Mailman 3 February 2010 - Python-Dev

PEP 1, PEP Purpose and Guidelines
by barry＠zope.com May 18, 2021

May 18, 2021

It has been a while since I posted a copy of PEP 1 to the mailing lists and newsgroups. I've recently done some updating of a few sections, so in the interest of gaining wider community participation in the Python development process, I'm posting the latest revision of PEP 1 here. A version of the PEP is always available on-line at http://www.python.org/peps/pep-0001.html Enjoy, -Barry -------------------- snip snip -------------------- PEP: 1 Title: PEP Purpose and Guidelines Version: … [View More]$Revision: 1.36 $ Last-Modified: $Date: 2002/07/29 18:34:59 $ Author: Barry A. Warsaw, Jeremy Hylton Status: Active Type: Informational Created: 13-Jun-2000 Post-History: 21-Mar-2001, 29-Jul-2002 What is a PEP? PEP stands for Python Enhancement Proposal. A PEP is a design document providing information to the Python community, or describing a new feature for Python. The PEP should provide a concise technical specification of the feature and a rationale for the feature. We intend PEPs to be the primary mechanisms for proposing new features, for collecting community input on an issue, and for documenting the design decisions that have gone into Python. The PEP author is responsible for building consensus within the community and documenting dissenting opinions. Because the PEPs are maintained as plain text files under CVS control, their revision history is the historical record of the feature proposal[1]. Kinds of PEPs There are two kinds of PEPs. A standards track PEP describes a new feature or implementation for Python. An informational PEP describes a Python design issue, or provides general guidelines or information to the Python community, but does not propose a new feature. Informational PEPs do not necessarily represent a Python community consensus or recommendation, so users and implementors are free to ignore informational PEPs or follow their advice. PEP Work Flow The PEP editor, Barry Warsaw <peps(a)python.org>, assigns numbers for each PEP and changes its status. The PEP process begins with a new idea for Python. It is highly recommended that a single PEP contain a single key proposal or new idea. The more focussed the PEP, the more successfully it tends to be. The PEP editor reserves the right to reject PEP proposals if they appear too unfocussed or too broad. If in doubt, split your PEP into several well-focussed ones. Each PEP must have a champion -- someone who writes the PEP using the style and format described below, shepherds the discussions in the appropriate forums, and attempts to build community consensus around the idea. The PEP champion (a.k.a. Author) should first attempt to ascertain whether the idea is PEP-able. Small enhancements or patches often don't need a PEP and can be injected into the Python development work flow with a patch submission to the SourceForge patch manager[2] or feature request tracker[3]. The PEP champion then emails the PEP editor <peps(a)python.org> with a proposed title and a rough, but fleshed out, draft of the PEP. This draft must be written in PEP style as described below. If the PEP editor approves, he will assign the PEP a number, label it as standards track or informational, give it status 'draft', and create and check-in the initial draft of the PEP. The PEP editor will not unreasonably deny a PEP. Reasons for denying PEP status include duplication of effort, being technically unsound, not providing proper motivation or addressing backwards compatibility, or not in keeping with the Python philosophy. The BDFL (Benevolent Dictator for Life, Guido van Rossum) can be consulted during the approval phase, and is the final arbitrator of the draft's PEP-ability. If a pre-PEP is rejected, the author may elect to take the pre-PEP to the comp.lang.python newsgroup (a.k.a. python-list(a)python.org mailing list) to help flesh it out, gain feedback and consensus from the community at large, and improve the PEP for re-submission. The author of the PEP is then responsible for posting the PEP to the community forums, and marshaling community support for it. As updates are necessary, the PEP author can check in new versions if they have CVS commit permissions, or can email new PEP versions to the PEP editor for committing. Standards track PEPs consists of two parts, a design document and a reference implementation. The PEP should be reviewed and accepted before a reference implementation is begun, unless a reference implementation will aid people in studying the PEP. Standards Track PEPs must include an implementation - in the form of code, patch, or URL to same - before it can be considered Final. PEP authors are responsible for collecting community feedback on a PEP before submitting it for review. A PEP that has not been discussed on python-list(a)python.org and/or python-dev(a)python.org will not be accepted. However, wherever possible, long open-ended discussions on public mailing lists should be avoided. Strategies to keep the discussions efficient include, setting up a separate SIG mailing list for the topic, having the PEP author accept private comments in the early design phases, etc. PEP authors should use their discretion here. Once the authors have completed a PEP, they must inform the PEP editor that it is ready for review. PEPs are reviewed by the BDFL and his chosen consultants, who may accept or reject a PEP or send it back to the author(s) for revision. Once a PEP has been accepted, the reference implementation must be