Mailman 3 April 2014 - Python-Dev

Apologies for last post
by Andrew Konstantaras April 26, 2014

April 26, 2014

I accidentally posted a question to here. I am returning to Python after a couple years away and I am trying to brush up my skills and make the switch to Python 3.x. ---Andrew

1 0

Help with changes in stack from 2.7 to 3.x
by Andrew Konstantaras April 26, 2014

April 26, 2014

I wrote the following code that works in Python 2.7 that takes the variables passed to the function into a dictionary. The following call: strA = 'a' intA = 1 dctA = makeDict(strA, intA) produces the following dictionary: {'strA':'a', 'intA':1} To access the names passed into the function, I had to find the information by parsing through the stack. The code that used to work is: from traceback import extract_stack def makeDict(*args): strAllStack = str(extract_stack()) intNumLevels = len(extract_stack()) intLevel = 0 blnFinished = False while not blnFinished: strStack = str(extract_stack()[intLevel]) if strStack.find("makeDict(")>0: blnFinished = True intLevel += 1 if intLevel >= intNumLevels: blnFinished = True strStartText = "= makeDict(" intLen = len(strStartText) intOpenParenLoc = strStack.find(strStartText) intCloseParenLoc = strStack.find(")", intOpenParenLoc) strArgs = strStack[ intOpenParenLoc+intLen : intCloseParenLoc ].strip() lstVarNames = strArgs.split(",") lstVarNames = [ s.strip() for s in lstVarNames ] if len(lstVarNames) == len(args): tplArgs = map(None, lstVarNames, args) newDict = dict(tplArgs) return newDict else: return "Error, argument name-value mismatch in function 'makeDict'. lstVarNames: " + str(lstVarNames) + "\n args: " + str(args), strAllStack The same code does not work in Python 3.3.4. I have tried parsing through the stack information and frames and I can't find any reference to the names of the arguments passed to the function. I have tried inspecting the function and other functions in the standard modules, but I can't seem to find anything that will provide this information. Can anyone point me in the direction to find this information? Any help is appreciated. ---Andrew

