Mailman 3 July 2021 - Python-Dev

Windows buildbots may be broken
by Jason R. Coombs 09 Aug '21

09 Aug '21

Jeremy informed me<https://github.com/python/cpython/pull/27436#issuecomment-889815333> that due to a race condition on a test file and the CPython repo configuration for newline conversion, build bots on Windows may now be failing. If you run such a buildbot, please consider running this command on your repo to bypass the issue: git rm -r :/ ; git checkout HEAD -- :/ You may want to consider adding this command after every update to the repo to avoid the stale state.

6 6

Roundup to GitHub Issues migration
by Ezio Melotti 05 Aug '21

05 Aug '21

As you might know, PEP 581 (Using GitHub Issues for CPython) has been approved. I've been working with Ewa, Ee, the Working Group, the Steering Council, and the GitHub folks to make this happen, and the SC encouraged me to give you all a quick update. This effort is being tracked at <https://github.com/psf/gh-migration/projects/1>: this board reflects the current status of the project. The PEPs (including PEP 588 -- GitHub Issues Migration Plan) haven't been updated yet and might contain outdated information, so please refer to the psf/gh-migration repo for the latest updates. During the next phase I will work with the WG to sort out all the major issues that we might encounter, and then I will once again reach out to you to gather feedback from the wider audience that follows these mailing lists. Best Regards, Ezio Melotti

19 32

Python3 OSF/1 support?
by Jay K 04 Aug '21

04 Aug '21

Hi. I have an Alpha/OSF machine up and running. It is little slow, but it works ok. I would like to run Python3 on it. I have it "compiling and working". It was easy enough so far. https://github.com/python/cpython/pull/27063 Admitted, I haven't figured out what is happening with the posixsubprocess module. Yes? No? Maybe? I can possibly provide ongoing "support" (I don't expect it will be much) and a buildbot (if really required), if I can get it working a bit more, if this is approved, etc. I haven't looked yet at what buildbot involves. Thank you, - Jay

6 6

Repealing PEP 509 (Add a private version to dict)
by Mark Shannon 04 Aug '21

04 Aug '21

Hi everyone, I would like to repeal PEP 509. We don't really have a process for repealing a PEP. Presumably I would just write another PEP. Before I do so, I would like to know if anyone thinks we should keep PEP 509. The dictionary version number is currently unused in CPython and just wastes memory. I am not claiming that we will never need it, just that we shouldn't be required to have it. It should be an internal implementation detail that we can add or remove depending on requirements. Thoughts? Cheers, Mark.

8 9

Request for review: issue 42815: new thread doesn't copy context of the parent thread
by Jesus Cea 31 Jul '21

31 Jul '21

https://bugs.python.org/issue42815 https://github.com/python/cpython/pull/24074 I would love to have this in Python 3.10, but the interaction with "decimal" context has a risk I don't know how to evaluate, neither the impact of a new "context" parameter when launching a new thread. It could collide with a "frequently used" parameter name. I know that we are quite late in 3.10 window since rc1 is planned in a couple of days, but I think this enhancement is sensible. In fact, I discovered it after being annoyed myself with this issue (threads should have their own contexts) and studying the code to write a patch myself. In particular, "concurrent.futures" threads should have independent contexts, like asyncio futures have. That would allow, for instance, to have a "requests.Session" object per thread since that object is not thread-safe (my use case today) and reuse it in different futures that happens to run in the same thread. Since "contextvars" is "threading.local" correctly done, let's do it for real. If legacy code expects a thread to be able to modify parent context, just pass that context to the thread explicitly. -- Jesús Cea Avión _/_/ _/_/_/ _/_/_/ jcea(a)jcea.es - https://www.jcea.es/ _/_/ _/_/ _/_/ _/_/ _/_/ Twitter: @jcea _/_/ _/_/ _/_/_/_/_/ jabber / xmpp:jcea@jabber.org _/_/ _/_/ _/_/ _/_/ _/_/ "Things are not so easy" _/_/ _/_/ _/_/ _/_/ _/_/ _/_/ "My name is Dump, Core Dump" _/_/_/ _/_/_/ _/_/ _/_/ "El amor es poner tu felicidad en la felicidad de otro" - Leibniz

