[Python-checkins] r86877 - in python/branches/release27-maint: Lib/test/test_itertools.py Misc/NEWS Modules/itertoolsmodule.c
raymond.hettinger
python-checkins at python.org
Tue Nov 30 04:15:35 CET 2010
Author: raymond.hettinger
Date: Tue Nov 30 04:15:35 2010
New Revision: 86877
Log:
Issue #10323: Predictable final state for slice().
Modified:
python/branches/release27-maint/Lib/test/test_itertools.py
python/branches/release27-maint/Misc/NEWS
python/branches/release27-maint/Modules/itertoolsmodule.c
Modified: python/branches/release27-maint/Lib/test/test_itertools.py
==============================================================================
--- python/branches/release27-maint/Lib/test/test_itertools.py (original)
+++ python/branches/release27-maint/Lib/test/test_itertools.py Tue Nov 30 04:15:35 2010
@@ -778,6 +778,11 @@
self.assertRaises(ValueError, islice, xrange(10), 1, 'a', 1)
self.assertEqual(len(list(islice(count(), 1, 10, maxsize))), 1)
+ # Issue #10323: Less islice in a predictable state
+ c = count()
+ self.assertEqual(list(islice(c, 1, 3, 50)), [1])
+ self.assertEqual(next(c), 3)
+
def test_takewhile(self):
data = [1, 3, 5, 20, 2, 4, 6, 8]
underten = lambda x: x<10
Modified: python/branches/release27-maint/Misc/NEWS
==============================================================================
--- python/branches/release27-maint/Misc/NEWS (original)
+++ python/branches/release27-maint/Misc/NEWS Tue Nov 30 04:15:35 2010
@@ -22,6 +22,10 @@
Library
-------
+- Issue #10323: itertools.islice() now consumes the minimum number of
+ inputs before stopping. Formerly, the final state of the underlying
+ iterator was undefined.
+
- Issue #10565: The collections.Iterator ABC now checks for both
``__iter__`` and ``next``.
Modified: python/branches/release27-maint/Modules/itertoolsmodule.c
==============================================================================
--- python/branches/release27-maint/Modules/itertoolsmodule.c (original)
+++ python/branches/release27-maint/Modules/itertoolsmodule.c Tue Nov 30 04:15:35 2010
@@ -1215,6 +1215,7 @@
{
PyObject *item;
PyObject *it = lz->it;
+ Py_ssize_t stop = lz->stop;
Py_ssize_t oldnext;
PyObject *(*iternext)(PyObject *);
@@ -1226,7 +1227,7 @@
Py_DECREF(item);
lz->cnt++;
}
- if (lz->stop != -1 && lz->cnt >= lz->stop)
+ if (stop != -1 && lz->cnt >= stop)
return NULL;
item = iternext(it);
if (item == NULL)
@@ -1234,8 +1235,8 @@
lz->cnt++;
oldnext = lz->next;
lz->next += lz->step;
- if (lz->next < oldnext) /* Check for overflow */
- lz->next = lz->stop;
+ if (lz->next < oldnext || (stop != -1 && lz->next > stop))
+ lz->next = stop;
return item;
}
More information about the Python-checkins
mailing list