2 1

Summary of Python tracker Issues
by Python tracker April 25, 2014

April 25, 2014

ACTIVITY SUMMARY (2014-04-18 - 2014-04-25) 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 4600 (+21) closed 28521 (+28) total 33121 (+49) Open issues with patches: 2126 Issues opened (41) ================== #21301: pathlib missing Path.expandvars(env=os.environ) http://bugs.python.org/issue21301 opened by Alain.Mellan #21302: time.sleep (floatsleep()) should use clock_nanosleep() on Linu http://bugs.python.org/issue21302 opened by shankarunni #21304: PEP 466: Backport hashlib.pbkdf2_hmac to Python 2.7 http://bugs.python.org/issue21304 opened by alex #21305: PEP 466: update os.urandom http://bugs.python.org/issue21305 opened by ncoghlan #21306: PEP 466: backport hmac.compare_digest http://bugs.python.org/issue21306 opened by ncoghlan #21307: PEP 466: backport hashlib changes http://bugs.python.org/issue21307 opened by ncoghlan #21308: PEP 466: backport ssl changes http://bugs.python.org/issue21308 opened by ncoghlan #21309: Confusing "see also" for generic C-level __init__ methods in h http://bugs.python.org/issue21309 opened by r.david.murray #21310: ResourceWarning when open() fails with io.UnsupportedOperation http://bugs.python.org/issue21310 opened by vadmium #21312: Update thread_foobar.h to include timed locking and TLS suppor http://bugs.python.org/issue21312 opened by Jack.McCracken #21313: Py_GetVersion() is broken when using mqueue and a long patch n http://bugs.python.org/issue21313 opened by eric.snow #21314: Bizarre help http://bugs.python.org/issue21314 opened by Vedran.Čačić #21315: email._header_value_parser does not recognise in-line encoding http://bugs.python.org/issue21315 opened by valhallasw #21316: mark test_devpoll to be meaningfull only for Solaris http://bugs.python.org/issue21316 opened by AapoRantalainen #21318: sdist fails with symbolic links do non-existing files http://bugs.python.org/issue21318 opened by jgosmann #21319: WindowsRegistryFinder never added to sys.meta_path http://bugs.python.org/issue21319 opened by eric.snow #21320: dict() allows keyword expansion with integer keys, e.g. dict(* http://bugs.python.org/issue21320 opened by Cyphase #21321: itertools.islice() doesn't release reference to the source ite http://bugs.python.org/issue21321 opened by Anton.Afanasyev #21322: Pathlib .owner() and .group() methods fail on broken links http://bugs.python.org/issue21322 opened by inigoserna #21323: CGI HTTP server not running scripts from subdirectories http://bugs.python.org/issue21323 opened by k.s.solnushkin #21324: dbhash/bsddb leaks random memory fragments to a database http://bugs.python.org/issue21324 opened by wodny #21325: Missing Generic EXIF library for images in the standard librar http://bugs.python.org/issue21325 opened by karlcow #21326: asyncio: request clearer error message when event loop closed http://bugs.python.org/issue21326 opened by mark.dickinson #21327: socket.type value changes after using settimeout() http://bugs.python.org/issue21327 opened by giampaolo.rodola #21328: Resize doesn't change reported length on create_string_buffer( http://bugs.python.org/issue21328 opened by Dustin.Oprea #21329: configparser can't parse MySQL style config http://bugs.python.org/issue21329 opened by dveeden #21331: Reversing an encoding with unicode-escape returns a different http://bugs.python.org/issue21331 opened by Sworddragon #21332: subprocess bufsize=1 docs are misleading http://bugs.python.org/issue21332 opened by raylu #21333: Document recommended exception for objects that shouldn't be p http://bugs.python.org/issue21333 opened by sschwarzer #21335: Update importlib.