A couple of tests exhibit some memory leaks in the py3k branch (when
invoked with "-R 3:2").

test_asyncore leaked [-78, 0] references, sum=-78
test_fileio leaked [1, 1] references, sum=2
test_httpservers leaked [-210, 157] references, sum=-53
test_socket leaked [8, 210] references, sum=218
test_urllib2 leaked [227, 227] references, sum=454
test_urllib2_localnet leaked [5, 4] references, sum=9

I'm filing this as critical so that we keep track of it, but it doesn't
look severe in itself (ISTR we actually had more leaks in 3.0).

I hope attached patch will fix test_fileio leak.

I hope attached patch will fix leak of test_socket.py.

Leak is happening in FileObjectClassTestCase#testFullRead and
testCloseAfterMakefile. (actually, IOBase#readall)

Applied in r70690, thanks!

The only remaining leaks now are:

test_urllib2 leaked [227, 227] references, sum=454
test_urllib2_localnet leaked [3, 3] references, sum=6

About test_urllib2_localnet, this leak happens because FakeProxyHandler
has class variable digest_auth_handler and its instance variables are
modified. Following workaround can fix this leak, but I'm not sure this
can be committed.

Index: Lib/test/test_urllib2_localnet.py
===================================================================
--- Lib/test/test_urllib2_localnet.py	(revision 70694)
+++ Lib/test/test_urllib2_localnet.py	(working copy)
@@ -241,6 +241,7 @@
 
     def tearDown(self):
         self.server.stop()
+        FakeProxyHandler.digest_auth_handler.__init__()
 
     def test_proxy_with_bad_password_raises_httperror(self):
         self._digest_auth_handler.add_password(self.REALM, self.URL,

I have the following tests leaking on my Linux build of py3k:


test_structmembers leaked [102, 102, 102] references, sum=306
test_structmembers leaked [102, 102, 102] references, sum=306
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [17, 17, 17, 17] references, sum=68
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102] references, sum=408
test_structmembers leaked [102, 102, 102, 102, 102, 102] references, sum=612
test_structmembers leaked [106, 102, 102] references, sum=310
test_structmembers leaked [102, 102, 102] references, sum=306
test_structmembers leaked [106, 102, 102] references, sum=310
test_structmembers leaked [106, 102, 102] references, sum=310
test_docxmlrpc leaked [166, -251, 0] references, sum=-85
test_httpservers leaked [-195, 0, 0] references, sum=-195
test_os leaked [0, 0, 23] references, sum=23
test_popen leaked [-23, 23, -23] references, sum=-23
test_telnetlib leaked [0, 0, 84] references, sum=84
test_threading leaked [-119, 119, -28] references, sum=-28
test_urllib2 leaked [227, 227, 227] references, sum=681
test_urllib2_localnet leaked [-251, 3, 3] references, sum=-245

Strange, I don't see any leaks in test_structmembers here.

test_structmembers
beginning 9 repetitions
123456789
.........
1 test OK.
[89785 refs]

This is with r71202 on a 64-bit build.

Dismiss my last comment. These are the tests actually leaking for my build: 

test_docxmlrpc leaked [85, -6, 0, 39] references, sum=118
test_httpservers leaked [-195, 195, 0, 64] references, sum=64
test_os leaked [23, -23, 0, 23] references, sum=23
test_pipes leaked [0, 0, 0, -23] references, sum=-23
test_popen leaked [0, -23, 0, 0] references, sum=-23
test_urllib2 leaked [227, 227, 227, 227] references, sum=908
test_urllib2_localnet leaked [3, 3, 3, 3] references, sum=12

Current status here:

test_multiprocessing leaked [24, 0] references, sum=24
test_urllib2 leaked [227, 227] references, sum=454
test_urllib2_localnet leaked [3, 3] references, sum=6

New results:

test_os leaked [1, 1] references, sum=2
test_urllib leaked [4, 2] references, sum=6
test_urllib2 leaked [227, 227] references, sum=454
test_urllib2_localnet leaked [3, 3] references, sum=6

Current results:

test_modulefinder leaked [145, 145] references, sum=290
test_urllib leaked [10, 0] references, sum=10
test_urllib2 leaked [227, 227] references, sum=454

These tests are leaking on my build of r73393:

test_docxmlrpc leaked [0, 0, 85, 0, 0, -85, 0, 0, 0, 0] references, sum=0
test_popen leaked [0, 23, -23, 0, 23, 0, -23, 23, -23, 23] references,
sum=23
test_urllib leaked [4, 4, 4, 4, 6, 0, 0, 0, 2, 0] references, sum=24
test_urllib2_localnet leaked [0, 0, 0, 0, 0, 0, 251, -250, 0, 0]
references, sum=1
test_os leaked [0, -26, 26, 0, -26, 26, 0, 23, 0, 0] references, sum=23

With the py3k branch head (r74140):

test_urllib leaked [6, 4] references, sum=10
test_urllib2 leaked [227, 227] references, sum=454

With r75397:

test___all__ leaked [1, 1] references, sum=2
test_asyncore leaked [1, 0] references, sum=1
test_distutils leaked [0, 2] references, sum=2
test_httpservers leaked [-259, 0] references, sum=-259
test_os leaked [-23, 23] references, sum=0
test_pydoc leaked [0, -21] references, sum=-21
test_threaded_import leaked [1, 0] references, sum=1
test_urllib leaked [4, 4] references, sum=8
test_uuid leaked [6, 6] references, sum=12
test_urllib2_localnet leaked [240, -239] references, sum=1

With r75820:

test_asyncore leaked [153, -152] references, sum=1
test_distutils leaked [0, 2] references, sum=2
test_httpservers leaked [0, 259] references, sum=259
test_pipes leaked [23, 0] references, sum=23
test_threaded_import leaked [1, 0] references, sum=1
test_tokenize leaked [0, 291] references, sum=291
test_urllib leaked [6, 4] references, sum=10
test_uuid leaked [6, 6] references, sum=12
test_zipimport_support leaked [748, 0] references, sum=748
test_zipfile leaked [2, 0] references, sum=2

test_asyncore and test_httpservers should now be fixed.

After quite a bit of work, here is the new status as of r75970:

test_textwrap leaked [0, -206] references, sum=-206
test_urllib leaked [2, 0] references, sum=2

And there was much rejoicing :)

test_textwrap seems OK with r76697

I still have leaks on test_pipes and test_urllib:

~ $ ./python Lib/test/regrtest.py -R : test_textwrap \
             test_pipes test_urllib
test_pipes leaked [0, -26, 0, 26] references, sum=0
test_pipes leaked [0, -26, 26, -26] references, sum=-26
test_pipes leaked [-26, 26, 0, 0] references, sum=0
test_pipes leaked [26, -26, 26, 0] references, sum=26
test_urllib leaked [0, 2, 0, 0] references, sum=2
test_urllib leaked [4, 6, 0, 2] references, sum=12
test_urllib leaked [2, 4, 2, 0] references, sum=8
test_urllib leaked [6, 6, 2, 0] references, sum=14

Patch for the test refleaks:
 * test_pipes
 * test_urllib

And the test_urllib may leak on 2.7, too.

Patch attached.

Another false-positive in test_zipimport_support.
Both on 2.7 and 3.2.

Patch attached.

I've committed fixes to test_urllib and test_zipimport_support similar
to the ones you proposed. Thank you!

No leaks anymore!
http://mail.python.org/pipermail/python-checkins/2009-December/088162.html
Thanks flox!