Mailman 3 September 2008 - Python-Dev

Summary of Python tracker Issues
by Python tracker 19 Sep '08

19 Sep '08

ACTIVITY SUMMARY (09/12/08 - 09/19/08) Python tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue number. Do NOT respond to this message. 2035 open (+36) / 13696 closed (+24) / 15731 total (+60) Open issues with patches: 652 Average duration of open issues: 715 days. Median duration of open issues: 1793 days. Open Issues Breakdown open 2022 (+36) pending 13 ( +0) Issues Created Or Reopened (60) _______________________________ FUD in documentation for urllib.urlopen() 09/12/08 http://bugs.python.org/issue3849 created raz find_recursion_limit.py is broken 09/12/08 CLOSED http://bugs.python.org/issue3850 created pitrou patch, easy, needs review IDLE: Pressing "Home" on Windows places cursor before ">>>" inst 09/12/08 http://bugs.python.org/issue3851 created serwy patch kqueue.control requires 2 params while docs say max_events (the 09/12/08 http://bugs.python.org/issue3852 created ionel.mc Windows SQLite DLL should be built with multithreading enabled 09/12/08 CLOSED http://bugs.python.org/issue3853 created ghaering easy Document sqlite3 vs. threads 09/12/08 http://bugs.python.org/issue3854 created ghaering Windows installation did not work; tried on two machines 09/13/08 CLOSED http://bugs.python.org/issue3855 created MLModel IDLE fails on startup on Mac 10.5 for 2.6b3 and 3.0b3 09/13/08 CLOSED http://bugs.python.org/issue3856 created MLModel ImportError: No module named test.test_support 09/13/08 CLOSED http://bugs.python.org/issue3857 created wplappert make install tries to install files outside of --prefix 09/13/08 CLOSED http://bugs.python.org/issue3858 created jjlee test_sys.Sizeof fails on win64 09/13/08 CLOSED http://bugs.python.org/issue3859 created amaury.forgeotdarc patch GzipFile and BZ2File should support context manager protocol 09/13/08 http://bugs.python.org/issue3860 created hagen distutils CCompiler._compile doesn't require lang keyword argume 09/14/08 CLOSED http://bugs.python.org/issue3861 created ikelos test_array fails on FreeBSD7 amd64 09/14/08 http://bugs.python.org/issue3862 created robrien patch 2.6rc1: test_threading hangs on FreeBSD 6.3 i386 09/14/08 http://bugs.python.org/issue3863 created aimacintyre patch 26.rc1: test_signal issue on FreeBSD 6.3 09/14/08 http://bugs.python.org/issue3864 created aimacintyre explain that profilers should be used for profiling, not benchma 09/14/08 http://bugs.python.org/issue3865 created effbot int() doesn't 'guess' 09/14/08 CLOSED http://bugs.python.org/issue3866 created kjohnson What's New in 2.6 doesn't mention stricter object.__init__ 09/14/08 CLOSED http://bugs.python.org/issue3867 created spiv patch for review: OS/2 EMX port fixes for 2.6 09/14/08 http://bugs.python.org/issue3868 created aimacintyre patch, patch Arrow keys not working with Python 2.6rc1 09/14/08 CLOSED http://bugs.python.org/issue3869 created Chewie Parser/asdl_c.py requires python in order to build python 09/14/08 CLOSED http://bugs.python.org/issue3870 created gregory.p.smith cross building python for mingw32 with distutils 09/14/08 http://bugs.python.org/issue3871 created rpetrov Tix ComboBox error 09/15/08 http://bugs.python.org/issue3872 created dwahli Unpickling is really slow 09/15/08 http://bugs.python.org/issue3873 created hagen documentation bug: HTMLParser needs to document unknown_decl 09/15/08 http://bugs.python.org/issue3874 created freyley provide a "cmem" role 09/15/08 http://bugs.python.org/issue3875 created benjamin.peterson multiprocessing does not compile on *BSD and potentialy other sy 09/16/08 http://bugs.python.org/issue3876 created henry.precheur test_fileio fails on OpenBSD 4.4 09/16/08 http://bugs.python.org/issue3877 created henry.precheur patch urllib2 is not working with proxy for HTTPS 09/16/08 CLOSED http://bugs.python.org/issue3878 created anupam 2.6 regression in urllib.getproxies_environment 09/16/08 http://bugs.python.org/issue3879 created vila patch, needs review _tkinter._flatten() doesn't check PySequence_Size() error code 09/16/08 http://bugs.python.org/issue3880 created haypo patch IDLE won't start in custom directory. 09/16/08 http://bugs.python.org/issue3881 created kimsey0 Bottom buttons of IDLE Preferences Pane on Mac not wide enough f 09/16/08 CLOSED http://bugs.python.org/issue3882 created MLModel Bottom buttons of IDLE Preferences Pane on Mac not wide enough f 09/16/08 http://bugs.python.org/issue3883 created MLModel turtle in the tkinter package? 