__init__ to reset _frozen_importlib's loader http://bugs.python.org/issue21335 opened by brett.cannon #21337: Add tests for Tix http://bugs.python.org/issue21337 opened by zach.ware #21338: Silent mode for compileall http://bugs.python.org/issue21338 opened by takluyver #21339: IDLE crash on OS X 1.9 upon shut-down with many windows open http://bugs.python.org/issue21339 opened by rhettinger #21340: Possible concurrency bug in asyncio, AttributeError in tasks.p http://bugs.python.org/issue21340 opened by Jack.Murray #21341: Configuring 'font' with ttk.Style for 'TEntry' does not change http://bugs.python.org/issue21341 opened by barron #21342: multiprocessing RLock and Lock raise incorrect exceptions when http://bugs.python.org/issue21342 opened by steinn #21343: os.path.relpath returns inconsistent types http://bugs.python.org/issue21343 opened by Matt.Bachmann #21344: save scores or ratios in difflib get_close_matches http://bugs.python.org/issue21344 opened by russellballestrini #21345: multiprocessing.Pool._handle_workers sleeps too long http://bugs.python.org/issue21345 opened by Johannes.Baiter #21347: Don't use a list argument together with shell=True in subproce http://bugs.python.org/issue21347 opened by akira #21349: crash in winreg SetValueEx with memoryview http://bugs.python.org/issue21349 opened by bdkearns Most recent 15 issues with no replies (15) ========================================== #21349: crash in winreg SetValueEx with memoryview http://bugs.python.org/issue21349 #21347: Don't use a list argument together with shell=True in subproce http://bugs.python.org/issue21347 #21345: multiprocessing.Pool._handle_workers sleeps too long http://bugs.python.org/issue21345 #21343: os.path.relpath returns inconsistent types http://bugs.python.org/issue21343 #21342: multiprocessing RLock and Lock raise incorrect exceptions when http://bugs.python.org/issue21342 #21341: Configuring 'font' with ttk.Style for 'TEntry' does not change http://bugs.python.org/issue21341 #21339: IDLE crash on OS X 1.9 upon shut-down with many windows open http://bugs.python.org/issue21339 #21337: Add tests for Tix http://bugs.python.org/issue21337 #21335: Update importlib.__init__ to reset _frozen_importlib's loader http://bugs.python.org/issue21335 #21333: Document recommended exception for objects that shouldn't be p http://bugs.python.org/issue21333 #21332: subprocess bufsize=1 docs are misleading http://bugs.python.org/issue21332 #21329: configparser can't parse MySQL style config http://bugs.python.org/issue21329 #21328: Resize doesn't change reported length on create_string_buffer( http://bugs.python.org/issue21328 #21323: CGI HTTP server not running scripts from subdirectories http://bugs.python.org/issue21323 #21319: WindowsRegistryFinder never added to sys.meta_path http://bugs.python.org/issue21319 Most recent 15 issues waiting for review (15) ============================================= #21349: crash in winreg SetValueEx with memoryview http://bugs.python.org/issue21349 #21347: Don't use a list argument together with shell=True in subproce http://bugs.python.org/issue21347 #21344: save scores or ratios in difflib get_close_matches http://bugs.python.org/issue21344 #21343: os.path.relpath returns inconsistent types http://bugs.python.org/issue21343 #21342: multiprocessing RLock and Lock raise incorrect exceptions when http://bugs.python.org/issue21342 #21338: Silent mode for compileall http://bugs.python.org/issue21338 #21322: Pathlib .owner() and .group() methods fail on broken links http://bugs.python.org/issue21322 #21321: itertools.islice() doesn't release reference to the source ite http://bugs.python.org/issue21321 #21315: email._header_value_parser does not recognise in-line encoding http://bugs.python.org/issue21315 #21313: Py_GetVersion() is broken when using mqueue and a long patch n http://bugs.python.org/issue21313 #21312: Update thread_foobar.h to include timed locking and TLS suppor http://bugs.python.org/issue21312 #21306: PEP 466: backport hmac.compare_digest http://bugs.python.org/issue21306 #21304: PEP 466: Backport hashlib.pbkdf2_hmac to Python 2.7 http://bugs.python.org/issue21304 #21300: Docs (incorrectly) suggest email.policy.default is the default http://bugs.python.org/issue21300 #21293: Remove "capsule hack" from object.c? http://bugs.python.org/issue21293 Top 10 most discussed