Mailman 3 May 2021 - Python-Dev

Mixed Python/C debugging
by Skip Montanaro April 26, 2023

April 26, 2023

Having tried comp.lang.python with no response, I turn here... After at least ten years away from Python's run-time interpreter & byte code compiler, I'm getting set to familiarize myself with that again. This will, I think, entail debugging a mixed Python/C environment. I'm an Emacs user and am aware that GDB since 7.0 has support for debugging at the Python code level. Is Emacs+GDB my best bet? Are there any Python IDEs which support C-level breakpoints and debugging? Thanks, Skip

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PEP 448 review
by Guido van Rossum March 29, 2023

March 29, 2023

I'm back, I've re-read the PEP, and I've re-read the long thread with "(no subject)". I think Georg Brandl nailed it: """ *I like the "sequence and dict flattening" part of the PEP, mostly because itis consistent and should be easy to understand, but the comprehension syntaxenhancements seem to be bad for readability and "comprehending" what the codedoes.The call syntax part is a mixed bag on the one hand it is nice to be consistent with the extended possibilities in literals (flattening), but on the other hand there would be small but annoying inconsistencies anyways (e.g. the duplicate kwarg case above).* """ Greg Ewing followed up explaining that the inconsistency between dict flattening and call syntax is inherent in the pre-existing different rules for dicts vs. keyword args: {'a':1, 'a':2} results in {'a':2}, while f(a=1, a=2) is an error. (This form is a SyntaxError; the dynamic case f(a=1, **{'a': 1}) is a TypeError.) For me, allowing f(*a, *b) and f(**d, **e) and all the other combinations for function calls proposed by the PEP is an easy +1 -- it's a straightforward extension of the existing pattern, and anybody who knows what f(x, *a) does will understand f(x, *a, y, *b). Guessing what f(**d, **e) means shouldn't be hard either. Understanding the edge case for duplicate keys with f(**d, **e) is a little harder, but the error messages are pretty clear, and it is not a new edge case. The sequence and dict flattening syntax proposals are also clean and logical -- we already have *-unpacking on the receiving side, so allowing *x in tuple expressions reads pretty naturally (and the similarity with *a in argument lists certainly helps). From here, having [a, *x, b, *y] is also natural, and then the extension to other displays is natural: {a, *x, b, *y} and {a:1, **d, b:2, **e}. This, too, gets a +1 from me. So that leaves comprehensions. IIRC, during the development of the patch we realized that f(*x for x in xs) is sufficiently ambiguous that we decided to disallow it -- note that f(x for x in xs) is already somewhat of a special case because an argument can only be a "bare" generator expression if it is the only argument. The same reasoning doesn't apply (in that form) to list, set and dict comprehensions -- while f(x for x in xs) is identical in meaning to f((x for x in xs)), [x for x in xs] is NOT the same as [(x for x in xs)] (that's a list of one element, and the element is a generator expression). The basic premise of this part of the proposal is that if you have a few iterables, the new proposal (without comprehensions) lets you create a list or generator expression that iterates over all of them, essentially flattening them: >>> xs = [1, 2, 3] >>> ys = ['abc', 'def'] >>> zs = [99] >>> [*xs, *ys, *zs] [1, 2, 3, 'abc', 'def', 99] >>> But now suppose you have a list of iterables: >>> xss = [[1, 2, 3], ['abc', 'def'], [99]] >>> [*xss[0], *xss[1], *xss[2]] [1, 2, 3, 'abc', 'def', 99] >>> Wouldn't it be nice if you could write the latter using a comprehension? >>> xss = [[1, 2, 3], ['abc', 'def'], [99]] >>> [*xs for xs in xss] [1, 2, 3, 'abc', 'def', 99] >>> This is somewhat seductive, and the following is even nicer: the *xs position may be an expression, e.g.: >>> xss = [[1, 2, 3], ['abc', 'def'], [99]] >>> [*xs[:2] for xs in xss] [1, 2, 'abc', 'def', 99] >>> On the other hand, I had to explore the possibilities here by experimenting in the interpreter, and I discovered some odd edge cases (e.g. you can parenthesize the starred expression, but that seems a syntactic accident). All in all I am personally +0 on the comprehension part of the PEP, and I like that it provides a way to "flatten" a sequence of sequences, but I think very few people in the thread have supported this part. Therefore I would like to ask Neil to update the PEP and the patch to take out the comprehension part, so that the two "easy wins" can make it into Python 3.5 (basically, I am accepting two-thirds of the PEP :-). There is some time yet until alpha 2. I would also like code reviewers (Benjamin?) to start reviewing the patch <http://bugs.python.org/issue2292>, taking into account that the comprehension part needs to be removed. -- --Guido van Rossum (python.org/~guido)

