Mailman 3 April 2011 - Python-Dev

running/stepping python backwards
by Adrian Johnston May 2, 2011

May 2, 2011

This may seem like an odd question, but I’m intrigued by the idea of using Python as a data definition language with “undo” support. If I were to try and instrument the Python interpreter to be able to step backwards, would that be an unduly difficult or inefficient thing to do? (Please reply to me directly.)

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Issue Tracker
by Ethan Furman May 2, 2011

May 2, 2011

Greetings! I'm not sure where the best place is to ask this question, so I'll start here -- feel free to redirect me if necessary. I would like to have some software to keep track of bugs, to-do's, ideas, etc., etc. -- you know, an issue tracker! Naturally I thought of the one we use to track Python. Is it available? Is it written in Python? Are there any others that are recommended? Thanks! ~Ethan~

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Socket servers in the test suite
by Vinay Sajip May 2, 2011

May 2, 2011

I've been recently trying to improve the test coverage for the logging package, and have got to a not unreasonable point: logging/__init__.py 99% (96%) logging/config.py 89% (85%) logging/handlers.py 60% (54%) where the figures in parentheses include branch coverage measurements. I'm at the point where to appreciably increase coverage, I'd need to write some test servers to exercise client code in SocketHandler, DatagramHandler and HTTPHandler. I notice there are no utility classes in test.support to help with this kind of thing - would there be any mileage in adding such things? Of course I could add test server code just to test_logging (which already contains some socket server code to exercise the configuration functionality), but rolling a test server involves boilerplate such as using a custom RequestHandler-derived class for each application. I had in mind a more streamlined approach where you can just pass a single callable to a server to handle requests, e.g. as outlined in https://gist.github.com/945157 I'd be grateful for any comments about adding such functionality to e.g. test.support. Regards, Vinay Sajip

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sys.settrace: behavior doesn't match docs
by Ned Batchelder May 2, 2011

May 2, 2011

This week I learned something new about trace functions (how to write a C trace function that survives a sys.settrace(sys.gettrace()) round-trip), and while writing up what I learned, I was surprised to discover that trace functions don't behave the way I thought, or the way the docs say they behave. The docs say: The trace function is invoked (with /event/ set to 'call') whenever a new local scope is entered; it should return a reference to a local trace function to be used that scope, or None if the scope shouldn't be traced. The local trace function should return a reference to itself (or to another function for further tracing in that scope), or None to turn off tracing in that scope. It's that last part that's wrong: returning None from the trace function only has an effect on the first call in a new frame. Once the trace function returns a function for a frame, returning None from subsequent calls is ignored. A "local trace function" can't turn off tracing in its scope. To demonstrate: import sys UPTO_LINE = 1 def t(frame, event, arg): num = frame.f_lineno print("line %d" % num) if num < UPTO_LINE: return t def try_it(): print("twelve") print("thirteen") print("fourteen") print("fifteen") UPTO_LINE = 1 sys.settrace(t) try_it() UPTO_LINE = 13 sys.settrace(t) try_it() Produces: line 11 twelve thirteen fourteen fifteen line 11 line 12 twelve line 13 thirteen line 14 fourteen line 15 fifteen line 15 The first call to try_it() returns None immediately, preventing tracing for the rest of the function. The second call returns None at line 13, but the rest of the function is traced anyway. This behavior is the same in all versions from 2.3 to 3.2, in fact, the 100 lines of code in sysmodule.c responsible for Python tracing functions are completely unchanged through those versions. (A deeper mystery that I haven't looked into yet is why Python 3.x intersperses all of these lines with "line 18" interjections.) I'm writing this email because I'm not sure whether this is a behavior bug or a doc bug. One of them is wrong, since they disagree. The documented behavior makes sense, and is what people have all along thought the trace function did. The actual behavior is a bit more complicated to explain, but is what people have actually been experiencing. FWIW, PyPy implements the documented behavior. Should we fix the code or the docs? I'd be glad to supply a patch for either. --Ned.