completed. When the reference implementation is complete and accepted by the BDFL, the status will be changed to `Final.' A PEP can also be assigned status `Deferred.' The PEP author or editor can assign the PEP this status when no progress is being made on the PEP. Once a PEP is deferred, the PEP editor can re-assign it to draft status. A PEP can also be `Rejected'. Perhaps after all is said and done it was not a good idea. It is still important to have a record of this fact. PEPs can also be replaced by a different PEP, rendering the original obsolete. This is intended for Informational PEPs, where version 2 of an API can replace version 1. PEP work flow is as follows: Draft -> Accepted -> Final -> Replaced ^ +----> Rejected v Deferred Some informational PEPs may also have a status of `Active' if they are never meant to be completed. E.g. PEP 1. What belongs in a successful PEP? Each PEP should have the following parts: 1. Preamble -- RFC822 style headers containing meta-data about the PEP, including the PEP number, a short descriptive title (limited to a maximum of 44 characters), the names, and optionally the contact info for each author, etc. 2. Abstract -- a short (~200 word) description of the technical issue being addressed. 3. Copyright/public domain -- Each PEP must either be explicitly labelled as placed in the public domain (see this PEP as an example) or licensed under the Open Publication License[4]. 4. Specification -- The technical specification should describe the syntax and semantics of any new language feature. The specification should be detailed enough to allow competing, interoperable implementations for any of the current Python platforms (CPython, JPython, Python .NET). 5. Motivation -- The motivation is critical for PEPs that want to change the Python language. It should clearly explain why the existing language specification is inadequate to address the problem that the PEP solves. PEP submissions without sufficient motivation may be rejected outright. 6. Rationale -- The rationale fleshes out the specification by describing what motivated the design and why particular design decisions were made. It should describe alternate designs that were considered and related work, e.g. how the feature is supported in other languages. The rationale should provide evidence of consensus within the community and discuss important objections or concerns raised during discussion. 7. Backwards Compatibility -- All PEPs that introduce backwards incompatibilities must include a section describing these incompatibilities and their severity. The PEP must explain how the author proposes to deal with these incompatibilities. PEP submissions without a sufficient backwards compatibility treatise may be rejected outright. 8. Reference Implementation -- The reference implementation must be completed before any PEP is given status 'Final,' but it need not be completed before the PEP is accepted. It is better to finish the specification and rationale first and reach consensus on it before writing code. The final implementation must include test code and documentation appropriate for either the Python language reference or the standard library reference. PEP Template PEPs are written in plain ASCII text, and should adhere to a rigid style. There is a Python script that parses this style and converts the plain text PEP to HTML for viewing on the web[5]. PEP 9 contains a boilerplate[7] template you can use to get started writing your PEP. Each PEP must begin with an RFC822 style header preamble. The headers must appear in the following order. Headers marked with `*' are optional and are described below. All other headers are required. PEP: <pep number> Title: <pep title> Version: <cvs version string> Last-Modified: <cvs date string> Author: <list of authors' real names and optionally, email addrs> * Discussions-To: <email address> Status: <Draft | Active | Accepted | Deferred | Final | Replaced> Type: <Informational | Standards Track> * Requires: <pep numbers> Created: <date created on, in dd-mmm-yyyy format> * Python-Version: <version number> Post-History: <dates of postings to python-list and python-dev> * Replaces: <pep number> * Replaced-By: <pep number> The Author: header lists the names and optionally, the email addresses of all the authors/owners of the PEP. The format of the author entry should be address(a)dom.ain (Random J. User) if the email address is included, and just Random J. User if the address is not given. If there are multiple authors, each should be on a separate line following RFC 822 continuation line conventions. Note that personal email addresses in PEPs will be obscured as a defense against spam harvesters. Standards track PEPs must have a Python-Version: header which indicates the version of Python that the feature will be released with. Informational PEPs do not need a Python-Version: header. While a PEP is in private discussions (usually during the initial Draft phase), a Discussions-To: header will indicate the mailing list or URL where the PEP is being discussed. No Discussions-To: header is necessary if the PEP is being discussed privately with the author, or on the python-list or python-dev email mailing lists. Note that email addresses in the Discussions-To: header will not be obscured. Created: records the date that the PEP was assigned a number, while Post-History: is used to record the dates of when new versions of the PEP are posted to python-list and/or python-dev. Both headers should be in dd-mmm-yyyy format, e.g. 14-Aug-2001. PEPs may have a Requires: header, indicating