Python-Dev January 2020

python-dev@python.org

75 participants
53 discussions

Python library for the ServiceNow REST API
by IT Canvass 28 Jan '20

28 Jan '20

It should be compatible with modern versions of ServiceNow. If there's API breakage or new features implemented, I usually have that fixed/incorporated into pysnow in a week or two. <a href="https://itcanvass.com/"> servicenow training</a>

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Are PyObject_RichCompareBool shortcuts part of Python or just CPython quirks?
by Tim Peters 26 Jan '20

26 Jan '20

PyObject_RichCompareBool(x, y, op) has a (valuable!) shortcut: if x and y are the same object, then equality comparison returns True and inequality False. No attempt is made to execute __eq__ or __ne__ methods in those cases. This has visible consequences all over the place, but they don't appear to be documented. For example, >>> import math >>> ([math.nan] * 5).count(math.nan) 5 despite that `math.nan == math.nan` is False. It's usually clear which methods will be called, and when, but not really here. Any _context_ that calls PyObject_RichCompareBool() under the covers, for an equality or inequality test, may or may not invoke __eq__ or __ne__, depending on whether the comparands are the same object. Also any context that inlines these special cases to avoid the overhead of calling PyObject_RichCompareBool() at all. If it's intended that Python-the-language requires this, that needs to be documented. Or if it's implementation-defined, then _that_ needs to be documented. Which isn't straightforward in either case, in part because PyObject_RichCompareBool isn't a language-level concept. This came up recently when someone _noticed_ the list.count(NaN) behavior, and Victor made a PR to document it: https://github.com/python/cpython/pull/18130 I'm pushing back, because documenting it _only_ for .count() makes .count() seem unique in a way it isn't, and doesn't resolve the fundamental issue: is this language behavior, or implementation behavior? Which I don't want to argue about. But you certainly should ;-)

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[RELEASE] Python 3.9.0a3 available for testing
by Łukasz Langa 25 Jan '20

25 Jan '20

Go get it here: https://www.python.org/downloads/release/python-390a3/ <https://www.python.org/downloads/release/python-390a3/> This is an early developer preview of Python 3.9 Python 3.9 is still in development. This releasee, 3.9.0a3 is the third of six planned alpha releases. Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process. During the alpha phase, features may be added up until the start of the beta phase (2020-05-18) and, if necessary, may be modified or deleted up until the release candidate phase (2020-08-10). Please keep in mind that this is a preview release and its use is not recommended for production environments. Major new features of the 3.9 series, compared to 3.8 Many new features for Python 3.9 are still being planned and written. Among the new major new features and changes so far: PEP 602 <https://www.python.org/dev/peps/pep-0602/>, Python adopts a stable annual release cadence BPO 38379 <https://bugs.python.org/issue38379>, garbage collection does not block on resurrected objects; BPO 38692 <https://bugs.python.org/issue38692>, os.pidfd_open added that allows process management without races and signals; A number of standard library modules (audioop, ast, grp, _hashlib, pwd, _posixsubprocess, random, select, struct, termios, zlib) are now using the stable ABI defined by PEP 384 <https://www.python.org/dev/peps/pep-0384/>. (Hey, fellow core developer, if a feature you find important is missing from this list, let Łukasz know <mailto:lukasz@python.org>.) The next pre-release of Python 3.9 will be 3.9.0a4, currently scheduled for 2020-02-17. - Ł

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Summary of Python tracker Issues
by Python tracker 24 Jan '20

