Mailman 3 October 2007 - Python-Dev

SSL 1.7
by Bill Janssen Oct. 12, 2007

Oct. 12, 2007

I've now got a large complex long-lived threaded server asyncore-based (Medusa) multi-client server program running on OS X with Python 2.3.5 and the "older-Python" SSL module. I had to make a number of changes to the code; primarily fixing the way that certain "socket" methods are called on the SSLSocket, and in the C code, allowing for changes to the socket blocking attribute that are made out-of-band from use of the SSL context. I'll fold that back into the trunk next week, and produce a patch for the 3K branch after that. Meanwhile, I've updated the PyPI package to SSL 1.7. Paul, this also fixes (I hope :-) the setup.py bug you mentioned in 1.6. Chris, you might want to try this one with Twisted; I believe it will work OK. One thing to watch out for: ssl.SSLError can't inherit from socket.error, as it does in 2.6+, so if you are catching exceptions, you need to trap them like: except ssl.SSLError, x: ... except socket.error, x: ... which idiom will continue to work for 2.6 and later. Bill

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Explicit Tail Calls
by Shane Hathaway Oct. 12, 2007

Oct. 12, 2007

Hello, I'm interested in seeing a good way to write tail calls in Python. Some algorithms are more readable when expressed using tail recursion. I know tail call optimization has been discussed before [1], but I would like to consider a different approach. The previous discussion centered on implicit tail call optimization, which incurs the risk of changing the behavior of currently working code. (For example, is it safe to optimize tail calls within try...finally blocks? Probably not. And I generally want all stack frames to appear in tracebacks, unless I say otherwise.) I would like to suggest an explicit form of tail calls. A new built-in exception type called "Return" will be added, and it will be used like this: def fact2(n, v): if n: raise Return(fact2, n-1, v*n) else: return v The interpreter will catch Return exceptions and use them to call something else. The caller of a function that uses "raise Return" will see the result of the tail call as the returned value, rather than the Return exception. I am not yet considering implementation details. Not all algorithms are good candidates for this. I used the fact2 example only because it's readily available. I know there are other people interested in tail call optimization in Python [2] [3]; perhaps some of them are watching and can provide better examples. Furthermore, there might be some explicit syntax that converts "return f(...)" statements to "raise Return(f, ...)", such as a decorator. However, I'm less interested in the syntax and more interested in the basic capability. Shane [1] http://mail.python.org/pipermail/python-dev/2004-July/046150.html [2] http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/474088 [3] http://www.voidspace.org.uk/python/weblog/arch_d7_2007_09_22.shtml#e833

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what license for a module derived from Objects/dictobjec.c
by Anthon van der Neut Oct. 12, 2007

Oct. 12, 2007

I would like to get some advice on which license to include/refer to in my setup.py (and probably the source files). This is for an extension module that is clearly (for the knowledgeable) derived from Python's Objects/dictobject.c and Include/dictobject.h. I first of all don't want to infringe any original license on that code. I second would like to make sure the license for code is not a problem to make it into Linux distributions like Ubuntu/Debian (assuming of course the code is acceptable and fills enough of a gap that these distros want to pick it up in the first place). And thirdly, I although I would like my name to be associated on further derivations of this module, that is not a strict requirement. Should I refer to MIT, LGPL or BSD. Any particular copy of a license I should put up on my website and refer to with a URL? Any examples or references with a brief explanation would be much appreciated. I know I could look at what other modules use, but at this point I rather spent time on finishing implementing the "insert" method (and some tests) and getting my first release out (and hopefullysome feedback), than comparing other modules for the license they chose and try to deduct what I should use/specify for a license. Thanks in advance Anthon For the curious: the module is called ordereddict. It is an implemenation in C of a dictionary with ordered keys based on Key Insertion Order. Value updating of existing Key/Value pairs does not reorder the keys, although I probably implement that as an (instantiation) option after the initial version. orderdict() does all that dict() does, except for instantiation it will only take another ordereddict() (not a dict) or an ordered list of pairs. Some extras (reverse(), index()) are already implemented and work like Larosa/Foord's odict.OrderedDict() (theirs is also the example I took for the representation of the ordereddict). ordereddict() is 5-10% slower than dict() (especially key deletion is 'expensive') and it is 5-9 times faster than odict.OrderedDict() I have done all of the development under Linux but will be proably be able to test things under Windows and may, at some point even dig up my old G4 to see how things go on OS X. I am fairly confident that the C code is still portable, or close to it.

