Mailman 3 June 2010 - Python-Dev

thoughts on the bytes/string discussion
by Bill Janssen 07 Jul '10

07 Jul '10

Here are a couple of ideas I'm taking away from the bytes/string discussion. First, it would probably be a good idea to have a String ABC. Secondly, maybe the string situation in 2.x wasn't as broken as we thought it was. In particular, those who deal with lots of encoded strings seemed to find it handy, and miss it in 3.x. Perhaps strings are more like numbers than we think. We have separate types for int, float, Decimal, etc. But they're all numbers, and they all cross-operate. In 2.x, it seems there were two missing features: no encoding attribute on str, which should have been there and should have been required, and the default encoding being "ASCII" (I can't tell you how many times I've had to fix that issue when a non-ASCII encoded str was passed to some output function). So maybe having a second string type in 3.x that consists of an encoded sequence of bytes plus the encoding, call it "estr", wouldn't have been a bad idea. It would probably have made sense to have estr cooperate with the str type, in the same way that two different kinds of numbers cooperate, "promoting" the result of an operation only when necessary. This would automatically achieve the kind of polymorphic functionality that Guido is suggesting, but without losing the ability to do x = e(ASCII)"bar" a = ''.join("foo", x) (or whatever the syntax for such an encoded string literal would be -- I'm not claiming this is a good one) which presume would bind "a" to a Unicode string "foobar" -- have to work out what gets promoted to what. The language moratorium kind of makes this all theoretical, but building a String ABC still would be a good start, and presumably isn't forbidden by the moratorium. Bill

19 38

Signs of neglect?
by Steve Holden 06 Jul '10

06 Jul '10

I was pretty stunned when I tried this. Remember that the Tools subdirectory is distributed with Windows, so this means we got through almost two releases without anyone realizing that 2to3 does not appear to have touched this code. Yes, I have: http://bugs.python.org/issue9083 When's 3.2 due out? regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 See Python Video! http://python.mirocommunity.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS: http://holdenweb.eventbrite.com/ "All I want for my birthday is another birthday" - Ian Dury, 1942-2000

10 10

Taking over the Mercurial Migration
by "Martin v. Löwis" 01 Jul '10

01 Jul '10

It seems that both Dirkjan and Brett are very caught up with real life for the coming months. So I suggest that some other committer who favors the Mercurial transition steps forward and takes over this project. If nobody volunteers, I propose that we release 3.2 from Subversion, and reconsider Mercurial migration next year. Regards, Martin

5 9

OS X buildbots: why am I skipping these tests?
by Bill Janssen 01 Jul '10

01 Jul '10

My Leopard and Tiger PPC buildbots are momentarily green! But I'm looking into why I'm skipping some tests. My buildbots are up-to-date OS-wise and very vanilla, with the latest applicable Xcode. 4 skips unexpected on darwin: test_gdb test_ioctl test_readline test_ttk_guionly Three of these (gdb, readline, ttk_guionly) are just bad predictions of which tests should skip on Darwin, I think -- gdb is only version 6, so that test won't run, readline doesn't get built, ttk doesn't work without Tcl/Tk 8.5. But the the skip of test_ioctl baffles me. "test_ioctl skipped -- Unable to open /dev/tty" But when I log in via ssh and try it with the system python: ~ wjanssen$ python python Python 2.5.1 (r251:54863, Jun 17 2009, 20:37:34) [GCC 4.0.1 (Apple Inc. build 5465)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> open("/dev/tty") open("/dev/tty") <open file '/dev/tty', mode 'r' at 0x597b8> >>> Seems to work fine. So this I don't understand. Any ideas, anyone? Bill

10 25

Mailbox module - timings and functionality changes
by Steve Holden 01 Jul '10

01 Jul '10

I hope this is an appropriate dev topic. It seems to me that the unicode discussions of recent days are well highlighted by difficulties I am having using the mailbox module (hardly surprising given the difficulties of handling email generally) even though it passes its tests. I can't find anything related in the issue tracker (symptoms: one program that works fine under Python 2 in under twenty seconds takes forever (over ten minutes) to fail while creating the (start, stop) index to the mailbox). My code reads Thunderbird mailboxen from file store on my Windows Vista system under 3.1. The failures I am experiencing could easily be encoding issues so I won't post any detail yet, but I am concerned about the timing - even when the code is "fixed", if it needs to be, the performance may still make the module of dubious value. Can someone who is set up to do easily just do a timing of test_mailbox under 2.6 and 3.2, to verify they see the same disparity as me? The test takes about twice as long under 3.1 here (and I am concerned that unexercised aspects of the code may extend real-world problem run times by an order of magnitude or more). regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 See Python Video! http://python.mirocommunity.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS: http://holdenweb.eventbrite.com/ "All I want for my birthday is another birthday" - Ian Dury, 1942-2000