24 Jan '20

ACTIVITY SUMMARY (2020-01-17 - 2020-01-24) Python tracker at https://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 7285 (+17) closed 43910 (+55) total 51195 (+72) Open issues with patches: 2852 Issues opened (45) ================== #29258: __init__.py required for pkgutil.walk_packages in python3 https://bugs.python.org/issue29258 reopened by inada.naoki #39353: Deprecate the binhex module, binhex4 and hexbin4 standards https://bugs.python.org/issue39353 reopened by vstinner #39372: The header files in Include/ have many declarations with no de https://bugs.python.org/issue39372 reopened by pablogsal #39374: Key in sort -> Callable Object instead of function https://bugs.python.org/issue39374 opened by Carlos Segura González #39375: Document os.environ[x] = y and os.putenv() as thread unsafe https://bugs.python.org/issue39375 opened by gregory.p.smith #39376: Avoid modifying the process global environment (not thread saf https://bugs.python.org/issue39376 opened by gregory.p.smith #39378: partial of PickleState struct should be traversed. https://bugs.python.org/issue39378 opened by shihai1991 #39379: sys.path[0] is already absolute path https://bugs.python.org/issue39379 opened by ksato9700 #39380: ftplib uses latin-1 as default encoding https://bugs.python.org/issue39380 opened by SebastianGPedersen #39382: abstract_issubclass() doesn't take bases tuple item ref https://bugs.python.org/issue39382 opened by Yonatan Goldschmidt #39384: Email parser creates a message object that can't be flattened https://bugs.python.org/issue39384 opened by msapiro #39385: Add an assertNoLogs context manager to unittest TestCase https://bugs.python.org/issue39385 opened by Kit Yan Choi #39388: IDLE: Changes to keybindings aren't reverted on cancel https://bugs.python.org/issue39388 opened by cheryl.sabella #39390: shutil.copytree - 3.8 changed argument types of the ignore cal https://bugs.python.org/issue39390 opened by mbarkhau #39392: Python Turtle is not filling alternate overlapping areas of a https://bugs.python.org/issue39392 opened by lijose #39393: Misleading error message upon dependent DLL resolution failure https://bugs.python.org/issue39393 opened by plimkilde #39394: re: DeprecationWarning for `flag not at the start of expressio https://bugs.python.org/issue39394 opened by jugmac00 #39400: pydoc: Use of MANPAGER variable is incorrect https://bugs.python.org/issue39400 opened by Brocellous #39401: Unsafe dll loading in getpathp.c on Win7 https://bugs.python.org/issue39401 opened by anthonywee #39405: Using relative path as a --prefix during configure. https://bugs.python.org/issue39405 opened by Sankark #39407: Bitfield Union does not work for bit widths greater than 8 bit https://bugs.python.org/issue39407 opened by jschulte #39408: Add support for SQLCipher https://bugs.python.org/issue39408 opened by Sebastian.Noack #39409: AIX: FAIL: test_specific_values (test.test_cmath.CMathTests) https://bugs.python.org/issue39409 opened by Michael.Felt #39410: CentOS 6.10 SQLite 3.30.1 - _sqlite3 builds successfully but i https://bugs.python.org/issue39410 opened by cehovski #39411: pyclbr rewrite using AST https://bugs.python.org/issue39411 opened by Batuhan Taskaya #39413: Implement os.unsetenv() on Windows https://bugs.python.org/issue39413 opened by vstinner #39414: Multiprocessing resolving object as None https://bugs.python.org/issue39414 opened by rdil #39416: Document default numeric string formats https://bugs.python.org/issue39416 opened by kop #39417: Link to "Python Packaging User Guide: Creating and using virtu https://bugs.python.org/issue39417 opened by angelcervera #39418: str.strip() should have a means of adding to the default behav https://bugs.python.org/issue39418 opened by senji #39419: Core dump when trying to use workaround for custom warning cat https://bugs.python.org/issue39419 opened by Gerrit.Holl #39423: Process finished with exit code -1073741819 (0xC0000005) when https://bugs.python.org/issue39423 