<chrono>: Adjust for leap seconds when formatting file_time (#1879)

microsoft · Jun 29, 2021 · ac661bf · ac661bf
1 parent a2e781b
commit ac661bf
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/stl/inc/chrono b/stl/inc/chrono
@@ -6469,8 +6469,9 @@ struct formatter<_CHRONO file_time<_Duration>, _CharT> {
 
     template <class _FormatContext>
     auto format(const _CHRONO file_time<_Duration>& _Val, _FormatContext& _FormatCtx) {
-        const auto _Sys = _CHRONO clock_cast<_CHRONO system_clock>(_Val);
-        return _Impl._Write(_FormatCtx, _Val, _Fill_tm(_Sys));
+        const auto _Utc = _CHRONO file_clock::to_utc(_Val);
+        const auto _Sys = _CHRONO utc_clock::to_sys(_Utc);
+        return _Impl._Write(_FormatCtx, _Utc, _Fill_tm(_Sys));
     }
 
 private:

diff --git a/tests/std/tests/P0355R7_calendars_and_time_zones_formatting/test.cpp b/tests/std/tests/P0355R7_calendars_and_time_zones_formatting/test.cpp
@@ -296,6 +296,11 @@ void test_clock_formatter() {
             }
         }
     }
+
+    empty_braces_helper(file_clock::from_utc(utc_2016_12_31), STR("2016-12-31 00:00:00"));
+    empty_braces_helper(file_clock::from_utc(utc_2016_12_31) + 24h, STR("2017-01-01 00:00:00"));
+    empty_braces_helper(file_clock::from_utc(utc_2021_05_04), STR("2021-05-04 00:00:00"));
+    // TRANSITION: Test a leap second insertion after 2018-06 when there is one
 }
 
 template <typename CharT>