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PEP 638: Syntactic macros
by Mark Shannon Feb. 5, 2023

Feb. 5, 2023

Hi everyone, I've submitted my PEP on syntactic macros as PEP 638. https://www.python.org/dev/peps/pep-0638/ All comments and suggestions are welcome. Cheers, Mark

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How about using modern C++ in development of CPython ?
by redradist＠gmail.com Oct. 19, 2022

Oct. 19, 2022

Hi all, What about of using modern C++ in developing CPython ? With C++ we can get the following benefits: 1) Readability - less code, most code is hidden by abstraction without losing performance 2) Maintainability - no code duplication in favor of using reusable classes 3) RAII - Resource Acquisition Is Initialization, predictable allocation and free resources ...

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PEP 563 and Python 3.10.
by Thomas Wouters July 22, 2022

July 22, 2022

(Starting a new thread so as not to derail any of the ongoing discussions.) Thanks, everyone, for your thoughts on Python 3.10 and the impact of PEP 563 (postponed evaluation of annotations) becoming the default. The Steering Council has considered the issue carefully, along with many of the proposed alternatives and solutions, and we’ve decided that at this point, we simply can’t risk the compatibility breakage of PEP 563. We need to roll back the change that made stringified annotations the default, at least for 3.10. (Pablo is already working on this.) To be clear, we are not reverting PEP 563 itself. The future import will keep working like it did since Python 3.7. We’re delaying making PEP 563 string-based annotations the default until Python 3.11. This will give us time to find a solution that works for everyone (or to find a feasible upgrade path for users who currently rely on evaluated annotations). Some considerations that led us to this decision: - PEP 563’s default change is clearly too disruptive to downstream users and third-party libraries to happen right now. We can’t risk breaking even a small subset of the FastAPI/pydantic users, not to mention other uses of evaluated type annotations that we’re not aware of yet. - PEP 563 provides no warning to users of the feature it’s disabling. Without that, we can’t expect users to be aware of the upcoming breakage. The lack of a warning was by design, and made sense in a world where type annotations were only consumed by static type checkers --- but that’s not actually the situation we’re in. There are clearly existing real-world, run-time uses of type annotations that would be adversely affected by this change. - Originally, PEP 563 was scheduled to take effect in Python 4, and this changed recently (after the discussion in the Language Summit of 2020). It's possible that third-party libraries and users didn’t plan to react in the current time frame as they were not aware of this change in timing. - There isn’t enough time to properly discuss PEP 649 or any of the alternatives before the beta 1 deadline, and we really need to make sure we don’t compound errors here. We need to look for a long term solution, which isn’t possible while still maintaining the release deadlines of Python 3.10. That means we’re also deferring PEP 649 to Python 3.11. In the Steering Council’s unanimous opinion, rolling back the default flip for stringified annotations in Python 3.10 is the least disruptive of all the options. We need to continue discussing the issue and potential solutions, since this merely postpones the problem until 3.11. (For the record, postponing the change further is not off the table, either, for example if the final decision is to treat evaluated annotations as a deprecated feature, with warnings on use.) For what it’s worth, the SC is also considering what we can do to reduce the odds of something like this happening again, but that’s a separate consideration, and a multi-faceted one at that. For the Steering Council, Thomas. -- Thomas Wouters <thomas(a)python.org> Hi! I'm an email virus! Think twice before sending your email to help me spread!

