Mailman 3 February 2008 - 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: $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:

8 14

pthreads, fork, import, and execvp
by Rotem Yaari Sept. 16, 2009

Sept. 16, 2009

Hello everyone! We have been encountering several deadlocks in a threaded Python application which calls subprocess.Popen (i.e. fork()) in some of its threads. This has occurred on Python 2.4.1 on a 2.4.27 Linux kernel. Preliminary analysis of the hang shows that the child process blocks upon entering the execvp function, in which the import_lock is acquired due to the following line: def _ execvpe(file, args, env=None): from errno import ENOENT, ENOTDIR ... It is known that when forking from a pthreaded application, acquisition attempts on locks which were already locked by other threads while fork() was called will deadlock. Due to these oddities we were wondering if it would be better to extract the above import line from the execvpe call, to prevent lock acquisition attempts in such cases. Another workaround could be re-assigning a new lock to import_lock (such a thing is done with the global interpreter lock) at PyOS_AfterFork or pthread_atfork. We'd appreciate any opinions you might have on the subject. Thanks in advance, Yair and Rotem

12 29

Re: subprocess and EINTR errnos
by Peter Astrand July 6, 2009

July 6, 2009

On Wed, 10 Nov 2004, John P Speno wrote: Hi, sorry for the delayed response. > While using subprocess (aka popen5), I came across one potential gotcha. I've had > exceptions ending like this: > > File "test.py", line 5, in test > cmd = popen5.Popen(args, stdout=PIPE) > File "popen5.py", line 577, in __init__ > data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB > OSError: [Errno 4] Interrupted system call > > (on Solaris 9) > > Would it make sense for subprocess to use a more robust read() function > which can handle these cases, i.e. when the parent's read on the pipe > to the child's stderr is interrupted by a system call, and returns EINTR? > I imagine it could catch EINTR and EAGAIN and retry the failed read(). I assume you are using signals in your application? The os.read above is not the only system call that can fail with EINTR. subprocess.py is full of other system calls that can fail, and I suspect that many other Python modules are as well. I've made a patch (attached) to subprocess.py (and test_subprocess.py) that should guard against EINTR, but I haven't committed it yet. It's quite large. Are Python modules supposed to handle EINTR? Why not let the C code handle this? Or, perhaps the signal module should provide a sigaction function, so that users can use SA_RESTART. Index: subprocess.py =================================================================== RCS file: /cvsroot/python/python/dist/src/Lib/subprocess.py,v retrieving revision 1.8 diff -u -r1.8 subprocess.py --- subprocess.py 7 Nov 2004 14:30:34 -0000 1.8 +++ subprocess.py 17 Nov 2004 19:42:30 -0000 @@ -888,6 +888,50 @@ pass + def _read_no_intr(self, fd, buffersize): + """Like os.read, but retries on EINTR""" + while True: + try: + return os.read(fd, buffersize) + except OSError, e: + if e.errno == errno.EINTR: + continue + else: + raise + + + def _read_all(self, fd, buffersize): + """Like os.read, but retries on EINTR, and reads until EOF""" + all = "" + while True: + data = self._read_no_intr(fd, buffersize) + all += data + if data == "": + return all + + + def _write_no_intr(self, fd, s): + """Like os.write, but retries on EINTR""" + while True: + try: + return os.write(fd, s) + except OSError, e: + if e.errno == errno.EINTR: + continue + else: + raise + + def _waitpid_no_intr(self, pid, options): + """Like os.waitpid, but retries on EINTR""" + while True: + try: + return os.waitpid(pid, options) + except OSError, e: + if e.errno == errno.EINTR: + continue + else: + raise + def _execute_child(self, args, executable, preexec_fn, close_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, @@ -963,7 +1007,7 @@ exc_value, tb) exc_value.child_traceback = ''.join(exc_lines) - os.write(errpipe_write, pickle.dumps(exc_value)) + self._write_no_intr(errpipe_write, pickle.dumps(exc_value)) # This exitcode won't be reported to applications, so it # really doesn't matter what we return. @@ -979,7 +1023,7 @@ os.close(errwrite) # Wait for exec to fail or succeed; possibly raising exception - data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB + data = self._read_all(errpipe_read, 1048576) # Exceptions limited to 1 MB os.close(errpipe_read) if data != "": child_exception = pickle.loads(data) @@ -1003,7 +1047,7 @@ attribute.""" if self.returncode == None: try: - pid, sts = os.waitpid(self.pid, os.WNOHANG) + pid, sts = self._waitpid_no_intr(self.pid, os.WNOHANG) if pid == self.pid: self._handle_exitstatus(sts) except os.error: @@ -1015,7 +1059,7 @@ """Wait for child process to terminate. Returns returncode attribute.""" if self.returncode == None: - pid, sts = os.waitpid(self.pid, 0) + pid, sts = self._waitpid_no_intr(self.pid, 0) self._handle_exitstatus(sts) return self.returncode @@ -1049,27 +1093,33 @@ stderr = [] while read_set or write_set: - rlist, wlist, xlist = select.select(read_set, write_set, []) + try: + rlist, wlist, xlist = select.select(read_set, write_set, []) + except select.error, e: + if e[0] == errno.EINTR: + continue + else: + raise if self.stdin in wlist: # When select has indicated that the file is writable, # we can write up to PIPE_BUF bytes without risk # blocking. POSIX defines PIPE_BUF >= 512 - bytes_written = os.write(self.stdin.fileno(), input[:512]) + bytes_written = self._write_no_intr(self.stdin.fileno(), input[:512]) input = input[bytes_written:] if not input: self.stdin.close() write_set.remove(self.stdin) if self.stdout in rlist: - data = os.read(self.stdout.fileno(), 1024) + data = self._read_no_intr(self.stdout.fileno(), 1024) if data == "": self.stdout.close() read_set.remove(self.stdout) stdout.append(data) if self.stderr in rlist: - data = os.read(self.stderr.fileno(), 1024) + data = self._read_no_intr(self.stderr.fileno(), 1024) if data == "": self.stderr.close() read_set.remove(self.stderr) Index: test/test_subprocess.py =================================================================== RCS file: /cvsroot/python/python/dist/src/Lib/test/test_subprocess.py,v retrieving revision 1.14 diff -u -r1.14 test_subprocess.py --- test/test_subprocess.py 12 Nov 2004 15:51:48 -0000 1.14 +++ test/test_subprocess.py 17 Nov 2004 19:42:30 -0000 @@ -7,6 +7,7 @@ import tempfile import time import re +import errno mswindows = (sys.platform == "win32") @@ -35,6 +36,16 @@ fname = tempfile.mktemp() return os.open(fname, os.O_RDWR|os.O_CREAT), fname + def read_no_intr(self, obj): + while True: + try: + return obj.read() + except IOError, e: + if e.errno == errno.EINTR: + continue + else: + raise + # # Generic tests # @@ -123,7 +134,7 @@ p = subprocess.Popen([sys.executable, "-c", 'import sys; sys.stdout.write("orange")'], stdout=subprocess.PIPE) - self.assertEqual(p.stdout.read(), "orange") + self.assertEqual(self.read_no_intr(p.stdout), "orange") def test_stdout_filedes(self): # stdout is set to open file descriptor @@ -151,7 +162,7 @@ p = subprocess.Popen([sys.executable, "-c", 'import sys; sys.stderr.write("strawberry")'], stderr=subprocess.PIPE) - self.assertEqual(remove_stderr_debug_decorations(p.stderr.read()), + self.assertEqual(remove_stderr_debug_decorations(self.read_no_intr(p.stderr)), "strawberry") def test_stderr_filedes(self): @@ -186,7 +197,7 @@ 'sys.stderr.write("orange")'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT) - output = p.stdout.read() + output = self.read_no_intr(p.stdout) stripped = remove_stderr_debug_decorations(output) self.assertEqual(stripped, "appleorange") @@ -220,7 +231,7 @@ stdout=subprocess.PIPE, cwd=tmpdir) normcase = os.path.normcase - self.assertEqual(normcase(p.stdout.read()), normcase(tmpdir)) + self.assertEqual(normcase(self.read_no_intr(p.stdout)), normcase(tmpdir)) def test_env(self): newenv = os.environ.copy() @@ -230,7 +241,7 @@ 'sys.stdout.write(os.getenv("FRUIT"))'], stdout=subprocess.PIPE, env=newenv) - self.assertEqual(p.stdout.read(), "orange") + self.assertEqual(self.read_no_intr(p.stdout), "orange") def test_communicate(self): p = subprocess.Popen([sys.executable, "-c", @@ -305,7 +316,8 @@ 'sys.stdout.write("\\nline6");'], stdout=subprocess.PIPE, universal_newlines=1) - stdout = p.stdout.read() + + stdout = self.read_no_intr(p.stdout) if hasattr(open, 'newlines'): # Interpreter with universal newline support self.assertEqual(stdout, @@ -343,7 +355,7 @@ def test_no_leaking(self): # Make sure we leak no resources - max_handles = 1026 # too much for most UNIX systems + max_handles = 10 # too much for most UNIX systems if mswindows: max_handles = 65 # a full test is too slow on Windows for i in range(max_handles): @@ -424,7 +436,7 @@ 'sys.stdout.write(os.getenv("FRUIT"))'], stdout=subprocess.PIPE, preexec_fn=lambda: os.putenv("FRUIT", "apple")) - self.assertEqual(p.stdout.read(), "apple") + self.assertEqual(self.read_no_intr(p.stdout), "apple") def test_args_string(self): # args is a string @@ -457,7 +469,7 @@ p = subprocess.Popen(["echo $FRUIT"], shell=1, stdout=subprocess.PIPE, env=newenv) - self.assertEqual(p.stdout.read().strip(), "apple") + self.assertEqual(self.read_no_intr(p.stdout).strip(), "apple") def test_shell_string(self): # Run command through the shell (string) @@ -466,7 +478,7 @@ p = subprocess.Popen("echo $FRUIT", shell=1, stdout=subprocess.PIPE, env=newenv) - self.assertEqual(p.stdout.read().strip(), "apple") + self.assertEqual(self.read_no_intr(p.stdout).strip(), "apple") def test_call_string(self): # call() function with string argument on UNIX @@ -525,7 +537,7 @@ p = subprocess.Popen(["set"], shell=1, stdout=subprocess.PIPE, env=newenv) - self.assertNotEqual(p.stdout.read().find("physalis"), -1) + self.assertNotEqual(self.read_no_intr(p.stdout).find("physalis"), -1) def test_shell_string(self): # Run command through the shell (string) @@ -534,7 +546,7 @@ p = subprocess.Popen("set", shell=1, stdout=subprocess.PIPE, env=newenv) - self.assertNotEqual(p.stdout.read().find("physalis"), -1) + self.assertNotEqual(self.read_no_intr(p.stdout).find("physalis"), -1) def test_call_string(self): # call() function with string argument on Windows /Peter Åstrand <astrand(a)lysator.liu.se>

