Mailman 3 March 2014 - Python-Dev

Python 4: don't remove anything, don't break backward compatibility
by Victor Stinner March 11, 2014

March 11, 2014

Hi, Last 5 years, I spend significant time to port a lot of Python 2 code on Python 3. First, using the 2to3 tool + extra manual patches. Sorry, it was not usable in practice. The conversion was very slow, it didn't fix doctests nor all other minor "details". "Fixing Python 2 code" was no always possible. I now use the six module (or a smaller subset) to port applications to Python 3. Today, they are still many dependencies blocking applications to be ported to Python 3. So can we please try … [View More]

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Re: [Python-Dev] What is the precise problem? [was: Reference cycles in Exception.__traceback__]
by Victor Stinner March 10, 2014

March 10, 2014

2014-03-08 1:14 GMT+01:00 Jim Jewett <jimjjewett(a)gmail.com>: >>> Could you clarify what the problem actually is? > >> Please see: >> http://bugs.python.org/file33238/never_deleted.py > > I would not expect it to be cleared at least until go runs ... and reading > the ticket, it sounds like it is cleared then. Attached script: never_deleted2.py, it's almost the same but it explains better the problem. The script creates MyObject and Future objects which … [View More]are never deleted. Calling gc.collect() does *not* break the reference cycle (between the future, the exception, traceback and frames). Stopping the event loop does not remove Future nor MyObject objects. Only exiting Python does remove the Future object. The Future destructor calls code between this code fails between Python is exiting and so most symbols are set to None. I'm testing with Python 3.4 default, so with Antoine's PEP 442 and Serhiy's changes on Python shutdown (restore builtins at exit). The Future destructor is used in asyncio to notice the developer that the application has a bug, the exception was not handled which may be a major bug. And MyObject is not destroyed which is an obvious memory leak, beause there is no more explicit reference to it. Script output: --- gc.collect stop! exit --- Logging error --- Traceback (most recent call last): --- Logging error --- Traceback (most recent call last): Exception ignored in: <bound method Future.__del__ of Future<exception=ValueError()>> Traceback (most recent call last): File "Lib/asyncio/futures.py", line 184, in __del__ File "Lib/asyncio/base_events.py", line 704, in call_exception_handler File "Lib/logging/__init__.py", line 1280, in error File "Lib/logging/__init__.py", line 1386, in _log File "Lib/logging/__init__.py", line 1396, in handle File "Lib/logging/__init__.py", line 1466, in callHandlers File "Lib/logging/__init__.py", line 837, in handle File "Lib/logging/__init__.py", line 961, in emit File "Lib/logging/__init__.py", line 890, in handleError File "Lib/traceback.py", line 169, in print_exception File "Lib/traceback.py", line 153, in _format_exception_iter File "Lib/traceback.py", line 18, in _format_list_iter File "Lib/traceback.py", line 65, in _extract_tb_or_stack_iter File "Lib/linecache.py", line 15, in getline File "Lib/linecache.py", line 41, in getlines File "Lib/linecache.py", line 126, in updatecache File "Lib/tokenize.py", line 437, in open AttributeError: 'module' object has no attribute 'open' DELETE OBJET --- Victor [View Less]

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Python 3.4 change in importlib/__init__.py breaking cxFreeze?
by Jurko Gospodnetić March 10, 2014

March 10, 2014

Hi all. Python 3.4 introduced a change to Lib/importlib/__init__.py that added the following code to it: > else: > # importlib._bootstrap is the built-in import, ensure we don't create > # a second copy of the module. > _bootstrap.__name__ = 'importlib._bootstrap' > _bootstrap.__package__ = 'importlib' > _bootstrap.__file__ = __file__.replace('__init__.py', '_bootstrap.py') > sys.modules['importlib._bootstrap'] = _bootstrap When attempting … [View More]

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Windows 'for current user' installation - 32/64-bit registrations overwrite each other
by Jurko Gospodnetić March 10, 2014

