Mailman 3 March 2008 - Python-Dev

Re: [Python-Dev] [Python-checkins] r61403 - python/trunk/Misc/NEWS
by Nick Coghlan March 16, 2008

March 16, 2008

skip.montanaro wrote: > Author: skip.montanaro > Date: Sat Mar 15 17:07:11 2008 > New Revision: 61403 > > Modified: > python/trunk/Misc/NEWS > Log: > . > > > Modified: python/trunk/Misc/NEWS > ============================================================================== > --- python/trunk/Misc/NEWS (original) > +++ python/trunk/Misc/NEWS Sat Mar 15 17:07:11 2008 > @@ -21,6 +21,10 @@ > Library > ------- > > +- Issue #1158: add %f format (fractions of a second represented as > + microseconds) to datetime objects. Understood by both strptime and > + strftime. %f makes me think femtoseconds :) Any particular reason we can't use '%u' to align with the convention of abbreviating microseconds as 'us' when a character encoding doesn't provide convenient access to the Greek letter mu? (e.g. ASCII) Cheers, Nick. -- Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia --------------------------------------------------------------- http://www.boredomandlaziness.org

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difference between diff string implementations
by Neal Norwitz March 16, 2008

March 16, 2008

This inconsistency goes back to 2.3 at least and probably to the initial unicode implementation. >>> set(dir(u'')) - set(dir('')) ['isnumeric', 'isdecimal'] UserString contains these two methods even though 8-bit strings do not. I'm not sure what we should do for 2.6 or 3.0. My preference would be to remove these methods on unicode/UserString if they aren't useful to a large audience. However, removing for 2.6 without a deprecation seems bad. Suggestions? n

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No __bases__ in dir()
by Facundo Batista March 15, 2008

March 15, 2008

Hi! My head crashed into this: >>> class C(object): ...: pass ...: >>> >>> dir(C) ['__class__', ...] >>> C.__bases__ (<type 'object'>,) Why __bases__ does not appear in dir()? Is there a good reason for this or should I file a bug? Thanks! -- . Facundo Blog: http://www.taniquetil.com.ar/plog/ PyAr: http://www.python.org/ar/

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Problems building python2.4 SRPM on RHEL4 x64
by Eric B. March 15, 2008

March 15, 2008

Hi, I appologize if this is not the right place to post this, but searching through the old archives, I ran across the same issue from 3 years ago, but I cannot find the resolution to it. Currently, I am trying to build the python2.4 SRPM from Python.org on a CentOS4.6_x64 platform, but the build is failing with a very non-descript error message. .... + cd /var/tmp/python2.4-2.4-root/usr/bin + mv -f pydoc pydoc2.4 + cd /var/tmp/python2.4-2.4-root/usr/bin + mv -f idle idle2.4 + echo '#!/bin/bash' + echo 'exec /usr/bin/python2.4 /usr/lib64/python2.4/idlelib/idle.py' + chmod 755 /var/tmp/python2.4-2.4-root/usr/bin/idle2.4 + cp -a Tools /var/tmp/python2.4-2.4-root/usr/lib64/python2.4 + rm -f mainpkg.files + find /var/tmp/python2.4-2.4-root/usr/lib64/python2.4/lib-dynload -type f + sed 's|^/var/tmp/python2.4-2.4-root|/|' + grep -v -e '_tkinter.so$' error: Bad exit status from /var/tmp/rpm-tmp.55639 (%install) RPM build errors: user jafo does not exist - using root group jafo does not exist - using root user jafo does not exist - using root group jafo does not exist - using root Bad exit status from /var/tmp/rpm-tmp.55639 (%install) The old post I found about this can be found here: http://mail.python.org/pipermail/python-bugs-list/2005-October/030670.html I checked the var/tmp/python2.4-2.4-root/usr/lib64 directories and see plenty of files in there, but not sure what I should be looking for. Can anyone point me in the right direction? Am not sure what to be looking for in order to get this to work. Thanks! Eric

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Complexity documentation request
by Dimitrios Apostolou March 15, 2008