issues (10) ================================= #18967: Find a less conflict prone approach to Misc/NEWS http://bugs.python.org/issue18967 22 msgs #17552: socket.sendfile() http://bugs.python.org/issue17552 19 msgs #21344: save scores or ratios in difflib get_close_matches http://bugs.python.org/issue21344 10 msgs #21207: urandom persistent fd - not re-openned after fd close http://bugs.python.org/issue21207 7 msgs #21306: PEP 466: backport hmac.compare_digest http://bugs.python.org/issue21306 7 msgs #8387: use universal newline mode in csv module examples http://bugs.python.org/issue8387 6 msgs #21305: PEP 466: update os.urandom http://bugs.python.org/issue21305 6 msgs #21312: Update thread_foobar.h to include timed locking and TLS suppor http://bugs.python.org/issue21312 6 msgs #21331: Reversing an encoding with unicode-escape returns a different http://bugs.python.org/issue21331 6 msgs #21338: Silent mode for compileall http://bugs.python.org/issue21338 6 msgs Issues closed (27) ================== #7221: DispatcherWithSendTests_UsePoll with test_asyncore does nothin http://bugs.python.org/issue7221 closed by pitrou #8297: AttributeError message text should include module name http://bugs.python.org/issue8297 closed by benjamin.peterson #9364: some problems with the documentation of pydoc http://bugs.python.org/issue9364 closed by r.david.murray #9764: Tools/buildbot/external.bat should download and built tix http://bugs.python.org/issue9764 closed by zach.ware #9765: tcl-8 vs tcl8 http://bugs.python.org/issue9765 closed by zach.ware #10291: Clean-up turtledemo in-package documentation http://bugs.python.org/issue10291 closed by ned.deily #10362: AttributeError: addinfourl instance has no attribute 'tell' http://bugs.python.org/issue10362 closed by orsenthil #11748: test_ftplib failure in test for source_address http://bugs.python.org/issue11748 closed by jesstess #12220: minidom xmlns not handling spaces in xmlns attribute value fie http://bugs.python.org/issue12220 closed by r.david.murray #20565: Update Tcl/Tk version for buildbots http://bugs.python.org/issue20565 closed by zach.ware #21068: Make ssl.PROTOCOL_* an enum http://bugs.python.org/issue21068 closed by pitrou #21127: Path objects cannot be constructed from str subclasses http://bugs.python.org/issue21127 closed by pitrou #21139: Idle: change default reformat width from 70 to 72 http://bugs.python.org/issue21139 closed by terry.reedy #21200: pkgutil.get_loader() fails on "__main__" http://bugs.python.org/issue21200 closed by eric.snow #21211: pkgutil.find_loader() raises ImportError instead of returning http://bugs.python.org/issue21211 closed by eric.snow #21232: Use of '1' instead of 'True' as 'splitlines' argument in diffl http://bugs.python.org/issue21232 closed by python-dev #21284: IDLE reformat tests fail in presence of non-default FormatPara http://bugs.python.org/issue21284 closed by terry.reedy #21289: make.bat not building documentation http://bugs.python.org/issue21289 closed by zach.ware #21291: subprocess Popen objects are not thread safe w.r.t. wait() and http://bugs.python.org/issue21291 closed by gregory.p.smith #21303: Python 2.7 Spinbox Format Behaves Differently On Windows Versu http://bugs.python.org/issue21303 closed by zach.ware #21311: Fix compiler detection when brew's ccache is installed on Mac http://bugs.python.org/issue21311 closed by ned.deily #21317: Home page certificate troubles http://bugs.python.org/issue21317 closed by alex #21330: Typo in "Unicode HOWTO" documentation http://bugs.python.org/issue21330 closed by benjamin.peterson #21334: nntplib throws exceptions making sinntp unusable http://bugs.python.org/issue21334 closed by randomcoder1 #21336: ntpath.splitdrive fails on None argument http://bugs.python.org/issue21336 closed by eric.smith #21346: typos in test_itertools.py http://bugs.python.org/issue21346 closed by zach.ware #21348: File "C:\Python27\lib\distutils\msvc9compiler.py", line 295, i http://bugs.python.org/issue21348 closed by skrah