the PEP numbers that this PEP depends on. PEPs may also have a Replaced-By: header indicating that a PEP has been rendered obsolete by a later document; the value is the number of the PEP that replaces the current document. The newer PEP must have a Replaces: header containing the number of the PEP that it rendered obsolete. PEP Formatting Requirements PEP headings must begin in column zero and the initial letter of each word must be capitalized as in book titles. Acronyms should be in all capitals. The body of each section must be indented 4 spaces. Code samples inside body sections should be indented a further 4 spaces, and other indentation can be used as required to make the text readable. You must use two blank lines between the last line of a section's body and the next section heading. You must adhere to the Emacs convention of adding two spaces at the end of every sentence. You should fill your paragraphs to column 70, but under no circumstances should your lines extend past column 79. If your code samples spill over column 79, you should rewrite them. Tab characters must never appear in the document at all. A PEP should include the standard Emacs stanza included by example at the bottom of this PEP. A PEP must contain a Copyright section, and it is strongly recommended to put the PEP in the public domain. When referencing an external web page in the body of a PEP, you should include the title of the page in the text, with a footnote reference to the URL. Do not include the URL in the body text of the PEP. E.g. Refer to the Python Language web site [1] for more details. ... [1] http://www.python.org When referring to another PEP, include the PEP number in the body text, such as "PEP 1". The title may optionally appear. Add a footnote reference that includes the PEP's title and author. It may optionally include the explicit URL on a separate line, but only in the References section. Note that the pep2html.py script will calculate URLs automatically, e.g.: ... Refer to PEP 1 [7] for more information about PEP style ... References [7] PEP 1, PEP Purpose and Guidelines, Warsaw, Hylton http://www.python.org/peps/pep-0001.html If you decide to provide an explicit URL for a PEP, please use this as the URL template: http://www.python.org/peps/pep-xxxx.html PEP numbers in URLs must be padded with zeros from the left, so as to be exactly 4 characters wide, however PEP numbers in text are never padded. Reporting PEP Bugs, or Submitting PEP Updates How you report a bug, or submit a PEP update depends on several factors, such as the maturity of the PEP, the preferences of the PEP author, and the nature of your comments. For the early draft stages of the PEP, it's probably best to send your comments and changes directly to the PEP author. For more mature, or finished PEPs you may want to submit corrections to the SourceForge bug manager[6] or better yet, the SourceForge patch manager[2] so that your changes don't get lost. If the PEP author is a SF developer, assign the bug/patch to him, otherwise assign it to the PEP editor. When in doubt about where to send your changes, please check first with the PEP author and/or PEP editor. PEP authors who are also SF committers, can update the PEPs themselves by using "cvs commit" to commit their changes. Remember to also push the formatted PEP text out to the web by doing the following: % python pep2html.py -i NUM where NUM is the number of the PEP you want to push out. See % python pep2html.py --help for details. Transferring PEP Ownership It occasionally becomes necessary to transfer ownership of PEPs to a new champion. In general, we'd like to retain the original author as a co-author of the transferred PEP, but that's really up to the original author. A good reason to transfer ownership is because the original author no longer has the time or interest in updating it or following through with the PEP process, or has fallen off the face of the 'net (i.e. is unreachable or not responding to email). A bad reason to transfer ownership is because you don't agree with the direction of the PEP. We try to build consensus around a PEP, but if that's not possible, you can always submit a competing PEP. If you are interested assuming ownership of a PEP, send a message asking to take over, addressed to both the original author and the PEP editor <peps(a)python.org>. If the original author doesn't respond to email in a timely manner, the PEP editor will make a unilateral decision (it's not like such decisions can be reversed. :). References and Footnotes [1] This historical record is available by the normal CVS commands for retrieving older revisions. For those without direct access to the CVS tree, you can browse the current and past PEP revisions via the SourceForge web site at http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/python/nondist/peps/?cvsroot=… [2] http://sourceforge.net/tracker/?group_id=5470&atid=305470 [3] http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse [4] http://www.opencontent.org/openpub/ [5] The script referred to here is pep2html.py, which lives in the same directory in the CVS tree as the PEPs themselves. Try "pep2html.py --help" for details. The URL for viewing PEPs on the web is http://www.python.org/peps/ [6] http://sourceforge.net/tracker/?group_id=5470&atid=305470 [7] PEP 9, Sample PEP Template http://www.python.org/peps/pep-0009.html Copyright This document has been placed in the public domain. Local Variables: mode: indented-text indent-tabs-mode: nil sentence-end-double-space: t fill-column: 70 End: [View Less]

