From 5daab45158094e577b9791cda7d8a0f4e34f45cb Mon Sep 17 00:00:00 2001
From: Mark Dickinson <dickinsm@gmail.com>
Date: Mon, 5 Apr 2010 18:09:39 +0000
Subject: [PATCH] Merged revisions 79804 via svnmerge from
 svn+ssh://pythondev@svn.python.org/python/trunk

........
  r79804 | mark.dickinson | 2010-04-05 19:07:51 +0100 (Mon, 05 Apr 2010) | 5 lines

  Use a more robust infinity check in _Py_HashDouble.

  This fixes a test_decimal failure on FreeBSD 8.0.  (modf apparently
  doesn't follow C99 Annex F on FreeBSD.)
........
---
 Lib/test/test_float.py | 9 +++++++++
 Objects/object.c       | 6 +++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py
index cabeb16c42b..b52b1db9e46 100644
--- a/Lib/test/test_float.py
+++ b/Lib/test/test_float.py
@@ -914,6 +914,15 @@ class InfNanTest(unittest.TestCase):
         self.assertFalse(NAN.is_inf())
         self.assertFalse((0.).is_inf())
 
+    def test_hash_inf(self):
+        # the actual values here should be regarded as an
+        # implementation detail, but they need to be
+        # identical to those used in the Decimal module.
+        self.assertEqual(hash(float('inf')), 314159)
+        self.assertEqual(hash(float('-inf')), -271828)
+        self.assertEqual(hash(float('nan')), 0)
+
+
 fromHex = float.fromhex
 toHex = float.hex
 class HexFloatTestCase(unittest.TestCase):
diff --git a/Objects/object.c b/Objects/object.c
index a332c6c85e3..0b22e380e78 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -656,15 +656,15 @@ _Py_HashDouble(double v)
 	 * of mapping keys will turn out weird.
 	 */
 
+	if (Py_IS_INFINITY(v))
+		/* can't convert to long int -- arbitrary */
+		v = v < 0 ? -271828.0 : 314159.0;
 	fractpart = modf(v, &intpart);
 	if (fractpart == 0.0) {
 		/* This must return the same hash as an equal int or long. */
 		if (intpart > LONG_MAX/2 || -intpart > LONG_MAX/2) {
 			/* Convert to long and use its hash. */
 			PyObject *plong;	/* converted to Python long */
-			if (Py_IS_INFINITY(intpart))
-				/* can't convert to long int -- arbitrary */
-				v = v < 0 ? -271828.0 : 314159.0;
 			plong = PyLong_FromDouble(v);
 			if (plong == NULL)
 				return -1;