5 5

deprecating BaseException.message
by Brett Cannon April 7, 2009

April 7, 2009

During the PyCon sprint I tried to make BaseException accept only a single argument and bind it to BaseException.message . I was successful (see the p3yk_no_args_on_exc branch), but it was very painful to pull off as anyone who sat around me the last three days of the sprint will tell you as they had to listen to me curse incessantly. Because of the pain that I went through in the transition and thus the lessons learned, Guido and I discussed it and we think it would be best to give up on forcing BaseException to accept only a single argument. I think it is still doable, but requires a multi-release transition period and not the one that 2.6 -> 3.0 is offering. And so Guido and I plan on deprecating BaseException.message as its entire point in existence was to help transition to what we are not going to have happen. =) Now that means BaseException.message might hold the record for shortest lived feature as it was only introduced in 2.5 and is now to be deprecated in 2.6 and removed in 2.7/3.0. =) Below is PEP 352, revised to reflect the removal of BaseException.messageand for letting the 'args' attribute stay (along with suggesting one should only pass a single argument to BaseException). Basically the interface for exceptions doesn't really change in 3.0 except for the removal of __getitem__. -------------------------------------------------------------------------- PEP: 352 Title: Required Superclass for Exceptions Version: $Revision: 53592 $ Last-Modified: $Date: 2007-01-28 21:54:11 -0800 (Sun, 28 Jan 2007) $ Author: Brett Cannon <brett(a)python.org> Guido van Rossum <guido(a)python.org> Status: Final Type: Standards Track Content-Type: text/x-rst Created: 27-Oct-2005 Post-History: Abstract ======== In Python 2.4 and before, any (classic) class can be raised as an exception. The plan for 2.5 was to allow new-style classes, but this makes the problem worse -- it would mean *any* class (or instance) can be raised! This is a problem as it prevents any guarantees from being made about the interface of exceptions. This PEP proposes introducing a new superclass that all raised objects must inherit from. Imposing the restriction will allow a standard interface for exceptions to exist that can be relied upon. It also leads to a known hierarchy for all exceptions to adhere to. One might counter that requiring a specific base class for a particular interface is unPythonic. However, in the specific case of exceptions there's a good reason (which has generally been agreed to on python-dev): requiring hierarchy helps code that wants to *catch* exceptions by making it possible to catch *all* exceptions explicitly by writing ``except BaseException:`` instead of ``except *:``. [#hierarchy-good]_ Introducing a new superclass for exceptions also gives us the chance to rearrange the exception hierarchy slightly for the better. As it currently stands, all exceptions in the built-in namespace inherit from Exception. This is a problem since this includes two exceptions (KeyboardInterrupt and SystemExit) that often need to be excepted from the application's exception handling: the default behavior of shutting the interpreter down without a traceback is usually more desirable than whatever the application might do (with the possible exception of applications that emulate Python's interactive command loop with ``>>>`` prompt). Changing it so that these two exceptions inherit from the common superclass instead of Exception will make it easy for people to write ``except`` clauses that are not overreaching and not catch exceptions that should propagate up. This PEP is based on previous work done for PEP 348 [#pep348]_. Requiring a Common Superclass ============================= This PEP proposes introducing a new exception named BaseException that is a new-style class and has a single attribute, ``args``. Below is the code as the exception will work in Python 3.0 (how it will work in Python 2.x is covered in the `Transition Plan`_ section):: class BaseException(object): """Superclass representing the base of the exception hierarchy. Provides a 'message' attribute that contains either the single argument to the constructor or the empty string. This attribute is used in the string representation for the exception. This is so that it provides the extra details in the traceback. """ def __init__(self, *args): """Set the 'message' attribute'""" self.args = args def __str__(self): """Return the str of 'message'""" if len(self.args) == 1: return str(self.args[0]) else: return str(self.args) def __repr__(self): return "%s(*%s)" % (self.__class__.__name__, repr(self.args)) No restriction is placed upon what may be passed in for ``args`` for backwards-compatibility reasons. In practice, though, only a single string argument should be used. This keeps the string representation of the exception to be a useful message about the exception that is human-readable; this is why the ``__str__`` method special-cases on length-1 ``args`` value. Including programmatic information (e.g., an error code number) should be stored as a separate attribute in a subclass. The ``raise`` statement will be changed to require that any object passed to it must inherit from BaseException. This will make sure that all exceptions fall within a single hierarchy that is anchored at BaseException [#hierarchy-good]_. This also guarantees a basic interface that is inherited from BaseException. The change to ``raise`` will be enforced starting in Python 3.0 (see the `Transition Plan`_ below). With BaseException being the root of the exception hierarchy, Exception will now inherit from it. Exception Hierarchy Changes =========================== With the exception hierarchy now even more important since it has a basic root, a change to the existing hierarchy is called for. As it stands now, if one wants to catch all exceptions that signal an error *and* do not mean the interpreter should be allowed to exit, you must specify all but two exceptions specifically in an ``except`` clause or catch the two exceptions separately and then re-raise them and have all other exceptions fall through to a bare ``except`` clause:: except (KeyboardInterrupt, SystemExit): raise except: ... That is needlessly explicit. This PEP proposes moving KeyboardInterrupt and SystemExit to inherit directly from BaseException. :: - BaseException |- KeyboardInterrupt |- SystemExit |- Exception |- (all other current built-in exceptions) Doing this makes catching Exception more reasonable. It would catch only exceptions that signify errors. Exceptions that signal that the interpreter should exit will not be caught and thus be allowed to propagate up and allow the interpreter to terminate. KeyboardInterrupt has been moved since users typically expect an application to exit when the press the interrupt key (usually Ctrl-C). If people have overly broad ``except`` clauses the expected behaviour does not occur. SystemExit has been moved for similar reasons. Since the exception is raised when ``sys.exit()`` is called the interpreter should normally be allowed to terminate. Unfortunately overly broad ``except`` clauses can prevent the explicitly requested exit from occurring. To make sure that people catch Exception most of the time, various parts of the documentation and tutorials will need to be updated to strongly suggest that Exception be what programmers want to use. Bare ``except`` clauses or catching BaseException directly should be discouraged based on the fact that KeyboardInterrupt and SystemExit almost always should be allowed to propagate up. Transition Plan =============== Since semantic changes to Python are being proposed, a transition plan is needed. The goal is to end up with the new semantics being used in Python 3.0 while providing a smooth transition for 2.x code. All deprecations mentioned in the plan will lead to the removal of the semantics starting in the version following the initial deprecation. Here is BaseException as implemented in the 2.x series:: class BaseException(object): """Superclass representing the base of the exception hierarchy. The __getitem__ method is provided for backwards-compatibility and will be deprecated at some point. """ def __init__(self, *args): """Set the 'args' attribute.""" self.args = args def __str__(self): """Return the str of args[0] or args, depending on length.""" return str(self.args[0] if len(self.args) <= 1 else self.args) def __repr__(self): func_args = repr(self.args) if self.args else "()" return self.__class__.__name__ + func_args def __getitem__(self, index): """Index into arguments passed in during instantiation. Provided for backwards-compatibility and will be deprecated. """ return self.args[index] Deprecation of features in Python 2.9 is optional. This is because it is not known at this time if Python 2.9 (which is slated to be the last version in the 2.x series) will actively deprecate features that will not be in 3.0 . It is conceivable that no deprecation warnings will be used in 2.9 since there could be such a difference between 2.9 and 3.0 that it would make 2.9 too "noisy" in terms of warnings. Thus the proposed deprecation warnings for Python 2.9 will be revisited when development of that version begins to determine if they are still desired. * Python 2.5 [done] - all standard exceptions become new-style classes - introduce BaseException - Exception, KeyboardInterrupt, and SystemExit inherit from BaseException - deprecate raising string exceptions * Python 2.6 - deprecate catching string exceptions - deprecate ``message`` attribute (see `Retracted Ideas`_) * Python 2.7 - deprecate raising exceptions that do not inherit from BaseException - remove ``message`` attribute * Python 2.8 - deprecate catching exceptions that do not inherit from BaseException * Python 2.9 - deprecate ``__getitem__`` (optional) * Python 3.0 [done] - drop everything that was deprecated above: + string exceptions (both raising and catching) + all exceptions must inherit from BaseException + drop ``__getitem__`` Retracted Ideas =============== A previous version of this PEP that was implemented in Python 2.5 included a 'message' attribute on BaseException. Its purpose was to begin a transition to BaseException accepting only a single argument. This was to tighten the interface and to force people to use attributes in subclasses to carry arbitrary information with an exception instead of cramming it all into ``args``. Unfortunately, while implementing the removal of the ``args`` attribute in Python 3.0 at the PyCon 2007 sprint [#pycon2007-sprint-email]_, it was discovered that the transition was very painful, especially for C extension modules. It was decided that it would be better to deprecate the ``message`` attribute in Python 2.6 (and remove in Python 2.7 and Python 3.0) and consider a more long-term transition strategy in Python 3.0 to remove multiple-argument support in BaseException in preference of accepting only a single argument. Thus the introduction of ``message`` and the original deprecation of ``args`` has been retracted. References ========== .. [#pep348] PEP 348 (Exception Reorganization for Python 3.0) http://www.python.org/peps/pep-0348.html .. [#hierarchy-good] python-dev Summary for 2004-08-01 through 2004-08-15 http://www.python.org/dev/summary/2004-08-01_2004-08-15.html#an-exception-i… .. [#SF_1104669] SF patch #1104669 (new-style exceptions) http://www.python.org/sf/1104669 .. [#pycon2007-sprint-email] python-3000 email ("How far to go with cleaning up exceptions") http://mail.python.org/pipermail/python-3000/2007-March/005911.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:

3 3

Re: [Python-Dev] [Distutils] unicode bug in distutils
by Phillip J. Eby April 5, 2009