8 14

Reviving restricted mode?
by Guido van Rossum Aug. 14, 2014

Aug. 14, 2014

I've received some enthusiastic emails from someone who wants to revive restricted mode. He started out with a bunch of patches to the CPython runtime using ctypes, which he attached to an App Engine bug: http://code.google.com/p/googleappengine/issues/detail?id=671 Based on his code (the file secure.py is all you need, included in secure.tar.gz) it seems he believes the only security leaks are __subclasses__, gi_frame and gi_code. (I have since convinced him that if we add "restricted" … [View More]

19 35

PEP 3145 (With Contents)
by Eric Pruitt Dec. 25, 2012

Dec. 25, 2012

Alright, I will re-submit with the contents pasted. I never use double backquotes as I think them rather ugly; that is the work of an editor or some automated program in the chain. Plus, it also messed up my line formatting and now I have lines with one word on them... Anyway, the contents of PEP 3145: PEP: 3145 Title: Asynchronous I/O For subprocess.Popen Author: (James) Eric Pruitt, Charles R. McCreary, Josiah Carlson Type: Standards Track Content-Type: text/plain Created: 04-Aug-2009 Python-… [View More]Version: 3.2 Abstract: In its present form, the subprocess.Popen implementation is prone to dead-locking and blocking of the parent Python script while waiting on data from the child process. Motivation: A search for "python asynchronous subprocess" will turn up numerous accounts of people wanting to execute a child process and communicate with it from time to time reading only the data that is available instead of blocking to wait for the program to produce data [1] [2] [3]. The current behavior of the subprocess module is that when a user sends or receives data via the stdin, stderr and stdout file objects, dead locks are common and documented [4] [5]. While communicate can be used to alleviate some of the buffering issues, it will still cause the parent process to block while attempting to read data when none is available to be read from the child process. Rationale: There is a documented need for asynchronous, non-blocking functionality in subprocess.Popen [6] [7] [2] [3]. Inclusion of the code would improve the utility of the Python standard library that can be used on Unix based and Windows builds of Python. Practically every I/O object in Python has a file-like wrapper of some sort. Sockets already act as such and for strings there is StringIO. Popen can be made to act like a file by simply using the methods attached the the subprocess.Popen.stderr, stdout and stdin file-like objects. But when using the read and write methods of those options, you do not have the benefit of asynchronous I/O. In the proposed solution the wrapper wraps the asynchronous methods to mimic a file object. Reference Implementation: I have been maintaining a Google Code repository that contains all of my changes including tests and documentation [9] as well as blog detailing the problems I have come across in the development process [10]. I have been working on implementing non-blocking asynchronous I/O in the subprocess.Popen module as well as a wrapper class for subprocess.Popen that makes it so that an executed process can take the place of a file by duplicating all of the methods and attributes that file objects have. There are two base functions that have been added to the subprocess.Popen class: Popen.send and Popen._recv, each with two separate implementations, one for Windows and one for Unix based systems. The Windows implementation uses ctypes to access the functions needed to control pipes in the kernel 32 DLL in an asynchronous manner. On Unix based systems, the Python interface for file control serves the same purpose. The different implementations of Popen.send and Popen._recv have identical arguments to make code that uses these functions work across multiple platforms. When calling the Popen._recv function, it requires the pipe name be passed as an argument so there exists the Popen.recv function that passes selects stdout as the pipe for Popen._recv by default. Popen.recv_err selects stderr as the pipe by default. "Popen.recv" and "Popen.recv_err" are much easier to read and understand than "Popen._recv('stdout' ..." and "Popen._recv('stderr' ..." respectively. Since the Popen._recv function does not wait on data to be produced before returning a value, it may return empty bytes. Popen.asyncread handles this issue by returning all data read over a given time interval. The ProcessIOWrapper class uses the asyncread and asyncwrite functions to allow a process to act like a file so that there are no blocking issues that can arise from using the stdout and stdin file objects produced from a subprocess.Popen call. References: [1] [ python-Feature Requests-1191964 ] asynchronous Subprocess http://mail.python.org/pipermail/python-bugs-list/2006-December/ 036524.html [2] Daily Life in an Ivory Basement : /feb-07/problems-with-subprocess http://ivory.idyll.org/blog/feb-07/problems-with-subprocess [3] How can I run an external command asynchronously from Python? - Stack Overflow http://stackoverflow.com/questions/636561/how-can-i-run-an-external- command-asynchronously-from-python [4] 18.1. subprocess - Subprocess management - Python v2.6.2 documentation http://docs.python.org/library/subprocess.html#subprocess.Popen.wait [5] 18.1. subprocess - Subprocess management - Python v2.6.2 documentation http://docs.python.org/library/subprocess.html#subprocess.Popen.kill [6] Issue 1191964: asynchronous Subprocess - Python tracker http://bugs.python.org/issue1191964 [7] Module to allow Asynchronous subprocess use on Windows and Posix platforms - ActiveState Code http://code.activestate.com/recipes/440554/ [8] subprocess.rst - subprocdev - Project Hosting on Google Code http://code.google.com/p/subprocdev/source/browse/doc/subprocess.rst?spec=s… [9] subprocdev - Project Hosting on Google Code http://code.google.com/p/subprocdev [10] Python Subprocess Dev http://subdev.blogspot.com/ Copyright: This P.E.P. is licensed under the Open Publication License; http://www.opencontent.org/openpub/. On Tue, Sep 8, 2009 at 22:56, Benjamin Peterson <benjamin(a)python.org> wrote: > 2009/9/7 Eric Pruitt <eric.pruitt(a)gmail.com>: >> Hello all, >> >> I have been working on adding asynchronous I/O to the Python >> subprocess module as part of my Google Summer of Code project. Now >> that I have finished documenting and pruning the code, I present PEP >> 3145 for its inclusion into the Python core code. Any and all feedback >> on the PEP (http://www.python.org/dev/peps/pep-3145/) is appreciated. > > Hi Eric, > One of the reasons you're not getting many response is that you've not > pasted the contents of the PEP in this message. That makes it really > easy for people to comment on various sections. > > BTW, it seems like you were trying to use reST formatting with the > text PEP layout. Double backquotes only mean something in reST. > > > -- > Regards, > Benjamin > [View Less]

10 26

http://www.pythonlabs.com/logos.html is gone
by Georg Brandl Feb. 8, 2011

Feb. 8, 2011

Which I noticed since it's cited in the BeOpen license we still refer to in LICENSE. Since pythonlabs.com itself is still up, it probably isn't much work to make the logos.html URI work again, but I don't know who maintains that page. cheer, Georg -- Thus spake the Lord: Thou shalt indent with four spaces. No more, no less. Four shall be the number of spaces thou shalt indent, and the number of thy indenting shall be four. Eight shalt thou not indent, nor either indent thou two, excepting … [View More]

