Merge 3.4 (datetime rounding)

1 files changed, 8 insertions, 0 deletions

diff --git a/Misc/NEWS b/Misc/NEWS
index 1910529..9df2fc7 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -14,6 +14,14 @@ Core and Builtins
 Library
 -------
 
+- Issue #23517: Fix rounding in fromtimestamp() and utcfromtimestamp() methods
+  of datetime.datetime: microseconds are now rounded to nearest with ties
+  going to nearest even integer (ROUND_HALF_EVEN), instead of being rounding
+  towards minus infinity (ROUND_FLOOR). It's important that these methods use
+  the same rounding mode than datetime.timedelta to keep the property:
+  (datetime(1970,1,1) + timedelta(seconds=t)) == datetime.utcfromtimestamp(t).
+  It also the rounding mode used by round(float) for example.
+
 - Issue #25155: Fix datetime.datetime.now() and datetime.datetime.utcnow() on
   Windows to support date after year 2038. It was a regression introduced in
   Python 3.5.0.