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Summary of Python tracker Issues
by Python tracker 30 Jul '21

30 Jul '21

ACTIVITY SUMMARY (2021-07-23 - 2021-07-30) 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 7395 (-25) closed 49121 (+80) total 56516 (+55) Open issues with patches: 2926 Issues opened (34) ================== #15870: PyType_FromSpec should take metaclass as an argument https://bugs.python.org/issue15870 reopened by belopolsky #36050: Why does http.client.HTTPResponse._safe_read use MAXAMOUNT https://bugs.python.org/issue36050 reopened by bmerry #41103: Removing old buffer support https://bugs.python.org/issue41103 reopened by methane #44479: Windows build doesn't regenerate some files https://bugs.python.org/issue44479 reopened by steve.dower #44676: Add ability to serialise types.Union https://bugs.python.org/issue44676 reopened by serhiy.storchaka #44729: sys.setprofile bug https://bugs.python.org/issue44729 opened by AliyevH #44730: unittest.mock.patch does not work as a decorator on generator https://bugs.python.org/issue44730 opened by garethmjwilliams #44733: Feature request: maxtasksperchild for ProcessPoolExecutor https://bugs.python.org/issue44733 opened by cool-RR #44735: Failed venv Activation With "&" In Folder Name https://bugs.python.org/issue44735 opened by adore_blvnk #44738: io_uring as a new backend to selectors and asyncio https://bugs.python.org/issue44738 opened by achimnol #44740: Lowercase "Internet" and "web" in docs https://bugs.python.org/issue44740 opened by felixxm #44742: smtplib: less confusing behaviour when giving incorrect multip https://bugs.python.org/issue44742 opened by cmatte #44743: asyncio DatagramProtocol stops calling callbacks after OSError https://bugs.python.org/issue44743 opened by JulianOrteil #44744: [security] Open redirect attack due to insufficient validation https://bugs.python.org/issue44744 opened by ready-research #44745: Manual for python 3.9.6 will not let me search https://bugs.python.org/issue44745 opened by matthman2019 #44748: argparse: a bool indicating if arg was encountered https://bugs.python.org/issue44748 opened by Thermi #44749: LOAD_NAME not using PyObject_GetItem when globals() is a dict https://bugs.python.org/issue44749 opened by douglas-raillard-arm #44760: Turtle Documentation - Contents Hyperlink conflict https://bugs.python.org/issue44760 opened by ray_giraffe #44762: getpass.getpass on Windows fallback detection is bad https://bugs.python.org/issue44762 opened by matejcik #44764: Handling interruption in async tasks https://bugs.python.org/issue44764 opened by ilian #44766: [easy doc] Remove redundant info in README.valgrind https://bugs.python.org/issue44766 opened by shihai1991 #44767: python -m flask run gives OSError: [WinError 10013] An attempt https://bugs.python.org/issue44767 opened by chandrakant.rvce #44769: socketserver.shutdown should stop serve_forever() immediately https://bugs.python.org/issue44769 opened by petr.viktorin #44771: Adopt changes from importlib_resources 5.2 https://bugs.python.org/issue44771 opened by jaraco #44772: Regression in memory use of instances due to dictionary orderi https://bugs.python.org/issue44772 opened by Mark.Shannon #44773: case_insensitive kwarg in str.replace() https://bugs.python.org/issue44773 opened by nimit.grover24 #44774: incorrect sys.stdout.encoding within a io.StringIO buffer https://bugs.python.org/issue44774 opened by pcarbonn #44775: Speed-up typing.cast by implementing it in C https://bugs.python.org/issue44775 opened by uriyyo #44776: Docs on mobile do not use monospace font for code snippets, mi https://bugs.python.org/issue44776 opened by alexprengere #44779: Checkouts stale following changes to .gitattributes https://bugs.python.org/issue44779 opened by jaraco #44780: Incorrect message: "Invalid decimal literal" (python 3.10) https://bugs.python.org/issue44780 opened by aroberge #44781: test_distutils emits deprecation warning about distutils https://bugs.python.org/issue44781 opened by iritkatriel #44782: LRU class given as example in OrderedDict docs not work on pop https://bugs.python.org/issue44782 opened by maximeLeurent #44783: SSL needs client OCSP stapling https://bugs.python.org/issue44783 opened by pprindeville Most recent 15 issues with no replies (15) ========================================== #44783: SSL needs client OCSP