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Summary of Tracker Issues
by Tracker Oct. 12, 2007

Oct. 12, 2007

ACTIVITY SUMMARY (10/05/07 - 10/12/07) 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. 1298 open (+26) / 11458 closed ( +7) / 12756 total (+33) Open issues with patches: 420 Average duration of open issues: 681 days. Median duration of open issues: 727 days. Open Issues Breakdown open 1293 (+26) pending 5 ( +0) Issues Created Or Reopened (34) _______________________________ split(None, maxsplit) does not strip whitespace correctly 10/07/07 CLOSED http://bugs.python.org/issue1123 reopened brett.cannon subprocess.py stdout of childprocess always buffered. 10/05/07 CLOSED http://bugs.python.org/issue1241 created jason.w.kim test 10/06/07 CLOSED http://bugs.python.org/issue1242 created gopiyadav26 option.dest not set when callback called with optparse 10/06/07 http://bugs.python.org/issue1243 created cjw296 Error on 'raise' does not show correct line number and Traceback 10/08/07 CLOSED http://bugs.python.org/issue1244 created alexander.shirokov Document PySys_* API functions 10/08/07 http://bugs.python.org/issue1245 created brett.cannon Document PySys_GetObject() 10/08/07 CLOSED http://bugs.python.org/issue1246 created brett.cannon PEP 3137 patch (repr, names, parser) 10/08/07 http://bugs.python.org/issue1247 created tiran patch ftplib needs a rewrite to use bytes/buffers 10/08/07 http://bugs.python.org/issue1248 created brett.cannon py3k PEP 3137 patch: PyBytes/PyUnicode comparisons 10/09/07 CLOSED http://bugs.python.org/issue1249 created thomas.lee Building external modules using Sun Studio 12 10/09/07 http://bugs.python.org/issue1250 created anilj ssl module doesn't support non-blocking handshakes 10/09/07 http://bugs.python.org/issue1251 created chris.stawarz IDLE - patch Delegator to support callables 10/10/07 http://bugs.python.org/issue1252 created taleinat patch IDLE - Percolator overhaul 10/10/07 http://bugs.python.org/issue1253 created taleinat patch pdb fails to launch some script. 10/10/07 http://bugs.python.org/issue1254 created romain_jacquet Strange Python hangup 10/10/07 http://bugs.python.org/issue1255 created kakacek subprocess Popen wait() function hangs when stdout is > 20480 10/10/07 http://bugs.python.org/issue1256 created superwesman atexit errors should result in nonzero exit code 10/10/07 http://bugs.python.org/issue1257 created aminusfu Removal of basestring type 10/10/07 http://bugs.python.org/issue1258 created tiran patch string find and rfind methods give a TypeError that is misleadin 10/10/07 http://bugs.python.org/issue1259 created rbcollins PEP 3137: Remove the buffer API from PyUnicode 10/11/07 http://bugs.python.org/issue1260 created alexandre.vassalotti patch PEP 3137: make bytesobject.c methods 10/11/07 http://bugs.python.org/issue1261 created gregory.p.smith py3k, patch IDLE does not start if windows environment variable containing ' 10/11/07 http://bugs.python.org/issue1262 created reto PEP 3137 patch - str8/str comparison should return false 10/11/07 http://bugs.python.org/issue1263 created thomas.lee patch __file__ and co_filename as unicode 10/11/07 http://bugs.python.org/issue1264 created tiran patch pdb bug with "with" statement 10/11/07 http://bugs.python.org/issue1265 created tiran segfault in curses when calling redrawwin() before refresh() 10/11/07 http://bugs.python.org/issue1266 created Thorben Py3K cannot run as ``python -S`` 10/11/07 http://bugs.python.org/issue1267 created brett.cannon py3k array unittest problems with UCS4 build 10/12/07 http://bugs.python.org/issue1268 created tiran patch Exception in pstats print_callers() 10/12/07 http://bugs.python.org/issue1269 created stromnov MemoryError when working on large dictionaries on Windows 2003 S 10/12/07 CLOSED http://bugs.python.org/issue1270 created amdescombes Raw string parsing fails with backslash as last character 10/12/07 CLOSED http://bugs.python.org/issue1271 created QuantumTim Decode __file__ and co_filename to