Mailman 3 December 2006 - Python-Dev

2.5.1 plans
by Neal Norwitz 04 Jan '07

04 Jan '07

I don't have a schedule in mind for 2.5.1 yet, however we should start preparing for it. The release will probably happen sometime in January if everyone is available. The branch has been pretty quiet, so I'm not expecting too many problems. Once we figure out a date for release I'll follow up here. If you have any bugs or patches that should be addressed prior to release, please assign them to me and bump the priority to 9. I'm not sure that there are any bugs which absolutely must be fixed before release, though there are a few that would be nice. Any other discussion for 2.5.1 necessary? n

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Non-blocking (asynchronous) timer without thread?
by Evgeniy Khramtsov 30 Dec '06

30 Dec '06

The question to python core developers: Is there any plans to implement non-blocking timer like a threading.Timer() but without thread? Some interpreted languages (like Tcl or Erlang) have such functionality, so I think it would be a great feature in Python :) The main goal is to prevent threads overhead and problems with race conditions and deadlocks. Thanks in advance!

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Possible platforms to drop in 2.6
by Brett Cannon 30 Dec '06

30 Dec '06

I originally posted this list to python-3000 since I figured we could be more aggressive with Py3K, but Guido said I should move it over here and just be aggressive in 2.6. So, here are the platforms I figured we should drop: * AtheOS * BeOS * FreeBSD 2 (maybe more?) * IRIX * NeXT * OS/2 * UnixWare I had SunoS 5 but Ronald Oussoren said that is actually Solaris through version 9, so I took that off. Several people have questioned AtheOS, but considering the site for the OS has not been updated since 2002 and it was a niche OS to begin with I doubt we really need the support. There is a fork of AtheOS called Syllable (http://www.syllable.org/) that is still being developed, but someone from that group should probably step forward and offer to help maintain the code if we are to keep it. Same goes with BeOS and Zeta (http://www.zeta-os.com/cms/news.php; there is a drop-down in the right-hand nav column to change the language to English for us non-German speakers). And I listed FreeBSD 2 as a drop since FreeBSD 3 seemed to have been released in 1999. But if most users have upgraded by now (release 6 is the most current) then we could consider dropping 3 as well. -Brett

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Weekly Python Patch/Bug Summary
by Kurt B. Kaiser 29 Dec '06