1 0

ref leaks
by Ethan Furman April 24, 2014

April 24, 2014

Command line: ./python -m test.regrtest -v -R3:3 test_tools Results: Ran 44 tests in 7.628s OK (skipped=1) . test_tools leaked [0, 2, 2] references, sum=4 1 test failed: test_tools Any words of wisdom for tracking those leaks? -- ~Ethan~

5 5

Language Summit notes
by Guido van Rossum April 24, 2014

April 24, 2014

To anyone who took notes at the language summit at PyCon today, even if you took them just for yourself, would you mind posting them here? It would be good to have some kind of (informal!) as soon as possible, before we collectively forget. You won't be held responsible for correctness. Here are some of my own recollections (I didn't take notes but I have a decent memory): - Packaging sucks, but we're improving, and we're actually doing better than other dynamic languages. - Kevin Modzelewski answered questions about Pyston, a new (very early stage) Python VM based on the new LLVM JIT engine (which is much different from what defeated Unladen Swallow). Alex Gaynor seemed unconcerned. :-) - Jukka Lehtosalo gave a talk and answered questions about mypy, his design and implementation of pragmatic type annotations (no new syntax required, uses Python 3 function annotations). See mypy-lang.org. In response, Greg P Smith pointed people to a similar project from Google, https://github.com/google/pytypedecl, which has annotations in a separate file (hence amenable to Python 2). Larry Hastings brought up that Argument Clinic (a new way of specifying signatures for C extensions), released as part of 3.4) encodes similar information in the docstring of C functions. - Maybe this is should be the year when we start getting agreement on a standard use of function annotations to specify argument and return types, now that we seem to have a somewhat critical mass of experience with annotations. - We should make an effort to publicize that we're NOT sunsetting Python 2.7 just yet; support will continue (hopefully with ample support from distro vendors), and someone should update PEP 373. (Unclear what the new EOL is but we should definitely rescind the currently published schedule.) - We (I) still don't want to do a 2.8 release, and I don't want to accelerate 3.5, but I do think we should make things better for people who have to straddle Python 2 and 3 in a single codebase, by developing more tools, and by security and possibly installer updates to 2.7 (PEP 466). - Some suggestions that were made: PSF financial support for tool development and/or porting, add more "-3" warnings to a future Python 2.7 release, additional 2to3 fixers to help convert Python-2-only code to Python-2-and-3-single-source code, a separate linter, a sumo 2.7 distribution that includes all known backported-from-Python-3-stdlib packages, adding ensure_pip to the 2.7.7 stdlib, and several more I forgot. IIRC Glyph and Alex Gaynor are going to compile a list of pain points for people. (I can't honestly say that I convinced Glyph and Alex and a few others not to pine for 2.8, but I also honestly don't believe it will have the effect that they expect. Nor do I believe any new feature we add to 3.5 can serve as a big enough carrot.) - The recommended and least painful way to develop for Python 2 and 3 is definitely to use a single source that runs under both without translation; we no longer recommend auto-generating Python 3 compatible source code using 2to3, for a variety of reasons. Several people attested that single-source has worked well for them; Mercurial is using the 2to3 approach but they're not too happy with it. - An argument for releasing something labeled 2.8 was made based on the unavailability (current or future?) of Visual Studio 2008; the uncomfortable alternative would be to switch to a newer compiler at some 2.7.x bugfix release, which would break extension modules compiled with for 2.7.0-2.7.6, and that would confuse and upset people. - Apparently no restaurant in downtown Montreal takes reservations for a group of 30 people to show up in one hour. -- --Guido van Rossum (python.org/~guido)

22 35

Import java classes from python
by babu April 24, 2014

April 24, 2014

Hi, I am new to python. I have a requirement to import java class from python. Is there any possibility to import java class from python. -- View this message in context: http://python.6.x6.nabble.com/Import-java-classes-from-python-tp5054707.html Sent from the Python - python-dev mailing list archive at Nabble.com.

2 1

Re: [Python-Dev] List vs Tuple / Homogeneous vs Heterogeneous / Mutable vs Immutable
by Chris Barker April 24, 2014

April 24, 2014

Ooops, Forgot "reply all" last time -- here it is again. On Wed, Apr 23, 2014 at 3:17 PM, Chris Barker <chris.barker(a)noaa.gov> wrote: > On Mon, Apr 21, 2014 at 11:39 PM, Raymond Hettinger < > raymond.hettinger(a)gmail.com> wrote: > >> In fact, the distinction is extrinsic to their implementations. It is >> only important >> because the rest of the language tends to treat them differently. For >> example, >> you could store ['raymond', 'red'] as a list or as a tuple ('raymond', >> 'red'), but you >> wouldn't be punished until later when you tried: >> >> 'I think %s likes %s' % container # str.__mod__ treats lists and >> tuples differently >> > > I've been bitten by that a lot -- I always wondered why that didn't work > with any sequence. like "tuple unpacking", which is really sequence > unpacking: > > x, y = [3,4] > > But anyway, when I teach Python, I do struggle with this issue -- I tend > to give the explanation of "structs" vs. "homogenous sequences", but I feel > like I am repeating a party line, rather than anything useful. What I do > is: > > If it needs to be immutable (dict key), then use a tuple > If it needs to be mutable, then use a list > > Otherwise, you can use either, but I tend to use a tuple for small things > I don't need to mutate, regardless of whether they are homogenous or not -- > it makes me feel better to get the perception of a *tiny* bit more > efficiency. > > And sometimes you want to mutate small collections of inhomogeneous values > (C sructs are mutable, after all). > > So I don't think this needs to be codified this in the docs anywhere. > > >> Likewise, there seems to be wide-spread confusion about make makes an >> object immutable. People seem to miss that ints, tuples, None and str are >> immutable only because they lack any mutating methods, >> > > not sure your point here -- that under the hood one could mutate them with > C code? > -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker(a)noaa.go <Chris.Barker(a)noaa.gov>