2 3

Problems with hex-conversion functions
by Ender Wiggin Oct. 2, 2010

Oct. 2, 2010

Hello everyone. I see several problems with the two hex-conversion function pairs that Python offers: 1. binascii.hexlify and binascii.unhexlify 2. bytes.fromhex and bytes.hex Problem #1: bytes.hex is not implemented, although it was specified in PEP 358. This means there is no symmetrical function to accompany bytes.fromhex. Problem #2: Both pairs perform the same function, although The Zen Of Python suggests that "There should be one-- and preferably only one --obvious way to do it." I do … [View More]not understand why PEP 358 specified the bytes function pair although it mentioned the binascii pair... Problem #3: bytes.fromhex may receive spaces in the input string, although binascii.unhexlify may not. I see no good reason for these two functions to have different features. Problem #4: binascii.unhexlify may receive both input types: strings or bytes, whereas bytes.fromhex raises an exception when given a bytes parameter. Again there is no reason for these functions to be different. Problem #5: binascii.hexlify returns a bytes type - although ideally, converting to hex should always return string types and converting from hex should always return bytes. IMO there is no meaning of bytes as an output of hexlify, since the output is a representation of other bytes. This is also the suggested behavior of bytes.hex in PEP 358 Problems #4 and #5 call for a decision about the input and output of the functions being discussed: Option A : Strict input and output unhexlify (and bytes.fromhex) may only receives string and may only return bytes hexlify (and bytes.hex) may only receives bytes and may only return strings Option B : Robust input and strict output unhexlify (and bytes.fromhex) may receive bytes and strings and may only return bytes hexlify (and bytes.hex) may receive bytes or strings and may only return strings Of course we may also consider a third option, which will allow the return type of all functions to be robust (perhaps specified in a keyword argument), but as I wrote in the description of problem #5, I see no sense in that. Note that PEP 3137 describes: "... the more strict definitions of encoding and decoding in Python 3000: encoding always takes a Unicode string and returns a bytes sequence, and decoding always takes a bytes sequence and returns a Unicode string." - suggesting option A. To repeat problems #4 and #5, the current behavior does not match any option: * The return type of binascii.hexlify should be string, and this is not the current behavior. As for the input: * Option A is not the current behavior because binascii.unhexlify may receive both input types. * Option B is not the current behavior because bytes.fromhex does not allow bytes as input. To fix these issues, three changes should be applied: 1. Deprecate bytes.fromhex. This fixes the following problems: #4 (go with option B and remove the function that does not allow bytes input) #2 (the binascii functions will be the only way to "do it") #1 (bytes.hex should not be implemented) 2. In order to keep the functionality that bytes.fromhex has over unhexlify, the latter function should be able to handle spaces in its input (fix #3) 3. binascii.hexlify should return string as its return type (fix #5) [View Less]

5 7

The fate of Distutils in Python 2.7
by Tarek Ziadé March 3, 2010

March 3, 2010

Hello, This is a follow-up of the Pycon summit + sprints on packaging. This is what we have planned to do: 1. refactor distutils in a new standalone version called distutils2 [this is done already and we are actively working in the code] 2. completely revert distutils in Lib/ and Doc/ so the code + doc is the same than the current 2.6.x branch 3. leave the new sysconfig module, that is used by the Makefile and the site module The rest of the work will happen in distutils2 and we will try to … [View More]

2 4

Re: [Python-Dev] __file__
by Barry Warsaw March 3, 2010

March 3, 2010

On Feb 03, 2010, at 12:42 PM, Brett Cannon wrote: >So what happens when only bytecode is present? We discussed this at Pycon and agreed that we will not support source-less deployments by default. The source file must exist or it will be an ImportError. This does not mean source-less deployments are not possible though. To support this use case, you'd have to write a custom import hook. We may write one as part of the PEP 3147 implementation. Contributions are of course welcome! -Barry

18 86

PEP 3188: Implementation Questions
by Meador Inge March 3, 2010

March 3, 2010

Hi All, Recently some discussion began in the issue 3132 thread ( http://bugs.python.org/issue3132) regarding implementation of the new struct string syntax for PEP 3118. Mark Dickinson suggested that I bring the discussion on over to Python Dev. Below is a summary of the questions\comments from the thread. Unpacking a long-double =================== 1. Should this return a Decimal object or a ctypes 'long double'? 2. Using ctypes 'long double' is easier to implement, but precision is … [View More]

6 10

Update xml.etree.ElementTree for Python 2.7 and 3.2
by Florent Xicluna March 1, 2010