29 Dec '06

Patch / Bug Summary ___________________ Patches : 413 open ( -7) / 3521 closed (+11) / 3934 total ( +4) Bugs : 946 open ( +2) / 6400 closed ( +9) / 7346 total (+11) RFE : 248 open ( -1) / 246 closed ( +1) / 494 total ( +0) New / Reopened Patches ______________________ Auto-completion list placement (2006-12-23) http://python.org/sf/1621265 opened by Tal Einat normalize namespace from minidom (2006-12-23) http://python.org/sf/1621421 opened by Paul Pacheco Allow __class __ assignment for classes with __slots__ (2006-12-28) http://python.org/sf/1623563 opened by TH fast subclasses of builtin types (2006-12-28) http://python.org/sf/1624059 opened by Neal Norwitz Patches Closed ______________ add direct access to MD5 compression function to md5 module (2003-03-16) http://python.org/sf/704676 closed by akuchling pty.fork() compatibility code wrong? (2003-08-04) http://python.org/sf/783050 closed by akuchling for i in range(N) optimization (2003-05-15) http://python.org/sf/738094 closed by gvanrossum Add --remove-source option to setup.py (2003-08-22) http://python.org/sf/793070 closed by akuchling SimpleHTTPServer directory-indexing "bug" fix (2003-10-21) http://python.org/sf/827559 closed by akuchling Remove unncessary NLST from ftp transfers (2004-10-12) http://python.org/sf/1045783 closed by akuchling add Bunch type to collections module (2005-01-02) http://python.org/sf/1094542 closed by akuchling HMAC hexdigest and general review (2005-04-13) http://python.org/sf/1182394 closed by akuchling tarfile.py: ExFileObject\'s tell() is wrong after readline() (2005-06-30) http://python.org/sf/1230446 closed by gustaebel tarfile: fix for bug #1257255 (2005-08-17) http://python.org/sf/1262036 closed by gustaebel Patch for 1496501 tarfile opener order (2006-06-10) http://python.org/sf/1504073 closed by gustaebel New / Reopened Bugs ___________________ minor inconsistency in socket.close (2006-12-22) http://python.org/sf/1620945 opened by Jonathan Ellis IDLE crashes on OS X 10.4 when "Preferences" selected (2006-12-23) http://python.org/sf/1621111 opened by Mick L random import works? (2006-12-23) CLOSED http://python.org/sf/1621367 opened by Msword this module (Zen of Python) docs list broken URL (2006-12-24) http://python.org/sf/1621660 opened by Calvin Spealman Tcl/Tk auto-expanding window (2006-12-25) http://python.org/sf/1622010 opened by Fabian_M null bytes in docstrings (2006-12-26) http://python.org/sf/1622533 opened by Fredrik Lundh language reference index links are broken (2006-12-26) http://python.org/sf/1622664 opened by Drew Perttula Exception when compressing certain data with bz2 (2006-12-27) http://python.org/sf/1622896 opened by Alex Gontmakher preferred diff format should be mentioned as "unified". (2006-12-27) http://python.org/sf/1623153 opened by Raghuram Devarakonda module docstring for subprocess is wrong (2006-12-28) CLOSED http://python.org/sf/1623890 opened by Neal Norwitz updating a set in a list of sets will update all of them (2006-12-29) CLOSED http://python.org/sf/1624534 opened by Amir Reza Khosroshahi webbrowser.open_new() suggestion (2006-12-30) http://python.org/sf/1624674 opened by Imre Péntek Bugs Closed ___________ gethostbyaddr lag (2002-07-19) http://python.org/sf/583975 closed by nnorwitz CGIHTTPServer does not handle scripts in sub-dirs (2003-05-13) http://python.org/sf/737202 closed by akuchling MacOS9: test_uu fails (2003-07-23) http://python.org/sf/776202 closed by akuchling Mode argument of dumbdbm does not work (2003-09-07) http://python.org/sf/802128 closed by akuchling random import works? (2006-12-23) http://python.org/sf/1621367 closed by rhettinger tarfile local name is local, should be abspath (2005-08-12) http://python.org/sf/1257255 closed by gustaebel Dictionary ordering docs are too unclear of dangers (2006-12-09) http://python.org/sf/1612113 closed by sf-robot logging %(module)s reporting wrong modules (2006-11-29) http://python.org/sf/1605110 closed by sf-robot array.array borks on deepcopy (2006-08-24) http://python.org/sf/1545837 closed by twouters tarfile.py: dict order dependency (2006-05-28) http://python.org/sf/1496501 closed by gustaebel module docstring for subprocess is wrong (2006-12-28) http://python.org/sf/1623890 closed by nnorwitz updating a set in a list of sets will update all of them (2006-12-29) http://python.org/sf/1624534 deleted by amir_reza Immediate Crash on Open (2006-11-20) http://python.org/sf/1599931 closed by sf-robot python-logging compatability with Zope. (2006-12-12) http://python.org/sf/1614460 closed by sf-robot RFE Closed __________ Promote list comprehensions to Language Integrated Query? (2006-12-19) http://python.org/sf/1618676 closed by jettlogic

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multiple interpreters and extension modules
by Jeremy Kloth 29 Dec '06