stapling https://bugs.python.org/issue44783 #44782: LRU class given as example in OrderedDict docs not work on pop https://bugs.python.org/issue44782 #44781: test_distutils emits deprecation warning about distutils https://bugs.python.org/issue44781 #44780: Incorrect message: "Invalid decimal literal" (python 3.10) https://bugs.python.org/issue44780 #44779: Checkouts stale following changes to .gitattributes https://bugs.python.org/issue44779 #44775: Speed-up typing.cast by implementing it in C https://bugs.python.org/issue44775 #44772: Regression in memory use of instances due to dictionary orderi https://bugs.python.org/issue44772 #44766: [easy doc] Remove redundant info in README.valgrind https://bugs.python.org/issue44766 #44764: Handling interruption in async tasks https://bugs.python.org/issue44764 #44760: Turtle Documentation - Contents Hyperlink conflict https://bugs.python.org/issue44760 #44743: asyncio DatagramProtocol stops calling callbacks after OSError https://bugs.python.org/issue44743 #44742: smtplib: less confusing behaviour when giving incorrect multip https://bugs.python.org/issue44742 #44735: Failed venv Activation With "&" In Folder Name https://bugs.python.org/issue44735 #44730: unittest.mock.patch does not work as a decorator on generator https://bugs.python.org/issue44730 #44729: sys.setprofile bug https://bugs.python.org/issue44729 Most recent 15 issues waiting for review (15) ============================================= #44781: test_distutils emits deprecation warning about distutils https://bugs.python.org/issue44781 #44779: Checkouts stale following changes to .gitattributes https://bugs.python.org/issue44779 #44775: Speed-up typing.cast by implementing it in C https://bugs.python.org/issue44775 #44771: Adopt changes from importlib_resources 5.2 https://bugs.python.org/issue44771 #44740: Lowercase "Internet" and "web" in docs https://bugs.python.org/issue44740 #44733: Feature request: maxtasksperchild for ProcessPoolExecutor https://bugs.python.org/issue44733 #44730: unittest.mock.patch does not work as a decorator on generator https://bugs.python.org/issue44730 #44726: Build macOS version with thin lto option https://bugs.python.org/issue44726 #44725: Expose specialization stats in python https://bugs.python.org/issue44725 #44712: Replace `type(literal)` with corresponding builtin types https://bugs.python.org/issue44712 #44690: Adopt binacii.a2b_base64's strict mode in base64.b64decode https://bugs.python.org/issue44690 #44678: Seperate error message for discontinuous padding in binascii.a https://bugs.python.org/issue44678 #44677: CSV sniffing falsely detects space as a delimiter https://bugs.python.org/issue44677 #44660: email.feedparser: support RFC 6532 section 3.5 https://bugs.python.org/issue44660 #44645: Python 3.10: Under some trivial circunstances, GIL not release https://bugs.python.org/issue44645 Top 10 most discussed issues (10) ================================= #41737: Improper NotADirectoryError when opening a file in a fake dire https://bugs.python.org/issue41737 9 msgs #44762: getpass.getpass on Windows fallback detection is bad https://bugs.python.org/issue44762 8 msgs #43950: Include column offsets for bytecode instructions https://bugs.python.org/issue43950 6 msgs #44660: email.feedparser: support RFC 6532 section 3.5 https://bugs.python.org/issue44660 6 msgs #44740: Lowercase "Internet" and "web" in docs https://bugs.python.org/issue44740 6 msgs #42626: readline history, vi-editingmode and ANSI color codes bug https://bugs.python.org/issue42626 5 msgs #43944: Processes in Python 3.9 exiting with code 1 when It's created https://bugs.python.org/issue43944 5 msgs #44748: argparse: a bool indicating if arg was encountered https://bugs.python.org/issue44748 5 msgs #44771: Adopt changes from importlib_resources 5.2 https://bugs.python.org/issue44771 5 msgs #44774: incorrect sys.stdout.encoding within a io.StringIO buffer https://bugs.python.org/issue44774 5 msgs Issues closed (79) ================== #25702: Link Time Optimizations support for GCC and CLANG https://bugs.python.org/issue25702 closed by methane #26153: PyImport_GetModuleDict: no module dictionary! when `__del__` t https://bugs.python.org/issue26153 closed by twouters #27827: pathlib is_reserved fails for some reserved paths on Windows https://bugs.python.org/issue27827 closed by lukasz.langa #29298: