Mailman 3 May 2013 - Python-Dev

Re: [Python-Dev] cpython: Introduce importlib.util.ModuleManager which is a context manager to
by Antoine Pitrou 30 May '13

30 May '13

On Tue, 28 May 2013 23:29:46 +0200 (CEST) brett.cannon <python-checkins(a)python.org> wrote: > > +.. class:: ModuleManager(name) > + > + A :term:`context manager` which provides the module to load. The module will > + either come from :attr:`sys.modules` in the case of reloading or a fresh > + module if loading a new module. Proper cleanup of :attr:`sys.modules` occurs > + if the module was new and an exception was raised. What use case does this API solve? (FWIW, I think "ModuleManager" is a rather bad name :-)) Regards Antoine.

8 21

Bilingual scripts
by Barry Warsaw 30 May '13

30 May '13

Here's something that seems to come up from time to time in Debian. Take a Python application like tox, nose, or pyflakes. Their executables work with both Python 2 and 3, but require a #! line to choose which interpreter to invoke. When we add Python 3 support in Debian for such a script, all the library installations are handled just fine, but we have conflicts about what to name the thing that lands in /usr/bin. Do we have /usr/bin/pyflakes and /usr/bin/pyflakes3? Do we call the latter py3flakes (as has been convention with some other scripts, but which breaks locate(1))? Do we simply remove the /usr/bin scripts and encourage people to use something like `$python -m nose`? One interesting recent suggestion is to create a shell driver script and make that thing accept --py3 and --py2 flags, which would then select the appropriate interpreter and invoke the actual Python driver. There are some technical details to iron out with that, but there's some appeal to it. Have any other *nix distros addressed this, and if so, how do you solve it? It would be nice if we could have some cross-platform recommendations so things work the same wherever you go. To that end, if we can reach some consensus, I'd be willing to put together an informational PEP and some scripts that might be of general use. -Barry

9 29

Structural cleanups to the main CPython repo
by Nick Coghlan 29 May '13

29 May '13

I have a feature branch where I'm intermittently working on the bootstrapping changes described in PEP 432. As part of those changes, I've cleaned up a few aspects of the repo layout: * moved the main executable source file from Modules to a separate Apps directory * moved the _freezeimportlib and _testembed source files from Modules to a separate Tools directory * split the monster pythonrun.h/c pair into 3 separate header/impl pairs: * bootstrap.h/bootstrap.c * shutdown.h/shutdown.c * pythonrun.h/pythonrun.c These structural changes generally mean automatic merges touching the build machinery or the startup or shutdown code fail fairly spectacularly and need a lot of TLC to complete them without losing any changes from the main repo. Would anyone object if I went ahead and posted patches for making these changes to the main repo? I found they made the code *much* easier to follow when I started to turn the ideas in PEP 432 into working software, and implementing these shifts should make future merges to my feature branch simpler, as well as producing significantly cleaner diffs when PEP 432 gets closer to completion. Cheers, Nick. -- Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia

8 13

Re: [Python-Dev] cpython (merge 3.3 -> default): Merge with 3.3
by Antoine Pitrou 29 May '13

29 May '13

On Tue, 28 May 2013 15:06:39 -0400 Terry Reedy <tjreedy(a)udel.edu> wrote: > On 5/28/2013 2:14 AM, Benjamin Peterson wrote: > > 2013/5/27 terry.reedy <python-checkins(a)python.org>: > >> http://hg.python.org/cpython/rev/c5d4c041ab47 > >> changeset: 83942:c5d4c041ab47 > >> parent: 83940:2ea849fde22b > >> parent: 83941:24c3e7e08168 > >> user: Terry Jan Reedy <tjreedy(a)udel.edu> > >> date: Mon May 27 21:33:40 2013 -0400 > >> summary: > >> Merge with 3.3 > >> > >> files: > >> Lib/idlelib/CallTips.py | 4 +- > >> Lib/idlelib/PathBrowser.py | 3 +- > >> Lib/idlelib/idle_test/(a)README.txt | 63 +++++++++++ > > Is @README really the intended name of this file? > Yes, Nick suggested README instead of what I had. I want a prefix to > keep it near the top of a directory listing even when other non > 'test_xxx' files are added. I thing '_' wold be better though. I don't think "prefixing with a weird character so that the filename show up top" is a very elegant trick, and we don't use it for other directories. "README.txt" *will* be easily visible because of the all-caps filename. > If I can > find how to rename in hg "Rename in hg" -> "hg rename" Antoine.