29 Dec '06

[[ This may be somewhat c.l.p.-ish but I feel that this crossed into CPython development enough to merit posting here ]] I have received a bug report for 4Suite that involves a PyObject_IsInstance check failing for what appears to be the correct class, that is, the class names match. With some investigating, I have found that the true problem is with multiple interpreters. The reason for this is that each sub-interpreter has a "new" copy of any pure Python module. The following issues are also true for modules that have been reloaded, but I think that is common knowledge. I mention it only for completeness. Here is where it crosses into CPython development. Now extension modules do not get reloaded into each sub-interpreter, but a copy of the module's dict from when it was first loaded. This particular extension, when initialized, loads the class in question from the pure Python module and stores in in a global variable for quick access. I know I can change this specific case to reload the class each time and for this exact case, it is most likely what I'll do. However, we have other extensions that make use of this same technique and their performance would suffer greatly by doing the lookup for each use of the class. Also performance isn't the only issue here as we also have C types that inherit from a Python class and those types will obviously fail an isinstance() check in Python code run in different interpreters as the base class is "frozen" at the first import. So I guess the questions are: 1) is subclassing Python classes in C as a static type supported? Even if they would be declared on the heap, they would be bound to the first loaded Python class. 2) would it be worthwhile to have an extension loading function similar to DllMain() for Windows' DLLs which is called multiple times with a flag stating the reason for the call? For reference, see: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/ba… I envision the reasons as: 'module init', 'module fini', 'interpreter init', 'interpreter fini'. I see no current need for special treatment of threads as they share the same interpreter space. As to question 2, I'm in the process of prototyping that approach to see if it is feasible in our code and if so, (and people find it useful) I'll attempt to write a PEP for that feature. My current thoughts on that are instead of the current init<module name> entry point in C modules, a new entry point is defined, and if found, used in its place. That way, this proposal would be optional for extension writers and existing modules would continue to work without change. Feedback appreciated. -- Jeremy Kloth http://4suite.org/

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Re: [Python-Dev] [Python-checkins] r53110 - python/trunk/Lib/mailbox.py
by A.M. Kuchling 29 Dec '06

29 Dec '06

On Thu, Dec 21, 2006 at 02:14:55AM -0500, Fred L. Drake, Jr. wrote: > I (only vaguely) recall Guido telling people that that's how it's documented, > and that's what they should use. Don't know if he still feels that way; if > he's recanted the obscure path, we can fix both the calls and the > documentation. I'd lend a hand! The constants were added in 2.5. I've gone ahead and made the documentation change to trunk and 25-maint, because why were the constants added if they weren't intended to be used? While looking at the code, I noticed a minor potential bug. Python defines SEEK_SET and friends to be 0,1,2 and then os.lseek() maps them to SEEK_SET, SEEK_CUR, SEEK_END. file.seek() does *not* do this; it just passes the 0,1,2 through to the stdio fseek(), and therefore would be broken if there's some weird platform where 0,1,2 aren't the correct values. This doesn't seem worth fixing, given that no one has ever run into it, and might be an argument for removing the conversion from os.lseek(); clearly it isn't needed. --amk

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classes and cell variables question
by tomer filiba 29 Dec '06

29 Dec '06

to my understanding of the object model, the code of snippet 1 and snippet 2 should be equivalent. a class is just a "special function" that returns its locals automatically and passes them to the metaclass constructor: --- snippet 1 --- class foo(object): x = 5 def f(self): print "f", x --- snippet 2 --- def bar(): x = 5 def g(self): print "g", x return locals() barcls = type("barcls", (object,), bar()) but there's one big difference. classes don't create cell variables to hold bound external variables. the "bar" version works, because "x" is a bound cell variable, but the "foo" version fails, as it attempts to access "x" as a global. .>>> barcls().g() g 5 .>>> foo().f() f Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 4, in f NameError: global name 'x' is not defined for reference, i attached the code of all four functions below. my question is, how come classes don't create cell variables, like normal functions? was this done on purpose? does it have to do with inheritance? if so, what's wrong with my "bar" version? [1] # code of class foo ############################################################ # 2 0 LOAD_NAME 0 (__name__) # 3 STORE_NAME 1 (__module__) # 3 6 LOAD_CONST 0 (5) # 9 STORE_NAME 2 (x) # # 4 12 LOAD_CONST 1 (<code object f at 009E5608, file "<stdin>", line 4>) # 15 MAKE_FUNCTION 0 # 18 STORE_NAME 3 (f) # 21 LOAD_LOCALS # 22 RETURN_VALUE [2] # code of foo.f: ############################################################ # 5 0 LOAD_CONST 1 ('f') # 3 PRINT_ITEM # 4 LOAD_GLOBAL 0 (x) # 7 PRINT_ITEM # 8 PRINT_NEWLINE # 9 LOAD_CONST 0 (None) # 12 RETURN_VALUE [3] # code of bar: ############################################################ # 2 0 LOAD_CONST 1 (5) # 3 STORE_DEREF 0 (x) # # 3 6 LOAD_CLOSURE 0 (x) # 9 BUILD_TUPLE 1 # 12 LOAD_CONST 2 (<code object g at 009F6698, file "<stdin>", line 3>) # 15 MAKE_CLOSURE 0 # 18 STORE_FAST 0 (g) # # 5 21 LOAD_GLOBAL 0 (locals) # 24 CALL_FUNCTION 0 # 27 RETURN_VALUE [4] # code of bar.g: ############################################################ # 4 0 LOAD_CONST 1 ('g') # 3 PRINT_ITEM # 4 LOAD_DEREF 0 (x) # 7 PRINT_ITEM # 8 PRINT_NEWLINE # 9 LOAD_CONST 0 (None) # 12 RETURN_VALUE