March 10, 2014

Hi. When running the Python Windows installer 'for all users', the 32-bit installation and the 64-bit installation each gets a separate registration in the Windows registry. E.g. under: HKEY_LOCAL_MACHINE\Software\Python\PythonCore\3.4 and: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Python\PythonCore\3.4 However, when running the installer 'for the current user only', the 32-bit and the 64-bit installation both use the same Windows registry key: HKEY_CURRENT_USER\Software\… [View More]

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Re: [Python-Dev] [Python-checkins] cpython: whatsnew: 'U' mode deprecation (#15204).
by Nick Coghlan March 10, 2014

March 10, 2014

On 10 Mar 2014 11:36, "r.david.murray" <python-checkins(a)python.org> wrote: > > http://hg.python.org/cpython/rev/2d5544afb510 > changeset: 89547:2d5544afb510 > user: R David Murray <rdmurray(a)bitdance.com> > date: Sun Mar 09 20:33:35 2014 -0400 > summary: > whatsnew: 'U' mode deprecation (#15204). > > files: > Doc/whatsnew/3.4.rst | 14 +++++++++++++- > 1 files changed, 13 insertions(+), 1 deletions(-) > > > diff --… [View More]

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Re: [Python-Dev] [Python-checkins] cpython: whatsnew: 'U' mode deprecation (#15204).
by Nick Coghlan March 10, 2014

March 10, 2014

On 10 Mar 2014 23:26, "Antoine Pitrou" <solipsis(a)pitrou.net> wrote: > > On Mon, 10 Mar 2014 23:09:53 +1000 > Nick Coghlan <ncoghlan(a)gmail.com> wrote: > > On 10 Mar 2014 11:36, "r.david.murray" <python-checkins(a)python.org> wrote: > > > > > > +* The ``U`` mode accepted by various ``open`` functions is deprecated. > > > + In Python3 it does not do anything useful, and should be replaced by > > > + appropriate uses of :… [View More]

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[RELEASED] Python 3.4.0 release candidate 3
by Larry Hastings March 10, 2014

March 10, 2014

On behalf of the Python development team, I'm pleased to announce the third and final** release candidate of Python 3.4. This is a preview release, and its use is not recommended for production settings. Python 3.4 includes a range of improvements of the 3.x series, including hundreds of small improvements and bug fixes. Major new features and changes in the 3.4 release series include: * PEP 428, a "pathlib" module providing object-oriented filesystem paths * PEP 435, a standardized "enum" … [View More]

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Re: [Python-Dev] [Python-checkins] cpython: whatsnew: venv with_pip, pyvenv --without-pip (#19552)
by Nick Coghlan March 10, 2014

March 10, 2014

On 10 Mar 2014 08:51, "r.david.murray" <python-checkins(a)python.org> wrote: > > http://hg.python.org/cpython/rev/a140caad76bc > changeset: 89539:a140caad76bc > user: R David Murray <rdmurray(a)bitdance.com> > date: Sun Mar 09 18:09:51 2014 -0400 > summary: > whatsnew: venv with_pip, pyvenv --without-pip (#19552) > > files: > Doc/whatsnew/3.4.rst | 11 +++++++++++ > 1 files changed, 11 insertions(+), 0 deletions(-) > > … [View More]

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[RELEASED] Python 3.3.5
by Georg Brandl March 9, 2014

March 9, 2014

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On behalf of the Python development team, I'm very happy to announce the release of Python 3.3.5. Python 3.3.5 includes fixes for these important issues: * a 3.3.4 regression in zipimport (see http://bugs.python.org/issue20621) * a 3.3.4 regression executing scripts with a coding declared and Windows newlines (see http://bugs.python.org/issue20731) * potential DOS using compression codecs in bytes.decode() (see http://bugs.python.org/… [View More]

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for Python + Java devs - real-world importance of the security model
by Sean Felipe Wolfe March 8, 2014

March 8, 2014

Hello everybody, I'm getting back into some Java game programming using the (excellent) libgdx library. It's been a couple years since I've written Java classes from scratch and it's got me thinking. The Java code I'm going through has lots 'final' and 'static' variable declarations, along with public vs private vs protected. For those of you who are Java devs in the real world ... is this security model really important? Is it protection against other developers somehow modifying state in … [View More]

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