unicode using fs default 10/12/07 http://bugs.python.org/issue1272 created tiran patch email module example email-unpack.py error 10/12/07 http://bugs.python.org/issue1273 created esv Issues Now Closed (28) ______________________ split(None, maxsplit) does not strip whitespace correctly 0 days http://bugs.python.org/issue1123 georg.brandl Idle - Save (buffer) - closes IDLE and does not save file (Windo 32 days http://bugs.python.org/issue1130 taleinat py3k Documentation for tp_as_number... version 2.6 14 days http://bugs.python.org/issue1199 georg.brandl patch ctypes doesn't work on Mac with --disable-toolbox-glue 16 days http://bugs.python.org/issue1203 theller Python2.5.1 fails to compile under VC.NET2002 ( 7.0 ) 15 days http://bugs.python.org/issue1216 loewis IDLE - Fix: pressing Ctrl+C while printing exception -> stuck 8 days http://bugs.python.org/issue1225 kbk lib/sched.py superfluous code for removal 6 days http://bugs.python.org/issue1226 georg.brandl 3.0 tutorial/datastructures.rst patch 6 days http://bugs.python.org/issue1228 georg.brandl patch 3.0 library/stdtypes.rst 6 days http://bugs.python.org/issue1229 brett.cannon py3k subprocess is not thread-safe 1 days http://bugs.python.org/issue1236 gvanrossum type_new doesn't allocate space for sentinal slot 1 days http://bugs.python.org/issue1237 gvanrossum dictobject and dictentry not used consistently in dictobject.c 5 days http://bugs.python.org/issue1238 brett.cannon patch str.split bug when using sep = None and maxsplit 2 days http://bugs.python.org/issue1240 brett.cannon subprocess.py stdout of childprocess always buffered. 1 days http://bugs.python.org/issue1241 gvanrossum test 0 days http://bugs.python.org/issue1242 georg.brandl Error on 'raise' does not show correct line number and Traceback 0 days http://bugs.python.org/issue1244 alexander.shirokov Document PySys_GetObject() 0 days http://bugs.python.org/issue1246 brett.cannon PEP 3137 patch: PyBytes/PyUnicode comparisons 0 days http://bugs.python.org/issue1249 gvanrossum MemoryError when working on large dictionaries on Windows 2003 S 0 days http://bugs.python.org/issue1270 amdescombes Raw string parsing fails with backslash as last character 0 days http://bugs.python.org/issue1271 georg.brandl Recursion limit too high for MacOSX 1576 days http://bugs.python.org/issue756576 brett.cannon Use correct encoding for printing SyntaxErrors 1116 days http://bugs.python.org/issue1031213 gvanrossum patch tools and demo missing from windows 420 days http://bugs.python.org/issue1541420 loewis Minor pasting patch 238 days http://bugs.python.org/issue1659326 kbk patch Ctrl+Shift block marking by words 161 days http://bugs.python.org/issue1710718 kbk patch character set in Japanese on Ubuntu distribution 158 days http://bugs.python.org/issue1713252 kbk patch IDLE - cursor color configuration bug 137 days http://bugs.python.org/issue1725576 kbk patch Display CallTips for classes using metaclasses. 54 days http://bugs.python.org/issue1775388 kbk Top Issues Most Discussed (10) ______________________________ 9 MemoryError when working on large dictionaries on Windows 2003 0 days closed http://bugs.python.org/issue1270 9 ssl module doesn't support non-blocking handshakes 3 days open http://bugs.python.org/issue1251 7 Use correct encoding for printing SyntaxErrors 1116 days closed http://bugs.python.org/issue1031213 6 Removal of basestring type 2 days open http://bugs.python.org/issue1258 5 option.dest not set when callback called with optparse 6 days open http://bugs.python.org/issue1243 4 PEP 3137 patch (repr, names, parser) 4 days open http://bugs.python.org/issue1247 4 dictobject and dictentry not used consistently in dictobject.c 5 days closed http://bugs.python.org/issue1238 3 implement warnings module in C 276 days open http://bugs.python.org/issue1631171 3 Raw string parsing fails with backslash as last character 0 days closed http://bugs.python.org/issue1271 3 PEP 3137: make bytesobject.c methods 1 days open http://bugs.python.org/issue1261

