Mailman 3 January 2021 - Python-Dev

[RELEASE] Python 3.10.0a4 is now available
by Pablo Galindo Salgado 04 Jan '21

04 Jan '21

Happy new year to all of you. I hope you all have a great start of the year! And how to best celebrate that we have left 2020 behind that with a new Python alpha release? :) Go get it here: https://www.python.org/downloads/release/python-3100a4/ *Major new features of the 3.10 series, compared to 3.9* Python 3.10 is still in development. This releasee, 3.10.0a4 is the second 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 (2021-05-03) and, if necessary, may be modified or deleted up until the release candidate phase (2021-10-04). Please keep in mind that this is a preview release and its use is not recommended for production environments. Many new features for Python 3.10 are still being planned and written. Among the new major new features and changes so far: * PEP 623 – Remove wstr from Unicode * PEP 604 – Allow writing union types as X | Y * PEP 612 – Parameter Specification Variables * PEP 626 – Precise line numbers for debugging and other tools. * bpo-38605: from __future__ import annotations (PEP 563) is now the default. * PEP 618 – Add Optional Length-Checking To zip. (Hey, fellow core developer, if a feature you find important is missing from this list, let me know.) The next pre-release of Python 3.10 will be 3.10.0a5, currently scheduled for 2021-02-01. *And now for something completely different* The Majumdar–Papapetrou spacetime <https://en.wikipedia.org/wiki/Sudhansu_Datta_Majumdar#Majumdar%E2%80%93Papa…> is one surprising solution of the coupled Einstein-Maxwell equations that describe a cluster of static charged black holes with the gravitational and the electrostatic forces cancelling each other out. Each one of these many black holes of the multi-black holes system has a spherical topology and follows the Reissner–Nordström metric <https://en.wikipedia.org/wiki/Reissner%E2%80%93Nordstr%C3%B6m_metric>. Unsurprisingly, the movement of a test particle in such spacetime is not only a very chaotic system but also has some fractals <https://arxiv.org/abs/gr-qc/9502014> hiding the complexity of its movement. Regards from cold London, Pablo Galindo Salgado

1 0

Enhancement request for PyUnicode proxies
by Nelson, Karl E. 04 Jan '21

04 Jan '21

I was directed to post this request to the general Python development community so hopefully this is on topic. One of the weaknesses of the PyUnicode implementation is that the type is concrete and there is no option for an abstract proxy string to a foreign source. This is an issue for an API like JPype in which java.lang.Strings are passed back from Java. Ideally these would be a type derived from the Unicode type str, but that requires transferring the memory immediately from Java to Python even when that handle is large and will never be accessed from within Python. For certain operations like XML parsing this can be prohibitable, so instead of returning a str we return a JString. (There is a separate issue that Java method names and Python method names conflict so direct inheritance creates some problems.) The JString type can of course be transferred to Python space at any time as both Python Unicode and Java string objects are immutable. However the CPython API which takes strings only accepts the Unicode type objects which have a concrete implementation. It is possible to extend strings, but those extensions do not allow for proxing as far as I can tell. Thus there is no option currently to proxy to a string representation in another language. The concept of the using the duck type ``__str__`` method is insufficient as this indices that an object can become a string, rather than "this object is effectively a string" for the purposes of the CPython API. One way to address this is to use currently outdated copy of READY to extend Unicode objects to other languages. A class like JString would be an unready Unicode object which when READY is called transfers the memory from Java, sets up the flags and sets up a pointer to the code point representation. Unfortunately the READY concept is scheduled for removal and thus the chance to address the needs for proxying a Unicode to another languages representation may be limited. There may be other methods to accomplish this without using the concept of READY. So long as access to the code points go through the Unicode API and the Unicode object can be extended such that the actual code points may be located outside of the Unicode object then a proxy can still be achieved if there are hooks in it to decided when a transfer should be performed. Generally the transfer request only needs to happen once but the key issue being that the number of code points (nor the kind of points) will not be known until the memory is transferred. Java has much the same problem. Although they defined an interface class "java.lang.CharacterArray" the actually "java.lang.String" class is concrete and almost all API methods take a String rather than the base interface even when the base interface would have been adequate. Thus just like Python has difficulty treating a foreign string class as it would a native one, Java cannot treat a Python string as native one as well. So Python strings get represented as CharacterArray type which effectively limits it use greatly. Summary: * A String proxy would need the address of the memory in the "wstr" slot though the code points may be char[], wchar[] or int[] depending the representation in the proxy. * API calls to interpret the data would need to check to see if the data is transferred first, if not it would call the proxy dependent transfer method which is responsible for creating a block of code points and set up flags (kind, ascii, ready, and compact). * The memory block allocated would need to call the proxy dependent destructor to clean up with the string is done. * It is not clear if this would have impact on performance. Python already has the concept of a string which needs actions before it can be accessed, but this is scheduled for removal. Are there any plans currently to address the concept of a proxy string in PyUnicode API?