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PEP 651, Robust Stack Overflow Handling, Rejection notice
by Python Steering Council Jan. 31, 2022

Jan. 31, 2022

Hi Mark, Thank you for submitting PEP 651. The Steering Council has spent the past two weeks reviewing PEP 651. After careful consideration, we have decided to reject the PEP. The following were the key points that led us to this decision: * The benefits are not compelling enough. Deep recursion is not a common tool in Python, and even with PEP 651 it would not be efficient enough to make it a common tool. * The benefit of PEP 651 is negated as soon as a non-Python function is involved in the recursion, making the likelihood of it being useful even smaller. It also creates easy pitfalls for users who do end up relying on recursion. * We believe the PEP understates the disruption created by the technical solution of multiple Python stack frames per C call. Although this may be solvable, it will certainly cause substantial disruption to existing debuggers, tracers, and state inspection tools as they need to adapt to this change (which may not be trivial). * As the way to approach this will be platform-specific (as some parts of the proposal are not portable), this can cause generic Python code to behave differently on different platforms, making this kind of code less portable and less predictable. In the end, the benefit of the PEP does not outweigh the cost of the potential breakage, confusion, and unpredictability of the feature. With our appreciation, The Python Steering Council

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PEP 646 (Variadic Generics): final call for comments
by Matthew Rahtz Jan. 18, 2022

Jan. 18, 2022

Hi everyone, We've got to the stage now with PEP 646 that we're feeling pretty happy with it. So far though we've mainly been workshopping it in typing-sig, so as PEP 1 requires we're asking for some feedback here too before submitting it to the steering council. If you have time over the next couple of weeks, please take a look at the current draft and let us know your thoughts: https://www.python.org/dev/peps/pep-0646/ (Note that the final couple of sections are out of date; https://github.com/python/peps/pull/1880 clarifies which grammar changes would be required, now that PEP 637 has been rejected. We also have a second PR in progress at https://github.com/python/peps/pull/1881 clarifying some of the motivation.) Thanks! Matthew and Pradeep

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Deprecate Py_TRASHCAN_SAFE_BEGIN/END in 3.10?
by Irit Katriel Aug. 19, 2021

Aug. 19, 2021

Re https://bugs.python.org/issue40608. I think it will be an act of kindness to deprecate Py_TRASHCAN_SAFE_BEGIN/END in 3.10 and tell people to use Py_TRASHCAN_BEGIN/END instead. TL;DR: There was a change in 3.8 that introduced the latter while leaving the former for backwards compatibility, but also inadvertently breaking them. This is not an easy bug to deal with in the wild, we found it because we have a unit test in our codebase referencing https:// bugs.python.org/issue16602. A deprecation note pointing to the new macros would have made it easier. Is there any reason not to deprecate the old macros? Irit

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Request for reviewers: pathlib improvements
by Barney Gale July 2, 2021

July 2, 2021

I’m working towards supporting subclassing pathlib.Path for things like zip/tar archives, iso files, S3, etc. This was first brought up a few years ago in bpo-24132 <https://bugs.python.org/issue24132> and discussed further on the python-ideas forum <https://discuss.python.org/t/make-pathlib-extensible/3428>. Before I can approach the meat of the issue, I'd like to land a handful of backwards-compatible patches that tidy up the pathlib internals. These are: - #19220 <https://github.com/python/cpython/pull/19220> / bpo-39924 <https://bugs.python.org/issue39924>: Handle missing os functions more consistently in pathlib - #18838 <https://github.com/python/cpython/pull/18838> / bpo-39895 <https://bugs.python.org/issue39895>: Move pathlib.Path.touch() implementation into the path accessor - #19342 <https://github.com/python/cpython/pull/19342> / bpo-40038 <https://bugs.python.org/issue40038>: Remove partial support for preserving accessor when modifying a path - #18841 <https://github.com/python/cpython/pull/18841> / bpo-39899 <https://bugs.python.org/issue39899>: Make pathlib use os.path.expanduser() to expand home directories - #18834 <https://github.com/python/cpython/pull/18834> / bpo-39659 <https://bugs.python.org/issue39659>: Route calls from pathlib.Path to os.getcwd() via the path accessor - #18864 <https://github.com/python/cpython/pull/18864> / bpo-39906 <https://bugs.python.org/issue39906>: Add follow_symlinks parameter to pathlib.Path.stat() and chmod() - #24294 <https://github.com/python/cpython/pull/24294> / bpo-42999 <https://bugs.python.org/issue42999>: Expand and clarify pathlib.Path.link_to() documentation Could I please request review of these patches? A couple may already be ready to land. (I appreciate they’re a little dry. This is all prep work for the introduction of a shiny new class, tentatively named ‘AbstractPath’). Thanks! Barney