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sched module - still useful?
by skip＠pobox.com Oct. 8, 2007

Oct. 8, 2007

I apologize in advance for the somewhat provocative subject. Is the sched module still appropriate in an increasingly event-driven world? If so, can someone suggest how it might be used with a non-blocking delay function such as gobject.timeout_add? It would be nice to either remark in the documentation that the sched module doesn't play nice with event-driven architectures or provide an example of how it can. It doesn't seem to be possible without resorting to threads (not generally a big problem, but not always the best choice either, depending on the environment in which you find yourself). The delayfunc is called and when it finishes, the action function is called. Thx, Skip

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Re: [Python-Dev] possible string formatting bug
by Eli Courtwright Oct. 8, 2007

Oct. 8, 2007

Thanks for the quick responses. Embarrassingly, this problem turned out to be a typo on my part. I visually double-and-triple-checked my code before posting to this list, but I still didn't notice the typo. Sorry to send everyone on a wild goose chase. - Eli

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possible string formatting bug
by Eli Courtwright Oct. 8, 2007

Oct. 8, 2007

Greetings, I've found what might be a bug in Python's % string formatting operator. Consider the following code: "%%(%s)=%%s" % "hello" On "Python 2.5.1 (r251:54863, May 18 2007, 16:56:43) [GCC 3.4.4 (cygming special, gdc 0.12, using dmd 0.125)] on cygwin" this produces the string "%(hello)s=%s" which is what I'd expect. On "Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)] on win32" this produces the following exception: Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: not enough arguments for format string Note that this is the exact same revision running on the same machine, but it doesn't work for the win32 version and does work for the cygwin version. I wish I had time to track down the source of the problem and submit a patch. But unfortunately I need to get back to work, and I won't even have the free time after work to tackle this. So I figured I'd kick it off to the Python Dev list in case anyone deems this important enough to be worth their time. By the way, Python is my favorite language and I use it whenever possible and have even gotten some co-workers to start using it. Thanks for the great language! - Eli

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anon svn down?
by Thomas Heller Oct. 8, 2007

Oct. 8, 2007

It looks like anonymous SVN is down: http://svn.python.org/projects/python/ Thomas

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GC Changes
by Justin Tulloss Oct. 7, 2007

Oct. 7, 2007

Hello, I've been doing some tests on removing the GIL, and it's becoming clear that some basic changes to the garbage collector may be needed in order for this to happen efficiently. Reference counting as it stands today is not very scalable. I've been looking into a few options, and I'm leaning towards the implementing IBMs recycler GC (http://www.research.ibm.com/people/d/dfb/recycler-publications.html ) since it is very similar to what is in place now from the users' perspective. However, I haven't been around the list long enough to really understand the feeling in the community on GC in the future of the interpreter. It seems that a full GC might have a lot of benefits in terms of performance and scalability, and I think that the current gc module is of the mark-and-sweep variety. Is the trend going to be to move away from reference counting and towards the mark-and-sweep implementation that currently exists, or is reference counting a firmly ingrained tradition? On a more immediately relevant note, I'm not certain I understand the full extent of the gc module. From what I've read, it sounds like it's fairly close to a fully functional GC, yet it seems to exist only as a cycle-detecting backup to the reference counting mechanism. Would somebody care to give me a brief overview on how the current gc module interacts with the interpreter, or point me to a place where that is done? Why isn't the mark-and-sweep mechanism used for all memory management? Thanks a lot! Justin

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Re: [Python-Dev] Where's the Starship's crew?
by Christian Tismer Oct. 6, 2007