argparse fails with required subparsers, un-named dest, and em https://bugs.python.org/issue29298 closed by petr.viktorin #31746: crashes in sqlite3.Connection in case it is uninitialized or p https://bugs.python.org/issue31746 closed by erlendaasland #34013: Inconsistent SyntaxError for print https://bugs.python.org/issue34013 closed by pablogsal #35728: Tkinter font nametofont requires default root https://bugs.python.org/issue35728 closed by terry.reedy #37224: [subinterpreters] test__xxsubinterpreters fails randomly https://bugs.python.org/issue37224 closed by lukasz.langa #37715: 2to3 set default encoding https://bugs.python.org/issue37715 closed by benjamin.peterson #40085: Argument parsing option c should accept int between -128 to 25 https://bugs.python.org/issue40085 closed by Dennis Sweeney #40263: ValueError exception on _winapi.WaitForMultipleObjects https://bugs.python.org/issue40263 closed by steve.dower #41911: Language reference for expressions incorrectly specifies what https://bugs.python.org/issue41911 closed by lukasz.langa #42167: Documentation for SETUP_WITH opcode is wrong https://bugs.python.org/issue42167 closed by iritkatriel #42357: Wrong Availability for signal.SIGCHLD https://bugs.python.org/issue42357 closed by zach.ware #42853: `OverflowError: signed integer is greater than maximum` in ssl https://bugs.python.org/issue42853 closed by lukasz.langa #42892: AttributeError in email.message.get_body() https://bugs.python.org/issue42892 closed by lukasz.langa #43184: Missing docs for LoggerAdapter manager and name property https://bugs.python.org/issue43184 closed by vinay.sajip #43235: Tools/scripts/stable_abi.py should also check PC/python3dll.c https://bugs.python.org/issue43235 closed by petr.viktorin #43443: Should shelve support dict union? https://bugs.python.org/issue43443 closed by lukasz.langa #43497: SyntaxWarning for "assertion is always true, perhaps remove pa https://bugs.python.org/issue43497 closed by iritkatriel #43565: PyUnicode_KIND macro does not has specified return type https://bugs.python.org/issue43565 closed by petr.viktorin #43625: CSV has_headers heuristic could be improved https://bugs.python.org/issue43625 closed by lukasz.langa #43897: Implement support for validation of pattern matching ASTs https://bugs.python.org/issue43897 closed by brandtbucher #43967: Valgrind memcheck on Py_Initialize https://bugs.python.org/issue43967 closed by shihai1991 #44021: enum docs in 3.10: missing "New in version 3.10" https://bugs.python.org/issue44021 closed by Akuli #44195: importlib.abc.TraversableReader is not implemented https://bugs.python.org/issue44195 closed by jaraco #44388: venv API Docs for EnvBuilder.ensure_directories incorrectly de https://bugs.python.org/issue44388 closed by vinay.sajip #44399: log rotator cookbook example might waste disk space https://bugs.python.org/issue44399 closed by vinay.sajip #44429: Tkinter Flow Geometry Manager https://bugs.python.org/issue44429 closed by Gary73 #44453: Documented return type of sysconfig.get_path() is wrong https://bugs.python.org/issue44453 closed by lukasz.langa #44461: 'Pdb' object has no attribute 'botframe' https://bugs.python.org/issue44461 closed by jaraco #44473: logging.handlers.QueueHandler acts unexpected https://bugs.python.org/issue44473 closed by vinay.sajip #44515: contextlib test incompatibility with non-refcounted GC https://bugs.python.org/issue44515 closed by lukasz.langa #44544: Add full list of possible args to textwrap: wrap, fill, shorte https://bugs.python.org/issue44544 closed by lukasz.langa #44590: Create frame objects lazily when needed https://bugs.python.org/issue44590 closed by Mark.Shannon #44600: match/case statements trace incorrectly in 3.10.0b4 https://bugs.python.org/issue44600 closed by brandtbucher #44648: Inspect.getsource raises wrong error on classes in interactive https://bugs.python.org/issue44648 closed by lukasz.langa #44657: instancemethod_call should use PyInstanceMethod_GET_FUNCTION m https://bugs.python.org/issue44657 closed by corona10 #44658: No ValueError for duplicate key value in mapping patern when l https://bugs.python.org/issue44658 closed by brandtbucher #44662: Add ability to annotate types.Union https://bugs.python.org/issue44662 closed by lukasz.langa #44666: compileall.compile_file fails when sys.stdout is redirected to https://bugs.python.org/issue44666 