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PyObject_RichCompareBool identity shortcut
by Hrvoje Niksic May 1, 2011

May 1, 2011

The other day I was surprised to learn this: >>> nan = float('nan') >>> nan == nan False >>> [nan] == [nan] True # also True in tuples, dicts, etc. # also: >>> l = [nan] >>> nan in l True >>> l.index(nan) 0 >>> l[0] == nan False The identity test is not in container comparators, but in PyObject_RichCompareBool: /* Quick result when objects are the same. Guarantees that identity implies equality. */ if (v == w) { if (op == Py_EQ) return 1; else if (op == Py_NE) return 0; } The guarantee referred to in the comment is not only (AFAICT) undocumented, but contradicts the documentation, which states that the result should be the "equivalent of o1 op o2". Calling PyObject_RichCompareBool is inconsistent with calling PyObject_RichCompare and converting its result to bool manually, something that wrappers (C++) and generators (cython) might reasonably want to do themselves, for various reasons. If this is considered a bug, I can open an issue. Hrvoje

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2to3 status, repositories and HACKING guide
by anatoly techtonik May 1, 2011

May 1, 2011

Hi, Currently 2to3 page at http://wiki.python.org/moin/2to3 lists http://svn.python.org/view/sandbox/trunk/2to3 as a repository for 2to3 tool. There is also an outdated repository at http://hg.python.org/ and the page says that the code is finally integrated into CPython 2.6 - you can see it at http://hg.python.org/cpython/file/default/Lib/lib2to3. So, what version is more up-to-date? In svn repository there is a HACKING guide advising to use find_pattern.py script for writing new fixer. However, there is no find_pattern.py in CPython repository, no HACKING guide, no any documentation about how to write fixers or description of PATTERN format. Did I miss something? -- anatoly t.

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Re: [Python-Dev] [Python-checkins] cpython: PyGILState_Ensure(), PyGILState_Release(), PyGILState_GetThisThreadState() are
by Jim Jewett April 30, 2011

April 30, 2011

Would it be a problem to make them available a no-ops? On 4/26/11, victor.stinner <python-checkins(a)python.org> wrote: > http://hg.python.org/cpython/rev/75503c26a17f > changeset: 69584:75503c26a17f > user: Victor Stinner <victor.stinner(a)haypocalc.com> > date: Tue Apr 26 23:34:58 2011 +0200 > summary: > PyGILState_Ensure(), PyGILState_Release(), PyGILState_GetThisThreadState() > are > not available if Python is compiled without threads. > > files: > Include/pystate.h | 10 +++++++--- > 1 files changed, 7 insertions(+), 3 deletions(-) > > > diff --git a/Include/pystate.h b/Include/pystate.h > --- a/Include/pystate.h > +++ b/Include/pystate.h > @@ -73,9 +73,9 @@ > struct _frame *frame; > int recursion_depth; > char overflowed; /* The stack has overflowed. Allow 50 more calls > - to handle the runtime error. */ > - char recursion_critical; /* The current calls must not cause > - a stack overflow. */ > + to handle the runtime error. */ > + char recursion_critical; /* The current calls must not cause > + a stack overflow. */ > /* 'tracing' keeps track of the execution depth when tracing/profiling. > This is to prevent the actual trace/profile code from being recorded > in > the trace/profile. */ > @@ -158,6 +158,8 @@ > enum {PyGILState_LOCKED, PyGILState_UNLOCKED} > PyGILState_STATE; > > +#ifdef WITH_THREAD > + > /* Ensure that the current thread is ready to call the Python > C API, regardless of the current state of Python, or of its > thread lock. This may be called as many times as desired > @@ -199,6 +201,8 @@ > */ > PyAPI_FUNC(PyThreadState *) PyGILState_GetThisThreadState(void); > > +#endif /* #ifdef WITH_THREAD */ > + > /* The implementation of sys._current_frames() Returns a dict mapping > thread id to that thread's current frame. > */ > > -- > Repository URL: http://hg.python.org/cpython >

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python and super
by Ricardo Kirkner April 29, 2011

April 29, 2011

Hi all, I recently stumbled upon an issue with a class in the mro chain not calling super, therefore breaking the chain (ie, further base classes along the chain didn't get called). I understand it is currently a requirement that all classes that are part of the mro chain behave and always call super. My question is, shouldn't/wouldn't it be better, if python took ownership of that part, and ensured all classes get called, even if some class misbehaved? For example, if using a stack-like structure, pushing super calls and popping until the stack was empty, couldn't this restriction be removed? Thanks, Ricardo

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Summary of Python tracker Issues
by Python tracker April 29, 2011