9 21

Re: [Python-ideas] Re: Add venv activate command to the venv modules
by Paul Sokolovsky 04 Jan '21

04 Jan '21

Hello, On Mon, 4 Jan 2021 21:07:23 +0400 Abdur-Rahmaan Janhangeer <arj.python(a)gmail.com> wrote: > @Christopher Barker <pythonchb(a)gmail.com> > > You nailed it! I've used the conda activate command many times. > It should in theory be possible in Python > > @Chris Angelico <rosuav(a)gmail.com> > > Yes mere shell commands passing via Py does not work, > maybe a file way with results in current shell as @M.-A. Lemburg > <mal(a)egenix.com> > points out, venv already generates the files. On windows it has an > activate.bat Knowing that, you're a step away from creating a "subshell" solution for *yourself*. For POSIX systems, that would be: venv-shell.sh: ---- . $1/bin/activate /bins/sh ---- Voila! If you want to add "--shell" switch to "python3 -m venv" with that functionality, to benefit the whole mankind, not just yourself, I'm +1. I'd say, you can start writing a patch for that. But I'd warn you that it likely will be rejected, as it will require a bunch of sustained user support (i.e. it won't work as expected on various OSes and various shells). -- Best regards, Paul mailto:pmiscml@gmail.com

1 0

Review patch fixing packed bitfields in ctypes struct/union
by Filipe Laíns 02 Jan '21

02 Jan '21

Hi folks, I know this is a high-volume list so sorry for being yet another voice screaming into your mailbox, but I do not know how else to handle this. A few months ago, I opened a pull request fixing packed bitfields in ctypes struct/union, which right now are being incorrectly created. The offsets and size are all wrong in some cases, fields which should be packed end up with padding between them. bpo: https://bugs.python.org/issue29753 PR: https://github.com/python/cpython/pull/19850 Since ctypes has no maintainer it has been very hard tracking down someone who is up to review this. So, if this issue sparks some interest to you, or you just want to help me out, please have a look :) Cheers, Filipe Laíns