opened by mapf #39424: [easy] test_signal: test_pidfd_send_signal() uses deprecated a https://bugs.python.org/issue39424 opened by vstinner #39427: python -X options are not documented in the CLI --help https://bugs.python.org/issue39427 opened by pablogsal #39428: allow creation of "symtable entry" objects from Python https://bugs.python.org/issue39428 opened by carljm #39430: tarfile.open(mode="r") race condition when importing lzma https://bugs.python.org/issue39430 opened by Maciej Gol #39432: Distutils generates the wrong export symbol for unicode module https://bugs.python.org/issue39432 opened by da-woods #39433: curses.setupterm can raise _curses.error https://bugs.python.org/issue39433 opened by mdk #39434: Remove unnecessary logic of float __floordiv__ https://bugs.python.org/issue39434 opened by corona10 #39435: pickle: inconsistent arguments pickle.py vs _pickle.c vs docs https://bugs.python.org/issue39435 opened by crusaderky #39438: better handling of foreign signal handlers in signal.signal https://bugs.python.org/issue39438 opened by Steven G. Johnson #39441: mimetypes.guess_extension unable to get non-lowercase mimetype https://bugs.python.org/issue39441 opened by Inkhey #39442: from __future__ import annotations makes dataclasses.Field.typ https://bugs.python.org/issue39442 opened by lopek #39443: Inhomogeneous behaviour for descriptors in between the class-i https://bugs.python.org/issue39443 opened by Hugo Ricateau #39444: Incorrect description of sorting for PrettyPrinter https://bugs.python.org/issue39444 opened by TextGeek Most recent 15 issues with no replies (15) ========================================== #39443: Inhomogeneous behaviour for descriptors in between the class-i https://bugs.python.org/issue39443 #39441: mimetypes.guess_extension unable to get non-lowercase mimetype https://bugs.python.org/issue39441 #39438: better handling of foreign signal handlers in signal.signal https://bugs.python.org/issue39438 #39435: pickle: inconsistent arguments pickle.py vs _pickle.c vs docs https://bugs.python.org/issue39435 #39432: Distutils generates the wrong export symbol for unicode module https://bugs.python.org/issue39432 #39428: allow creation of "symtable entry" objects from Python https://bugs.python.org/issue39428 #39424: [easy] test_signal: test_pidfd_send_signal() uses deprecated a https://bugs.python.org/issue39424 #39419: Core dump when trying to use workaround for custom warning cat https://bugs.python.org/issue39419 #39407: Bitfield Union does not work for bit widths greater than 8 bit https://bugs.python.org/issue39407 #39405: Using relative path as a --prefix during configure. https://bugs.python.org/issue39405 #39392: Python Turtle is not filling alternate overlapping areas of a https://bugs.python.org/issue39392 #39388: IDLE: Changes to keybindings aren't reverted on cancel https://bugs.python.org/issue39388 #39385: Add an assertNoLogs context manager to unittest TestCase https://bugs.python.org/issue39385 #39382: abstract_issubclass() doesn't take bases tuple item ref https://bugs.python.org/issue39382 #39378: partial of PickleState struct should be traversed. https://bugs.python.org/issue39378 Most recent 15 issues waiting for review (15) ============================================= #39435: pickle: inconsistent arguments pickle.py vs _pickle.c vs docs https://bugs.python.org/issue39435 #39434: Remove unnecessary logic of float __floordiv__ https://bugs.python.org/issue39434 #39432: Distutils generates the wrong export symbol for unicode module https://bugs.python.org/issue39432 #39430: tarfile.open(mode="r") race condition when importing lzma https://bugs.python.org/issue39430 #39427: python -X options are not documented in the CLI --help https://bugs.python.org/issue39427 #39416: Document default numeric string formats https://bugs.python.org/issue39416 #39413: Implement os.unsetenv() on Windows https://bugs.python.org/issue39413 #39411: pyclbr rewrite using AST https://bugs.python.org/issue39411 #39400: pydoc: Use of MANPAGER variable is incorrect https://bugs.python.org/issue39400 #39393: Misleading error message upon dependent DLL resolution failure https://bugs.python.org/issue39393 #39390: shutil.copytree - 3.8 changed argument types of the ignore cal https://bugs.python.org/issue39390 #39388: IDLE: Changes to keybindings aren't reverted on cancel https://bugs.python.org/issue39388 #39385: Add an assertNoLogs context manager to unittest TestCase https://bugs.python.org/issue39385 #39384: Email parser creates a message object that can't be flattened https://bugs.python.org/issue39384 #39382: abstract_issubclass() doesn't take bases tuple item ref https://bugs.python.org/issue39382 Top 10 most discussed issues (10) ================================= #39390: shutil.copytree - 3.8 changed argument types of the ignore cal https://bugs.python.org/issue39390 12 msgs #38076: Make struct module PEP-384 compatible https://bugs.python.org/issue38076 9 msgs #39413: Implement os.unsetenv() on Windows https://bugs.python.org/issue39413 9 msgs #39430: tarfile.open(mode="r") race condition when importing lzma https://bugs.python.org/issue39430 9 msgs #39353: Deprecate the binhex module, binhex4 and hexbin4 standards https://bugs.python.org/issue39353 7 msgs #39408: Add support for SQLCipher https://bugs.python.org/issue39408 6 msgs #39434: Remove unnecessary logic of float __floordiv__ https://bugs.python.org/issue39434 6 msgs #39372: The header files in Include/ have many declarations with no de https://bugs.python.org/issue39372 5 msgs #39418: str.strip() should have a means of adding to the default behav https://bugs.python.org/issue39418 5 msgs #17005: Add a topological sort algorithm https://bugs.python.org/issue17005 4 msgs Issues closed (54) ================== #18091: Remove PyNoArgsFunction https://bugs.python.org/issue18091 closed by serhiy.storchaka #18842: Add float.is_finite is_nan is_infinite to match Decimal method https://bugs.python.org/issue18842 closed by corona10 #21600: mock.patch.stopall doesn't work with patch.dict https://bugs.python.org/issue21600 closed by cjw296 #24658: open().write() and .read() fails on 2 GB+ data (OS X) https://bugs.python.org/issue24658 closed by zach.ware #29435: Allow to pass fileobj to is_tarfile https://bugs.python.org/issue29435 closed by ethan.furman #32989: IDLE: Fix pyparse.find_good_parse_start https://bugs.python.org/issue32989 closed by terry.reedy #34145: uuid3 and uuid5 hard to use portably between Python 2 and 3 https://bugs.python.org/issue34145 closed by zach.ware #34834: test_ssl.test_options does not correctly account for built-in https://bugs.python.org/issue34834 closed by zach.ware #35182: Popen.communicate() breaks when child closes its side of pipe https://bugs.python.org/issue35182 closed by gregory.p.smith #35561: Valgrind reports Syscall param epoll_ctl(event) points to unin https://bugs.python.org/issue35561 closed by vstinner #36417: unicode.isdecimal bug in online Python 2 documentation https://bugs.python.org/issue36417 closed by zach.ware #37669: Make mock_open return per-file content https://bugs.python.org/issue37669 closed by cjw296 #38536: Trailing space in formatted currency with international=True a https://bugs.python.org/issue38536 closed by inada.naoki #39035: Travis CI fail on backports: pyvenv not installed https://bugs.python.org/issue39035 closed by vstinner #39146: too much memory consumption in re.compile unicode https://bugs.python.org/issue39146 closed by zach.ware #39197: argparse: title and description for mutually exclusive arg gro https://bugs.python.org/issue39197 closed by paul.j3 #39295: usage of bitfields in ctypes structures changed between 3.7.5 https://bugs.python.org/issue39295 closed by vinay.sajip #39331: 2to3 mishandles indented imports https://bugs.python.org/issue39331 closed by cheryl.sabella #39336: Immutable module type can't be used as package in custom loade https://bugs.python.org/issue39336 closed by dino.viehland #39343: Travis CI: documentation job fails in library/nntplib.rst with https://bugs.python.org/issue39343 closed by vstinner #39361: [C API] Document PyTypeObject.tp_print removal in What's New I https://bugs.python.org/issue39361 closed by vstinner #39365: Support (SEEK_END/SEEK_CUR) relative seeking in StringIO https://bugs.python.org/issue39365 closed by serhiy.storchaka #39366: Remove deprecated nntplib method https://bugs.python.org/issue39366 closed by berker.peksag #39370: askopenfilename is missing from the Tkinter filedialog library https://bugs.python.org/issue39370 closed by ned.deily #39373: -- https://bugs.python.org/issue39373 closed by zach.ware #39377: json.loads encoding parameter deprecation removal in Python 3. https://bugs.python.org/issue39377 closed by inada.naoki #39381: Fix get_event_loop documentation https://bugs.python.org/issue39381 closed by asvetlov #39383: Mention Darwin as a potential value for platform.system() https://bugs.python.org/issue39383 closed by ned.deily #39386: Prevent double awaiting of async iterator https://bugs.python.org/issue39386 closed by asvetlov #39387: configparser read_file() with variable https://bugs.python.org/issue39387 closed by Mattia Verga #39389: gzip metadata fails to reflect compresslevel https://bugs.python.org/issue39389 closed by serhiy.storchaka #39391: Nondeterministic Pydoc output on functions that have functions https://bugs.python.org/issue39391 closed by serhiy.storchaka #39395: The os module should unset() environment variable at exit https://bugs.python.org/issue39395 closed by vstinner #39396: AIX: self.assertEqualSign(math.nextafter(-0.0, +0.0), +0.0) te https://bugs.python.org/issue39396 closed by vstinner #39397: Mac : fail to launch Python 3.8 https://bugs.python.org/issue39397 closed by inada.naoki #39398: AMD64 Fedora Rawhide Clang 3.x: C compiler cannot create execu https://bugs.python.org/issue39398 closed by vstinner #39399: Cross compilation using different libc is broken https://bugs.python.org/issue39399 closed by ned.deily #39402: Consistent use of terms https://bugs.python.org/issue39402 closed by rhettinger #39403: Objects equal (assertEqual return True) but behave differently https://bugs.python.org/issue39403 closed by zach.ware #39404: Pexpect : setwinsize() not working in SLES 12.4 kernel 4.12.14 https://bugs.python.org/issue39404 closed by archi-pandey #39406: Implement os.putenv() with setenv() if available https://bugs.python.org/issue39406 closed by vstinner #39412: Install launcher for all users https://bugs.python.org/issue39412 closed by steve.dower #39415: Remove unused code from longobject.c complexobject.c floatobje https://bugs.python.org/issue39415 closed by benjamin.peterson #39420: Windows: convertenviron() doesn't parse environment variables https://bugs.python.org/issue39420 closed by vstinner #39421: Use-after-free in heappushpop() of heapq module https://bugs.python.org/issue39421 closed by pablogsal #39422: datetime.datetime.strptime incorrectly interpretting format '% https://bugs.python.org/issue39422 closed by SilentGhost #39425: list.count performance regression https://bugs.python.org/issue39425 closed by pablogsal #39426: Pickler docstring misstates default and highest protocols https://bugs.python.org/issue39426 closed by pitrou #39429: Add a new "Python Development Mode" page to the documentation https://bugs.python.org/issue39429 closed by vstinner #39431: Mention nonlocal too in assignment quirk https://bugs.python.org/issue39431 closed by terry.reedy #39436: Strange behavior of comparing int and float numbers https://bugs.python.org/issue39436 closed by mrabarnett #39437: collections.Counter support multiplication https://bugs.python.org/issue39437 closed by ammar2 #39439: Windows Multiprocessing in Virtualenv: sys.prefix is incorrect https://bugs.python.org/issue39439 closed by eryksun #39440: Use PyNumber_InPlaceAdd in sum() for the second iteration onwa https://bugs.python.org/issue39440 closed by edk