April 29, 2011

ACTIVITY SUMMARY (2011-04-22 - 2011-04-29) Python tracker at http://bugs.python.org/ To view or respond to any of the issues listed below, click on the issue. Do NOT respond to this message. Issues counts and deltas: open 2760 ( +8) closed 20976 (+39) total 23736 (+47) Open issues with patches: 1201 Issues opened (33) ================== #3561: Windows installer should add Python and Scripts directories to http://bugs.python.org/issue3561 reopened by ncoghlan #10912: PyObject_RichCompare differs in behaviour from PyObject_RichCo http://bugs.python.org/issue10912 reopened by ncoghlan #10914: Python sub-interpreter test http://bugs.python.org/issue10914 reopened by pitrou #11895: pybench prep_times calculation error http://bugs.python.org/issue11895 reopened by jcea #11908: Weird `slice.stop or sys.maxint` http://bugs.python.org/issue11908 opened by cool-RR #11909: Doctest sees directives in strings when it should only see the http://bugs.python.org/issue11909 opened by Devin Jeanpierre #11910: test_heapq C tests are not skipped when _heapq is missing http://bugs.python.org/issue11910 opened by ezio.melotti #11912: Python shouldn't use the mprotect() system call http://bugs.python.org/issue11912 opened by breun #11913: sdist should allow for README.rst http://bugs.python.org/issue11913 opened by ingy #11914: pydoc modules/help('modules') crash in dirs with unreadable su http://bugs.python.org/issue11914 opened by okopnik #11916: A few errnos from OSX http://bugs.python.org/issue11916 opened by pcarrier #11920: ctypes: Strange bitfield structure sizing issue http://bugs.python.org/issue11920 opened by Steve.Thompson #11921: distutils2 should be able to compile an Extension based on the http://bugs.python.org/issue11921 opened by dholth #11924: Pickle and copyreg modules don't document the interface http://bugs.python.org/issue11924 opened by jcea #11925: test_ttk_guionly.test_traversal() failed on "x86 Windows7 3.x" http://bugs.python.org/issue11925 opened by haypo #11927: SMTP_SSL doesn't use port 465 by default http://bugs.python.org/issue11927 opened by pitrou #11928: fail on filename with space at the end http://bugs.python.org/issue11928 opened by techtonik #11930: Remove time.accept2dyear http://bugs.python.org/issue11930 opened by belopolsky #11931: Regular expression documentation patch http://bugs.python.org/issue11931 opened by Retro #11933: newer() function in dep_util.py mixes up new vs. old files due http://bugs.python.org/issue11933 opened by jsjgruber #11934: build with --prefix=/dev/null and zlib enabled in Modules/Setu http://bugs.python.org/issue11934 opened by ysj.ray #11935: MMDF/MBOX mailbox need utime http://bugs.python.org/issue11935 opened by sdaoden #11937: Interix support http://bugs.python.org/issue11937 opened by mduft #11939: Implement stat.st_dev and os.path.samefile on windows http://bugs.python.org/issue11939 opened by amaury.forgeotdarc #11941: Support st_atim, st_mtim and st_ctim attributes in os.stat_res http://bugs.python.org/issue11941 opened by Arfrever #11943: Add TLS-SRP (RFC 5054) support to ssl, _ssl, http, and urllib http://bugs.python.org/issue11943 opened by sqs #11944: Function call with * and generator hide exception raised by ge http://bugs.python.org/issue11944 opened by falsetru #11945: Adopt and document consistent semantics for handling NaN value http://bugs.python.org/issue11945 opened by ncoghlan #11948: Tutorial/Modules - small fix to better clarify the modules sea http://bugs.python.org/issue11948 opened by sandro.tosi #11949: Make float('nan') unorderable http://bugs.python.org/issue11949 opened by belopolsky #11950: logger use dict for loggers instead of WeakValueDictionary http://bugs.python.org/issue11950 opened by mmarkk #11953: Missing WSA* error codes http://bugs.python.org/issue11953 opened by pitrou #11954: 3.3 - 'make test' fails http://bugs.python.org/issue11954 opened by Jason.Vas.Dias Most recent 15 issues with no replies (15) ========================================== #11950: logger use dict for loggers instead of WeakValueDictionary http://bugs.python.org/issue11950 #11935: MMDF/MBOX mailbox need utime http://bugs.python.org/issue11935 #11934: build with --prefix=/dev/null and zlib enabled in Modules/Setu http://bugs.python.org/issue11934 #11924: Pickle and copyreg modules don't document the interface http://bugs.python.org/issue11924 #11916: A few errnos from OSX http://bugs.python.org/issue11916 #11909: Doctest sees directives in strings