Re: [Python-Dev] PEP 416: Add a frozendict builtin type

2012-03-04 Thread Victor Stinner
Is your implementation (adapted to a standalone type) something you could put up on the cheeseshop? Short answer: no. My implementation (attached to the issue #14162) reuses most of private PyDict functins which are not exported and these functions have to be modified to accept a frozendict as

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Vinay Sajip
Nick Coghlan ncoghlan at gmail.com writes: My rewritten version of PEP 414 is now up (http://www.python.org/dev/peps/pep-0414/). It describes in detail a lot more of the historical background that was taken as read when Guido accepted the PEP. Nice work - thanks! I've implemented a first

Re: [Python-Dev] Assertion in _PyManagedBuffer_FromObject()

2012-03-04 Thread Stefan Krah
Thomas Wouters tho...@python.org wrote: Do you test against pydebug builds of Python, or otherwise a build that actually enables asserts? Yes, I do (and much more than that): http://hg.python.org/features/cdecimal/file/40917e4b51aa/Modules/_decimal/python/runall-memorydebugger.sh

[Python-Dev] Defending against stack overflow (was Sandboxing Python)

2012-03-04 Thread Mark Shannon
Having a look at the crashers in Lib/test/crashers it seems to me that they fall into four groups. 1. Unsafe gc functions like getreferrers() 2. Stack overflows. 3. Normal bugs that can be fixed on a case-by-case basis (like borrowed_ref_1.py and borrowed_ref_2.py) 4. Things that don't crash

[Python-Dev] Matrix testing against CPython releases (was: Re: Assertion in _PyManagedBuffer_FromObject())

2012-03-04 Thread Stefan Behnel
Stefan Krah, 04.03.2012 12:33: Thomas Wouters wrote: Do you test against pydebug builds of Python, or otherwise a build that actually enables asserts? Yes, I do (and much more than that):

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Zbigniew Jędrzejewski-Szmek
On 03/04/2012 10:34 AM, Vinay Sajip wrote: https://bitbucket.org/vinay.sajip/uprefix/ import uprefix; uprefix.register_hook() import frob.subwob.subsubwob frob.subwob.subsubwob.w Hi, it's pretty cool that 150 lines is enough to have this functionality. This guard: if sys.version_info[0]

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Vinay Sajip
Zbigniew Jędrzejewski-Szmek zbyszek at in.waw.pl writes: if sys.version_info[0] 3: raise NotImplementedError('This hook is implemented for Python 3 only') Wouldn't it be better if the hook did nothing when on python 2? I think it'll make it necessary to use something like Actually

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Armin Ronacher
Hi, It should also be added that the Python 3.3 alpha will release with support: Python 3.3.0a0 (default:042e7481c7b4, Mar 4 2012, 12:37:26) [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin Type help, copyright, credits or license for more information. uHello + ' World!' 'Hello

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Nick Coghlan
On Sun, Mar 4, 2012 at 11:46 PM, Armin Ronacher armin.ronac...@active-4.com wrote: Hi, It should also be added that the Python 3.3 alpha will release with support:  Python 3.3.0a0 (default:042e7481c7b4, Mar  4 2012, 12:37:26)  [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin  Type

Re: [Python-Dev] slice subscripts for sequences and mappings

2012-03-04 Thread Antoine Pitrou
On Sat, 3 Mar 2012 18:20:22 -0800 Thomas Wouters tho...@python.org wrote: I'm not sure how the ABCs, which are abstract declarations of semantics, tie into this specific implementation detail. ABCs work just as well for Python types as for C types, and Python types don't have this

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Armin Ronacher
Hi, On 3/4/12 2:01 PM, Nick Coghlan wrote: Nice :) Do you have any more updates left to do? I saw the change, the tests, the docs and the tokenizer updates go by on python-checkins, so if you're done we can mark the PEP as Final (at which point the inclusion in the first alpha is implied).

[Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Armin Ronacher
Hi, Jut to reiterate what I wrote on IRC: Please do not write or advocate for import hooks, especially not for porting purposes. It would either mean that people start adding that hook on their own to the code (and that awfully reminds me of the days of 'require rubygems' in the Ruby world) or

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Serhiy Storchaka
$ python execfile.py badhash.py Hang up. class badhash: __hash__ = int(42).__hash__ set([badhash() for _ in range(10)]) ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe:

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Serhiy Storchaka
There is even easier way to exceed the time-limit timeout and to eat CPU: sum(xrange(10)). ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe:

[Python-Dev] Install / import hooks

2012-03-04 Thread Vinay Sajip
Armin Ronacher armin.ronacher at active-4.com writes: Please do not write or advocate for import hooks, especially not for porting purposes. It would either mean that people start adding that hook on their own to the code (and that awfully reminds me of the days of 'require rubygems' in the

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Guido van Rossum
On Sat, Mar 3, 2012 at 11:34 PM, Nick Coghlan ncogh...@gmail.com wrote: My rewritten version of PEP 414 is now up (http://www.python.org/dev/peps/pep-0414/). It describes in detail a lot more of the historical background that was taken as read when Guido accepted the PEP. Thanks very much! It

Re: [Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Guido van Rossum
On Sun, Mar 4, 2012 at 6:43 AM, Armin Ronacher armin.ronac...@active-4.com wrote: Please do not write or advocate for import hooks, especially not for porting purposes.  It would either mean that people start adding that hook on their own to the code (and that awfully reminds me of the days of

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Armin Rigo
Hi all, On Sun, Mar 4, 2012 at 03:51, Guido van Rossum gu...@python.org wrote: Could we put asserts in the places where segfaults may happen? No. I checked Lib/test/crashers/*.py and none of them would be safe with just a failing assert. If they were, we'd have written the assert long ago :-(

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Mark Shannon
Armin Rigo wrote: Hi all, On Sun, Mar 4, 2012 at 03:51, Guido van Rossum gu...@python.org wrote: Could we put asserts in the places where segfaults may happen? No. I checked Lib/test/crashers/*.py and none of them would be safe with just a failing assert. If they were, we'd have written

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Barry Warsaw
On Mar 04, 2012, at 05:34 PM, Nick Coghlan wrote: My rewritten version of PEP 414 is now up (http://www.python.org/dev/peps/pep-0414/). It describes in detail a lot more of the historical background that was taken as read when Guido accepted the PEP. Nick, really great job with your rewrite of

Re: [Python-Dev] PEP 414 updated

2012-03-04 Thread Chris McDonough
On Sun, 2012-03-04 at 17:34 +1000, Nick Coghlan wrote: My rewritten version of PEP 414 is now up (http://www.python.org/dev/peps/pep-0414/). It describes in detail a lot more of the historical background that was taken as read when Guido accepted the PEP. Just as support for string

Re: [Python-Dev] PEP 414

2012-03-04 Thread PJ Eby
On Sat, Mar 3, 2012 at 5:02 AM, Lennart Regebro rege...@gmail.com wrote: I'm not sure that's true at all. In most cases where you support both Python 2 and Python 3, most strings will be native, ie, without prefix in either Python 2 or Python 3. The native case is the most common case.

Re: [Python-Dev] Defending against stack overflow (was Sandboxing Python)

2012-03-04 Thread Martin v. Löwis
So, how to handle stack overflows (of the C stack)? To prevent a stack overflow an exception must be raised before the VM runs out C stack. To do this we need 2 pieces of info: a) How much stack we've used b) How much stack is available. Python has already dedicated counters for stack depth,

Re: [Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Vinay Sajip
Armin Ronacher armin.ronacher at active-4.com writes: The current work in progress install time hook can be found here: https://github.com/mitsuhiko/unicode-literals-pep/tree/master/install-hook I realise that the implementation is different, using tokenize rather than lib2to3, but in terms

Re: [Python-Dev] slice subscripts for sequences and mappings

2012-03-04 Thread Greg Ewing
Thomas Wouters wrote: Why even have separate tp_as_sequence and tp_as_mapping anymore? That particular distinction never existed for Python types, so why should it exist for C types at all? I forget if there was ever a real point to it, I imagine the original motivation was to provide a fast

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Greg Ewing
Maciej Fijalkowski wrote: Segfaults (most of them) can generally be made into arbitrary code execution, Can you give an example of how this can be done? -- Greg ___ Python-Dev mailing list Python-Dev@python.org