4 4

Summary of Python tracker Issues
by Python tracker 01 Jan '21

01 Jan '21

ACTIVITY SUMMARY (2020-12-25 - 2021-01-01) 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 7556 ( +2) closed 46984 (+59) total 54540 (+61) Open issues with patches: 3033 Issues opened (44) ================== #40521: [subinterpreters] Make free lists and unicode caches per-inter https://bugs.python.org/issue40521 reopened by vstinner #40631: PEG Parser: Cannot used starred expression in parenthesised ex https://bugs.python.org/issue40631 reopened by pablogsal #41224: Document is_annotate() in symtable and update doc strings https://bugs.python.org/issue41224 reopened by serhiy.storchaka #42744: pkg_resources seems to treat python 3.10 as python 3.1 https://bugs.python.org/issue42744 opened by RhinosF1 #42746: python3.7.3 - ssl.SSLContext() - "Killed" https://bugs.python.org/issue42746 opened by hgmmym #42747: Remove Py_TPFLAGS_HAVE_VERSION_TAG flag? https://bugs.python.org/issue42747 opened by vstinner #42752: multiprocessing Queue leaks a file descriptor associated with https://bugs.python.org/issue42752 opened by crazycasta #42756: smtplib.LMTP.connect() raises TypeError if `timeout` is not sp https://bugs.python.org/issue42756 opened by wuestengecko #42757: Class has two prototypes https://bugs.python.org/issue42757 opened by SinTh0r4s #42759: Take into acount a Tcl interpreter when compare variables and https://bugs.python.org/issue42759 opened by serhiy.storchaka #42760: inspect.iscoroutine returns False for asynchronous generator m https://bugs.python.org/issue42760 opened by plammens #42762: infinite loop resulted by "yield" https://bugs.python.org/issue42762 opened by xxm #42763: Exposing a race in the "_warnings" resulting Python parser cra https://bugs.python.org/issue42763 opened by xxm #42765: Introduce new data model method __iter_items__ https://bugs.python.org/issue42765 opened by conqp #42766: urllib.request.HTTPPasswordMgr uses commonprefix instead of co https://bugs.python.org/issue42766 opened by nagdon #42767: Review usage of atomic variables in signamodule.c https://bugs.python.org/issue42767 opened by vstinner #42769: concurrent.futures.ProcessPoolExecutor is unable to forward ex https://bugs.python.org/issue42769 opened by damien.levac #42771: Implement interactive hotkey, Ctrl+L to clear the console in W https://bugs.python.org/issue42771 opened by mixmastamyk #42772: randrange() mishandles step when stop is None https://bugs.python.org/issue42772 opened by rhettinger #42773: build.yml workflow not testing on pushes https://bugs.python.org/issue42773 opened by ammar2 #42775: __init_subclass__ should be called in __init__ https://bugs.python.org/issue42775 opened by ethan.furman #42776: The string find method shows the problem https://bugs.python.org/issue42776 opened by andyye #42777: WindowsPath does not implement is_mount but ntpath implements https://bugs.python.org/issue42777 opened by db #42778: Add follow_symlinks=True parameter to both os.path.samefile() https://bugs.python.org/issue42778 opened by Tom Hale #42780: os.set_inheritable() fails for O_PATH file descriptors on Linu https://bugs.python.org/issue42780 opened by cptpcrd #42782: shutil.move creates a new directory even on failure https://bugs.python.org/issue42782 opened by winsonluk #42783: asyncio.sleep(0) idiom is not documented https://bugs.python.org/issue42783 opened by simonw #42784: issues with object.h includes https://bugs.python.org/issue42784 opened by bigbossbro08 #42785: Support operator module callables in inspect.signature https://bugs.python.org/issue42785 opened by plammens #42787: email.utils.getaddresses improper parsing of unicode realnames https://bugs.python.org/issue42787 opened by konstantin2 #42789: Do not skip test_curses on non-tty https://bugs.python.org/issue42789 opened by serhiy.storchaka #42790: test.regrtest outputs to stdout instead of stderr https://bugs.python.org/issue42790 opened by serhiy.storchaka #42791: There is no way to json encode object to str. https://bugs.python.org/issue42791 opened by kaltovichartyom #42794: test_nntplib fails on CI https://bugs.python.org/issue42794 opened by serhiy.storchaka #42795: Asyncio loop.create_server doesn't bind to any interface if ho https://bugs.python.org/issue42795 opened by plammens #42796: tempfile doesn't seem to play nicely with os.chdir on Windows