when it should only see the http://bugs.python.org/issue11909 #11898: Sending binary data with a POST request in httplib can cause U http://bugs.python.org/issue11898 #11894: test_multiprocessing failure on "AMD64 OpenIndiana 3.x": KeyEr http://bugs.python.org/issue11894 #11893: Obsolete SSLFakeFile in smtplib? http://bugs.python.org/issue11893 #11887: unittest fails on comparing str with bytes if python has the - http://bugs.python.org/issue11887 #11870: test_3_join_in_forked_from_thread() of test_threading hangs 1 http://bugs.python.org/issue11870 #11869: Include information about the bug tracker Rietveld code review http://bugs.python.org/issue11869 #11866: race condition in threading._newname() http://bugs.python.org/issue11866 #11838: IDLE: make interactive code savable as a runnable script http://bugs.python.org/issue11838 #11836: multiprocessing.queues.SimpleQueue is undocumented http://bugs.python.org/issue11836 Most recent 15 issues waiting for review (15) ============================================= #11949: Make float('nan') unorderable http://bugs.python.org/issue11949 #11948: Tutorial/Modules - small fix to better clarify the modules sea http://bugs.python.org/issue11948 #11943: Add TLS-SRP (RFC 5054) support to ssl, _ssl, http, and urllib http://bugs.python.org/issue11943 #11937: Interix support http://bugs.python.org/issue11937 #11935: MMDF/MBOX mailbox need utime http://bugs.python.org/issue11935 #11931: Regular expression documentation patch http://bugs.python.org/issue11931 #11930: Remove time.accept2dyear http://bugs.python.org/issue11930 #11927: SMTP_SSL doesn't use port 465 by default http://bugs.python.org/issue11927 #11916: A few errnos from OSX http://bugs.python.org/issue11916 #11910: test_heapq C tests are not skipped when _heapq is missing http://bugs.python.org/issue11910 #11909: Doctest sees directives in strings when it should only see the http://bugs.python.org/issue11909 #11898: Sending binary data with a POST request in httplib can cause U http://bugs.python.org/issue11898 #11895: pybench prep_times calculation error http://bugs.python.org/issue11895 #11887: unittest fails on comparing str with bytes if python has the - http://bugs.python.org/issue11887 #11883: Call connect() before sending an email with smtplib http://bugs.python.org/issue11883 Top 10 most discussed issues (10) ================================= #11954: 3.3 - 'make test' fails http://bugs.python.org/issue11954 16 msgs #10914: Python sub-interpreter test http://bugs.python.org/issue10914 13 msgs #11945: Adopt and document consistent semantics for handling NaN value http://bugs.python.org/issue11945 11 msgs #3526: Customized malloc implementation on SunOS and AIX http://bugs.python.org/issue3526 9 msgs #9614: _pickle is not entirely 64-bit safe http://bugs.python.org/issue9614 7 msgs #11849: glibc allocator doesn't release all free()ed memory http://bugs.python.org/issue11849 7 msgs #11912: Python shouldn't use the mprotect() system call http://bugs.python.org/issue11912 7 msgs #11930: Remove time.accept2dyear http://bugs.python.org/issue11930 7 msgs #11933: newer() function in dep_util.py mixes up new vs. old files due http://bugs.python.org/issue11933 7 msgs #9390: Error in sys.excepthook on windows when redirecting output of http://bugs.python.org/issue9390 6 msgs Issues closed (39) ================== #2736: datetime needs an "epoch" method http://bugs.python.org/issue2736 closed by belopolsky #6780: startswith error message is incomplete http://bugs.python.org/issue6780 closed by ezio.melotti #8326: Cannot import name SemLock on Ubuntu http://bugs.python.org/issue8326 closed by barry #10517: test_concurrent_futures crashes with "--with-pydebug" on RHEL5 http://bugs.python.org/issue10517 closed by pitrou #10632: multiprocessing generates a fatal error http://bugs.python.org/issue10632 closed by jnoller #10761: tarfile.extractall fails to overwrite symlinks http://bugs.python.org/issue10761 closed by python-dev #11005: Assertion error on RLock._acquire_restore http://bugs.python.org/issue11005 closed by haypo #11236: getpass.getpass does not respond to ctrl-c or ctrl-z http://bugs.python.org/issue11236 closed by orsenthil #11324: ConfigParser(interpolation=None) doesn't work http://bugs.python.org/issue11324 closed by python-dev #11332: Increase logging/__init__.py coverage to 97% http://bugs.python.org/issue11332 closed by vinay.sajip #11382: some posix module functions unnecessarily release the GIL http://bugs.python.org/issue11382 closed by pitrou #11670: configparser read_file now iterates over f, docs still say it http://bugs.python.org/issue11670 closed by python-dev #11786: ConfigParser.