April 5, 2009

At 02:47 PM 2/24/2007 -0600, Tarek Ziadé wrote: >I have created a setup.py file for distirbution and I bumped into >a small bug when i tried to set my name in the contact field (Tarek Ziadé) > >Using string (utf8 file): > >setup( > maintainer="Tarek Ziadé" >) > >leads to: > > File ".../lib/python2.5/distutils/command/register.py", line 162, in > send_metadata > auth) > File ".../lib/python2.5/distutils/command/register.py", line 257, in > post_to_server > value = unicode(value).encode("utf-8") >UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 10: >ordinal not in range(128) > > >Using unicode: > >setup( > maintainer=u"Tarek Ziadé" >) > >leads to: > > File ".../lib/python2.5/distutils/dist.py", line 1094, in write_pkg_file > file.write('Author: %s\n' % self.get_contact() ) >UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in >position 18: ordinal not in range(128) > >I would propose a patch for this problem but i don't know what would be >the best input (i guess unicode > for names) At 05:45 PM 2/24/2007 -0500, Tres Seaver wrote: >Don't you still need to tell Python about the encoding of your string >literals [1] [2] ? E.g.:: That's not the problem, it's that the code that writes the PKG-INFO file doesn't handle Unicode. See distutils.dist.DistributionMetadata.write_pkg_info(). It needs to use a file with encoding support, if it's doing unicode However, there's currently no standard, as far as I know, for what encoding the PKG-INFO file should use. Meanwhile, the 'register' command accepts Unicode, but is broken in handling it. Essentially, the problem is that Python 2.5 broke this by adding a unicode *requirement* to the "register" command. Previously, register simply sent whatever you gave it, and the PKG-INFO writing code still does. Unfortunately, this means that there is no longer any one value that you can use for your name that will be accepted by both "register" and anything that writes a PKG-INFO file. Both register and write_pkg_info() are arguably broken here, and should be able to work with either strings or unicode, and degrade gracefully in the event of non-ASCII characters in a string. (Because even though "register" is only run by the package's author, users may run other commands that require a PKG-INFO, so a package prepared using Python <2.5 must still be usable with Python 2.5 distutils, and Python <2.5 allows 8-bit maintainer names.) Unfortunately, this isn't fixable until there's a new 2.5.x release. For previous Python versions, both register and write_pkg_info() accepted 8-bit strings and passed them on as-is, so the only workaround for this issue at the moment is to revert to Python 2.4 or less.

4 5

Python + Java Integration
by Chas Emerick Dec. 5, 2008

Dec. 5, 2008

This may seem like it's coming out of left field for a minute, but bear with me. There is no doubt that Ruby's success is a concern for anyone who sees it as diminishing Python's status. One of the reasons for Ruby's success is certainly the notion (originally advocated by Bruce Tate, if I'm not mistaken) that it is the "next Java" -- the language and environment that mainstream Java developers are, or will, look to as a natural next step. One thing that would help Python in this "debate" (or, perhaps simply put it in the running, at least as a "next Java" candidate) would be if Python had an easier migration path for Java developers that currently rely upon various third-party libraries. The wealth of third-party libraries available for Java has always been one of its great strengths. Ergo, if Python had an easy-to-use, recommended way to use those libraries within the Python environment, that would be a significant advantage to present to Java developers and those who would choose Ruby over Java. Platform compatibility is always a huge motivator for those looking to migrate or upgrade. In that vein, I would point to JPype (http://jpype.sourceforge.net). JPype is a module that gives "python programs full access to java class libraries". My suggestion would be to either: (a) include JPype in the standard library, or barring that, (b) make a very strong push to support JPype (a) might be difficult or cumbersome technically, as JPype does need to build against Java headers, which may or may not be possible given the way that Python is distributed, etc. However, (b) is very feasible. I can't really say what "supporting JPype" means exactly -- maybe GvR and/or other heavyweights in the Python community make public statements regarding its existence and functionality, maybe JPype gets a strong mention or placement on python.org....all those details are obviously not up to me, and I don't know the workings of the "official" Python organizations enough to make serious suggestions. Regardless of the form of support, I think raising people's awareness of JPype and what it adds to the Python environment would be a Good Thing (tm). For our part, we've used JPype to make PDFTextStream (our previously Java-only PDF text extraction library) available and supported for Python. You can read some about it here: http://snowtide.com/PDFTextStream.Python And I've blogged about how PDFTextStream.Python came about, and how we worked with Steve Ménard, the maintainer of JPype, to make it all happen (watch out for this URL wrapping): http://blog.snowtide.com/2006/08/21/working-together-pythonjava-open- sourcecommercial Cheers, Chas Emerick Founder, Snowtide Informatics Systems Enterprise-class PDF content extraction cemerick(a)snowtide.com http://snowtide.com | +1 413.519.6365

3 2

Buildbots for trunk are all red
by Facundo Batista May 16, 2008

May 16, 2008

All fail in test_compiler.py. -- . Facundo Blog: http://www.taniquetil.com.ar/plog/ PyAr: http://www.python.org/ar/

21 51

Py3k and asyncore/asynchat
by Daniel Arbuckle March 26, 2008

March 26, 2008

A while back, I volunteered to update asyncore and asynchat for py3k. I posted a patch, and in response to feedback posted a more complicated patch+modification. Both versions have been languishing at http://bugs.python.org/issue1563 for a couple of months now without any further feedback or action. I need some more experienced member of the community to take some sort of action: reviews and suggestions are welcome, as is advice about which version I should continue on with. Committing the patch would also be acceptable :)

11 26

Adventures with x64, VS7 and VS8 on Windows
by Mark Hammond March 22, 2008

March 22, 2008

Hi all, I hope the cross-post is appropriate. I've started playing with getting the pywin32 extensions building under the AMD64 architecture. I started building with Visual Studio 8 (it was what I had handy) and I struck a few issues relating to the compiler version that I thought worth sharing. * In trying to build x64 from a 32bit VS7 (ie, cross-compiling via the PCBuild directory), the python.exe project fails with: pythoncore fatal error LNK1112: module machine type 'X86' conflicts with target machine type 'AMD64' is this a known issue, or am I doing something wrong? * The PCBuild8 project files appear to work without modification (I only tried native compilation here though, not a cross-compile) - however, unlike the PCBuild directory, they place all binaries in a 'PCBuild8/x64' directory. While this means that its possible to build for multiple architectures from the same source tree, it makes life harder for tools like 'distutils' - eg, distutils already knows about the 'PCBuild' directory, but it knows nothing about either PCBuild8 or PCBuild8/x64. A number of other build processes also know to look inside a PCBuild directory (eg, Mozilla), so instead of formalizing PCBuild8, I think we should merge PCBuild8 into PCBuild. This could mean PCBuild/vs7 and PCBuild/vs8 directories with the "project" files, but binaries would still be generated in the 'PCBuild' (or PCBuild/x64) directory. This would mean the same tree isn't capable of hosting 2 builds from different VS compilers, but I think that is reasonable (if it's a problem, just have multiple source directories). I understand that PCBuild8 is not "official", but in the assumption that future versions of Python will use a compiler later than VS7, it makes sense to me to clean this up now - what are others opinions on this? * Re the x64 directory used by the PCBuild8 process. IMO, it makes sense to generate x64 binaries to their own directory - my expectation is that cross-compiling between platforms is a reasonable use-case, and we should support multiple achitectures for the same compiler version. This would mean formalizing the x64 directory in both 'PCBuild' and distutils, and leaving other external build processes to update as they support x64 builds. Does this make sense? Would this fatally break other scripts used for packaging (eg, the MSI framework)? * Wide characters in VS8: PC/pyconfig.h defines PY_UNICODE_TYPE as 'unsigned short', which corresponds with both 'WCHAR' and 'wchar' in previous compiler versions. VS8 defines this as wchar_t, which I'm struggling to find a formal definition for beyond being 2 bytes. My problem is that code which assumes a 'Py_UNICODE *' could be used in place of a 'WCHAR *' now fails. I believe the intent on Windows has always been "PyUNICODE == 'native unicode'" - should PC/pyconfig.h reflect this (ie, should pyconfig.h grow a version specific definition of PyUNICODE as wchar_t)? * Finally, as something from left-field which may well take 12 months or more to pull off - but would there be any interest to moving the Windows build process to a cygwin environment based on the existing autoconf scripts? I know a couple of projects are doing this successfully, including Mozilla, so it has precendent. It does impose a greater burden on people trying to build on Windows, but I'd suggest that in recent times, many people who are likely to want to build Python on Windows are already likely to have a cygwin environment. Simpler mingw builds and nuking MSVC specific build stuff are among the advantages this would bring. It is not worth adding this as "yet another windows build option" - so IMO it is only worth progressing with if it became the "blessed" build process for windows - if there is support for this, I'll work on it as the opportunity presents itself... I'm (obviously) only suggesting we do this on the trunk and am happy to make all agreed changes - but I welcome all suggestions or critisisms of this endeavour... Cheers, Mark