09/16/08 CLOSED http://bugs.python.org/issue3884 created kirill_simonov errors on _bsddb creation and dealloc 09/16/08 http://bugs.python.org/issue3885 created haypo patch, needs review Integer overflow in _hashopenssl.c (CVE-2008-2316) 09/18/08 http://bugs.python.org/issue3886 reopened benjamin.peterson patch, patch, 64bit Python 2.6 doesn't run after installation on amd64 09/17/08 CLOSED http://bugs.python.org/issue3887 created jpe [PATCH] Document more deprecated modules in What's New in Python 09/17/08 CLOSED http://bugs.python.org/issue3888 created pjenvey patch Demo/parser/unparse.py 09/17/08 http://bugs.python.org/issue3889 created gregdarke patch ssl.SSLSocket.recv() implementation may not work with non-blocki 09/17/08 http://bugs.python.org/issue3890 created giampaolo.rodola collections.deque should have empty() method 09/17/08 http://bugs.python.org/issue3891 created roysmith bsddb: test01_basic_replication fails on Windows sometimes 09/18/08 http://bugs.python.org/issue3892 created benjamin.peterson timedelta overflows in a surprising way 09/18/08 CLOSED http://bugs.python.org/issue3893 created jjinux imageop issue 09/18/08 http://bugs.python.org/issue3894 created brett.cannon _lsprof issue 09/18/08 http://bugs.python.org/issue3895 created brett.cannon idle should be installed as idle3.0 09/18/08 http://bugs.python.org/issue3896 created HWJ collections 09/18/08 http://bugs.python.org/issue3897 created kadelka 3.0 documentation fails to build 09/18/08 CLOSED http://bugs.python.org/issue3898 created loewis test_ssl.py doesn't properly test ssl integration with asyncore 09/18/08 http://bugs.python.org/issue3899 created giampaolo.rodola patch ctypes: wrong calling convention for _string_at 09/18/08 CLOSED http://bugs.python.org/issue3900 created haypo patch Slight readme.txt fix (VC9) 09/18/08 http://bugs.python.org/issue3901 created ocean-city patch distutils does not correctly create packages for compiled extens 09/18/08 http://bugs.python.org/issue3902 created Peaker pickle error in python3.0rc1 09/18/08 CLOSED http://bugs.python.org/issue3903 created Georg asynchat async_chat __init__() arguments changed in python 2.6 09/18/08 CLOSED http://bugs.python.org/issue3904 created forest subprocess failing in GUI applications on Windows 09/18/08 http://bugs.python.org/issue3905 created twhitema lib2to3\main.py will not run 09/19/08 CLOSED http://bugs.python.org/issue3906 created rupole "for line in file" doesn't work for pipes 09/19/08 CLOSED http://bugs.python.org/issue3907 created endolith Strange heapq behavior on Python 3.0 when overriding __le__ 09/19/08 http://bugs.python.org/issue3908 created giampaolo.rodola Issues Now Closed (51) ______________________ Add a factorial function 182 days http://bugs.python.org/issue2138 maix Nested module import clutters package namespace 202 days http://bugs.python.org/issue2210 brett.cannon Fixer for new metaclass syntax is needed 179 days http://bugs.python.org/issue2366 benjamin.peterson patch, 26backport Fixer for new integer literals are needed 180 days http://bugs.python.org/issue2369 benjamin.peterson 26backport Multiple buffer overflows in unicode processing 158 days http://bugs.python.org/issue2620 brett.cannon patch bsddb3 needs to be ported to Python 3.0 124 days http://bugs.python.org/issue2887 jcea 2to3 doesn't handle print(whatever); print nor string.* function 106 days http://bugs.python.org/issue3000 benjamin.peterson integer overflow in hashlib causes wrong results for cryptograph 108 days http://bugs.python.org/issue3026 loewis patch sqlite defines a few global symbols. 92 days http://bugs.python.org/issue3103 ghaering Documentation: timeit: "lower bound" should read "upper bound" 68 days http://bugs.python.org/issue3318 unutbu file read preallocs 'size' bytes which can cause memory problems 36 days http://bugs.python.org/issue3531 pitrou Add MS EULA to the list of third-party licenses in the Windows i 25 days http://bugs.python.org/issue3617 loewis patch test_cpickle crash on AMD64 Windows build 22 days http://bugs.python.org/issue3640 pitrou patch, 64bit latexwriter: \footnotemark can only take numbers as arguments 20 days http://bugs.python.org/issue3655 georg.brandl incompatible arguments in warning formatting for idle 17 days http://bugs.python.org/issue3698 gpolo os.urandom(1.1): infinite loop 22 days http://bugs.python.org/issue3708 rpetrov patch, easy