4 files changed, 17 insertions, 36 deletions
diff --git a/absl/time/internal/cctz/src/civil_time_test.cc b/absl/time/internal/cctz/src/civil_time_test.cc
index 6df0395bad4a..f6648c8f1f21 100644
--- a/absl/time/internal/cctz/src/civil_time_test.cc
+++ b/absl/time/internal/cctz/src/civil_time_test.cc
@@ -37,7 +37,7 @@ std::string Format(const T& t) {
 
 }  // namespace
 
-#if __clang__ && __cpp_constexpr >= 201304
+#if __cpp_constexpr >= 201304 || _MSC_VER >= 1910
 // Construction constexpr tests
 
 TEST(CivilTime, Normal) {
@@ -319,7 +319,7 @@ TEST(CivilTime, YearDay) {
   constexpr int yd = get_yearday(cd);
   static_assert(yd == 28, "YearDay");
 }
-#endif  // __clang__ && __cpp_constexpr >= 201304
+#endif  // __cpp_constexpr >= 201304 || _MSC_VER >= 1910
 
 // The remaining tests do not use constexpr.
 
diff --git a/absl/time/internal/cctz/src/time_zone_fixed.cc b/absl/time/internal/cctz/src/time_zone_fixed.cc
index 8d3b1442524c..65eba3569d97 100644
--- a/absl/time/internal/cctz/src/time_zone_fixed.cc
+++ b/absl/time/internal/cctz/src/time_zone_fixed.cc
@@ -27,7 +27,7 @@ namespace cctz {
 namespace {
 
 // The prefix used for the internal names of fixed-offset zones.
-const char kFixedOffsetPrefix[] = "Fixed/";
+const char kFixedOffsetPrefix[] = "Fixed/UTC";
 
 int Parse02d(const char* p) {
   static const char kDigits[] = "0123456789";
@@ -50,13 +50,11 @@ bool FixedOffsetFromName(const std::string& name, sys_seconds* offset) {
 
   const std::size_t prefix_len = sizeof(kFixedOffsetPrefix) - 1;
   const char* const ep = kFixedOffsetPrefix + prefix_len;
-  if (name.size() != prefix_len + 12)  // "<prefix>UTC+99:99:99"
+  if (name.size() != prefix_len + 9)  // <prefix>+99:99:99
     return false;
   if (!std::equal(kFixedOffsetPrefix, ep, name.begin()))
     return false;
   const char* np = name.data() + prefix_len;
-  if (*np++ != 'U' || *np++ != 'T' || *np++ != 'C')
-    return false;
   if (np[0] != '+' && np[0] != '-')
     return false;
   if (np[3] != ':' || np[6] != ':')  // see note below about large offsets
@@ -97,8 +95,8 @@ std::string FixedOffsetToName(const sys_seconds& offset) {
   }
   int hours = minutes / 60;
   minutes %= 60;
-  char buf[sizeof(kFixedOffsetPrefix) + sizeof("UTC-24:00:00")];
-  snprintf(buf, sizeof(buf), "%sUTC%c%02d:%02d:%02d",
+  char buf[sizeof(kFixedOffsetPrefix) + sizeof("-24:00:00")];
+  snprintf(buf, sizeof(buf), "%s%c%02d:%02d:%02d",
            kFixedOffsetPrefix, sign, hours, minutes, seconds);
   return buf;
 }
@@ -106,22 +104,14 @@ std::string FixedOffsetToName(const sys_seconds& offset) {
 std::string FixedOffsetToAbbr(const sys_seconds& offset) {
   std::string abbr = FixedOffsetToName(offset);
   const std::size_t prefix_len = sizeof(kFixedOffsetPrefix) - 1;
-  const char* const ep = kFixedOffsetPrefix + prefix_len;
-  if (abbr.size() >= prefix_len) {
-    if (std::equal(kFixedOffsetPrefix, ep, abbr.begin())) {
-      abbr.erase(0, prefix_len);
-      if (abbr.size() == 12) {                     // UTC+99:99:99
-        abbr.erase(9, 1);                          // UTC+99:9999
-        abbr.erase(6, 1);                          // UTC+999999
-        if (abbr[8] == '0' && abbr[9] == '0') {    // UTC+999900
-          abbr.erase(8, 2);                        // UTC+9999
-          if (abbr[6] == '0' && abbr[7] == '0') {  // UTC+9900
-            abbr.erase(6, 2);                      // UTC+99
-            if (abbr[4] == '0') {                  // UTC+09
-              abbr.erase(4, 1);                    // UTC+9
-            }
-          }
-        }
+  if (abbr.size() == prefix_len + 9) {         // <prefix>+99:99:99
+    abbr.erase(0, prefix_len);                 // +99:99:99
+    abbr.erase(6, 1);                          // +99:9999
+    abbr.erase(3, 1);                          // +999999
+    if (abbr[5] == '0' && abbr[6] == '0') {    // +999900
+      abbr.erase(5, 2);                        // +9999
+      if (abbr[3] == '0' && abbr[4] == '0') {  // +9900
+        abbr.erase(3, 2);                      // +99
       }
     }
   }
diff --git a/absl/time/internal/cctz/src/time_zone_lookup.cc b/absl/time/internal/cctz/src/time_zone_lookup.cc
index fbd86e16b485..d549d862a769 100644
--- a/absl/time/internal/cctz/src/time_zone_lookup.cc
+++ b/absl/time/internal/cctz/src/time_zone_lookup.cc
@@ -134,6 +134,9 @@ time_zone local_time_zone() {
 
   time_zone tz;
   load_time_zone(name, &tz);  // Falls back to UTC.
+  // TODO: Follow the RFC3339 "Unknown Local Offset Convention" and
+  // arrange for %z to generate "-0000" when we don't know the local
+  // offset because the load_time_zone() failed and we're using UTC.
   return tz;
 }
 
diff --git a/absl/time/internal/cctz/src/time_zone_lookup_test.cc b/absl/time/internal/cctz/src/time_zone_lookup_test.cc
index a5d73d5492e2..2dfe53b26764 100644
--- a/absl/time/internal/cctz/src/time_zone_lookup_test.cc
+++ b/absl/time/internal/cctz/src/time_zone_lookup_test.cc
@@ -1119,18 +1119,6 @@ TEST(TimeZoneEdgeCase, AfricaMonrovia) {
   auto tp = convert(civil_second(1972, 1, 6, 23, 59, 59), tz);
   ExpectTime(tp, tz, 1972, 1, 6, 23, 59, 59, -44.5 * 60, false, "MMT");
   tp += seconds(1);
-#ifndef TZDATA_2017B_IS_UBIQUITOUS
-  // The 2017b tzdata release moved the shift from -004430 to +00
-  // from 1972-05-01 to 1972-01-07, so we temporarily accept both
-  // outcomes until 2017b is ubiquitous.
-  if (tz.lookup(tp).offset == -44.5 * 60) {
-    tp = convert(civil_second(1972, 4, 30, 23, 59, 59), tz);
-    ExpectTime(tp, tz, 1972, 4, 30, 23, 59, 59, -44.5 * 60, false, "LRT");
-    tp += seconds(1);
-    ExpectTime(tp, tz, 1972, 5, 1, 0, 44, 30, 0 * 60, false, "GMT");
-    return;
-  }
-#endif
   ExpectTime(tp, tz, 1972, 1, 7, 0, 44, 30, 0 * 60, false, "GMT");
 }