile.h