12 57

Re: [Python-Dev] [Python-checkins] r45510 - python/trunk/Lib/pkgutil.py python/trunk/Lib/pydoc.py
by M.-A. Lemburg March 21, 2008

March 21, 2008

Phillip.eby wrote: > Author: phillip.eby > Date: Tue Apr 18 02:59:55 2006 > New Revision: 45510 > > Modified: > python/trunk/Lib/pkgutil.py > python/trunk/Lib/pydoc.py > Log: > Second phase of refactoring for runpy, pkgutil, pydoc, and setuptools > to share common PEP 302 support code, as described here: > > http://mail.python.org/pipermail/python-dev/2006-April/063724.html Shouldn't this new module be named "pkglib" to be in line with the naming scheme used for all the other utility modules, e.g. httplib, imaplib, poplib, etc. ? > pydoc now supports PEP 302 importers, by way of utility functions in > pkgutil, such as 'walk_packages()'. It will properly document > modules that are in zip files, and is backward compatible to Python > 2.3 (setuptools installs for Python <2.5 will bundle it so pydoc > doesn't break when used with eggs.) Are you saying that the installation of setuptools in Python 2.3 and 2.4 will then overwrite the standard pydoc included with those versions ? I think that's the wrong way to go if not made an explicit option in the installation process or a separate installation altogether. I bothered by the fact that installing setuptools actually changes the standard Python installation by either overriding stdlib modules or monkey-patching them at setuptools import time. > What has not changed is that pydoc command line options do not support > zip paths or other importer paths, and the webserver index does not > support sys.meta_path. Those are probably okay as limitations. > > Tasks remaining: write docs and Misc/NEWS for pkgutil/pydoc changes, > and update setuptools to use pkgutil wherever possible, then add it > to the stdlib. Add setuptools to the stdlib ? I'm still missing the PEP for this along with the needed discussion touching among other things, the change of the distutils standard "python setup.py install" to install an egg instead of a site package. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Apr 18 2006) >>> Python/Zope Consulting and Support ... http://www.egenix.com/ >>> mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/ ________________________________________________________________________ ::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,FreeBSD for free ! ::::

14 51

Python XML Validator
by Medhat Gayed March 12, 2008

March 12, 2008

I tested and tried a few XML validators but none of them is able to successfully validate a string of xml (not a file just a string) to programatically be able to validate messages of xml that flow in and out of the different systems. Teh validators I used were XSV, oNVDL and lxml, can we implement a pure python module for validating strings of xml using XML Schema (not DTD). lxml is good but not written in python and difficult to install and didn't work on MacOS X. XSV very poor documentation and only validates xml files not strings. oNVDL not writtem in python and only validates xml files not strings.

8 12

Get rid of strerror.c and memmove.c?
by Brett Cannon March 10, 2008

March 10, 2008

I ran LLVM's under-development C front-end, clang (http://clang.llvm.org), against Python today. While a ton of message crop up thanks to lacking header files, I did come across a handful of semi-useful warnings (e.g., the change I checked into Python/compile.c). One thing it picked up is that on OS X Python/strerror.c disagrees with the declaration of sys_nerr and such. But then I thought I remembered strerror() being in C89. I checked configure-in to make sure that it wasn't special for some reason, it it isn't; only used when the function is not normally available. Same goes for memmove(). Since both strerror() and memmove() are both in C89 (they are listed in K&R), can we ditch these files? -Brett

3 2

Re: [Python-Dev] Python 2.6 and 3.0 ...and applink.c?
by Bugbee, Larry March 4, 2008

March 4, 2008

Hi Barry, A question.... Do you know if OpenSSL's applink.c will be included in the Windows builds? If so, and I hope it is, great! If not, I'd like to encourage its inclusion. Doing so will permit Python to be used with OpenSSL 0.9.8x on Windows platforms without a user trying to find somebody with the right compiler to rebuild a Python for him/her. This is needed for M2Crypto, or any other OpenSSL wrapper for that matter. A lot more can be said here, but in the interest of brevity... ;-) applink.c is perhaps two dozen links and some error codes, and is benign for those not calling these APIs. applink.c may be found in <openssl_source_dir>/ms and the one line include stmt that would be added to <py-src>/Modules/python.c is: #include "<path_to>/applink.c" That's it. And the OpenSSL FAQ: http://www.openssl.org/support/faq.html#PROG2 Tx, Larry

7 13

Upcoming 2.4.5 and 2.3.7 releases
by "Martin v. Löwis" March 3, 2008

March 3, 2008

Along with the release of 2.5.2, I would also like to release new versions of 2.3 and 2.4. These will be security-only releases, and include a few security-relevant bug fixes that are still being finalized. As we don't have the infrastructure to produce full releases of 2.3 or 2.4 anymore, this will be a source release only. As such, it will likely see less testing than other releases, and users will have more difficulties in obtaining the software for their system - the releases will be targeted primarily at system vendors who can chose to include them as security patches in their system updates. As a consequence, I would like to roll back all changes from the 2.3 and 2.4 branches which aren't security fixes. In specific cases, the nature of a change might be debatable; clear security fixes are prevention of memory corruption and interpreter crashes, clear non-security fixes are documentation and test-suite changes. For 2.3, there are only few revisions that would be rolled back: r52798, r52803, r52824, r54342. For 2.4, the list is longer; all changes on the branch since r52382 are candidate for roll-back. I would like to prepare a white-list of patches that should be preserved; if you think any of the patches committed in the 2.4 branch is a security fix, please let me know. Regards, Martin

6 15

Fixing buildbot/external(-amd64).bat files on Windows
by Trent Nelson Feb. 29, 2008

Feb. 29, 2008

Howdy, I'm going through the motions of getting my newly added build slave in a half decent state. The external.bat and external-amd64.bat files needed the following in order to build db-4.4.20: Index: external.bat =================================================================== --- external.bat (revision 61125) +++ external.bat (working copy) @@ -10,7 +10,8 @@ @rem Sleepycat db if not exist db-4.4.20 svn export http://svn.python.org/projects/external/db-4.4.20 if not exist db-4.4.20\build_win32\debug\libdb44sd.lib ( - vcbuild db-4.4.20\build_win32\Berkeley_DB.sln /build Debug /project db_static + devenv /upgrade db-4.4.20\build_win32\Berkeley_DB.sln + devenv db-4.4.20\build_win32\Berkeley_DB.sln /build Debug /project db_static ) @rem OpenSSL (This is against trunk, same thing would apply to py3k I guess, given that we're using %VS90COMNTOOLS%vsvars32.bat there too.) Regards, Trent. -- http://www.onresolve.com

4 14

Code freeze?
by Christian Heimes Feb. 29, 2008

Feb. 29, 2008

Hey Barry! When are you planing to freeze the code of the trunk and branches/py3k for the upcoming alpha releases? I'll merge the last modifications from 2.6 to 3.0 in a couple of minutes. All tests on Linux are looking good, except for the two profile tests on 3.0. I'm going to test Windows later. Christian

9 20

download python-2.6 docs?
by Neal Becker Feb. 29, 2008

Feb. 29, 2008

http://docs.python.org/dev/download.html I want a pdf. The above link says: "To download an archive containing all the documents for this version of Python in one of various formats, follow one of links in this table. " But there are no links.

