Merge pull request #1550 from BillyONeal/fix_leap_year_last_day

Fix year calculation for the last day of a leap year.
microsoft · Dec 31, 2020 · fca7ac8 · fca7ac8
2 parents eb6801f + 198b034
commit fca7ac8
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diff --git a/Release/src/utilities/asyncrt_utils.cpp b/Release/src/utilities/asyncrt_utils.cpp
@@ -736,6 +736,12 @@ static compute_year_result compute_year(int64_t secondsSince1900)
  int secondsInt = static_cast<int>(secondsLeft - year4 * SecondsIn4Years);
 
  int year1 = secondsInt / SecondsInYear;
+ if (year1 == 4)
+ {
+ // this is the last day in a leap year
+ year1 = 3;
+ }
+
  secondsInt -= year1 * SecondsInYear;
 
  // shift back to 1900 base from 1601:

diff --git a/Release/tests/functional/utils/datetime.cpp b/Release/tests/functional/utils/datetime.cpp
@@ -133,6 +133,21 @@ SUITE(datetime)
  TestDateTimeRoundtrip(_XPLATSTR("9999-12-31T23:59:59Z"));
  }
 
+ TEST(parsing_time_roundtrip_year_2016)
+ {
+ TestDateTimeRoundtrip(_XPLATSTR("2016-12-31T20:59:59Z"));
+ }
+
+ TEST(parsing_time_roundtrip_year_2020)
+ {
+ TestDateTimeRoundtrip(_XPLATSTR("2020-12-31T20:59:59Z"));
+ }
+
+ TEST(parsing_time_roundtrip_year_2021)
+ {
+ TestDateTimeRoundtrip(_XPLATSTR("2021-01-01T20:59:59Z"));
+ }
+
  TEST(emitting_time_correct_day) {
  const auto test = utility::datetime() + UINT64_C(132004507640000000); // 2019-04-22T23:52:44 is a Monday
  const auto actual = test.to_string(utility::datetime::RFC_1123);