Issue 11131: Fix sign of zero result on decimal.Decimal plus and minus operations in ROUND_FLOOR rounding mode.

1 files changed, 11 insertions, 8 deletions

diff --git a/Lib/decimal.py b/Lib/decimal.py
index c61b549c48..5e53d8e3c5 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -1040,14 +1040,16 @@ class Decimal(object):
             if ans:
                 return ans
 
-        if not self:
-            # -Decimal('0') is Decimal('0'), not Decimal('-0')
+        if context is None:
+            context = getcontext()
+
+        if not self and context.rounding != ROUND_FLOOR:
+            # -Decimal('0') is Decimal('0'), not Decimal('-0'), except
+            # in ROUND_FLOOR rounding mode.
             ans = self.copy_abs()
         else:
             ans = self.copy_negate()
 
-        if context is None:
-            context = getcontext()
         return ans._fix(context)
 
     def __pos__(self, context=None):
@@ -1060,14 +1062,15 @@ class Decimal(object):
             if ans:
                 return ans
 
-        if not self:
-            # + (-0) = 0
+        if context is None:
+            context = getcontext()
+
+        if not self and context.rounding != ROUND_FLOOR:
+            # + (-0) = 0, except in ROUND_FLOOR rounding mode.
             ans = self.copy_abs()
         else:
             ans = Decimal(self)
 
-        if context is None:
-            context = getcontext()
         return ans._fix(context)
 
     def __abs__(self, round=True, context=None):