https://bugs.python.org/issue42796 opened by Gabriele Tornetta #42797: Allow doctest to select tests via -m/--match option https://bugs.python.org/issue42797 opened by costas-basdekis #42798: pip search fails https://bugs.python.org/issue42798 opened by Paul Watson #42799: Please document fnmatch LRU cache size (256) and suggest alter https://bugs.python.org/issue42799 opened by joshtriplett #42800: Traceback objects allow accessing frame objects without trigge https://bugs.python.org/issue42800 opened by ammar2 #42801: Exception catching function crashes on recursive list https://bugs.python.org/issue42801 opened by steven.daprano #42802: distutils: Remove bdist_wininst command https://bugs.python.org/issue42802 opened by vstinner #42803: Traced line number is wrong for "if not __debug__" https://bugs.python.org/issue42803 opened by nedbat #42804: Unable to compile the cpython code x86 windows https://bugs.python.org/issue42804 opened by pbharat Most recent 15 issues with no replies (15) ========================================== #42804: Unable to compile the cpython code x86 windows https://bugs.python.org/issue42804 #42803: Traced line number is wrong for "if not __debug__" https://bugs.python.org/issue42803 #42800: Traceback objects allow accessing frame objects without trigge https://bugs.python.org/issue42800 #42798: pip search fails https://bugs.python.org/issue42798 #42795: Asyncio loop.create_server doesn't bind to any interface if ho https://bugs.python.org/issue42795 #42791: There is no way to json encode object to str. https://bugs.python.org/issue42791 #42790: test.regrtest outputs to stdout instead of stderr https://bugs.python.org/issue42790 #42789: Do not skip test_curses on non-tty https://bugs.python.org/issue42789 #42784: issues with object.h includes https://bugs.python.org/issue42784 #42783: asyncio.sleep(0) idiom is not documented https://bugs.python.org/issue42783 #42777: WindowsPath does not implement is_mount but ntpath implements https://bugs.python.org/issue42777 #42769: concurrent.futures.ProcessPoolExecutor is unable to forward ex https://bugs.python.org/issue42769 #42766: urllib.request.HTTPPasswordMgr uses commonprefix instead of co https://bugs.python.org/issue42766 #42760: inspect.iscoroutine returns False for asynchronous generator m https://bugs.python.org/issue42760 #42757: Class has two prototypes https://bugs.python.org/issue42757 Most recent 15 issues waiting for review (15) ============================================= #42802: distutils: Remove bdist_wininst command https://bugs.python.org/issue42802 #42797: Allow doctest to select tests via -m/--match option https://bugs.python.org/issue42797 #42794: test_nntplib fails on CI https://bugs.python.org/issue42794 #42789: Do not skip test_curses on non-tty https://bugs.python.org/issue42789 #42783: asyncio.sleep(0) idiom is not documented https://bugs.python.org/issue42783 #42782: shutil.move creates a new directory even on failure https://bugs.python.org/issue42782 #42780: os.set_inheritable() fails for O_PATH file descriptors on Linu https://bugs.python.org/issue42780 #42778: Add follow_symlinks=True parameter to both os.path.samefile() https://bugs.python.org/issue42778 #42775: __init_subclass__ should be called in __init__ https://bugs.python.org/issue42775 #42773: build.yml workflow not testing on pushes https://bugs.python.org/issue42773 #42772: randrange() mishandles step when stop is None https://bugs.python.org/issue42772 #42759: Take into acount a Tcl interpreter when compare variables and https://bugs.python.org/issue42759 #42756: smtplib.LMTP.connect() raises TypeError if `timeout` is not sp https://bugs.python.org/issue42756 #42752: multiprocessing Queue leaks a file descriptor associated with https://bugs.python.org/issue42752 #42737: PEP 563: drop annotations for complex assign targets https://bugs.python.org/issue42737 Top 10 most discussed issues (10) ================================= #42794: test_nntplib fails on CI https://bugs.python.org/issue42794 17 msgs #42742: Add abc.Mapping to dataclass https://bugs.python.org/issue42742 9 msgs #40631: PEG Parser: Cannot used starred expression in parenthesised ex https://bugs.python.org/issue40631 8 msgs #42737: PEP 563: drop annotations for complex assign targets https://bugs.python.org/issue42737 8 msgs #42747: Remove Py_TPFLAGS_HAVE_VERSION_TAG flag? https://bugs.python.org/issue42747 