March 1, 2010

Hello, On November 2006 and September 2007 Fredrik proposed to update "xml.etree" in Python 2.6 with the upcoming version 1.3. Now we are three years later, and the version shipped with 2.7alpha3 is 1.2.6. http://bugs.python.org/issue1602189#msg54944 http://bugs.python.org/issue1143 This would not be an issue, without the numerous bug reports accumulating on bugs.python.org. Most of these reports are waiting for the 1.3 release. Three months ago I worked on some of these issues, and after … [View More]fixing them separately, I proposed a patch which merges the latest 1.3 snapshot (released in 2007) within the standard library. The aim is to provide a bug-free version of ElementTree/cElementTree in the standard library. For this purpose, I grew the test suite from 300 lines to 1800 lines, using both the tests from upstream and the tests proposed by Neil Muller on issue #6232. To ensure consistency, now the test_suite for the C implementation is the same as the Python implementation. http://bugs.python.org/issue6472 We are still interested with the upcoming release of ElementTree, but we should adopt a pragmatic approach: the xml.etree.ElementTree needs to be fixed for all Python users, even if 1.3 is not ready before 2.7beta. This is the only purpose of the patch. The patch sticks as much as possible to the upstream library. Initially I kept all the new features of the 1.3 branch in the patch. It should ease the integration of 1.3 final when it is released. With the last comment from Fredrik, I think to be more conservative: I plan to split out the experimental C API from the package. It is not required for the bug-fix release, and there's some risk of incompatibility with the final design of the API, which is still secret. As a side-effect, the patch will add some features and methods from the 1.3 branch (some of them where requested in the bug tracker): - ET.fromstringlist(), ET.tostringlist() - Element.extend(), Element.iter(), Element.itertext() - new selector engine - extended slicing However the highlighted features of this patch are: - to fix many bugs which were postponed because of 1.3 release - to ensure consistency between C and Python implementations (with tests) - to provide a better test coverage The patch is uploaded on Rietveld for review. The 3.x version of the patch will be updated after 2.x is merged in trunk. The patch covers documentation, too. http://codereview.appspot.com/207048/show It's time to comment and review. The proposed plan is to merge the patch in trunk before 2.7 alpha4. Best regards, -- Florent Xicluna [View Less]

9 23

Challenge: escape from the pysandbox
by Victor Stinner Feb. 28, 2010

Feb. 28, 2010

Hi, pysandbox is a new Python sandbox project under development. By default, untrusted code executed in the sandbox cannot modify the environment (write a file, use print or import a module). But you can configure the sandbox to choose exactly which features are allowed or not, eg. import sys module and read the file /etc/issue. Website: http://github.com/haypo/pysandbox/ Download the repository using git: git clone git://github.com/haypo/pysandbox.git or git clone http://github.com/… [View More]haypo/pysandbox.git Or download the .zip or .tar.gz tarball using the "Download source" button on the website. I think that the project reached the "testable" stage. I launch a new challenge: try to escape from the sandbox. I'm unable to write strict rules. The goal is to access objects outside the sandbox. Eg. write into a file, import a module which is not in the whitelist, modify an object outside the sandbox, etc. To test the sandbox, you have 3 choices: - interpreter.py: interactive interpreter executed in the sandbox, use: --verbose to display the whole sandbox configuration, --features=help to enable help() function, --features=regex to enable regex, --help to display the help. - execfile.py <your_script.py>: execute your script in the sandbox. It has also --features option: use --features=stdout to be able to use the print instruction :-) - use directly the Sandbox class: use methods call(), execute() or createCallback() Don't use "with sandbox: ..." because there is known but with local frame variables. I think that I will later drop this syntax because of this bug. Except of debug_sandbox, I consider that all features are safe and so you can enable all features :-) There is no prize, it's just for fun! But I will add the name of hackers founding the best exploits. pysandbox is not ready for production, it's under heavy development. Anyway I *hope* that you will quickly find bugs! -- Use tests.py to found some examples of how you can escape a sandbox. pysandbox is protected against all methods described in tests.py ;-) See the README file to get more information about how pysandbox is implemented and get a list of other Python sandboxes. pysandbox is currently specific to CPython, and it uses some ugly hacks to patch CPython in memory. In the worst case it will crash the pysandbox Python process, that's all. I tested it under Linux with Python 2.5 and 2.6. The portage to Python3 is not done yet (is someone motivated to write a patch? :-)). -- Victor Stinner http://www.haypocalc.com/ [View Less]

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Another version of Python
by skip＠pobox.com Feb. 27, 2010

Feb. 27, 2010

Some of you have probably already seen this, but in case you haven't: http://www.staringispolite.com/likepython/ :-) Skip

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Python 2.6.5 rc 1
by Barry Warsaw Feb. 26, 2010

Feb. 26, 2010

Hello everybody! I hope you all had as great a time at Pycon 2010 as I did. No time to begin recovering though, we're on to Python 2.6.5 rc 1, which I would like to release on Monday. We have one showstopper still open, and I'll try to respond to that asap. http://bugs.python.org/issue7250 If there is anything else that absolutely should go into 2.6.5, now's the time to let me know. If there are no patches ready to be reviewed and landed though, you're probably running out of time. I … [View More]

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Add UTC to 2.7 (PyCon sprint idea)
by anatoly techtonik Feb. 26, 2010

Feb. 26, 2010

Hello, So far, Python timezone handling is far from "pythonic". There is no function to get current UTC offset, intuitive API to get DST of current time zone and whenever it is active, no functions to work with internet timestamps (RFC 3339). In my case [1] it took about one month and five people to get the right solution for a valid RFC 3339 timestamp. One of the reasons I see is that date/time functions are implemented in C, they expose C API, and there are not many people who can help and … [View More]