socket.socket.recv broken (unbearably slow) 10 days http://bugs.python.org/issue3766 pitrou os.write accepts unicode strings 11 days http://bugs.python.org/issue3782 pitrou patch python-2.6b3.msi and python-2.6b3.amd64.msi can't both be instal 2 days http://bugs.python.org/issue3833 jretz can't run close through itertools.chain on inner generator 1 days http://bugs.python.org/issue3842 rhettinger hexadecimal, not decimal 2 days http://bugs.python.org/issue3843 benjamin.peterson sqlite3 module: Improved concurrency 0 days http://bugs.python.org/issue3846 ghaering needs review Begging for review 0 days http://bugs.python.org/issue3847 loewis find_recursion_limit.py is broken 1 days http://bugs.python.org/issue3850 pitrou patch, easy, needs review Windows SQLite DLL should be built with multithreading enabled 6 days http://bugs.python.org/issue3853 loewis easy Windows installation did not work; tried on two machines 0 days http://bugs.python.org/issue3855 loewis IDLE fails on startup on Mac 10.5 for 2.6b3 and 3.0b3 2 days http://bugs.python.org/issue3856 gpolo ImportError: No module named test.test_support 0 days http://bugs.python.org/issue3857 benjamin.peterson make install tries to install files outside of --prefix 1 days http://bugs.python.org/issue3858 pitrou test_sys.Sizeof fails on win64 3 days http://bugs.python.org/issue3859 schuppenies patch distutils CCompiler._compile doesn't require lang keyword argume 0 days http://bugs.python.org/issue3861 ikelos int() doesn't 'guess' 0 days http://bugs.python.org/issue3866 benjamin.peterson What's New in 2.6 doesn't mention stricter object.__init__ 1 days http://bugs.python.org/issue3867 benjamin.peterson Arrow keys not working with Python 2.6rc1 0 days http://bugs.python.org/issue3869 benjamin.peterson Parser/asdl_c.py requires python in order to build python 3 days http://bugs.python.org/issue3870 theller urllib2 is not working with proxy for HTTPS 0 days http://bugs.python.org/issue3878 amaury.forgeotdarc Bottom buttons of IDLE Preferences Pane on Mac not wide enough f 0 days http://bugs.python.org/issue3882 benjamin.peterson turtle in the tkinter package? 0 days http://bugs.python.org/issue3884 brett.cannon Python 2.6 doesn't run after installation on amd64 3 days http://bugs.python.org/issue3887 loewis [PATCH] Document more deprecated modules in What's New in Python 0 days http://bugs.python.org/issue3888 georg.brandl patch timedelta overflows in a surprising way 1 days http://bugs.python.org/issue3893 benjamin.peterson 3.0 documentation fails to build 0 days http://bugs.python.org/issue3898 georg.brandl ctypes: wrong calling convention for _string_at 0 days http://bugs.python.org/issue3900 haypo patch pickle error in python3.0rc1 0 days http://bugs.python.org/issue3903 benjamin.peterson asynchat async_chat __init__() arguments changed in python 2.6 0 days http://bugs.python.org/issue3904 josiahcarlson lib2to3\main.py will not run 0 days http://bugs.python.org/issue3906 benjamin.peterson "for line in file" doesn't work for pipes 0 days http://bugs.python.org/issue3907 amaury.forgeotdarc -S hides standard dynamic modules 2247 days http://bugs.python.org/issue586680 brett.cannon classic division in demos/ directory 2035 days http://bugs.python.org/issue687648 akuchling patch, easy digit-only tag values are mishandled in Tkinter 1286 days http://bugs.python.org/issue1160383 gpolo tkapp read-only attributes 1130 days http://bugs.python.org/issue1257772 gpolo Top Issues Most Discussed (10) ______________________________ 11 errors on _bsddb creation and dealloc 3 days open http://bugs.python.org/issue3885 11 Major reworking of Python 2.5.2 re module 10 days open http://bugs.python.org/issue3825 9 2.6rc1: test_threading hangs on FreeBSD 6.3 i386 5 days open http://bugs.python.org/issue3863 9 test_array fails on FreeBSD7 amd64 6 days open http://bugs.python.org/issue3862 8 bsddb: test01_basic_replication fails on Windows sometimes 2 days open http://bugs.python.org/issue3892 8 Integer overflow in _hashopenssl.c (CVE-2008-2316) 2 days open http://bugs.python.org/issue3886 8 tkinter goes into an infinite loop (pydoc.gui) 8 days open http://bugs.python.org/issue3835 7 Add MS EULA to the list of third-party licenses in the Windows 25 days closed http://bugs.python.org/issue3617 6 find_recursion_limit.py is broken 1 days closed http://bugs.python.org/issue3850 6 sqlite3 module: Improved concurrency 0 days closed http://bugs.python.org/issue3846