2 1

Summary of Tracker Issues
by Tracker Feb. 29, 2008

Feb. 29, 2008

ACTIVITY SUMMARY (02/22/08 - 02/29/08) Tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue number. Do NOT respond to this message. 1711 open (+34) / 12326 closed (+13) / 14037 total (+47) Open issues with patches: 457 Average duration of open issues: 741 days. Median duration of open issues: 1110 days. Open Issues Breakdown open 1690 (+34) pending 21 ( +0) Issues Created Or Reopened (50) _______________________________ sqlite numeric type conversion problems 02/27/08 http://bugs.python.org/issue2157 reopened ghaering patch dl broken on non-ILP32 platforms 02/22/08 CLOSED http://bugs.python.org/issue2164 created notting Fix for test_logging 02/23/08 CLOSED http://bugs.python.org/issue2165 created therve pydistutils.cfg won't be found on Windows 02/23/08 http://bugs.python.org/issue2166 created tarek Remove unused imports 02/23/08 CLOSED http://bugs.python.org/issue2167 created calvin patch gdbm needs to be iterable 02/23/08 CLOSED http://bugs.python.org/issue2168 created therve patch Adding DOCTYPE and "html", "body" tags to SimpleHTTPServer 02/23/08 CLOSED http://bugs.python.org/issue2169 created ajaksu2 rewrite of minidom.Node.normalize 02/23/08 http://bugs.python.org/issue2170 created maltehelmert Add map, filter, zip to future_builtins 02/24/08 http://bugs.python.org/issue2171 created georg.brandl Add doc-string to UserDict and DictMixin 02/24/08 http://bugs.python.org/issue2172 created belopolsky patch Python fails silently on bad locale 02/24/08 http://bugs.python.org/issue2173 created motteneder xml.sax.xmlreader does not support the InputSource protocol 02/24/08 http://bugs.python.org/issue2174 created ygale Expat sax parser silently ignores the InputSource protocol 02/24/08 http://bugs.python.org/issue2175 created ygale Undocumented lastrowid attribute i sqlite3 cursor class 02/24/08 http://bugs.python.org/issue2176 created bukaj Update compiler module to handle class decorators 02/24/08 CLOSED http://bugs.python.org/issue2177 created therve patch Problems with Belarusian Latin locale 02/24/08 http://bugs.python.org/issue2178 created booxter with should be as fast as try/finally 02/24/08 http://bugs.python.org/issue2179 created jyasskin tokenize: mishandles line joining 02/25/08 http://bugs.python.org/issue2180 created jaredgrubb optimize out local variables at end of function 02/25/08 http://bugs.python.org/issue2181 created nnorwitz patch, patch tokenize: does not allow CR for a newline 02/25/08 http://bugs.python.org/issue2182 created jaredgrubb optimize list comprehensions 02/25/08 http://bugs.python.org/issue2183 created nnorwitz patch, patch Speed up Thread.start() 02/25/08 CLOSED http://bugs.python.org/issue2184 created jyasskin patch, patch code objects should conserve memory 02/25/08 http://bugs.python.org/issue2185 created nnorwitz patch, patch map and filter shouldn't support None as first argument (in Py3k 02/25/08 http://bugs.python.org/issue2186 created gvanrossum patch, easy map and filter objects shouldn't call themselves itertools.imap 02/25/08 http://bugs.python.org/issue2187 created gvanrossum easy [patch] urllib2 hint - disabled ProxyHandler() 02/25/08 http://bugs.python.org/issue2188 created techtonik urllib.quote() throws KeyError when passed an iterator 02/25/08 http://bugs.python.org/issue2189 created djc MozillaCookieJar ignore HttpOnly cookies 02/25/08 http://bugs.python.org/issue2190 created douyuan patch SubProcess Startup error 02/25/08 CLOSED http://bugs.python.org/issue2191 created madhusudan.sk error with backslash as last character in raw string 02/25/08 CLOSED http://bugs.python.org/issue2192 created aka Cookie Colon Name Bug 02/26/08 http://bugs.python.org/issue2193 created BM Tiny patch to docs 02/26/08 CLOSED http://bugs.python.org/issue2194 created tim.golden patch urlparse() does not handle URLs with port numbers properly 02/26/08 http://bugs.python.org/issue2195 created gawain Fix hasattr's exception problems 02/26/08 http://bugs.python.org/issue2196 created benjamin.peterson patch Further simplify dict literal bytecode 02/27/08 http://bugs.python.org/issue2197 created belopolsky patch code_hash() can be the same for different code objects 02/27/08 http://bugs.python.org/issue2198 created sdeibel cPickle error with gtk GEnum classes 02/28/08 http://bugs.python.org/issue2199 created pyscripter find_executable fails to find .bat files on win32 02/28/08 http://bugs.python.org/issue2200 created abbot Documentation Section 4.4 02/28/08 CLOSED http://bugs.python.org/issue2201 created str8lazy urllib2 fails against IIS 6.0 (No support for MD5-sess auth) 02/28/08 http://bugs.python.org/issue2202 created bwmcadams easy ssl module getpeercert returns empty dict when cert_reqs=ssl.CER 02/28/08 http://bugs.python.org/issue2203 created mryden document ConfigParser behaviour when a file has same section mul 02/28/08 http://bugs.python.org/issue2204 created draghuram os.times() returns incorrect value 02/29/08 CLOSED http://bugs.python.org/issue2205 created kwatch patch critical memory leak in hashlib.md5 02/29/08 CLOSED http://bugs.python.org/issue2206 created agateriver Bug in Sphinx highlighting when pygments not available 02/29/08 http://bugs.python.org/issue2207 created tim.golden patch Patch to doc/make.bat to allow non-standard HTML Help location 02/29/08 http://bugs.python.org/issue2208 created tim.golden patch mailbox module doesn't support compressed mbox 02/29/08 http://bugs.python.org/issue2209 created jae Nested module import clutters package namespace 02/29/08 http://bugs.python.org/issue2210 created ruediger.kupper Enhance file.readlines by making line separator selectable 02/27/08 http://bugs.python.org/issue1152248 reopened rhettinger thread + import => crashes? 02/24/08 http://bugs.python.org/issue1720705 reopened ncoghlan Issues Now Closed (73) ______________________ Test issue 177 days http://bugs.python.org/issue1064 loewis patch race in SocketServer.ForkingMixIn.collect_children 161 days http://bugs.python.org/issue1183 jyasskin patch test_resource fails on recent linux systems 129 days http://bugs.python.org/issue1291 akuchling easy Embedded python reinitialization 127 days http://bugs.python.org/issue1306 tiran os.path.exists(os.devnull) regression on windows 124 days http://bugs.python.org/issue1311 akuchling BaseHTTPServer hard-codes Content-Type for error messages 92 days http://bugs.python.org/issue1492 georg.brandl easy Problem with httplib and Content-Length: -1 71 days http://bugs.python.org/issue1627 georg.brandl easy Move Demo/classes/Rat.py to Lib/fractions.py and fix it up. 70 days http://bugs.python.org/issue1682 jyasskin patch Backport of PEP 3129 "class decorators" 46 days http://bugs.python.org/issue1759 tiran patch Inheriting from ABCs makes classes slower. 51 days http://bugs.python.org/issue1762 jyasskin ConfigParser: add_section('DEFAULT') causes duplicate sections. 