March 15, 2008

Hello all, Is it possible to include algorithm complexity information for the various built-in types (strings, sets, lists, dictionaries...)? This would ease the decision for choosing the correct type. The information could simply be added as a new column in the tables found on pages as the following: http://docs.python.org/lib/types-set.html http://docs.python.org/lib/typesseq.html It took me a while to find some information for my purposes, however I'm not sure whether it's outdated or incomplete. The best sources I found are python-list archive and a PEP: http://www.python.org/dev/peps/pep-3128/ http://mail.python.org/pipermail/python-list/2007-June/446877.html Nevertheless, algorithm complexity is not always the answer. I remember some years ago I preferred using "x in list" rather than "x in set" as member checking in a tight loop, because the list was rather small (10-20 elements) and the overhead for the set was far greater than the better algorithm complexity advantage. So if this information is available, it would be nice to document constant time factors too. :-) Thanks in advance, Dimitris

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range in future_builtins?
by Eric Smith March 15, 2008

March 15, 2008

In the keynote, Guido mentioned switching from range to xrange in 2.6 code, as a migration strategy. Another option would be to add range to future_builtins, and have it call xrange. Would that be desirable?

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Link in license broken
by Georg Brandl March 15, 2008

March 15, 2008

While fixing the broken links in the docs, I saw that the link to http://www.pythonlabs.com/logos.html in the "BEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1" is broken. What to do about that? Georg

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Summary of Tracker Issues
by Tracker March 14, 2008