closed by lukasz.langa #44671: Create a built-in yaml module https://bugs.python.org/issue44671 closed by terry.reedy #44682: Pdb commands allows to add commands to invalid breakpoint https://bugs.python.org/issue44682 closed by lukasz.langa #44688: [sqlite3] Remove ASCII limitation from sqlite3.Connection.crea https://bugs.python.org/issue44688 closed by erlendaasland #44693: Unclear definition of the "__future__" module in Docs https://bugs.python.org/issue44693 closed by terry.reedy #44698: Undefined behaviour in Objects/complexobject.c's complex_pow https://bugs.python.org/issue44698 closed by lukasz.langa #44707: runtime error: applying zero offset to null pointer in Objects https://bugs.python.org/issue44707 closed by lukasz.langa #44709: [3.7] Popen Control Characters in stdout affect shell session https://bugs.python.org/issue44709 closed by terry.reedy #44711: Optimize type check in pipes.py https://bugs.python.org/issue44711 closed by lukasz.langa #44717: Improve AttributeError on circular imports of submodules https://bugs.python.org/issue44717 closed by lukasz.langa #44719: Incorrect callable object crashes Python 3.11.0a0 https://bugs.python.org/issue44719 closed by Dennis Sweeney #44720: Weakref proxy crashes on null tp_iternext slot. https://bugs.python.org/issue44720 closed by lukasz.langa #44722: RFC: string Multiline Formatter https://bugs.python.org/issue44722 closed by creative-resort #44731: Simplify implementation of the union type https://bugs.python.org/issue44731 closed by pablogsal #44732: Rename types.Union to types.UnionType https://bugs.python.org/issue44732 closed by pablogsal #44734: turtle: tests for Vec2D.__abs__ are too strict https://bugs.python.org/issue44734 closed by lukasz.langa #44736: '\t' Escape Sequence behaving differently. https://bugs.python.org/issue44736 closed by steven.daprano #44737: Mapping from to collections.abc https://bugs.python.org/issue44737 closed by Jelle Zijlstra #44739: Tkinter text horizontal scrollbar is not stationary https://bugs.python.org/issue44739 closed by logon_name #44741: Pattern Matching - star subpattern with a subject derived from https://bugs.python.org/issue44741 closed by brandtbucher #44746: Improper behaviour of 'finally' keyword https://bugs.python.org/issue44746 closed by steven.daprano #44747: Refactor usage of sys._getframe at typing module https://bugs.python.org/issue44747 closed by lukasz.langa #44750: .popitem() is inconsistent in collections and collections.abc https://bugs.python.org/issue44750 closed by rhettinger #44751: crypt.h should be in _cryptmodule.c, not in public header https://bugs.python.org/issue44751 closed by miss-islington #44752: Tab completion executes @property getter function https://bugs.python.org/issue44752 closed by lukasz.langa #44753: backupCount is not respected in TimedRotatingFileHandler when https://bugs.python.org/issue44753 closed by vinay.sajip #44754: Documentation for pop in Built-in Types https://bugs.python.org/issue44754 closed by lukasz.langa #44755: cpython Lib bisect.py overflow (lo + hi) // 2 a problem? https://bugs.python.org/issue44755 closed by Dennis Sweeney #44756: In ./Doc, "make html" and "make build" should depend on "make https://bugs.python.org/issue44756 closed by lukasz.langa #44757: Insecure Deserialization https://bugs.python.org/issue44757 closed by steven.daprano #44758: Why " True != 3 in [3] " is True? https://bugs.python.org/issue44758 closed by steven.daprano #44759: ctype generates misleading error-msg opening lib.so when compi https://bugs.python.org/issue44759 closed by stephan.boekelmann #44761: NewType __module__ attr default value https://bugs.python.org/issue44761 closed by lukasz.langa #44763: "width defaults to 70." in textwrap.wrap documentation is repe https://bugs.python.org/issue44763 closed by lukasz.langa #44765: Misspelled Word In Docs https://bugs.python.org/issue44765 closed by lukasz.langa #44768: dataclasses.dataclass and collections.namedtuple do the same t https://bugs.python.org/issue44768 closed by steven.daprano #44770: float('nan') is True https://bugs.python.org/issue44770 closed by tim.peters #44777: Create mechanism to contact buildbot worker owners https://bugs.python.org/issue44777 closed by lukasz.langa #44778: os seperator error. str method of PureWindowsPath on Ming64 en https://bugs.python.org/issue44778 closed by eryksun

