[Python-checkins] cpython (2.7): Issue #15544: Fix Decimal.__float__ to work with payload-carrying NaNs.
mark.dickinson
python-checkins at python.org
Fri Aug 24 21:06:51 CEST 2012
http://hg.python.org/cpython/rev/5dd5f824428c
changeset: 78754:5dd5f824428c
branch: 2.7
parent: 78743:b60875fec9b7
user: Mark Dickinson <mdickinson at enthought.com>
date: Fri Aug 24 20:06:30 2012 +0100
summary:
Issue #15544: Fix Decimal.__float__ to work with payload-carrying NaNs.
files:
Lib/decimal.py | 8 +++++++-
Lib/test/test_decimal.py | 14 ++++++++++++++
Misc/NEWS | 2 ++
3 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/Lib/decimal.py b/Lib/decimal.py
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -1581,7 +1581,13 @@
def __float__(self):
"""Float representation."""
- return float(str(self))
+ if self._isnan():
+ if self.is_snan():
+ raise ValueError("Cannot convert signaling NaN to float")
+ s = "-nan" if self._sign else "nan"
+ else:
+ s = str(self)
+ return float(s)
def __int__(self):
"""Converts self to an int, truncating if necessary."""
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -1448,6 +1448,20 @@
self.assertEqual(float(d1), 66)
self.assertEqual(float(d2), 15.32)
+ def test_nan_to_float(self):
+ # Test conversions of decimal NANs to float.
+ # See http://bugs.python.org/issue15544
+ for s in ('nan', 'nan1234', '-nan', '-nan2468'):
+ f = float(Decimal(s))
+ self.assertTrue(math.isnan(f))
+ sign = math.copysign(1.0, f)
+ self.assertEqual(sign, -1.0 if s.startswith('-') else 1.0)
+
+ def test_snan_to_float(self):
+ for s in ('snan', '-snan', 'snan1357', '-snan1234'):
+ d = Decimal(s)
+ self.assertRaises(ValueError, float, d)
+
def test_eval_round_trip(self):
#with zero
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -95,6 +95,8 @@
Library
-------
+- Issue #15544: Fix Decimal.__float__ to work with payload-carrying NaNs.
+
- Issue #15199: Fix JavaScript's default MIME type to application/javascript.
Patch by Bohuslav Kabrda.
--
Repository URL: http://hg.python.org/cpython
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