8 msgs #1635741: Py_Finalize() doesn't clear all Python objects at exit https://bugs.python.org/issue1635741 8 msgs #29708: support reproducible Python builds https://bugs.python.org/issue29708 7 msgs #40522: [subinterpreters] Get the current Python interpreter state fro https://bugs.python.org/issue40522 7 msgs #42762: infinite loop resulted by "yield" https://bugs.python.org/issue42762 7 msgs #42772: randrange() mishandles step when stop is None https://bugs.python.org/issue42772 6 msgs Issues closed (57) ================== #8481: doc: ctypes no need to explicitly allocate writable memory wit https://bugs.python.org/issue8481 closed by orsenthil #15303: Minor revision to the <BaseWidget._setup> method in Tkinter https://bugs.python.org/issue15303 closed by serhiy.storchaka #23328: urllib.request fails for proxy credentials that contain a '/' https://bugs.python.org/issue23328 closed by orsenthil #27640: Add --disable-test-modules configure option to not build nor i https://bugs.python.org/issue27640 closed by vstinner #27794: setattr a read-only property; the AttributeError should show t https://bugs.python.org/issue27794 closed by rhettinger #30963: xxlimited.c XxoObject_Check should be XxoObject_CheckExact https://bugs.python.org/issue30963 closed by petr.viktorin #32825: warn user of creation of multiple Tk instances https://bugs.python.org/issue32825 closed by serhiy.storchaka #34752: warnings.warn fails silently with unicode input https://bugs.python.org/issue34752 closed by corona10 #37193: Memory leak while running TCP/UDPServer with socketserver.Thre https://bugs.python.org/issue37193 closed by pablogsal #39171: Missing default root in tkinter simpledialog.py https://bugs.python.org/issue39171 closed by serhiy.storchaka #39177: In tkinter, simple dialogs, askstrings, etc. with flexible coo https://bugs.python.org/issue39177 closed by serhiy.storchaka #39465: [subinterpreters] Design a subinterpreter friendly alternative https://bugs.python.org/issue39465 closed by vstinner #40288: [subinterpreters] atexit module should not be loaded more than https://bugs.python.org/issue40288 closed by vstinner #40494: collections.abc.Callable and type variables https://bugs.python.org/issue40494 closed by gvanrossum #41450: OSError is not documented in ssl library, but still can be thr https://bugs.python.org/issue41450 closed by orsenthil #41781: Typos in typing.py https://bugs.python.org/issue41781 closed by shihai1991 #41884: tempfile.py TemporaryDirectory/mkdtemp defaults to mode 0o700, https://bugs.python.org/issue41884 closed by ray-sit #42042: sphinx3 renders diffrently docs.python.org for 3.10 https://bugs.python.org/issue42042 closed by corona10 #42222: Modernize integer test/conversion in randrange() https://bugs.python.org/issue42222 closed by rhettinger #42243: Don't access the module dictionary directly https://bugs.python.org/issue42243 closed by erlendaasland #42318: [tkinter] surrogate pairs in Tcl/Tk string when pasting an emo https://bugs.python.org/issue42318 closed by serhiy.storchaka #42393: Raise overflow errors iso. deprecation warnings in socket.hton https://bugs.python.org/issue42393 closed by serhiy.storchaka #42655: Fix subprocess extra_groups gid conversion https://bugs.python.org/issue42655 closed by serhiy.storchaka #42687: tokenize module does not recognize Barry as FLUFL https://bugs.python.org/issue42687 closed by esoma #42694: Failed test_new_curses_panel in test_curses https://bugs.python.org/issue42694 closed by vstinner #42700: xml.parsers.expat.errors description of codes/messages is flip https://bugs.python.org/issue42700 closed by serhiy.storchaka #42713: Segmentation fault in running eval() with large expression siz https://bugs.python.org/issue42713 closed by terry.reedy #42714: Segmentation fault in running compile() with large expression https://bugs.python.org/issue42714 closed by terry.reedy #42715: Segmentation fault in running exec() with large expression siz https://bugs.python.org/issue42715 closed by terry.reedy #42716: Segmentation fault in running ast.parse() with large expressio https://bugs.python.org/issue42716 closed by terry.reedy #42721: Using of simple dialogs without default root window https://bugs.python.org/issue42721 closed by serhiy.storchaka #42724: Change library name when building. https://bugs.python.org/issue42724 closed by eric.smith #42728: Typo