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Greg Ewing
Mark Shannon wrote: You can't solve the too much time, without solving the halting problem, but you can make sure all code is interruptable (i.e. Cntrl-C works). If you can arrange for Ctrl-C to interrupt the process cleanly, then (at least on Unix) you can arrange to receive a signal after a

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Armin Rigo
Hi Mark, On Sun, Mar 4, 2012 at 18:34, Mark Shannon m...@hotpy.org wrote: I don't think it is as hard as all that. All the crashers can be fixed, and with minimal effect on performance. I will assume that you don't mean just to fix the files in Lib/test/crashers, but to fix the general issues

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Armin Rigo
Hi Greg, On Sun, Mar 4, 2012 at 22:44, Greg Ewing greg.ew...@canterbury.ac.nz wrote: Segfaults (most of them) can generally be made into arbitrary code execution, Can you give an example of how this can be done? You should find tons of documented examples of various attacks. It's not easy,

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Armin Rigo
Hi Mark, On Sun, Mar 4, 2012 at 18:34, Mark Shannon m...@hotpy.org wrote: You can't solve the too much time, without solving the halting problem, Not sure what you mean by that. It seems to me that it's particularly easy to do in a roughly portable way, with alarm() for example on all UNIXes.

Re: [Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Armin Ronacher
Hi, On 3/4/12 4:44 PM, Guido van Rossum wrote: I'd love a pointer to the rubygems debacle... Setuptools worked because Python had .pth files for a long, long time. When the Ruby world started moving packages into nonstandard locations (GameName/the files in that gem) something needed to activate

Re: [Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Armin Ronacher
Hi, On 3/4/12 9:00 PM, Vinay Sajip wrote: I realise that the implementation is different, using tokenize rather than lib2to3, but in terms of its effect on the transformed code, what are the differences between this hook and running 2to3 with just the fix_unicode fixer? I would hope they

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Steven D'Aprano
Armin Rigo wrote: Hi Mark, On Sun, Mar 4, 2012 at 18:34, Mark Shannon m...@hotpy.org wrote: You can't solve the too much time, without solving the halting problem, Not sure what you mean by that. It seems to me that it's particularly easy to do in a roughly portable way, with alarm() for

Re: [Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Vinay Sajip
Armin Ronacher armin.ronacher at active-4.com writes: Considering such an import hook has to run over all imports because it would not know which to rewrite and which not I think it would be equally problematic, especially if libraries would magically activate that hook. You could be right,

Re: [Python-Dev] Sandboxing Python

2012-03-04 Thread Martin v. Löwis
Am 04.03.2012 23:53, schrieb Steven D'Aprano: Armin Rigo wrote: Hi Mark, On Sun, Mar 4, 2012 at 18:34, Mark Shannon m...@hotpy.org wrote: You can't solve the too much time, without solving the halting problem, Not sure what you mean by that. It seems to me that it's particularly easy to

Re: [Python-Dev] Install Hook [Was: Re: PEP 414 updated]

2012-03-04 Thread Vinay Sajip
Armin Ronacher armin.ronacher at active-4.com writes: I would hope they both have the same effect. Namely stripping the 'u' prefix in all variations. Okay, that's all I was curious about. Why did I go with the tokenize approach? Because I never even considered a 2to3 solution. Part of

Re: [Python-Dev] Defending against stack overflow (was Sandboxing Python)

2012-03-04 Thread Maciej Fijalkowski
On Sun, Mar 4, 2012 at 12:35 PM, Martin v. Löwis mar...@v.loewis.de wrote: So, how to handle stack overflows (of the C stack)? To prevent a stack overflow an exception must be raised before the VM runs out C stack. To do this we need 2 pieces of info: a) How much stack we've used b) How much

[Python-Dev] [RELEASED] Python 3.3.0 alpha 1

2012-03-04 Thread Georg Brandl
On behalf of the Python development team, I'm happy to announce the first alpha release of Python 3.3.0. This is a preview release, and its use is not recommended in production settings. Python 3.3 includes a range of improvements of the 3.x series, as well as easier porting between 2.x and