Fix rfc3339_to_system_time handling of fractional seconds

erlang · Jan 10, 2025 · b7f702a · b7f702a
1 parent eda3df1
commit b7f702a
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Showing 2 changed files with 7 additions and 4 deletions.
diff --git a/lib/stdlib/src/calendar.erl b/lib/stdlib/src/calendar.erl
@@ -576,7 +576,7 @@ rfc3339_to_system_time_1(DateTimeIn, Options, Year, Month, Day, Hour, Min, Sec,
     Secs = Time - offset_string_adjustment(Time, second, UtcOffset),
     check(DateTimeIn, Options, Secs),
     ScaledEpoch = erlang:convert_time_unit(Secs, second, Unit),
-    ScaledEpoch + copy_sign(fraction(Unit, FractionStr), ScaledEpoch).
+    ScaledEpoch + fraction(Unit, FractionStr).
 
 
 
@@ -1042,9 +1042,6 @@ fraction(_, "") ->
 fraction(Unit, FractionStr) ->
     round(factor(Unit) * list_to_float([$0|FractionStr])).
 
-copy_sign(N1, N2) when N2 < 0 -> -N1;
-copy_sign(N1, _N2) -> N1.
-
 factor(second)      -> 1;
 factor(millisecond) -> 1000;
 factor(microsecond) -> 1_000_000;

diff --git a/lib/stdlib/test/calendar_SUITE.erl b/lib/stdlib/test/calendar_SUITE.erl
@@ -316,6 +316,12 @@ rfc3339(Config) when is_list(Config) ->
     -1613833200000000 = do_parse("1918-11-11T11:00:00+02:00", Mys),
     -1613833200000000 = do_parse("1918-11-11T09:00:00Z", Mys),
 
+    %% GH-9279
+    -1500 = do_parse("1969-12-31T23:59:58.5Z", Ms),
+    -500 = do_parse("1969-12-31T23:59:59.5Z", Ms),
+    500 = do_parse("1970-01-01T00:00:00.5Z", Ms),
+    1500 = do_parse("1970-01-01T00:00:01.5Z", Ms),
+
     "1970-01-01T00:00:00.000000Z" = do_format_z(0, Mys),
     "1970-01-01T00:00:01Z" = do_format_z(1, S),
     "1970-01-01T00:00:00.001Z" = do_format_z(1, Ms),