1 0

pep8 reasoning
by Chris Withers April 24, 2014

April 24, 2014

Hi All, Apologies if this is considered off topic, but I'm keen to get the "language designers" point of view and short of emailing Barry, Guido and Nick directly, this seemed like the best place. I'm having a tough time persuading some people of the benefits of pep8, particularly when it comes to applying to an existing large code base. The biggest sticking point is naming, particularly as it's the one thing that can't necessarily be changed module by module. What were the compelling reasons to go from mixedCase to underscore_separated? What's considered the best approach for migrating from the former to the latter? A couple of others that have raised some consternation; what are the technical reasons for this pattern being bad: if len(seq) if not len(seq) ...or, for me, the rather ugly: if 0 != len(seq) Likewise, these: if greeting == True: if greeting is True: Please don't misunderstand me: I dislike the above intensely, but it's an emotional response based on 10-15 years of doing things the other way. I'm interested in arguments that don't include things like "it's pythonic" (which some people consider a derogatory term ;-)), or "just because", I trust that the stuff in pep8 was done with specific reasoning in mind, but I'm feeling rather useless at giving that reasoning and I'm hoping you can help :-) cheers, Chris

2 1

List vs Tuple / Homogeneous vs Heterogeneous / Mutable vs Immutable
by Leandro Pereira de Lima e Silva April 24, 2014

April 24, 2014

Hello there! I've stumbled upon this discussion on python-dev about what the choice between using a list or a tuple is all about in 2003: 1. https://mail.python.org/pipermail/python-dev/2003-March/033962.html 2. https://mail.python.org/pipermail/python-dev/2003-March/034029.html There's a vague comment about it on python documentation but afaik there the discussion hasn't made into any PEPs. Is there an understanding about it? Cheers, Leandro

10 13

Re: [Python-Dev] [Python-checkins] cpython (3.4): Prevent Sphinx error on whatsnew/changelog
by Zachary Ware April 24, 2014

April 24, 2014

On April 23, 2014 5:24:53 PM CDT, Terry Reedy <tjreedy(a)udel.edu> wrote: >On 4/23/2014 11:05 AM, zach.ware wrote: >> http://hg.python.org/cpython/rev/75419257fec3 >> changeset: 90440:75419257fec3 >> branch: 3.4 >> parent: 90437:5d745d97b7da >> user: Zachary Ware <zachary.ware(a)gmail.com> >> date: Wed Apr 23 10:04:20 2014 -0500 >> summary: >> Prevent Sphinx error on whatsnew/changelog >> >> files: >> Misc/NEWS | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> >> diff --git a/Misc/NEWS b/Misc/NEWS >> --- a/Misc/NEWS >> +++ b/Misc/NEWS >> @@ -44,7 +44,7 @@ >> at the same time without losing the Popen.returncode value. >> >> - Issue #21127: Path objects can now be instantiated from str >subclass >> - instances (such as numpy.str_). >> + instances (such as ``numpy.str_``). > >Could you explain this? I thought NEWS was a plain text file without >.rst markup. Doc/whatsnew/changelog.rst includes the full text of Misc/NEWS, which means Sphinx doesn't like markup issues in NEWS. -- Zach (on a phone)

1 0