From 8a48808f3317dad53fac3dd648cba8730c17bce4 Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Tue, 6 Apr 2010 21:55:35 +0000
Subject: [PATCH] Merged revisions 79866-79867 via svnmerge from
 svn+ssh://pythondev@svn.python.org/python/trunk

........
  r79866 | benjamin.peterson | 2010-04-06 16:37:06 -0500 (Tue, 06 Apr 2010) | 1 line

  use skip decorator
........
  r79867 | benjamin.peterson | 2010-04-06 16:50:00 -0500 (Tue, 06 Apr 2010) | 1 line

  remove a optimization that resulted in unexpected behavior #8929
........
---
 Lib/test/test_select.py | 13 +++++++++----
 Misc/NEWS               |  3 +++
 Modules/selectmodule.c  |  8 --------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Lib/test/test_select.py b/Lib/test/test_select.py
index 52805e625de..647d71ef209 100644
--- a/Lib/test/test_select.py
+++ b/Lib/test/test_select.py
@@ -4,6 +4,8 @@ import select
 import os
 import sys
 
+@unittest.skipIf(sys.platform[:3] in ('win', 'mac', 'os2', 'riscos'),
+                 "can't easily test on this system")
 class SelectTestCase(unittest.TestCase):
 
     class Nope:
@@ -19,11 +21,14 @@ class SelectTestCase(unittest.TestCase):
         self.assertRaises(TypeError, select.select, [self.Almost()], [], [])
         self.assertRaises(TypeError, select.select, [], [], [], "not a number")
 
+    def test_returned_list_identity(self):
+        # See issue #8329
+        r, w, x = select.select([], [], [], 1)
+        self.assertIsNot(r, w)
+        self.assertIsNot(r, x)
+        self.assertIsNot(w, x)
+
     def test_select(self):
-        if sys.platform[:3] in ('win', 'mac', 'os2', 'riscos'):
-            if test_support.verbose:
-                print "Can't test select easily on", sys.platform
-            return
         cmd = 'for i in 0 1 2 3 4 5 6 7 8 9; do echo testing...; sleep 1; done'
         p = os.popen(cmd, 'r')
         for tout in (0, 1, 2, 4, 8, 16) + (None,)*10:
diff --git a/Misc/NEWS b/Misc/NEWS
index 3595306d16c..5bdce3350f4 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@ What's New in Python 2.6.6 alpha 1?
 Core and Builtins
 -----------------
 
+- Issue #8329: Don't return the same lists from select.select when no fds are
+  changed.
+
 - Raise a TypeError when trying to delete a T_STRING_INPLACE struct member.
 
 - Issue #1583863: An unicode subclass can now override the __unicode__ method
diff --git a/Modules/selectmodule.c b/Modules/selectmodule.c
index dd1166c65b2..09c687c9603 100644
--- a/Modules/selectmodule.c
+++ b/Modules/selectmodule.c
@@ -287,14 +287,6 @@ select_select(PyObject *self, PyObject *args)
 		PyErr_SetFromErrno(SelectError);
 	}
 #endif
-	else if (n == 0) {
-                /* optimization */
-		ifdlist = PyList_New(0);
-		if (ifdlist) {
-			ret = PyTuple_Pack(3, ifdlist, ifdlist, ifdlist);
-			Py_DECREF(ifdlist);
-		}
-	}
 	else {
 		/* any of these three calls can raise an exception.  it's more
 		   convenient to test for this after all three calls... but