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What's New in 2.6 link wasn't what I expected
by skip＠pobox.com 19 Sep '08

19 Sep '08

>From this page: http://www.python.org/download/releases/2.6/ I clicked the link labelled "What's new in Python 2.6rc2". This didn't take me to the What's New page. Instead it took me to: http://www.python.org/download/releases/2.6/NEWS.txt Seems a bit mislabelled if nothing else. Poking around I see that the 2.5 What's New document is at: http://docs.python.org/dev/whatsnew/whatsnew25.html but http://docs.python.org/dev/whatsnew/whatsnew26.html doesn't exist. Am I missing something? Skip

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ssl module, non-blocking sockets and asyncore integration
by Giampaolo Rodola' 18 Sep '08

18 Sep '08

Hi, I try to revamp a discussion I raised some time ago and which seems to be not solved yet. I'm interested in using the ssl module with asyncore but since there's no real documentation about how using ssl module with non-blocking sockets I've not been able to write something useful with it. I took a look at Test/test_ssl.py which seems to include a test consisting in an asyncore-based secure server but I noticed something strange: def __init__(self, conn, certfile): asyncore.dispatcher_with_send.__init__(self, conn) self.socket = ssl.wrap_socket(conn, server_side=True, certfile=certfile, do_handshake_on_connect=True) I'm not sure about the real meaning of the do_handshake_on_connect parameter but if it does what I think it should block the application as long as the handshake isn't finished, which is not acceptable in an asynchronous environment. Am I misunderstanding something? Does the ssl module can actually be used with non-blocking sockets? If so which is the proper/recommended way to do that? Thanks in advance --- Giampaolo http://code.google.com/p/pyftpdlib/

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FreeBSD 7 amd64 and large memory tests
by Andrew MacIntyre 18 Sep '08

18 Sep '08

I noticed issue 3862 (http://bugs.python.org/issue3862), which appears to be exposed only on FreeBSD 7.0 amd64 (perhaps 64 bit FreeBSD 7, but amd64 is the only 64bit hardware I can check). As far as I can make out from a couple of quick checks, this appears to be happening because the process is killed before the malloc() that exhausts the available swap space is allowed to report an out of memory condition. FreeBSD's default process virtual memory limit (ulimit -v) on both i386 and amd64 is "unlimited" for 6.3 and 7.0. Setting ulimit -v to a finite value on 7.0 amd64 seems to give rise to "normal" malloc() behaviour so that test_array passes. FreeBSD 7 uses a different malloc() implementation than FreeBSD 6 and earlier, and the new implementation uses mmap() in preference to sbrk(). So I suspect that behaviour was "normal" on FreeBSD 6 amd64 (can't test at the moment as I don't have that installed anywhere). Behaviour appears "normal" on FreeBSD 7 i386 as well. I haven't yet tried posting a query to a FreeBSD list, as it could simply be a bug on amd64, but I was wondering whether there was anything (other than deactivating tests and documenting use of ulimit -v on this platform) that could be done to work around this behaviour. Andrew. -- ------------------------------------------------------------------------- Andrew I MacIntyre "These thoughts are mine alone..." E-mail: andymac(a)bullseye.apana.org.au (pref) | Snail: PO Box 370 andymac(a)pcug.org.au (alt) | Belconnen ACT 2616 Web: http://www.andymac.org/ | Australia

