Bug 1003935: xrange overflows

Added XXX comment about why the undocumented PyRange_New() API function
is too broken to be worth the considerable pain of repairing.

Changed range_new() to stop using PyRange_New().  This fixes a variety
of bogus errors.  Nothing in the core uses PyRange_New() now.

Documented that xrange() is intended to be simple and fast, and that
CPython restricts its arguments, and length of its result sequence, to
native C longs.

Added some tests that failed before the patch, and repaired a test that
relied on a bogus OverflowError getting raised.

1 files changed, 6 insertions, 1 deletions

diff --git a/Lib/test/test_xrange.py b/Lib/test/test_xrange.py
index ce5284d..f33373e 100644
--- a/Lib/test/test_xrange.py
+++ b/Lib/test/test_xrange.py
@@ -48,10 +48,15 @@ class XrangeTest(unittest.TestCase):
         self.assertRaises(TypeError, xrange, 0, "spam")
         self.assertRaises(TypeError, xrange, 0, 42, "spam")
 
-        self.assertRaises(OverflowError, xrange, 0, sys.maxint, sys.maxint-1)
+        self.assertEqual(len(xrange(0, sys.maxint, sys.maxint-1)), 2)
+
         self.assertRaises(OverflowError, xrange, -sys.maxint, sys.maxint)
         self.assertRaises(OverflowError, xrange, 0, 2*sys.maxint)
 
+        self.assertEqual(len(xrange(-sys.maxint, sys.maxint, 2)),
+                         sys.maxint)
+        self.assertRaises(OverflowError, xrange, -sys.maxint-1, sys.maxint, 2)
+
 def test_main():
     test.test_support.run_unittest(XrangeTest)