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possibly incorrect docs re: constant initialization
by Josh Haberman 29 Jul '21

29 Jul '21

The documentation for PyTypeObject.tp_base (https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_base) says the following: > Note: Slot initialization is subject to the rules of initializing > globals. C99 requires the initializers to be “address constants”. > Function designators like PyType_GenericNew(), with implicit > conversion to a pointer, are valid C99 address constants. > > However, the unary ‘&’ operator applied to a non-static variable > like PyBaseObject_Type() is not required to produce an address > constant. Compilers may support this (gcc does), MSVC does not. Both > compilers are strictly standard conforming in this particular > behavior. I think this may be incorrect. Specifically, it seems to be confusing "static variable" with "static storage duration." It is true that C99 requires address constants to have static storage duration. The relevant text in C99 is 6.6p9: > An address constant is a null pointer, a pointer to an lvalue > designating an object of static storage duration, or a pointer to a > function designator; it shall be created explicitly using the unary > & operator or an integer constant cast to pointer type, or > implicitly by the use of an expression of array or function type. Note that the language here is "static storage duration", not "static variable". The standard doesn't define the term "static variable", but in common usage it means any variable that includes the static storage-class specifier. Under this definition, PyBaseObject_Type is indeed not a static variable: // These are commonly referred to as "static variables" because they // use the "static" keyword: static int x; void f() { static int y; } // Not a static variable. extern PyTypeObject PyBaseObject_Type However "static storage duration" is a broader concept that describes the lifetime of an object. An object can have static storage duration even if it does not use the "static" keyword. From 6.2.4p3: > An object whose identifier is declared with external or internal > linkage, or with the storage-class specifier static has static > storage duration. Its lifetime is the entire execution of the > program and its stored value is initialized only once, prior to > program startup. Under this definition, PyBaseObject_Type does indeed have static storage duration, because it has external linkage. So I believe that &PyBaseObject_Type should be a valid address constant according to C99. Indeed, MSVC accepts an address of an extern as an address constant in the simple case: https://godbolt.org/z/8Tdc999z3 It is only when the extern is imported from another DLL that MSVC rejects it: https://godbolt.org/z/fMM1fr743 I believe that MSVC may be out of conformance in rejecting the latter case. If this is true, it wouldn't necessarily change the guidance in the docs (tp_base should still be initialized dynamically if the base could possibly come from a DLL on Windows). However it may make sense to change the language about both compilers being "strictly standard conforming." It also may be worth mentioning that this issue appears to be specific to DLLs; if the base class will never come from another DLL, this workaround may be unnecessary. One other minor nit; there is a small typographical error in the docs I quoted above: > However, the unary ‘&’ operator applied to a non-static variable > like PyBaseObject_Type() is not required to produce an address PyBaseObject_Type is not a function, so it shouldn't have the trailing '()'. Thanks, Josh