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RELEASED Python 2.6rc2 and 3.0rc1
by Barry Warsaw 18 Sep '08

18 Sep '08

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On behalf of the Python development team and the Python community, I am happy to announce the second and final planned release candidate for Python 2.6, as well as the first release candidate for Python 3.0. These are release candidates, so while they are not suitable for production environments, we strongly encourage you to download and test them on your software. We expect only critical bugs to be fixed between now and the final releases. Currently Python 2.6 is scheduled for October 1st, 2008. Python 3.0 release candidate 2 is planned for October 1st, with the final release planned for October 15, 2008. If you find things broken or incorrect, please submit bug reports at http://bugs.python.org For more information and downloadable distributions, see the Python 2.6 website: http://www.python.org/download/releases/2.6/ and the Python 3.0 web site: http://www.python.org/download/releases/3.0/ See PEP 361 for release schedule details: http://www.python.org/dev/peps/pep-0361/ Enjoy, - -Barry Barry Warsaw barry(a)python.org Python 2.6/3.0 Release Manager (on behalf of the entire python-dev team) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iQCVAwUBSNHpw3EjvBPtnXfVAQLW9wP/RBCaUvhuheIh+BjLLIHQFBQi7D3uVgqi l0+4fhhoKGJvtWklLfSM9I1prcjH/d6tzUu4fIOjX7aM+wZSG++vkfmBoehnhyZW AvU9Lax4mqDwhOJA2QA0WMx0obpYYVHeUl7D1g9kWzbRUkZDX9NZGMWThhEOC1qA UA3bBYbvWiQ= =BFNH -----END PGP SIGNATURE-----

1 0

switching on -3 from within a program?
by Anthon van der Neut 17 Sep '08

17 Sep '08

With a minor modification to the Makefile I was able to get mod_wsgi v2.3 to work with python2.6rc1. I promptly got a warning in my apache log files on the depcrecated use of 'sha' in the paste's cookie module, good! And easily fixed. After that I was looking for a way to switch on the -3 warnings from within my code to have extra warnings show up in my apache log file. After reading some documentation I tried from the python2.6 prompt: import sys sys.py3kwarning = True x = { 'abc': 1 }; x.has_key('abc') which does not give a warning (starting python2.6 with the -3 option of course does). Is there anyway to switch this on from within a program with a Python statement? If not, would I need to make a small C-extension module (to be imported as the first module) that sets Py_Py3WarningFlag or something else at the C level, or would that better be done by mod_wsgi's C code. Regards Anthon

6 5

RELEASED Python 2.6rc1
by Barry Warsaw 17 Sep '08

17 Sep '08

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On behalf of the Python development team and the Python community, I am happy to announce the first release candidate for Python 2.6. This is a release candidate, so while it is not suitable for production environments, we strongly encourage you to download the release and test it on your software. We expect only critical bugs to be fixed between now and the final 2.6 release, still scheduled for October 1st, 2008. There is one more release candidate planned for September 17th. You might notice that unlike earlier releases, we are /not/ releasing Python 3.0rc1 at this time. It was decided that 3.0 still needs time to resolve open issues and that we would not hold up the 2.6 release for this. We feel that Python 2.6 is nearly ready for its final release. If you find things broken or incorrect, please submit bug reports at http://bugs.python.org For more information and downloadable distributions, see the Python 2.6 website: http://www.python.org/download/releases/2.6/ (Note that the Windows installers will be uploaded shortly.) See PEP 361 for release schedule details: http://www.python.org/dev/peps/pep-0361/ Enjoy, - -Barry Barry Warsaw barry(a)python.org Python 2.6/3.0 Release Manager (on behalf of the entire python-dev team) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iQCVAwUBSMsXV3EjvBPtnXfVAQJFsgP9GxZYQocbDTd0Z/0yEjpHfZ/FTd8y83jV 5JouO07lB8XtLawnWB9hF8sUrCuBVog5He3mLVUPDmlyn30qvjYWMG2J6zW0yYMX yZdjUyUmta0IMCsXe7YXj369xebh4nWuwG4tDygly4donA7GYPXAlxI48MmyDJxw 1v07LM4Dttw= =Nd3s -----END PGP SIGNATURE-----