44 days http://bugs.python.org/issue1781 facundobatista patch, easy msilib.add_data() takes exactly three parameters 40 days http://bugs.python.org/issue1825 georg.brandl patch, easy operator.attrgetter() should accept dotted attribute paths 40 days http://bugs.python.org/issue1826 georg.brandl easy unhelpful error when calling "python <dirname>" 34 days http://bugs.python.org/issue1877 ncoghlan easy increase parser stack limit 33 days http://bugs.python.org/issue1881 tiran Document that with is slower than try/finally 33 days http://bugs.python.org/issue1910 jyasskin easy [patch] syslogmodule: Release GIL when calling syslog(3) 26 days http://bugs.python.org/issue1957 tiran patch, easy Slight adjustment to sphinx print-media stylesheet 25 days http://bugs.python.org/issue1964 georg.brandl patch io.StringIO allows any parameter 25 days http://bugs.python.org/issue1986 georg.brandl PYO file permission problem 15 days http://bugs.python.org/issue2051 tiran file.__exit__ does not call subclass' close method 12 days http://bugs.python.org/issue2067 schmir SimpleXMLRPCServer documentation about rpc_paths might be wrong 12 days http://bugs.python.org/issue2072 akuchling xml.dom documentation doesn't match implementation 10 days http://bugs.python.org/issue2101 georg.brandl easy Implement __format__ for Decimal 15 days http://bugs.python.org/issue2110 marketdickinson patch [feature-request] Please add bool data type to "optparse" module 7 days http://bugs.python.org/issue2130 facundobatista easy os.environ should inherit dict 4 days http://bugs.python.org/issue2144 belopolsky patch Queue.maxsize, __init__() accepts any value as maxsize 3 days http://bugs.python.org/issue2149 benjamin.peterson STORE_LOCAL byte code is not documented 1 days http://bugs.python.org/issue2161 georg.brandl test_socket is flakey 3 days http://bugs.python.org/issue2163 gvanrossum easy dl broken on non-ILP32 platforms 0 days http://bugs.python.org/issue2164 loewis Fix for test_logging 0 days http://bugs.python.org/issue2165 georg.brandl Remove unused imports 0 days http://bugs.python.org/issue2167 tiran patch gdbm needs to be iterable 2 days http://bugs.python.org/issue2168 rhettinger patch Adding DOCTYPE and "html", "body" tags to SimpleHTTPServer 5 days http://bugs.python.org/issue2169 akuchling Update compiler module to handle class decorators 1 days http://bugs.python.org/issue2177 facundobatista patch Speed up Thread.start() 3 days http://bugs.python.org/issue2184 jyasskin patch, patch SubProcess Startup error 0 days http://bugs.python.org/issue2191 madhusudan.sk error with backslash as last character in raw string 1 days http://bugs.python.org/issue2192 aka Tiny patch to docs 0 days http://bugs.python.org/issue2194 georg.brandl patch Documentation Section 4.4 0 days http://bugs.python.org/issue2201 str8lazy os.times() returns incorrect value 1 days http://bugs.python.org/issue2205 georg.brandl patch critical memory leak in hashlib.md5 0 days http://bugs.python.org/issue2206 georg.brandl os.spawnv(P_WAIT, ...) on Linux doesn't handle EINTR 1838 days http://bugs.python.org/issue686667 facundobatista urllib2 doesn't handle urls without scheme 1735 days http://bugs.python.org/issue745097 facundobatista Applets don't work on 10.1 1667 days http://bugs.python.org/issue781445 akuchling Module-specific PDFs 1632 days http://bugs.python.org/issue800929 akuchling More obvious indication of __reduce__ documentation. 1572 days http://bugs.python.org/issue835521 akuchling catch invalid chunk length in httplib read routine 1465 days http://bugs.python.org/issue900744 georg.brandl patch long <-> byte-string conversion 1430 days http://bugs.python.org/issue923643 marketdickinson patch [PATCH] tty needs a way to restore the terminal mode. 1161 days http://bugs.python.org/issue1088077 facundobatista need siginterrupt() on Linux - impossible to do timeouts 1159 days http://bugs.python.org/issue1089358 facundobatista patch Memory leak in socket.py on Mac OS X 1152 days http://bugs.python.org/issue1092502 akuchling curses.initscr - initscr exit w/o env(TERM) set 1109 days http://bugs.python.org/issue1119331 akuchling descrintro describes __new__ and __init__ behavior wrong 1106 days http://bugs.python.org/issue1123716 facundobatista doctest should support -m 1087 days http://bugs.python.org/issue1156430 georg.brandl PEP 328 and Python 2.4 error 1089 days http://bugs.python.org/issue1157255 facundobatista import statement likely to crash if module launches threads 1058 days http://bugs.python.org/issue1175194 georg.brandl datetime/xmlrpclib.DateTime comparison 858 days http://bugs.python.org/issue1330538 akuchling patch Remove usage of UserDict from os.py 818 days http://bugs.python.org/issue1367711 loewis patch, easy imaplib causes excessive fragmentation for large documents 792 days http://bugs.python.org/issue1389051 akuchling patch, easy httplib patch to make _read_chunked() more robust 764 days http://bugs.python.org/issue1411097 georg.brandl patch normalize function in minidom unlinks empty child nodes 736 days http://bugs.python.org/issue1433694 akuchling easy httplib: read/_read_chunked failes with ValueError sometime 654 days http://bugs.python.org/issue1486335 georg.brandl Add "methodcaller" to the operator module 619 days http://bugs.python.org/issue1506171 georg.brandl ConfigParser: whitespace leading comment lines 499 days http://bugs.python.org/issue1576208 facundobatista popen() slow on AIX due to large FOPEN_MAX value 449 days http://bugs.python.org/issue1607087 georg.brandl patch Speed up PyArg_ParseTupleAndKeywords() and improve error msg 333 days http://bugs.python.org/issue1691070 tiran patch glibc error: corrupted double linked list (CPython 2.5.1) 285 days http://bugs.python.org/issue1718942 facundobatista Allow interpreter to execute a zip file 96 days http://bugs.python.org/issue1739468 ncoghlan patch "%d" format handling for long values 244 days http://bugs.python.org/issue1742669 facundobatista patch class mutex doesn't do anything atomically 237 days http://bugs.python.org/issue1746071 facundobatista patch, easy poll() on cygwin sometimes fails [PATCH] 214 days http://bugs.python.org/issue1759997 georg.brandl Minor corrections to smtplib 190 days http://bugs.python.org/issue1776581 facundobatista patch Top Issues Most Discussed (10) ______________________________ 45 os.times() is bogus 1243 days open http://bugs.python.org/issue1040026 16 simple patch, improving unreachable bytecode removing 116 days open http://bugs.python.org/issue1394 14 map and filter shouldn't support None as first argument (in Py3 5 days open http://bugs.python.org/issue2186 14 os.environ should inherit dict 4 days closed http://bugs.python.org/issue2144 10 thread + import => crashes? 5 days open http://bugs.python.org/issue1720705 8 Add VS CRT redist to the MSI installer 84 days open http://bugs.python.org/issue1569 8 Bug in range() function for large values 91 days open http://bugs.python.org/issue1533 7 Restructure import.c into PEP 302 importer objects 12 days open http://bugs.python.org/issue2135 7 Distutils default exclude doesn't match top level .svn 280 days open http://bugs.python.org/issue1725737 6 optimize out local variables at end of function 5 days open http://bugs.python.org/issue2181