1 0

咨询python的相关问题(Consult python related issues)
by C 28 Jul '21

28 Jul '21

您好，我想咨询阅读python语言参考手册时遇到的相关问题，我在这个网址https://mail.python.org/archives/list/python-dev@python.org/thread/HQ… 看到该邮箱地址，不知道是否可以用来咨询此类问题？或请推荐咨询的渠道。《python语言参考手册》--数据模型章节--静态方法对象： “避免函数对象转换为方法对象”是指在实例对象在获取属性时，避免类中定义的方法（即：函数对象）转换为实例方法么？为什么在python中，会设置这种在类中将用户定义的函数封装起来从而防止其转换为实例方法，这种封装一般应用在哪些情况下呢？ Hello, I would like to consult related issues encountered when reading the python language reference manual, I am at this URL https://mail.python.org/archives/list/python-dev@python.org/thread/HQPEBKZR… Seeing the email address, I wonder if it can be used to consult such questions? Or please recommend a channel for consultation. "Python Language Reference Manual"-Data Model Chapter-Static Method Object: "Avoid converting function objects into method objects" refers to avoiding the methods defined in the class (ie: function objects) from being converted into instance methods when the instance object gets properties? Why is it set up in python to encapsulate user-defined functions in a class to prevent them from being converted into instance methods? In what situations is this encapsulation generally used?

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Comments on PEP 558
by Mark Shannon 28 Jul '21

28 Jul '21

Hi, First of all let me say that I agree with the aims of PEP 558 and most of the design. I do find the wording of the PEP itself a bit confusing in a couple of places. This critique is based on my understanding of the PEP. If I am mistaken in my misunderstanding, then treat that as an implied request for clarification of the PEP :) Critique of PEP 558 =================== Layout of the PEP ----------------- [This is largely to help the reader, it doesn't change the nature of the PEP] Could we replace the section "CPython Implementation Changes" with a section that states what the behavior will be, not how it changes. Having to mentally apply the suggested changes to the existing (and convoluted) implementation makes it hard to work out what the proposed behavior will be. Could the design discussion be moved to an appendix or another document? The key parts of it should be moved to the Rationale or Motivation. There should be a Motivation section explaining why this PEP is necessary, for those not familiar with the weirdness of `locals()`. Much of what is in the Rationale should perhaps be in the Motivation. Proposal -------- [Ditto; this is largely to help the reader, it doesn't change the nature of the PEP] Drop the definitions of the type of scope. They are (at least they should be) clearly defined in existing documentation. Why "largely" eliminate the concept of a separate tracing mode? Wasn't the plan to eliminate it entirely? Rather than specifying what the documentation will be, could you specify the semantics. The language here should be precise. The documentation needs to explain the behavior to the majority of users, but the PEP should be worded so that it can be implemented correctly from just reading the PEP. There is no reason to remove the sugested documentation changes, but they should be secondary to the more formal specification. Resolving the issues with tracing mode behaviour ------------------------------------------------ According to this section the `f_locals` object (_PyFastLocalsProxy_Type in C) will have *two* fields. It should only have *one*, the pointer to the underlying frame object. In order to maximize backwards compatibility and, more importantly, avoid the synchronization issues that lead to obscure bugs, all the state of the `f_locals` object should be kept on the frame. Any changes to `f_locals` should be instantly visible to any thread both through other `f_locals` objects (for the same frame) and the underlying local variable (if it exists). E.g. def __getitem__(self, name): f = self.frame if name in f.f_code.co_varnames: index = f.f_code.co_varnames.index(name) obj = f.locals[index] # f.locals refers to the fast array of variables if obj is NULL: raise KeyError(name) return obj else: return f._extra_locals[name] def __setitem__(self, name, value): f = self.frame if name in f.f_code.co_varnames: index = f.f_code.co_varnames.index(name) CLEAR(f.locals[index]) f.locals[index] = value else: f._extra_locals[name] = value def items(self): f = self.frame for index, name in enumerate(f.f_code.co_varnames) obj = f.locals[index] if obj is not NULL: yield name, obj yield from f._extra_locals.items() Where `_extra_locals` is a normal dictionary that is not visible to either Python or the C API. C API changes ------------- The PEP suggests adding four new functions to the stable API. Then in the "Changes to the public CPython C API" section, another five functions are added for a total of nine new functions! At the Python level, there are two ways to access a locals mapping. 1. locals() 2. frame.f_locals We only need two C functions, one for each of the above. `PyEval_GetLocals()` should be equivalent to `locals()`. It will have to return a new reference. It cannot return a borrowed reference as it would be returning freed memory. There is nothing to borrow the reference from, for a function scope. `PyFrame_GetLocals(PyFrameObject *)` should be equivalent to `frame.f_locals`. The PEP doesn't explicitly state why `PyLocals_GetKind()` is needed, but I believe it is avoid unnecessary copying? Why is creating an extra copy an issue? It takes a microsecond or so to create the copy. If a function that returns a copy of the local namespace is really needed, then why not offer that functionality directly? E.g. `PyFrame_GetLocalsCopy()` which is roughly: PyObject *locals = PyEval_GetLocals(); if (current_scope_is_function()) return locals; return PyDict_Copy(locals); // This leaks, need to decref locals Reducing the runtime overhead of trace hooks -------------------------------------------- I'm confused by this part. Since `_PyFrame_FastToLocals` and friends do not alter the logical state of the frame object (or anything else), they should no-ops. It is `PyFrame_GetLocals()` that creates the proxy object, surely. Cheers, Mark. p.s. I'd be happy to help with the implementation.