3 3

pep 422 "Safe object finalization" question: why break weakrefs first?
by Russell E. Owen 28 May '13

28 May '13

Pep 422 proposes the following order for dealing with cyclic isolates: 1. Weakrefs to CI objects are cleared, and their callbacks called. At this point, the objects are still safe to use. 2. The finalizers of all CI objects are called. 3. The CI is traversed again to determine if it is still isolated. If it is determined that at least one object in CI is now reachable from outside the CI, this collection is aborted and the whole CI is resurrected. Otherwise, proceed. 4. The CI becomes a CT as the GC systematically breaks all known references inside it (using the tp_clear function). Why are weakrefs are broken first, before determining if any of the objects should become resurrected? Naively I would expect weakrefs to be broken after step 3, once the system is sure no objects have been resurrected. I request that this information be added to PEP 422. -- Russell

2 1

PEP 8 and function names
by Sébastien Durand 28 May '13

28 May '13

Hi all, "There should be one-- and preferably only one --obvious way to do it." We all love this mantra. But one thing that often confuses people : function naming. The standard library is kind of inconsistent. Some functions are separated by underscores and others aren't. It's not intuitive and new pythonistas end up constantly reading the doc. (Time saving one char typing vs time guessing function names.) Would it be a good idea to clarify PEP 8 on this ? I mean for future libraries. Regards, Sébastien

7 6

Re: [Python-Dev] [Python-checkins] cpython (merge 3.3 -> default): Merge with 3.3
by Benjamin Peterson 28 May '13

28 May '13

2013/5/27 terry.reedy <python-checkins(a)python.org>: > http://hg.python.org/cpython/rev/c5d4c041ab47 > changeset: 83942:c5d4c041ab47 > parent: 83940:2ea849fde22b > parent: 83941:24c3e7e08168 > user: Terry Jan Reedy <tjreedy(a)udel.edu> > date: Mon May 27 21:33:40 2013 -0400 > summary: > Merge with 3.3 > > files: > Lib/idlelib/CallTips.py | 4 +- > Lib/idlelib/PathBrowser.py | 3 +- > Lib/idlelib/idle_test/(a)README.txt | 63 +++++++++++ Is @README really the intended name of this file? Would README-TEST or something similar be better? -- Regards, Benjamin

1 0

__subclasses__() return order
by Antoine Pitrou 26 May '13

26 May '13

Hello, In http://bugs.python.org/issue17936, I proposed making tp_subclasses (the internal container implementing object.__subclasses__) a dict. This would make the return order of __subclasses__ completely undefined, while it is right now slightly predictable. I have never seen __subclasses__ actually used in production code, so I'm wondering whether someone might be affected by such a change. Regards Antoine.