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Pickling named tuples on IronPython
by Michael Foord Feb. 26, 2010

Feb. 26, 2010

Hello Raymond, Named tuples have compatibility code to enable them to work on IronPython without frame support, but unfortunately this doesn't allow pickling / unpickling of named tuples. One fix is to manually set __module__ on the named tuples once created, but I wonder if it would be possible to change the API to better support this - perhaps a default __module__ or providing an optional argument to specify it at creation time? Michael -- http://www.ironpythoninaction.com/ http://… [View More]

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contributor to committer
by Florent Xicluna Feb. 26, 2010

Feb. 26, 2010

Hello, I am a semi-regular contributor for Python: I have contributed many patches since end of last year, some of them were reviewed by Antoine. Lately, he suggested that I should apply for commit rights. Some of the accepted patches: - Fix refleaks in py3k branch (#5596) - Extend stringlib fastsearch for various methods of bytes, bytearray and unicode objects (#7462 and #7622) - Various documentation patches, including FAQ Recently, I worked with Ezio to fix some tests and to silence … [View More]

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Re: [Python-Dev] __file__
by Barry Warsaw Feb. 25, 2010

Feb. 25, 2010

On Feb 03, 2010, at 01:07 PM, Antoine Pitrou wrote: >Well, I don't think we need another transition... Just keep __file__ for the >source file, and add a __cache__ or __compiled__ attribute for the compiled >file(s). >Since there might be several compiled files for a single source file (for >example, a .pyc along with a JITted native .so), __cache__ should probably be >a tuple rather than a string. I'm going to call the attribute __cached__ and leave its contents … [View More]

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status of issue #7242
by Doug Hellmann Feb. 25, 2010

Feb. 25, 2010

We've recently run into an issue with subprocess on Solaris, as described (by an earlier reporter) in issue #7242. The patch there solves our problem, and has been verified to work by other users as well. What's the status of the ticket? Is there anything I can do to help move it forward to be included in a patch release for 2.6? Thanks, Doug

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Platform extension for distutils on other interpreters than CPython
by Maciej Fijalkowski Feb. 25, 2010

Feb. 25, 2010

Hello. I would like to have a feature on platform module (or sys or somewhere) that can tell distutils or distutils2 that this platform (be it PyPy or Jython) is not able to compile any C module. The purpose of this is to make distutils bail out in more reasonable manner than a compilation error in case this module is not going to work on anything but CPython. What do you think? Cheers, fijal

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Re: [Python-Dev] Mercurial repository for Python benchmarks
by Dave Fugate Feb. 25, 2010

Feb. 25, 2010

Would there be any interest in accepting IronPython's in-house benchmarks into this repository as well? Internally we run the usual suspects (PyStone, PyBench, etc), but we also have a plethora of custom benchmarks we've written that also happen to run under CPython. My best, Dave ------------------------------ Message: 2 Date: Mon, 22 Feb 2010 15:17:09 -0500 From: Collin Winter <collinwinter(a)google.com> To: Daniel Stutzbach <daniel(a)stutzbachenterprises.com> Cc: Dirkjan … [View More]Ochtman <djc.ochtman(a)gmail.com>, Python Dev <python-dev(a)python.org> Subject: Re: [Python-Dev] Mercurial repository for Python benchmarks Message-ID: <3c8293b61002221217v4b7f3b91y76b78763d69fb99d(a)mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 On Sun, Feb 21, 2010 at 9:43 PM, Collin Winter <collinwinter(a)google.com> wrote: > Hey Daniel, > > On Sun, Feb 21, 2010 at 4:51 PM, Daniel Stutzbach > <daniel(a)stutzbachenterprises.com> wrote: >> On Sun, Feb 21, 2010 at 2:28 PM, Collin Winter <collinwinter(a)google.com> >> wrote: >>> >>> Would it be possible for us to get a Mercurial repository on >>> python.org for the Unladen Swallow benchmarks? Maciej and I would like >>> to move the benchmark suite out of Unladen Swallow and into >>> python.org, where all implementations can share it and contribute to >>> it. PyPy has been adding some benchmarks to their copy of the Unladen >>> benchmarks, and we'd like to have as well, and Mercurial seems to be >>> an ideal solution to this. >> >> If and when you have a benchmark repository set up, could you announce it >> via a reply to this thread?? I'd like to check it out. > > Will do. The benchmarks repository is now available at http://hg.python.org/benchmarks/. It contains all the benchmarks that the Unladen Swallow svn repository contains, including the beginnings of a README.txt that describes the available benchmarks and a quick-start guide for running perf.py (the main interface to the benchmarks). This will eventually contain all the information from http://code.google.com/p/unladen-swallow/wiki/Benchmarks, as well as guidelines on how to write good benchmarks. If you have svn commit access, you should be able to run `hg clone ssh://hg@hg.python.org/repos/benchmarks`. I'm not sure how to get read-only access; Dirkjan can comment on that. Still todo: - Replace the static snapshots of 2to3, Mercurial and other hg-based projects with clones of the respective repositories. - Fix the 2to3 and nbody benchmarks to work with Python 2.5 for Jython and PyPy. - Import some of the benchmarks PyPy has been using. Any access problems with the hg repo should be directed to Dirkjan. Thanks so much for getting the repo set up so fast! Thanks, Collin Winter [View Less]