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[IMPORTANT] [Release communication] Python 3.10.0rc1 next week: get ready!
by Pablo Galindo Salgado 28 Jul '21

28 Jul '21

Hi everyone, This is a friendly reminder from the release management team that the first release candidate of Python 3.10 is next Monday. Now is a fantastic time you make sure that: ## If you are a user or library developer * If you filed a bug for something not working in any of the betas for 3.10, check that the bug is properly fixed. * Ensure that your library/application works as expected with Python 3.10. * Ensure that if your library needs to interact with the Python syntax or type system, it works with the new additions in 3.10 <https://docs.python.org/3.10/whatsnew/3.10.html#summary-release-highlights> . * [Optional] Check that there are no performance regressions in your application/library with Python 3.10 ## If you are a core developer or a member of the triage team * Merge or review any urgent bugfixes that you are interested in * Your changes are properly documented. * There isn't any critical bug in the tracker regarding a feature you implemented/merged. * If your change is relevant enough, it appears in the What's new document <https://docs.python.org/3.10/whatsnew/3.10.html> (if you have doubts, you can ask me ;) ). Some technical details of the release candidate: Once the 3.10 branch reaches RC status, it only can have bug fixes applied that have been reviewed by other core developers (so you cannot merge your own PR without review even if you are a core dev). Generally, these issues must be severe enough (e.g. crashes) that they deserve fixing before the final release. All other issues should be deferred to the next development cycle (Python 3.10.1) since stability is the strongest concern at this point. Also bear in mind that once we reach the RC, the *ABI is frozen* and cannot change even for bug fixes. While the goal is to have no code changes between an RC and a final release, there may be a need for final documentation o test fixes. Any such proposed changes should be discussed first with the release manager. *You cannot skip the peer review during an RC*, no matter how small! Even if it is a simple copy-and-paste change, everything requires peer review from a core developer. (You can find these instructions and details in the devguide <https://devguide.python.org/devcycle/#rc>). Thank you all for your help! Regards from rainy London, Pablo Galindo Salgado

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