7 8

Summary of Python tracker Issues
by Python tracker 24 May '13

24 May '13

ACTIVITY SUMMARY (2013-05-17 - 2013-05-24) Python tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue. Do NOT respond to this message. Issues counts and deltas: open 3972 ( +6) closed 25850 (+45) total 29822 (+51) Open issues with patches: 1773 Issues opened (41) ================== #13146: Writing a pyc file is not atomic http://bugs.python.org/issue13146 reopened by barry #15535: Fix pickling efficiency of named tuples in 2.7.3 http://bugs.python.org/issue15535 reopened by rhettinger #18000: _md5 should be built if _ssl cannot be built http://bugs.python.org/issue18000 opened by jdemeyer #18003: New lzma crazy slow with line-oriented reading. http://bugs.python.org/issue18003 opened by Michael.Fox #18004: test_list.test_overflow crashes Win64 http://bugs.python.org/issue18004 opened by anselm.kruis #18009: os.write.__doc__ is misleading http://bugs.python.org/issue18009 opened by shai #18010: pydoc search chokes on import errors http://bugs.python.org/issue18010 opened by pitrou #18011: Inconsistency between b32decode() documentation, docstring and http://bugs.python.org/issue18011 opened by serhiy.storchaka #18013: cgi.FieldStorage does not parse W3C sample http://bugs.python.org/issue18013 opened by flox #18014: Problem compiling on Windows, VC++Express 2010 http://bugs.python.org/issue18014 opened by terry.reedy #18015: python 2.7.5 fails to unpickle namedtuple pickled by 2.7.3 or http://bugs.python.org/issue18015 opened by anselm.kruis #18016: subprocess should open stdin in mode w+b on windows http://bugs.python.org/issue18016 opened by Jason.Gross #18017: ctypes.PyDLL documentation http://bugs.python.org/issue18017 opened by Marc.Brünink #18018: SystemError: Parent module '' not loaded, cannot perform relat http://bugs.python.org/issue18018 opened by flox #18020: html.escape 10x slower than cgi.escape http://bugs.python.org/issue18020 opened by flox #18021: Update broken link to Apple Publication Style Guide http://bugs.python.org/issue18021 opened by madison.may #18022: Inconsistency between quopri.decodestring() and email.quoprimi http://bugs.python.org/issue18022 opened by serhiy.storchaka #18023: msi product code for 2.7.5150 not in Tools/msi/uuids.py http://bugs.python.org/issue18023 opened by anselm.kruis #18024: dbm module fails to build on SLES11SP1 using 2.7.5 source http://bugs.python.org/issue18024 opened by wempa #18025: Buffer overflow in BufferedIOBase.readinto() http://bugs.python.org/issue18025 opened by serhiy.storchaka #18027: distutils should access stat_result timestamps via .st_*time a http://bugs.python.org/issue18027 opened by jwilk #18028: Warnings with -fstrict-aliasing http://bugs.python.org/issue18028 opened by bkabrda #18029: Python SSL support is missing from SPARC build http://bugs.python.org/issue18029 opened by eeiddne #18032: set methods should specify whether they consume iterators "laz http://bugs.python.org/issue18032 opened by hhm #18033: Example for Profile Module shows incorrect method http://bugs.python.org/issue18033 opened by jough #18034: Last two entries in the programming FAQ are out of date (impor http://bugs.python.org/issue18034 opened by r.david.murray #18035: telnetlib incorrectly assumes that select.error has an errno a http://bugs.python.org/issue18035 opened by gregory.p.smith #18036: "How do I create a .pyc file?" FAQ entry is out of date http://bugs.python.org/issue18036 opened by r.david.murray #18037: 2to3 passes through string literal which causes SyntaxError in http://bugs.python.org/issue18037 opened by vinay.sajip #18038: Unhelpful error message on invalid encoding specification http://bugs.python.org/issue18038 opened by Max.Cantor #18039: dbm.open(..., flag="n") does not work and does not give a warn http://bugs.python.org/issue18039 opened by sonyachiko #18040: SIGINT catching regression on windows in 2.7 http://bugs.python.org/issue18040 opened by David.Gilman #18041: mention issues with code churn in the devguide http://bugs.python.org/issue18041 opened by tshepang #18042: Provide enum.unique class decorator http://bugs.python.org/issue18042 opened by ncoghlan #18043: No mention of `match.regs` in `re` documentation http://bugs.python.org/issue18043 opened by cool-RR #18044: Email headers do not properly decode to unicode. http://bugs.python.org/issue18044 opened by Tim.Rawlinson #18045: get_python_version is not import in bdist_rpm.py http://bugs.python.org/issue18045 opened by maoliping455 #18046: Simplify and clarify logging internals http://bugs.python.org/issue18046 opened by alex #18047: Descriptors get invoked in old-style objects and classes http://bugs.python.org/issue18047 opened by icecrime #18048: Merging test_pep263.py and test_coding.py http://bugs.python.org/issue18048 opened by serhiy.storchaka #18049: Re-enable threading test on OSX