3 3

Re: [Python-Dev] ',' precedence in documentation]
by Christopher Lee 16 Sep '08

16 Sep '08

> ----- Forwarded message from Guido van Rossum <guido(a)python.org> ----- > > Note that in any case, the 'in' operator binds more tightly than the > comma: e.g. f(x in y, z) means f((x in y), z). Exactly the point I was trying to make. As far as the user's concerned, an expression list x,y can itself be part of an expression; x in y is also an expression. Such expressions can be combined to form larger expressions, so it follows logically that you need to know which has precedence when *both* occur in an expression, e.g. whether x in y,z evaluates as (x in y),z or x in (y,z) The page that Fredrik sent you to (http://docs.python.org/ref/exprlists.html ) doesn't address that question. I still think the precedence table (http://docs.python.org/ref/summary.html ) should show that "in" has higher precedence than comma in an expression. Can anyone show us "where it is written" in the Python docs that "in" has higher precedence than comma, *and* why there is a good reason that this information should NOT be included in the precedence table? -- Chris Adding comma to the precedence table would also disambiguate expressions like: x and y,z x,y or z not x,y

8 18

Re: [Python-Dev] [Python-checkins] Python Regression Test Failures basics (1)
by Nick Coghlan 15 Sep '08

15 Sep '08

Neal Norwitz wrote: > test_epoll skipped -- kernel doesn't support epoll() ... > test_ioctl skipped -- Unable to open /dev/tty ... > test_multiprocessing skipped -- OSError raises on RLock creation, see issue 3111! ... > test test_normalization failed -- Traceback (most recent call last): > File "/tmp/python-test/local/lib/python2.6/test/test_normalization.py", line 90, in test_main > self.failUnless(X == NFC(X) == NFD(X) == NFKC(X) == NFKD(X), c) > AssertionError: 6918 ... > 326 tests OK. > 1 test failed: > test_normalization ... > 3 skips unexpected on linux2: > test_epoll test_multiprocessing test_ioctl Neal, What environment are you using to run the debug-mode regression tests? The above four tests run without any problems for me, but I'm just running them in a normal Kubuntu desktop shell. Cheers, Nick. P.S. I'm in the process of creating a --with-pydebug build to see if that makes any difference. -- Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia --------------------------------------------------------------- http://www.boredomandlaziness.org

3 4

Weak Dictionary Iteration Behavior in Python 3
by Armin Ronacher 15 Sep '08

15 Sep '08

Hi everybody, In Python 2.x when iterating over a weak key dictionary for example, the common idom for doing that was calling dictionary.keys() to ensure that a list of all objects is returned it was safe to iterate over as a weak reference could stop existing during dict iteration which of course raises a runtime error by the dict iterator. This was documented behavior and worked pretty well, with the small problem that suddenly all references in the dict wouldn't die until iteration is over because the list holds references to the object. This no longer works in Python 3 because .keys() on the weak key dictionary returns a generator over the key view of the internal dict which of course has the same problem as iterkeys in Python 2.x. The following code shows the problem:: from weakref import WeakKeyDictionary f1 = Foo() f2 = Foo() d = WeakKeyDictionary() d[f1] = 42 d[f2] = 23 i = iter(d.keys()) # or use d.keyrefs() here which has the same problem print(next(i)) del f2 print(next(i)) This example essentially dies with "RuntimeError: dictionary changed size during iteration" as soon as f2 is deleted. Iterating over weak key dictionaries might not be the most common task but I know some situations where this is necessary. Unfortunately I can't see a way to achieve that in Python 3. Regards, Armin

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