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Add alternate float formatting styles to new-style formatting: allowed under moratorium?
by Eric Smith Feb. 24, 2010

Feb. 24, 2010

http://bugs.python.org/issue7094 proposes adding "alternate" formatting [1] to floating point new-style formatting (float.__format__ and probably Decimal.__format__). I'd like to add this to make automated translation from %-formatting strings to str.format strings easier. Would this be allowed under the moratorium? I think it falls under the Case-by-Case Exemptions section, but let me know what you think. Eric. [1] Alternate formatting for floats modifies how trailing zeros and decimal … [View More]

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Using git to checkout Python
by Neil Schemenauer Feb. 24, 2010

Feb. 24, 2010

For those interested, I updated my instructions for using the git repositories on svn.python.org. They are now on the Python wiki: http://wiki.python.org/moin/Git Regards, Neil

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'languishing' status for the tracker
by R. David Murray Feb. 24, 2010

Feb. 24, 2010

I believe Brett mentioned the 'languishing' status for the tracker in passing in his notes from the language summit. To expand on this: the desire for this arises from the observation that we have a lot of bugs in the tracker that we don't want to close, because they are real bugs or non-crazy enhancement requests, but for one reason or another (lack of an interested party, lack of a good, non-controversial solution, lack of a test platform on which to test the bug fix, the fix is hard but the … [View More]bug is not of a commensurate priority, etc) the issue just isn't getting dealt with, and won't get dealt with until the blocking factor changes. The motivation for introducing a new status, rather than continuing to leave these bugs in 'open' state, is to make it clear which bugs are the *active* bugs, the ones we should be focusing on and working to fix first. This would allow the count of open bugs to be a more meaningful metric than it is currently, and might even allow us to get to a point where the open bug count stops increasing. More importantly, however, it would act as a first level partition of the non-closed bugs, such that the ones for which it is most likely that effective action can be taken will be what appear first. This is especially important for new people coming in to help. How many people have looked at the tracker, and decided to start from the oldest bugs and see what they can fix? I know I started out that way. Looking through those oldest bugs can be quite discouraging, since many of them are old because they are hard, or blocked for one reason or another. We would in addition propose that a 'languishing' search be added to the standard searches. I would also propose that the default search be changed to search all bugs, and group them by status, not priority. This will make it more likely that bug *reporters* will find existing bugs that relate to the problem they are experiencing or the feature they want to propose. The other searches (except open) should probably return languishing issues as well as open, since they sort in reverse chronological order the more active bugs will be at the top, and that way the languishing bugs won't be forgotten. (Note: languishing bugs should probably never have the 'needs review' keyword, since bugs should not be allowd to languish simply for need of a review.) To move a bug to state languishing, the procedure should be to post a comment saying why you are moving the bug to that status, that by implication or explicitly lays out the conditions required for it to move back to open. Doing so may wake someone up who wants to and can deal with the issue, in which case it can be moved back to open. --David PS: I believe that the other change that would be required in addition to adding the new status and search is to alter the bug summary email script to handle the languishing state. If I've missed anything else please let me know. [View Less]

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Question for you
by Connor, Craig A. Feb. 24, 2010

Feb. 24, 2010

Hello, Dave; My name is Craig Connor and I am a senior s/w developer at Northrop Grumman. I have a question for you. I have installed Boost (via the Installer), and stored it into my C Drive inside a dir called: C:\boost_1_42 I also installed the Boost Jam into a directory called: C:\boost-jam-3.1.17 I am using 2 separate compilers in my Win OS XP (SP3) and I would like to be able to use the Python module of Boost in order to embed Python.h into my C++ compiler. The C++ … [View More]

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PEP 385 progress report
by Dirkjan Ochtman Feb. 24, 2010

Feb. 24, 2010

It's been a long time! So for the past few weeks, Mercurial crew member Patrick Mezard has been hunting for the ugly bug in hgsubversion that I'd previously been looking at, and it finally got fixed. A new bug popped up, but then we managed to fix that, too (thanks to the PSF for partially funding our sprint, it was very succesful!). In a joyous moment, I nagged Augie Fackler to actually put a hgsubversion release out there so hopefully more people can start using it, so we now have that, too. … [View More]

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3.1 and 2.7 break format() when used with complex (sometimes)
by Eric Smith Feb. 23, 2010

Feb. 23, 2010

This code works on 2.6 and 3.0: >>> format(1+1j, '10s') '(1+1j) ' That's because format ends up calling object.__format__ because complex doesn't have its own __format__. Then object.__format__ calls str(self) which returns '(1+1j) '. So the original call basically turns into "format('(1+1j) ', '10s')". In 3.1 (released) and 2.7 (not yet released) I implemented __format__ on complex. So now that same code is an error: >>> format(1+1j, '10s') Traceback (most … [View More]

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