http://bugs.python.org/issue18049 opened by ronaldoussoren Most recent 15 issues with no replies (15) ========================================== #18049: Re-enable threading test on OSX http://bugs.python.org/issue18049 #18047: Descriptors get invoked in old-style objects and classes http://bugs.python.org/issue18047 #18046: Simplify and clarify logging internals http://bugs.python.org/issue18046 #18045: get_python_version is not import in bdist_rpm.py http://bugs.python.org/issue18045 #18044: Email headers do not properly decode to unicode. http://bugs.python.org/issue18044 #18043: No mention of `match.regs` in `re` documentation http://bugs.python.org/issue18043 #18040: SIGINT catching regression on windows in 2.7 http://bugs.python.org/issue18040 #18039: dbm.open(..., flag="n") does not work and does not give a warn http://bugs.python.org/issue18039 #18036: "How do I create a .pyc file?" FAQ entry is out of date http://bugs.python.org/issue18036 #18034: Last two entries in the programming FAQ are out of date (impor http://bugs.python.org/issue18034 #18033: Example for Profile Module shows incorrect method http://bugs.python.org/issue18033 #18032: set methods should specify whether they consume iterators "laz http://bugs.python.org/issue18032 #18027: distutils should access stat_result timestamps via .st_*time a http://bugs.python.org/issue18027 #18025: Buffer overflow in BufferedIOBase.readinto() http://bugs.python.org/issue18025 #18023: msi product code for 2.7.5150 not in Tools/msi/uuids.py http://bugs.python.org/issue18023 Most recent 15 issues waiting for review (15) ============================================= #18049: Re-enable threading test on OSX http://bugs.python.org/issue18049 #18046: Simplify and clarify logging internals http://bugs.python.org/issue18046 #18038: Unhelpful error message on invalid encoding specification http://bugs.python.org/issue18038 #18025: Buffer overflow in BufferedIOBase.readinto() http://bugs.python.org/issue18025 #18020: html.escape 10x slower than cgi.escape http://bugs.python.org/issue18020 #18015: python 2.7.5 fails to unpickle namedtuple pickled by 2.7.3 or http://bugs.python.org/issue18015 #18013: cgi.FieldStorage does not parse W3C sample http://bugs.python.org/issue18013 #18011: Inconsistency between b32decode() documentation, docstring and http://bugs.python.org/issue18011 #18010: pydoc search chokes on import errors http://bugs.python.org/issue18010 #18000: _md5 should be built if _ssl cannot be built http://bugs.python.org/issue18000 #17998: internal error in regular expression engine http://bugs.python.org/issue17998 #17978: Python crashes if Py_Initialize/Py_Finalize are called multipl http://bugs.python.org/issue17978 #17976: file.write doesn't raise IOError when it should http://bugs.python.org/issue17976 #17974: Migrate unittest to argparse http://bugs.python.org/issue17974 #17956: add ScheduledExecutor http://bugs.python.org/issue17956 Top 10 most discussed issues (10) ================================= #18003: New lzma crazy slow with line-oriented reading. http://bugs.python.org/issue18003 17 msgs #13612: xml.etree.ElementTree says unknown encoding of a regular encod http://bugs.python.org/issue13612 14 msgs #12641: Remove -mno-cygwin from distutils http://bugs.python.org/issue12641 13 msgs #15392: Create a unittest framework for IDLE http://bugs.python.org/issue15392 11 msgs #13146: Writing a pyc file is not atomic http://bugs.python.org/issue13146 9 msgs #17140: Provide a more obvious public ThreadPool API http://bugs.python.org/issue17140 9 msgs #7727: xmlrpc library returns string which contain null ( \x00 ) http://bugs.python.org/issue7727 7 msgs #14097: Improve the "introduction" page of the tutorial http://bugs.python.org/issue14097 7 msgs #17683: socket.getsockname() inconsistent return type with AF_UNIX http://bugs.python.org/issue17683 7 msgs #17839: base64 module should use memoryview http://bugs.python.org/issue17839 7 msgs Issues closed (42) ================== #3006: subprocess.Popen causes socket to remain open after close http://bugs.python.org/issue3006 closed by neologix #3489: add rotate{left,right} methods to bytearray http://bugs.python.org/issue3489 closed by terry.reedy #7146: platform.uname()[4] returns 'amd64' on Windows and 'x86-64' on http://bugs.python.org/issue7146 closed by r.david.murray #7214: TreeBuilder.end(tag) differs between cElementTree and ElementT http://bugs.python.org/issue7214 closed by eli.bendersky #11011: More functools functions http://bugs.python.org/issue11011 closed by r.david.murray #11995: test_pydoc loads all Python modules http://bugs.python.org/issue11995 closed by pitrou #14009: Clearer documentation for cElementTree http://bugs.python.org/issue14009 closed by eli.bendersky #15758: FileIO.readall() has worst case O(n^2) complexity http://bugs.python.org/issue15758 closed by sbt #16603: Sporadic