[Python-checkins] r53099 - in python/trunk: Lib/random.py Lib/test/test_random.py Misc/NEWS

[raymond.hettinger]

Author: raymond.hettinger
Date: Wed Dec 20 07:42:06 2006
New Revision: 53099

Modified:
   python/trunk/Lib/random.py
   python/trunk/Lib/test/test_random.py
   python/trunk/Misc/NEWS
Log:
Bug #1590891:   random.randrange don't return correct value for big number

Needs to be backported.



Modified: python/trunk/Lib/random.py
==============================================================================
--- python/trunk/Lib/random.py	(original)
+++ python/trunk/Lib/random.py	Wed Dec 20 07:42:06 2006
@@ -205,7 +205,7 @@
             raise ValueError, "empty range for randrange()"
 
         if n >= maxwidth:
-            return istart + self._randbelow(n)
+            return istart + istep*self._randbelow(n)
         return istart + istep*int(self.random() * n)
 
     def randint(self, a, b):

Modified: python/trunk/Lib/test/test_random.py
==============================================================================
--- python/trunk/Lib/test/test_random.py	(original)
+++ python/trunk/Lib/test/test_random.py	Wed Dec 20 07:42:06 2006
@@ -438,6 +438,14 @@
             self.assertEqual(k, numbits)        # note the stronger assertion
             self.assert_(2**k > n > 2**(k-1))   # note the stronger assertion
 
+    def test_randrange_bug_1590891(self):
+        start = 1000000000000
+        stop = -100000000000000000000
+        step = -200
+        x = self.gen.randrange(start, stop, step)
+        self.assert_(stop < x <= start)
+        self.assertEqual((x+stop)%step, 0)
+
 _gammacoeff = (0.9999999999995183, 676.5203681218835, -1259.139216722289,
               771.3234287757674,  -176.6150291498386, 12.50734324009056,
               -0.1385710331296526, 0.9934937113930748e-05, 0.1659470187408462e-06)

Modified: python/trunk/Misc/NEWS
==============================================================================
--- python/trunk/Misc/NEWS	(original)
+++ python/trunk/Misc/NEWS	Wed Dec 20 07:42:06 2006
@@ -12,6 +12,8 @@
 Core and builtins
 -----------------
 
+- Bug #1590891: random.randrange don't return correct value for big number
+
 - Patch #1586791: Better exception messages for some operations on strings,
   tuples and lists.