March 14, 2008

ACTIVITY SUMMARY (03/07/08 - 03/14/08) 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. 1735 open (+23) / 12380 closed (+14) / 14115 total (+37) Open issues with patches: 474 Average duration of open issues: 739 days. Median duration of open issues: 1152 days. Open Issues Breakdown open 1711 (+23) pending 24 ( +0) Issues Created Or Reopened (37) _______________________________ "continue" documentation 03/07/08 CLOSED http://bugs.python.org/issue2252 created blp "continue" documentation internally inconsistent 03/07/08 CLOSED http://bugs.python.org/issue2253 created blp Python CGIHTTPServer information disclosure 03/07/08 http://bugs.python.org/issue2254 created m.sucajtys patch Change Mandrake by Mandriva for platform.dist() 03/07/08 CLOSED http://bugs.python.org/issue2255 created neoclust patch Install failure of 2.6a1 on Windows XP without VS8 installed 03/07/08 http://bugs.python.org/issue2256 created jkleckner typo in tutorial section 4.4 - final break statement is missing 03/08/08 CLOSED http://bugs.python.org/issue2257 created Kyte999 Update command line docs for issue 1739468 03/09/08 http://bugs.python.org/issue2258 created ncoghlan easy Poor support other than 44.1khz, 16bit audio files? 03/09/08 http://bugs.python.org/issue2259 created loki_dePlume patch conditional jump to a POP_TOP optimization 03/09/08 http://bugs.python.org/issue2260 created _doublep patch Warning: could not send message for past 4 hours 03/09/08 CLOSED http://bugs.python.org/issue2261 created barnabas79 Helping the compiler avoid memory references in PyEval_EvalFrame 03/09/08 http://bugs.python.org/issue2262 created jyasskin patch, patch struct.pack() + numpy int raises SystemError 03/10/08 http://bugs.python.org/issue2263 created jvr empty specifier for float.__format__ does not always print at le 03/10/08 http://bugs.python.org/issue2264 created eric.smith A line in the second example of "7.3.5 Examples" in "Python Libr 03/10/08 CLOSED http://bugs.python.org/issue2265 created furutaka Missing documentation about old/new-style classes 03/10/08 http://bugs.python.org/issue2266 created Yinon datetime.datetime operator methods are not subclass-friendly 03/10/08 CLOSED http://bugs.python.org/issue2267 created stingray patch Fold slice constants 03/10/08 http://bugs.python.org/issue2268 created belopolsky patch Problem reporting non-keyword arg after keyword arg syntax error 03/10/08 CLOSED http://bugs.python.org/issue2269 created ijmorlan Typo on 8.6.2.5 Document Objects page 03/10/08 CLOSED http://bugs.python.org/issue2270 created throw6617 msi installs to the incorrect location (C drive) 03/10/08 http://bugs.python.org/issue2271 created rossmclendon Segment Violation when using smtp with tls 03/11/08 CLOSED http://bugs.python.org/issue2272 created hareldvd test_decimal: possible thread lockup in test case 03/11/08 http://bugs.python.org/issue2273 created jaredgrubb patch heapq API 03/11/08 CLOSED http://bugs.python.org/issue2274 created rhettinger urllib2 header capitalization 03/11/08 http://bugs.python.org/issue2275 created frispete patch distutils out-of-date for runtime_library_dirs flag on OS X 03/12/08 http://bugs.python.org/issue2276 created janssen easy MozillaCookieJar does not support Firefox3 cookie files 03/12/08 http://bugs.python.org/issue2277 created thekorn patch [Py30a3] xml.parsers.expat recognizes encoding="utf-8" but not e 03/12/08 http://bugs.python.org/issue2278 created mark distutils sdist add_defaults does not add data_files 03/12/08 http://bugs.python.org/issue2279 created dripton parser module chokes on unusual characters 03/12/08 http://bugs.python.org/issue2280 created dbinger patch Enhanced cPython profiler with high-resolution timer 03/12/08 http://bugs.python.org/issue2281 created MrJean1 TextIOWrapper.seekable() always returns False 03/13/08 http://bugs.python.org/issue2282 created netzhen lambda *a, **k: a, k # does not work 03/13/08 CLOSED http://bugs.python.org/issue2283 created mark [PATCH] -x64 option added to pcbuild/rt.bat to facilitate testin 03/14/08 CLOSED http://bugs.python.org/issue2284 created Trent.Nelson patch list.sort.