in documentation: importlib.metadata https://bugs.python.org/issue42728 closed by barry #42733: io's r+ mode truncate(0) https://bugs.python.org/issue42733 closed by terry.reedy #42734: Outdated CodeType call in "bogus_code_obj.py" https://bugs.python.org/issue42734 closed by serhiy.storchaka #42740: typing.py get_args and get_origin should support PEP 604 and 6 https://bugs.python.org/issue42740 closed by gvanrossum #42741: Sync 3.9's whatsnew document in 3.10 with 3.9 branch https://bugs.python.org/issue42741 closed by pablogsal #42745: [subinterpreters] Make the type attribute lookup cache per-int https://bugs.python.org/issue42745 closed by vstinner #42748: test_asdl_parser: load_module() method is deprecated https://bugs.python.org/issue42748 closed by corona10 #42749: test_tcl failed on 32-bit POWER6 AIX 3.9: big int issue with 9 https://bugs.python.org/issue42749 closed by vstinner #42750: tkinter.Variable equality inconsistency https://bugs.python.org/issue42750 closed by serhiy.storchaka #42751: Imaplib https://bugs.python.org/issue42751 closed by steven.daprano #42753: "./configure" linux chrome beta https://bugs.python.org/issue42753 closed by eric.smith #42754: Unpacking of literals inside other literals should be optimise https://bugs.python.org/issue42754 closed by pablogsal #42755: sqlite3.Connection.backup default value is diffrent between im https://bugs.python.org/issue42755 closed by pablogsal #42758: pathlib.Path to support the "in" operator (x in y) https://bugs.python.org/issue42758 closed by eric.smith #42761: Why does python's Popen fail to pass environment variables on https://bugs.python.org/issue42761 closed by benjamin.peterson #42764: HTMLParser close() issue https://bugs.python.org/issue42764 closed by aeh #42768: super().__new__() of list expands arguments https://bugs.python.org/issue42768 closed by serhiy.storchaka #42770: Typo in email.headerregistry docs https://bugs.python.org/issue42770 closed by zach.ware #42774: 'ipaddress' module, bad result for 'is_private' on "192.0.0.0" https://bugs.python.org/issue42774 closed by trevormarvin #42779: pow() of huge input does not complete https://bugs.python.org/issue42779 closed by serhiy.storchaka #42781: functools.cached_property docs should explain that it is non-o https://bugs.python.org/issue42781 closed by rhettinger #42786: Different repr for collections.abc.Callable and typing.Callabl https://bugs.python.org/issue42786 closed by Prometheus3375 #42788: Issue with Python’s Floor Division https://bugs.python.org/issue42788 closed by rhettinger #42792: [MacOS] Can't open file in a separate (threading.Thread) threa https://bugs.python.org/issue42792 closed by mark.dickinson #42793: Bug of round function https://bugs.python.org/issue42793 closed by serhiy.storchaka

1 0

Need help with python
by hadi esmaeely 01 Jan '21

01 Jan '21

hi my name is hadi i'm from iran (the country which filtering others and be filtered by others) i have started programming with python about 3 months and i'm very interested in learning programming and python language but duo to limitations of technologies and filtering the learning sources in my country i can not find proper source for learning programming(we can use vpn for some of websites but not effective enough). Because of that I must learn and work in another country (In my country, programmers are not valued). I am very interested in learning and immigrating to the Netherlands(my dream country) for work and to meet with you and other great programmers. But I don't know where to begin and how I can learn programming and python language in the right way without wasting time. I have studied 10 hours a day but I cannot conclude results. i have read this books and articles: beginning python from novice to professional django 3 by example antonio mele django for apis william s vincent django for professionals django web development with python - packt fluent python head first python practical python design patterns apress(currently reading) python in a nutshell(currently reading) the self taught programmer python 3 for absolute beginners some django official documents some python official documents but i don't know how to use my learnings from books If you help me to know how I can study in the right way ,I will appreciate you for my whole life thank you and happy new year :)

3 2

Python-Dev January 2021