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Re: SWIFT Confirmation and request for Updated Statement for DEC invoice
by ron＠ronstruckandauto.com 24 Jan '20

24 Jan '20

Sir, Please note that and we are Transferring payment again to your Designated bank As advised earlier. Kindly see attached covering letter with Bank Swift for follow up with your bank. Also see below specification Of payment breakdown. USD 3,146.05 USD 28,550.00 Please kindly confirm the attached swifts and Send Updated Statement of Account for our records Purpose. Regards Brian Alex Head Of Finance Treasury Department. Address: ul. 327 Abdrakhmanova (Bayalinov lane) +996 312 37 67 70

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Comparing UUID objects to strings: why not?
by Michael Anckaert 23 Jan '20

23 Jan '20

Hello everyone I have a usecase where I'm comparing a UUID instance with string quite often. A case where I have to convert the UUID instance to a string using str(uuid_obj), leading to redundant code: if str(uuid_obj) == uuid: # do stuff... In my experience I can't find a case where you wouldn't want the implicit conversion to string before comparing a UUID with string. So I would like to propose improving the __eq__ method of UUID to: def __eq__(self, other): if isinstance(other, UUID): return self.int == other.int elif isinstance(other, str): return str(self) == other return NotImplemented Based on my testing and experience I don't think this is a breaking change and would be a meaningful change to the way UUID works. Of course please don't hesitate to change my view or point out any flaws in my reasoning. If other people support this change I'd start the work of creating an issue and PR to get this change implemented. -- Michael Anckaert +32 474 066 467 https://www.sinax.be

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Re: Documenting Python's float.__str__()
by Vedran Čačić 22 Jan '20

22 Jan '20

> ints print the same in just about every single programming language that uses base ten Arabic-Hindu digits 0...9. It's kind of a universal. Not actually true: C64's Basic V2 printed positive numbers with space in front. -- Vedran Čačić

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Documenting Python's float.__str__()
by Karl O. Pinc 22 Jan '20

22 Jan '20

Hello, There appears to be extremely minimal documentation on how floats are formatted on output. All I really see is that float.__str__() is float.__repr__(). So that means that float->str->float does not result in a different value. It would be nice if the output format for float was documented, to the extent this is possible. #python suggested that I propose a patch, but I see no way to write a documentation patch without having any clue about what Python promises, whether in the CPython implementation or as part of a specification for Python. What are the promises Python makes about the str() of a float? Will it produce 1.0 today and 1.0e0 or +1.0 tomorrow? When is the result in exponential notation and when not? Does any of this depend on the underlying OS or hardware or Python implementation? Etc. I'm guessing that Python is consistent with an IEEE 754 "external character sequence", but don't know what the IEEE specification says or whether python conforms. I don't really care whether there's documentation for __str__() or __repr__() or something else. I'm just thinking that there should be some way to guarantee a well defined "useful" float output formatting. By "useful" I mean in exponential notation when non-exponential notation is over-long. I am writing a program that sometimes prints python floats and want to be able to document what is printed. Right now I can't truly guarantee anything, other than the nan and inf and -inf representations. (I feel comfortable with nan and the like because I don't see it likely that their representations will change.) Of course I could always re-implement Python's float.__repr__() in Python so as to have full control, but this should be pointless. Python's output representation is unlikely to change and Python should be able to make sufficient promises about its existing float representation. I suppose there are similar issues with integers, but the varieties of floating point number implementations and the existence of both exponential and non-exponential representations make float particularly problematic and representations potentially mercurial. I also don't know if documentation changes with regard to external representations would require a PEP. I have found the following related information: Use shorter float repr when possible https://bugs.python.org/issue1580 https://github.com/python/cpython/blob/master/Python/pystrtod.c#L831 String conversion and formatting https://docs.python.org/3/c-api/conversion.html sys.float_repr_style https://docs.python.org/3/library/sys.html#sys.float_repr_style object.__str__(self) https://docs.python.org/3/reference/datamodel.html#object.__str__ At the end of the day I don't _really_ care. But having put thought into the matter I care enough to write this email and ask the question. Regards, Karl <kop(a)karlpinc.com> Free Software: "You don't pay back, you pay forward." -- Robert A. Heinlein

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PEP 587
by Zak Mabbott 21 Jan '20

21 Jan '20

I am really confused on writing python and what app I need to write it in any tips or any ideas for apps??

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About "python-porting" mail list
by Facundo Batista 20 Jan '20

20 Jan '20

Hello! This list (which I co-admin, with Georg) is getting less and less traffic as months pass by. See: https://mail.python.org/pipermail/python-porting/ The interwebs has been collecting ton of resources about porting py2 to 3 during these years. Any not-yet-answered question surely can be done in a list with more participants. Can we kill this list? Thanks! Regards, -- . Facundo Blog: http://www.taniquetil.com.ar/plog/ PyAr: http://www.python.org.ar/ Twitter: @facundobatista

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Python-Dev January 2020