__doc__ says "cmp" is a keyword, but it isn't. 03/14/08 CLOSED http://bugs.python.org/issue2285 created dbinger Stack overflow exception caused by test_marshal on Windows x64 03/14/08 http://bugs.python.org/issue2286 created Trent.Nelson Problems using logging module with logging.basicConfig(level=log 03/14/08 http://bugs.python.org/issue2287 created panhudie Confusing documentation for urllib.urlopen 03/14/08 http://bugs.python.org/issue2288 created marketdickinson Issues Now Closed (35) ______________________ Patch to make py3k/Lib/test/test_thread.py use unittest 182 days http://bugs.python.org/issue1163 brett.cannon patch str.format() produces different output on different platforms (P 89 days http://bugs.python.org/issue1600 eric.smith locale.strxfrm can't handle non-ascii strings 86 days http://bugs.python.org/issue1618 loewis test_select.py converted to unittest 46 days http://bugs.python.org/issue1952 brett.cannon patch test_gdbm.py converted to unittest 45 days http://bugs.python.org/issue1960 brett.cannon patch localeconv() does not encode returned strings 36 days http://bugs.python.org/issue1995 loewis test_fcntl.py converted to unittest 33 days http://bugs.python.org/issue2055 brett.cannon patch Empty test 23 days http://bugs.python.org/issue2119 loewis with should be as fast as try/finally 14 days http://bugs.python.org/issue2179 jyasskin patch map and filter shouldn't support None as first argument (in Py3k 17 days http://bugs.python.org/issue2186 belopolsky patch, easy map and filter objects shouldn't call themselves itertools.imap 17 days http://bugs.python.org/issue2187 rhettinger easy Additional Flag For Unit-Test Module: There Can Be Only One (Err 3 days http://bugs.python.org/issue2241 bcwhite To document "assertTrue" in unittest 2 days http://bugs.python.org/issue2249 georg.brandl patch "continue" documentation 0 days http://bugs.python.org/issue2252 georg.brandl "continue" documentation internally inconsistent 1 days http://bugs.python.org/issue2253 georg.brandl Change Mandrake by Mandriva for platform.dist() 0 days http://bugs.python.org/issue2255 lemburg patch typo in tutorial section 4.4 - final break statement is missing 0 days http://bugs.python.org/issue2257 georg.brandl Warning: could not send message for past 4 hours 0 days http://bugs.python.org/issue2261 loewis A line in the second example of "7.3.5 Examples" in "Python Libr 3 days http://bugs.python.org/issue2265 georg.brandl datetime.datetime operator methods are not subclass-friendly 0 days http://bugs.python.org/issue2267 belopolsky patch Problem reporting non-keyword arg after keyword arg syntax error 0 days http://bugs.python.org/issue2269 facundobatista Typo on 8.6.2.5 Document Objects page 2 days http://bugs.python.org/issue2270 georg.brandl Segment Violation when using smtp with tls 1 days http://bugs.python.org/issue2272 facundobatista heapq API 2 days http://bugs.python.org/issue2274 rhettinger lambda *a, **k: a, k # does not work 0 days http://bugs.python.org/issue2283 draghuram [PATCH] -x64 option added to pcbuild/rt.bat to facilitate testin 0 days http://bugs.python.org/issue2284 loewis patch list.sort.__doc__ says "cmp" is a keyword, but it isn't. 0 days http://bugs.python.org/issue2285 georg.brandl struct.pack of floats in non-native endian order 1823 days http://bugs.python.org/issue705836 marketdickinson patch pyconfig.h duplicates common defines 1697 days http://bugs.python.org/issue771479 loewis exclude CVS conflict files in sdist command 1159 days http://bugs.python.org/issue1095784 georg.brandl patch slightly easier way to debug from the exception handler 1143 days http://bugs.python.org/issue1106316 facundobatista long -> Py_ssize_t (C/API 1.2.1) 588 days http://bugs.python.org/issue1533486 georg.brandl thread + import => crashes? 18 days http://bugs.python.org/issue1720705 georg.brandl slice type is unhashable 275 days http://bugs.python.org/issue1733184 rhettinger string formatter %x problem with indirectly given long 260 days http://bugs.python.org/issue1741218 facundobatista Top Issues Most Discussed (10) ______________________________ 8 To document "assertTrue" in unittest 2 days closed http://bugs.python.org/issue2249 7 slice type is unhashable 275 days closed http://bugs.python.org/issue1733184 6 Helping the compiler avoid memory references in PyEval_EvalFram 5 days open http://bugs.python.org/issue2262 6 Instance methods compare equal when their self's are equal 454 days open http://bugs.python.org/issue1617161 5 Poor support other than 44.1khz, 16bit audio files? 5 days open http://bugs.python.org/issue2259 5 setitimer, getitimer wrapper 9 days open http://bugs.python.org/issue2240 4 datetime.datetime operator methods are not subclass-friendly 0 days closed http://bugs.python.org/issue2267 4 Change Mandrake by Mandriva for platform.dist() 0 days closed http://bugs.python.org/issue2255 4 Enhanced hotshot profiler with high-resolution timer 12 days open http://bugs.python.org/issue2218 4 map and filter shouldn't support None as first argument (in Py3 17 days closed http://bugs.python.org/issue2186