[Raw]ConfigParser optionxform() http://bugs.python.org/issue11786 closed by python-dev #11811: ssl.get_server_certificate() does not work for IPv6 addresses http://bugs.python.org/issue11811 closed by pitrou #11832: Add option to pause regrtest to attach a debugger http://bugs.python.org/issue11832 closed by brian.curtin #11856: Optimize parsing of JSON numbers http://bugs.python.org/issue11856 closed by pitrou #11858: configparser.ExtendedInterpolation and section case http://bugs.python.org/issue11858 closed by python-dev #11860: reference 2.3 has text that runs past the page http://bugs.python.org/issue11860 closed by terry.reedy #11884: Argparse calls ngettext but doesn't import it http://bugs.python.org/issue11884 closed by eric.araujo #11901: Docs for sys.hexversion should give the algorithm http://bugs.python.org/issue11901 closed by r.david.murray #11907: SysLogHandler can't send long messages http://bugs.python.org/issue11907 closed by vinay.sajip #11911: Interlink Python versions docs http://bugs.python.org/issue11911 closed by ezio.melotti #11915: test_ctypes hangs in sandbox http://bugs.python.org/issue11915 closed by Arfrever #11917: Test Error http://bugs.python.org/issue11917 closed by Abbaszadeh #11918: Drop OS/2 and VMS support in Python 3.3 http://bugs.python.org/issue11918 closed by haypo #11919: test_imp failures http://bugs.python.org/issue11919 closed by pitrou #11922: Add General Index to Windows .chm help file Contents http://bugs.python.org/issue11922 closed by terry.reedy #11923: gcc: unrecognized option '-n32' http://bugs.python.org/issue11923 closed by paulg_ca #11926: help("keywords") returns incomplete list of keywords http://bugs.python.org/issue11926 closed by ezio.melotti #11929: Improve usage of PEP8 in Docs/includes/* http://bugs.python.org/issue11929 closed by rhettinger #11932: Email multipart boundary detection fails on a wrapped header http://bugs.python.org/issue11932 closed by davidstrauss #11936: plistlib.writePlistToBytes does not exist on 2.6 (osx) and do http://bugs.python.org/issue11936 closed by ned.deily #11938: duplicated test name in getattr_static's test case http://bugs.python.org/issue11938 closed by ezio.melotti #11940: Howto/Advocacy - update the link to John Ousterhout paper http://bugs.python.org/issue11940 closed by rhettinger #11942: Fix signature of Py_AddPendingCall http://bugs.python.org/issue11942 closed by ezio.melotti #11946: 2.7.1 'test_commands' build test fails http://bugs.python.org/issue11946 closed by r.david.murray #11947: re.IGNORECASE does not match literal "_" (underscore) http://bugs.python.org/issue11947 closed by ezio.melotti #11951: Mac OSX IDLE 3.2 does not allow entering text into toolbar win http://bugs.python.org/issue11951 closed by ned.deily #11952: typo in multiprocessing documentation: __main__ method should http://bugs.python.org/issue11952 closed by ezio.melotti

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Proposal for a common benchmark suite
by DasIch April 29, 2011

April 29, 2011

Hello, As announced in my GSoC proposal I'd like to announce which benchmarks I'll use for the benchmark suite I will work on this summer. As of now there are two benchmark suites (that I know of) which receive some sort of attention, those are the ones developed as part of the PyPy project[1] which is used for http://speed.pypy.org and the one initially developed for Unladen Swallow which has been continued by CPython[2]. The PyPy benchmarks contain a lot of interesting benchmarks some explicitly developed for that suite, the CPython benchmarks have an extensive set of microbenchmarks in the pybench package as well as the previously mentioned modifications made to the Unladen Swallow benchmarks. I'd like to "simply" merge both suites so that no changes are lost. However I'd like to leave out the waf benchmark which is part of the PyPy suite, the removal was proposed on pypy-dev for obvious deficits[3]. It will be easier to add a better benchmark later than replacing it at a later point. Unless there is a major issue with this plan I'd like to go forward with this. .. [1]: https://bitbucket.org/pypy/benchmarks .. [2]: http://hg.python.org/benchmarks .. [3]: http://mailrepository.com/pypy-dev.codespeak.net/msg/3627509/

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