1 0

Re: [Python-Dev] [Python-3000] Code freeze?
by Nick Coghlan Feb. 29, 2008

Feb. 29, 2008

Christian Heimes wrote: > Is this documented somewhere? The docs say "See the > :meth:`__getattribute__` method below for a way to actually get total > control over attribute access.". I just checked, and the restriction is now documented in the development docs in the section on special methods at [1]. It was backported from the Py3k docs and isn't part of the docs for 2.5 or earlier versions. The gist is that special methods *must* be defined directly on a new-style class in order for the interpreter to reliably access them, but defining them on a new-style instance *may* still affect the interpreter's behaviour in some cases (but won't necessarily do so). In composing this response, I also realised why the new tempfile tests worked for me before I checked them in: I was testing it on the trunk, where _TemporaryFileWrapper is a classic class. Special method lookup on classic classes doesn't include the 'direct-to-type' optimisation, so those tests work with the tempfile module as written on 2.x. Unfortunately, proxies like _TemporaryFileWrapper that rely on __getattr__ to provide special methods simply won't work properly when implemented as new-style classes - for that, they need to spell out the overridden special methods the way SpooledTemporaryFile does. I think we may need a -3 warning that detects situations where "__*__" attributes are retrieved via a __getattr__ implementation on a classic class - classes being used that way have a very high chance of breaking when ported to 3.0 and I can't see any possible way for 2to3 to detect them. Cheers, Nick. [1] http://docs.python.org/dev/reference/datamodel.html#special-method-names -- Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia --------------------------------------------------------------- http://www.boredomandlaziness.org

2 1

Google Summer of Code 2008
by James Tauber Feb. 29, 2008

Feb. 29, 2008

The Google Summer of Code is on again and I've been asked to coordinate the PSF's involvement. You can find out more about GSoC at http://code.google.com/soc/2008/ There is also a page on the Python wiki: http://wiki.python.org/moin/SummerOfCode Although the PSF does act as an umbrella organization for a number of different projects, we'd like to give as much opportunity as possible for students to work on core Python development. At this stage it would be great if you could start thinking about potential projects and/or whether you would be willing to be a mentor. Two mailing lists have been set up: http://mail.python.org/mailman/listinfo/soc2008-mentors http://mail.python.org/mailman/listinfo/soc2008-general If you are interested in being a mentor, please join both lists. The mentor list requires approval and the archive is private. The general list is for anyone interested in the summer of code and all potential mentors, potential students and interested lurkers should join. Let me know if you have any questions. James -- James Tauber http://jtauber.com/ journeyman of some http://jtauber.com/blog/

2 1

Python 2.6 and 3.0
by Barry Warsaw Feb. 27, 2008

Feb. 27, 2008

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi everyone, I've volunteered to be the release manager for Python 2.6 and 3.0. It's been several years since I've RM'd a Python release, and I'm happy to do it again (he says while the medication is still working :). I would like to get the next alpha releases of both versions out before Pycon, so I propose next Friday, February 29 for both. Guido reminded me that we released Python 1.6 and 2.0 together and it makes sense to both of us to do the same for Python 2.6 and 3.0. I don't think it will be that much more work (for me at least :) to release them in lockstep, so I think we should try it. I won't try to sync their pre-release version numbers except at the milestones (e.g. first beta, release candidates, final releases). I propose to change PEP 361 to outline the release schedule for both Python 2.6 and 3.0. I'm hoping we can work out a more definite schedule at Pycon, but for now I want to at least describe the lockstep release schedule and the Feb 29 date. I'd also like for us to consider doing regular monthly releases. Several other FLOSS projects I'm involved with are doing this to very good success. The nice thing is that everyone knows well in advance when the next release is going to happen, and so all developers and users know what to expect and what is needed from them. I'd like to propose that we do a joint release the last Friday of every month. For the alphas, it's basically what's in svn. This gives us some time to experiment with the process out and see if we like it enough to keep it going through the betas and final releases. Comments? - -Barry -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (Darwin) iQCVAwUBR79ek3EjvBPtnXfVAQJrmQP+KAzy0lSzake2BZsVxErD0kpFQJM+Iij0 qN86wjH0NoqARMfYKVA6eUzEY8vZPu7sJl+SjCOmhnE/KP+l/ArOdis5smiSKwQI klL4XKd/qdorTMqQ9mWgA0DeBb0Asvln9y64nxzNqgve+36q9j6ytPuRey1GjSI5 nVWoJDb3WsM= =4SRa -----END PGP SIGNATURE-----

11 31

Adding a new Windows x64 buildbot
by Trent Nelson Feb. 27, 2008

Feb. 27, 2008

Hi, I've got a Windows Server 2008 x64 server I'd like to contribute as a buildbot. As per the recommendation on http://wiki.python.org/moin/BuildBot, it sounds like I'm looking for Martin, Anthony or Neal to sort me out with slave credentials. Feel free to drop me a line! Regards, Trent.

1 0

hello
by panrui pan Feb. 27, 2008

Feb. 27, 2008

1 0

Getting a second review on a rewrite of test_logging
by Brett Cannon Feb. 27, 2008

Feb. 27, 2008

I think over a week ago I applied some GHOP work that turned test_logging into a doctest, but it turns out it is still flaky. Luckily Antoine Pitrou rewrote test_logging using unittest and seems to have made it more sound. But before I replace test_logging again (especially with a more dramatic change) I would like to get a second pair of eyes on the patch as I really don't know the logging package that well. It's issue 1740 (http://bugs.python.org/issue1740). If you happen to know the logging package I would really appreciate it if you could give the patch a look. -Brett

1 0

getpass and stdin
by Shaya Potter Feb. 26, 2008

Feb. 26, 2008

[please cc me on responses] I was wondering if getpass could be changed to enable piped stdin to work. For instance, the getmail program can read my email password in via stdin using getpass functionality. However, if I do echo password | getmail4 it will fail due to stdin not being a terminal and therefore not being able to do a old = termios.tcgetattr(fd) on it. From what I can tell, the point of this is to only to prevent echoing the password, which isn't a problem in the echo case I give (especially if using bash, then it wont even be on the cmdline when run from a script as it's a builtin, script can also read in the password and store it in memory). currently the code is ----- def unix_getpass(prompt='Password: '): """Prompt for a password, with echo turned off. Restore terminal settings at end. """ try: fd = sys.stdin.fileno() except: return default_getpass(prompt) old = termios.tcgetattr(fd) # a copy to save new = old[:] new[3] = new[3] & ~termios.ECHO # 3 == 'lflags' try: termios.tcsetattr(fd, termios.TCSADRAIN, new) passwd = _raw_input(prompt) finally: termios.tcsetattr(fd, termios.TCSADRAIN, old) sys.stdout.write('\n') return passwd ----- it would seem that if the tcgetattr() line is moved into the initial try, my echo case would work as expected (as it would fail, but be caught and then just run default_getpass() (which should just read it from stdin). Is there any reason not to do it this way?

4 10