Revert change 0eb8c182131e:

"""Issue #23517: datetime.timedelta constructor now rounds microseconds to
nearest with ties going away from zero (ROUND_HALF_UP), as Python 2 and Python
older than 3.3, instead of rounding to nearest with ties going to nearest even
integer (ROUND_HALF_EVEN)."""

datetime.timedelta uses rounding mode ROUND_HALF_EVEN again.

2 files changed, 14 insertions, 8 deletions

diff --git a/Lib/datetime.py b/Lib/datetime.py
index 6b2ac33..3c25ef8 100644
--- a/Lib/datetime.py
+++ b/Lib/datetime.py
@@ -407,7 +407,7 @@ class timedelta:
         # secondsfrac isn't referenced again
 
         if isinstance(microseconds, float):
-            microseconds = _round_half_up(microseconds + usdouble)
+            microseconds = round(microseconds + usdouble)
             seconds, microseconds = divmod(microseconds, 1000000)
             days, seconds = divmod(seconds, 24*3600)
             d += days
@@ -418,7 +418,7 @@ class timedelta:
             days, seconds = divmod(seconds, 24*3600)
             d += days
             s += seconds
-            microseconds = _round_half_up(microseconds + usdouble)
+            microseconds = round(microseconds + usdouble)
         assert isinstance(s, int)
         assert isinstance(microseconds, int)
         assert abs(s) <= 3 * 24 * 3600
diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
index f23add3..d87b106 100644
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -663,14 +663,16 @@ class TestTimeDelta(HarmlessMixedComparison, unittest.TestCase):
         # Single-field rounding.
         eq(td(milliseconds=0.4/1000), td(0))    # rounds to 0
         eq(td(milliseconds=-0.4/1000), td(0))    # rounds to 0
-        eq(td(milliseconds=0.5/1000), td(microseconds=1))
-        eq(td(milliseconds=-0.5/1000), td(microseconds=-1))
+        eq(td(milliseconds=0.5/1000), td(microseconds=0))
+        eq(td(milliseconds=-0.5/1000), td(microseconds=-0))
         eq(td(milliseconds=0.6/1000), td(microseconds=1))
         eq(td(milliseconds=-0.6/1000), td(microseconds=-1))
-        eq(td(seconds=0.5/10**6), td(microseconds=1))
-        eq(td(seconds=-0.5/10**6), td(microseconds=-1))
-        eq(td(seconds=1/2**7), td(microseconds=7813))
-        eq(td(seconds=-1/2**7), td(microseconds=-7813))
+        eq(td(milliseconds=1.5/1000), td(microseconds=2))
+        eq(td(milliseconds=-1.5/1000), td(microseconds=-2))
+        eq(td(seconds=0.5/10**6), td(microseconds=0))
+        eq(td(seconds=-0.5/10**6), td(microseconds=-0))
+        eq(td(seconds=1/2**7), td(microseconds=7812))
+        eq(td(seconds=-1/2**7), td(microseconds=-7812))
 
         # Rounding due to contributions from more than one field.
         us_per_hour = 3600e6
@@ -683,6 +685,10 @@ class TestTimeDelta(HarmlessMixedComparison, unittest.TestCase):
         eq(td(hours=-.2/us_per_hour), td(0))
         eq(td(days=-.4/us_per_day, hours=-.2/us_per_hour), td(microseconds=-1))
 
+        # Test for a patch in Issue 8860
+        eq(td(microseconds=0.5), 0.5*td(microseconds=1.0))
+        eq(td(microseconds=0.5)//td.resolution, 0.5*td.resolution//td.resolution)
+
     def test_massive_normalization(self):
         td = timedelta(microseconds=-1)
         self.assertEqual((td.days, td.seconds, td.microseconds),