test_socket failures: testFDPassCMSG_SPACE on Mac OS http://bugs.python.org/issue16603 closed by neologix #16986: ElementTree incorrectly parses strings with declared encoding http://bugs.python.org/issue16986 closed by serhiy.storchaka #17269: getaddrinfo segfaults on OS X when provided with invalid argum http://bugs.python.org/issue17269 closed by ronaldoussoren #17453: logging.config.fileConfig error http://bugs.python.org/issue17453 closed by lukasz.langa #17532: IDLE: Always include "Options" menu on MacOSX http://bugs.python.org/issue17532 closed by ned.deily #17644: str.format() crashes http://bugs.python.org/issue17644 closed by python-dev #17684: Skip tests in test_socket like testFDPassSeparate on OS X http://bugs.python.org/issue17684 closed by neologix #17743: Use extended syntax of `set` command in activate.bat/deactivat http://bugs.python.org/issue17743 closed by python-dev #17744: Unset VIRTUAL_ENV environment variable in deactivate.bat http://bugs.python.org/issue17744 closed by python-dev #17812: Quadratic complexity in b32encode http://bugs.python.org/issue17812 closed by serhiy.storchaka #17844: Add link to alternatives for bytes-to-bytes codecs http://bugs.python.org/issue17844 closed by ncoghlan #17900: Recursive OrderedDict pickling http://bugs.python.org/issue17900 closed by serhiy.storchaka #17901: _elementtree.TreeBuilder raises IndexError on end if construct http://bugs.python.org/issue17901 closed by eli.bendersky #17917: use PyModule_AddIntMacro() instead of PyModule_AddIntConstant( http://bugs.python.org/issue17917 closed by neologix #17937: Collect garbage harder at shutdown http://bugs.python.org/issue17937 closed by pitrou #17955: Minor updates to Functional HOWTO http://bugs.python.org/issue17955 closed by akuchling #17957: remove outdated (and unexcellent) paragraph in whatsnew http://bugs.python.org/issue17957 closed by ezio.melotti #17979: Cannot build 2.7 with --enable-unicode=no http://bugs.python.org/issue17979 closed by serhiy.storchaka #17980: CVE-2013-2099 ssl.match_hostname() trips over crafted wildcard http://bugs.python.org/issue17980 closed by pitrou #17988: ElementTree.Element != ElementTree._ElementInterface http://bugs.python.org/issue17988 closed by eli.bendersky #17989: ElementTree.Element broken attribute setting http://bugs.python.org/issue17989 closed by eli.bendersky #17996: socket module should expose AF_LINK http://bugs.python.org/issue17996 closed by giampaolo.rodola #17999: test_super fails in refleak runs http://bugs.python.org/issue17999 closed by python-dev #18001: TypeError: dict is not callable in ConfigParser.py http://bugs.python.org/issue18001 closed by ethan.furman #18002: AMD64 Windows7 SP1 3.x buildbot: compilation of _ssl module fa http://bugs.python.org/issue18002 closed by pitrou #18005: faster modular exponentiation in some cases http://bugs.python.org/issue18005 closed by mark.dickinson #18006: Set thread name in linux kernel http://bugs.python.org/issue18006 closed by neologix #18007: CookieJar expects request objects with origin_req_host attribu http://bugs.python.org/issue18007 closed by orsenthil #18008: python33-3.3.2 Parser/pgen: Permission denied http://bugs.python.org/issue18008 closed by ned.deily #18012: cannot assign unicode keys to SimpleCookie http://bugs.python.org/issue18012 closed by flox #18019: dictionary views lead to segmentation fault http://bugs.python.org/issue18019 closed by python-dev #18030: IDLE shell crashes when reporting errors in Windows 7 http://bugs.python.org/issue18030 closed by serhiy.storchaka #18031: The Python Tutorial says % string formatting will be removed http://bugs.python.org/issue18031 closed by rhettinger #18026: Typo in ctypes documentation http://bugs.python.org/issue18026 closed by ned.deily

1 0

Re: [Python-Dev] PEP 443 - Single-dispatch generic functions
by Łukasz Langa 24 May '13

24 May '13

On 24 maj 2013, at 14:53, Ronan Lamy <ronan.lamy(a)gmail.com> wrote: >> 2013/5/24 Łukasz Langa <lukasz(a)langa.pl> >> >> I recognize the need for such behaviour to be discoverable. This is >> important for debugging purposes. This is why I'm going to let users >> inspect registered overloads, as well as provide their own mapping >> for the registry. I'm working on the reference implementation now, >> stay tuned. > > OK, I agree that preventing silent overwriting is actually not desirable. Specifying an interface for the implementation registry sounds like the best possible solution to my concerns. Users can now inspect the dispatcher and specify their own mapping for a registry: http://hg.python.org/features/pep-443/file/tip/Lib/functools.py#l359 Documentation: http://hg.python.org/features/pep-443/file/tip/Doc/library/functools.rst#l1… ABC support is still not there, I'm working on it. -- Best regards, Łukasz Langa WWW: http://lukasz.langa.pl/ Twitter: @llanga IRC: ambv on #python-dev

1 0