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Windows x64 & bsddb 4.4.20 woes
by Trent Nelson March 14, 2008

March 14, 2008

I've been trying to give the Windows x64 builds a bit of TLC the past few evenings. I managed to get a successful build with all external modules last night (Tcl/Tk required about a half a dozen code/configuration changes each in order to build in a Windows x64 environment with Visual Studio 9, I'll deal with that in a separate thread or roundup issue). Unfortunately, though, we're back to more bsddb issues. I got about 15 tests in without error before test_whichdb ran, which results in the following being called in dbhash.py: return bsddb.hashopen(file, flag, mode) I can trace that call to DBEnv_open() in _bsddb.c: static PyObject* DBEnv_open(DBEnvObject* self, PyObject* args) { int err, flags=0, mode=0660; char *db_home; if (!PyArg_ParseTuple(args, "z|ii:open", &db_home, &flags, &mode)) return NULL; CHECK_ENV_NOT_CLOSED(self); MYDB_BEGIN_ALLOW_THREADS; err = self->db_env->open(self->db_env, db_home, flags, mode); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Placing a breakpoint at the line above and stepping in results in Visual Studio reporting: " A buffer overrun has occurred in python_d.exe which has corrupted the program's internal state. Press Break to debug the program or Continue to terminate the program.". FWIW, the exception is being raised as part of the /GS buffer overflow checks (implemented in gs_result.c, which is provided in my VS9 installation). This has been annoyingly awkward to debug. I can't break down that call into multiple steps in order to try place breakpoints in the db_static module. The callstack isn't that useful either: _bsddb_d.pyd!__crt_debugger_hook() _bsddb_d.pyd!__report_gsfailure(unsigned __int64 StackCookie=2211040) _bsddb_d.pyd!__GSHandlerCheckCommon(void * EstablisherFrame=0x000000000021bce0, ...) _bsddb_d.pyd!__GSHandlerCheck(_EXCEPTION_RECORD * ExceptionRecord=0x000000000021bbc0, ...) ntdll.dll!00000000773ae13d() [Frames below may be incorrect and/or missing, no symbols loaded for ntdll.dll] ntdll.dll!00000000773aea57() ntdll.dll!00000000773b59f8() _bsddb_d.pyd!__os_strdup() + 0x18 bytes _bsddb_d.pyd!__os_tmpdir() + 0x281 bytes You'd think placing breakpoints in db 4.4.20's __os_strdup and __os_tmpdir methods would do something, but alas, the bufferoverflow exception is raised before any breakpoints are set. This makes me suspect there's something funky going on with the entire build and linking of db_static (VS should honour those breakpoints if the code is being entered, I even added db_static to pcbuild.sln and rebuilt but no dice). I've noticed that they're not using consistent compiler flags by default (we use /GS, they use /GS-, we allow function level linking, they don't -- note that I did change db_static's options to align with _bsddb's but the bufferoverflow exception is still being thrown). Greg, Jesús, I'm CC'ing you guys as stfw'ing seems to bring back you two the most when it comes to bsddb issues. I've still got a list of things to try with regarding to debugging this x64 issue, but I wanted to reach out now to see if anyone else had encountered it before. Has bsddb ever been built successfully on Win64 and passed all tests or am I venturing into new ground? Martin, you've changed externals/bsddb-4.4.20 with regards to x64 builds recently -- have you been able to get things working in your x64 environments? Regards, Trent.

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The Case Against Floating Point ==
by Imri Goldberg March 13, 2008

March 13, 2008

Heya I've been using Python for development for some years now, but up until now, I didn't participate much in work on Python itself. I've decided to 'take a shot at it', even if a small one at first. To the subject at hand: Most experienced programmers know that you shouldn’t compare floating point numbers with ==. If you want to check floating point equality, you usually decide on a precision, and check either the absolute error, or the relative error. Another option is to use the decimal module. Hence, floating point == isn’t used, maybe except for rare circumstances. I would even venture to say that when possible, static checkers should emit warnings on floating point ==. On the other hand there are the beginner programmers. They usually use == by mistake, and will be surprised by the strange results they sometimes get back. My suggestion is to do either of the following: 1. Change floating point == to behave like a valid floating point comparison. That means using precision and some error measure. 2. Change floating point == to raise an exception, with an error string suggesting using precision comparison, or the decimal module. Since this change is not backwards compatible, I suggest it be added only to Python 3. Personally, I prefer the second option (== to raise an exception). It is clearer, and less confusing. Arguments against this suggestion are: 1. This change breaks existing programs: I believe it most likely triggers hidden bugs. Since the suggestion is to change it only in Python 3, Those programs will most likely be broken by other changes as well, and will need to be changed anyway. 2. This change breaks compatibility with C-like languages: I agree. However, the already agreed on change of the / operator is even a stronger break. Most arguments for changing the / operator apply here as well. 3. Programmers will still need the regular ==: Maybe, and even then, only for very rare cases. For these, a special function\method might be used, which could be named floating_exact_eq. I tried looking up other material about this subject, and while there is plenty of material about how to do floating point code right, I didn't find any suggestion similar to this one. I also wrote this suggestion at my blog, and discussed it a little bit on #python. I'll be glad to read other peoples' thoughts on this. Cheers, Imri -- ------------------------- Imri Goldberg www.algorithm.co.il/blogs www.imri.co.il ------------------------- Insert Signature Here -------------------------

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