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cpython (merge 3.2 -> default): Issue #13496: Merge from 3.2
 

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Apr 15, 2012, 8:43 AM


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cpython (merge 3.2 -> default): Issue #13496: Merge from 3.2

http://hg.python.org/cpython/rev/1a9252280f07
changeset: 76324:1a9252280f07
parent: 76321:7eca620feb10
parent: 76323:35a3a7e0d66d
user: Mark Dickinson <mdickinson [at] enthought>
date: Sun Apr 15 16:32:04 2012 +0100
summary:
Issue #13496: Merge from 3.2

files:
Lib/test/test_bisect.py | 7 +++++++
Misc/NEWS | 3 +++
Modules/_bisectmodule.c | 10 ++++++++--
3 files changed, 18 insertions(+), 2 deletions(-)


diff --git a/Lib/test/test_bisect.py b/Lib/test/test_bisect.py
--- a/Lib/test/test_bisect.py
+++ b/Lib/test/test_bisect.py
@@ -122,6 +122,13 @@
self.assertRaises(ValueError, mod.insort_left, [1, 2, 3], 5, -1, 3),
self.assertRaises(ValueError, mod.insort_right, [1, 2, 3], 5, -1, 3),

+ def test_large_range(self):
+ # Issue 13496
+ mod = self.module
+ data = range(sys.maxsize-1)
+ self.assertEqual(mod.bisect_left(data, sys.maxsize-3), sys.maxsize-3)
+ self.assertEqual(mod.bisect_right(data, sys.maxsize-3), sys.maxsize-2)
+
def test_random(self, n=25):
from random import randrange
for i in range(n):
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -29,6 +29,9 @@
Library
-------

+- Issue #13496: Fix potential overflow in bisect.bisect algorithm when applied
+ to a collection of size > sys.maxsize / 2.
+
- Have importlib take advantage of ImportError's new 'name' and 'path'
attributes.

diff --git a/Modules/_bisectmodule.c b/Modules/_bisectmodule.c
--- a/Modules/_bisectmodule.c
+++ b/Modules/_bisectmodule.c
@@ -21,7 +21,10 @@
return -1;
}
while (lo < hi) {
- mid = (lo + hi) / 2;
+ /* The (size_t)cast ensures that the addition and subsequent division
+ are performed as unsigned operations, avoiding difficulties from
+ signed overflow. (See issue 13496.) */
+ mid = ((size_t)lo + hi) / 2;
litem = PySequence_GetItem(list, mid);
if (litem == NULL)
return -1;
@@ -123,7 +126,10 @@
return -1;
}
while (lo < hi) {
- mid = (lo + hi) / 2;
+ /* The (size_t)cast ensures that the addition and subsequent division
+ are performed as unsigned operations, avoiding difficulties from
+ signed overflow. (See issue 13496.) */
+ mid = ((size_t)lo + hi) / 2;
litem = PySequence_GetItem(list, mid);
if (litem == NULL)
return -1;

--
Repository URL: http://hg.python.org/cpython

Subject User Time
cpython (merge 3.2 -> default): Issue #13496: Merge from 3.2 python-checkins at python Apr 15, 2012, 8:43 AM

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