9 25

Pickle security and remote logging
by anatoly techtonik 30 Jun '10

30 Jun '10

Hello, I need to send logging module output over the network. The module has everything to make this happen, except security. SocketHandler and DatagramHandler examples are using pickle module that is said to be insecure. SocketHandler and DatagramHandler docs should at least contain a warning about danger of exposing unpickling interfaces to insecure networks. pickle documentation mentions that it is possible to control what gets unpickled, but there is any no example or security analysis if the proposed solution will be secure. Is there any way to implement secure network logging? I do not care about data encryption - I just do not want my server exploited by malformed data. -- anatoly t.

3 4

what environment variable should contain compiler warning suppression flags?
by Brett Cannon 30 Jun '10

30 Jun '10

I finally realized why clang has not been silencing its warnings about unused return values: I have -Wno-unused-value set in CFLAGS which comes before OPT (which defines -Wall) as set in PY_CFLAGS in Makefile.pre.in. I could obviously set OPT in my environment, but that would override the default OPT settings Python uses. I could put it in EXTRA_CFLAGS, but the README says that's for stuff that tweak binary compatibility. So basically what I am asking is what environment variable should I use? If CFLAGS is correct then does anyone have any issues if I change the order of things for PY_CFLAGS in the Makefile so that CFLAGS comes after OPT?

8 23

[ANN]: "newthreading" - an approach to simplified thread usage, and a path to getting rid of the GIL
by John Nagle 29 Jun '10

29 Jun '10

We have just released a proof-of-concept implementation of a new approach to thread management - "newthreading". It is available for download at https://sourceforge.net/projects/newthreading/ The user's guide is at http://www.animats.com/papers/languages/newthreadingintro.html This is a pure Python implementation of synchronized objects, along with a set of restrictions which make programs race-condition free, even without a Global Interpreter Lock. The basic idea is that classes derived from SynchronizedObject are automatically locked at entry and unlocked at exit. They're also unlocked when a thread blocks within the class. So at no time can two threads be active in such a class at one time. In addition, only "frozen" objects can be passed in and out of synchronized objects. (This is somewhat like the multiprocessing module, where you can only pass objects that can be "pickled". But it's not as restrictive; multiple threads can access the same synchronized object, one at a time. This pure Python implementation is usable, but does not improve performance. It's a proof of concept implementation so that programmers can try out synchronized classes and see what it's like to work within those restrictions. The semantics of Python don't change for single-thread programs. But when the program forks off the first new thread, the rules change, and some of the dynamic features of Python are disabled. Some of the ideas are borrowed from Java, and some are from "safethreading". The point is to come up with a set of liveable restrictions which would allow getting rid of the GIL. This is becoming essential as Unladen Swallow starts to work and the number of processors per machine keeps climbing. This may in time become a Python Enhancement Proposal. We'd like to get some experience with it first. Try it out and report back. The SourceForge forum for the project is the best place to report problems. John Nagle

6 8

Access a function
by Zohair 29 Jun '10

29 Jun '10

I am a very new to python and have a small question.. I have a function: set_time_at_next_pps(self, *args, **kwargs) but don't know how to use it... Askign for your help please. Cheers, Zoh -- View this message in context: http://old.nabble.com/Access-a-function-tp29008798p29008798.html Sent from the Python - python-dev mailing list archive at Nabble.com.

4 3

WPython 1.1 was released
by Cesare Di Mauro 29 Jun '10

29 Jun '10

I've released WPython 1.1, which brings many optimizations and refactorings. The project is hosted at Google Code: http://code.google.com/p/wpython2/ and available as a Mercurial repository http://code.google.com/p/wpython2/source/checkout?repo=wpython11 . In the download section http://code.google.com/p/wpython2/downloads/listthere are the slides of the last italian PyCon where I have presented the project and illustrated the changes. You can also download the binaries for Windows (compressed in 7-Zip format: http://www.7-zip.org/ ) and sources (for Unix users, Parser/Python.asdl and configure files need to be chmod +x ). Attached there are some benchmarks with the Unladen Swallow tests suite (against Python 2.6.4). Regards Cesare

4 5