Oct. 6, 2007

exhuma.twn wrote: > On Oct 5, 10:31 am, Dick Moores <r...(a)rcblue.com> wrote: >> <http://starship.python.net/crew/index.html> >> >> I didn't check on all of them, but the only one I found was Mark >> Hammond <http://starship.python.net/crew/mhammond/>. >> >> Dick Moores > > Doing 6 random clicks, revealed: > > http://starship.python.net/crew/hooft/ > > all the others are dead links. I realised this fact as well some time > ago already. I thought the page itself was still "in development" and > did not find a single one page. These two obviously eluded me ;) There are actually 20 active links, different from the error default. Ok, this is not the best result for a total of 273 members. > Strange to see that the situation did not yet improve. But then again, > we all probably know how much of a hassle it is to keep 10 different > web-pages with personal info's up-to-date. I suppose that the starship > crew all have som homes elsewhere and don't find the time to update > yet another page. No, I think the Starship lost a lot of its popularity after a couple of havaries, and its initiator failed to lead it and to push it further. I think this is something that needs to be done by somebody. There was a couple of very helpful supporters, but they were all on their own, and the originally driving person did not care any longer for many years. This has changed. > I myself don't even bother anymore at all. I have > about 2 hours of free time per day (given that I like to sleep a > lot!). What makes things worse, the network at work is completely cut > off from the rest of the world for security reasons. I am happy that I > at least can access usenet by using google-groups *sigh*. So you have HTTP access? Then ask the starship to support that! I will take care! > An interesting task might be to find the homes of the starship crew, > and post them here? Maybe? If lucky, the right person picks this up > and updates the crew-quarter labels of the starship. Or would > "Turbolift Buttons" be a better analogy for hyperlinks? Args. > Supposing, that these turbolifts *do* have buttons. How retro! ;) The Starship has gone through quite some problems and different hands. They all were good, and I wish to thank Stefan Drees especially for hosting it alone for four years from his personal budget. Not to forget the years where we were hosted by zope.org, and beopen.com, and some Service created by Mike Mc. Lay before. Please excuse me, the I don't remember all the details, this will go into a history page or blog ASAP. After a long journey through space and time, I am getting back at my roots, and I want to fill the gap of a driving person, again. This is not selfish in any way, and not saying that it must be me at all, but somehow I feel the wish to bring something to a working future that I started long time ago. I invented, created and hosted the Starship, ten years ago. Now I think, after spending a lot of time with other projects like Stackless Python and PyPy, time has come to redo the Starship idea, which was my first contribution for the Python community, a time where I was not able to really contribute by code. Especially, I could not work on the Python core because I was no C programmer. So I created Starship, learned C, understood all the internals and invented Stackless. But after all, I think I owe the Starship a lot, and I want it to continue, and to become a valued resource, again. As a starter, I moved the ship to my stackless server, this time using OpenVZ. This transfer worked much smoother than expected; I consider OpenVZ a great piece of software. The Starship is therefore right now not very different from its outside view, it was just moved and upgraded. That is just the beginning. To turn it into a resource of desire, again, a row of improvements are necessary. My personal vision, amoung new projects, is to split my time between Starship, Stackless and PyPy. If that works depends on the goodwill of sponsors. But it has worked, so I believe it will work, again. -- Here is an incomplete list of things that I want to do or initiate. First, I want to revive as many as crew homes that are archived. This will fill the tiny list from above, reasonably, and probably it will result in people updating their outdated pages. Then, I want to split the Starship into many sub-sites, first on my server, then by using a lot of more servers. I am seeking for sponsors who are willing to support this. In the end, my vision is turning python.net into a real network of many servers, each running a very small number of services through openVZ. Python.net should be something like a server farm, which runs everything available in Python. Really everything, including the myriads of possible PyPy builds. I want to separate all of these things by utilizing OpenVZ, as fine-grained as makes sense. I am investigating this these days. Right now, the Starship is a single VE. It will turn into a growing set of smaller VE's in the next weeks. And as soon as we get sponsorship, python.net will split itself over multiple machines. After all, my vision is to create the ultimate Python showdown, running everything possible in isolated environments and allowing people to play with different configurations. python.net should become the ultimate python resource site for interactive playing and trying, and providing a home for people to show their development. I will also try to get the PSF interested in that; maybe there is also some PSF funding possible. But this is an option, I will continue Starship without support as well. I believe I can do that, with your help. feeling stronger than before that stroke attack -- sincerely - chris -- This is much more work than I can do alone. Therefore, I am asking for people to help me with this. I also don't want to miss any of the current supporters, and we will name them all on the revised contributors pages to come. In order to support really many Python projects, we will need not only sponsors, but probably the support of the individual project maintainers as well. I am open to make this my goal of life, if there are enough people interested. But they will, I know it. I do believe in Python, Starship, PyPy and Stackless. Please help me to make this life-dream into reality. happily being back to the roots -- chris -- Christian Tismer :^) <mailto:tismer@stackless.com> tismerysoft GmbH : Have a break! Take a ride on Python's Johannes-Niemeyer-Weg 9A : *Starship* http://starship.python.net/ 14109 Berlin : PGP key -> http://wwwkeys.pgp.net/ work +49 30 802 86 56 mobile +49 173 24 18 776 fax +49 30 80 90 57 05 PGP 0x57F3BF04 9064 F4E1 D754 C2FF 1619 305B C09C 5A3B 57F3 BF04 whom do you want to sponsor today? http://www.stackless.com/

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