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Cached Property Pattern
by Calvin Spealman 29 Dec '06

29 Dec '06

A very common pattern in using properties is as follows: class Foo(object): @property def c(self): if not hasattr(self, '_c'): self._c = some_operation(self.a, self.b) return self._c Basically, the common usage is to only calculate a properties value once, and to reuse the result for every lookup after that. This is so common, that it seems most of my uses of property come in this form. To this end, should a cachedproperty builtin be included to do this automatically? Optionally, it might automatically include a default fset (change the cached value) and fdel (remove the cached value, to be regenerated next time). I will contribute code, if such a patch would be accepted. PS - It seems I am taking over the python-dev summaries, but the holidays have interfered with those duties! I apologize, and promise they will come shortly. -- Read my blog! I depend on your acceptance of my opinion! I am interesting! http://ironfroggy-code.blogspot.com/

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Looking for python SIP and MGCP stacks
by Jenny Zhao (zhzhao) 29 Dec '06

29 Dec '06

Hi Python developers, I am using python to write a testing tools, currently this tool only supports skinny protocol. I am planning to add SIP and MGCP support as well, wondering if you have written these protocol stacks before which can be leveraged from. thanks Jenny

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Fwd: survey about the use of agile practices
by Guido van Rossum 25 Dec '06

25 Dec '06

Anyone? ---------- Forwarded message ---------- From: Selene Uras <s.uras(a)diee.unica.it> Date: Dec 24, 2006 9:24 AM Subject: survey about the use of agile practices To: s.uras(a)diee.unica.it Dear project manager/developer I am conducting at the University of Cagliari, under the supervision of prof. Michele Marchesi, a survey about the use of agile practices in open source successful projects. I would really appreciate if you can devote 5 mins. of your time, answering the following questionnaire directly in the "Reply" mail to me. Thanking in advance, Selene Uras 1. Project management: - Do you use fixed (time-boxed) iterations? Y/N How many days do they last? ___ - Do you plan development by gathering a list of features, and then assign them to an iteration? Y/N Since when? Since the start of the project / Since ___ years. - Are users actively involved in requirements gathering and in project management? Y/N 2. Testing: - Has the project an automatic unit test suite? Y/N Which one? ___________ - If Yes, what is the percentage of code covered by tests? ___ % - Do you use automatic acceptance tests? Y/N - Since when have you been using automatic tests? Since the start of the project / Since ___ years. 3. Refactoring: - Do you practice explicit code refactoring? Y/N - What is the percentage of developing effort for refactoring? ___% - Since when have you been using refactoring? Since the start of the project / Since ___ years. 4. Integration and releases: - How long does it take to produce the executable code starting from source code? ____ - Do you have a "working version" of the code, which is often updated by developers who add their code and run tests? Y/N 5. General: - Can you mention some other agile practices you are using in the project? For each of them, since when has it been used? - Practice: __________________________ Used since: ______ - Practice: __________________________ Used since: ______ - .... -- --Guido van Rossum (home page: http://www.python.org/~guido/)

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