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[RELEASE] Python 3.8.10, 3.9.5, and 3.10.0b1 are now available
by Łukasz Langa June 11, 2021

June 11, 2021

This has been a very busy day for releases and on behalf of the Python development community we’re happy to announce the availability of three new Python releases. Python 3.10 is now in Beta Get it here: Python 3.10.0b1 <https://www.python.org/downloads/release/python-3100b1/> Python 3.10 is still in development. 3.10.0b1 is the first of four planned beta release previews. Beta release previews are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to support the new feature release. We strongly encourage maintainers of third-party Python projects to test with 3.10 during the beta phase and report issues found to the Python bug tracker <https://bugs.python.org/> as soon as possible. While the release is planned to be feature complete entering the beta phase, it is possible that features may be modified or, in rare cases, deleted up until the start of the release candidate phase (Monday, 2021-08-02). Our goal is have no ABI changes after beta 4 and as few code changes as possible after 3.10.0rc1, the first release candidate. To achieve that, it will be extremely important to get as much exposure for 3.10 as possible during the beta phase. Please keep in mind that this is a preview release and its use is not recommended for production environments. The next pre-release, the second beta release of Python 3.10, will be 3.10.0b2. It is currently scheduled for 2021-05-25. Please see PEP 619 <https://www.python.org/dev/peps/pep-0619/> for details. Development Begins on Python 3.11 With Python 3.10 moving to beta, it received its own 3.10 branch in the repository <https://github.com/python/cpython/>. All new features are now targeting Python 3.11, to be released in October 2022. Using the opportunity with the creation of the 3.10 branch, we renamed the master branch of the repository to main. It’s been a bit rocky <https://github.community/t/renaming-python-master-branch-to-main-1-4k-prs-7…> but looks like we’re open for business. Please rename the main branch of your personal fork using the guide GitHub will give you when you go to your fork’s main page. In case of any outstanding issues, please contact the 3.11 RM <https://devguide.python.org/devcycle/#current-administrators>. Python 3.9.5 Get it here: Python 3.9.5 <https://www.python.org/downloads/release/python-395/> Python 3.9.5 is the newest major stable release of the Python programming language, and it contains many new features and optimizations. There’s been 111 commits since 3.9.4 which is a similar amount compared to 3.8 at the same stage of the release cycle. See the change log <https://docs.python.org/release/3.9.5/whatsnew/changelog.html> for details. On macOS, we encourage you to use the universal2 variant whenever possible. The legacy 10.9+ Intel-only variant will not be provided for Python 3.10 and the universal2 variant will become the default download for future 3.9.x releases. You may need to upgrade third-party components, like pip, to later versions once they are released. You may experience differences in behavior in IDLE and other Tk-based applications due to using the newer version of Tk. As always, if you encounter problems when using this installer variant, please check https://bugs.python.org <https://bugs.python.org/> for existing reports and for opening new issues. The next Python 3.9 maintenance release will be 3.9.6, currently scheduled for 2021-06-28. The Last Regular Bugfix Release of Python 3.8 Get it here: Python 3.8.10 <https://www.python.org/downloads/release/python-3810/> According to the release calendar specified in PEP 569 <https://www.python.org/dev/peps/pep-0569/>, Python 3.8.10 is the final regular maintenance release. Starting now, the 3.8 branch will only accept security fixes and releases of those will be made in source-only form until October 2024. To keep receiving regular bug fixes, please upgrade to Python 3.9. Compared to the 3.7 series, this last regular bugfix release is relatively dormant at 92 commits since 3.8.9. Version 3.7.8, the final regular bugfix release of Python 3.7, included 187 commits. But there’s a bunch of important updates here regardless, the biggest being macOS Big Sur and Apple Silicon build support. This work would not have been possible without the effort of Ronald Oussoren, Ned Deily, Maxime Bélanger, and Lawrence D’Anna from Apple. Thank you! Take a look at the change log <https://docs.python.org/release/3.8.10/whatsnew/changelog.html> for details. We hope you enjoy the new releases Your friendly release team, Ned Deily @nad <https://discuss.python.org/u/nad> Steve Dower @steve.dower <https://discuss.python.org/u/steve.dower> Pablo Galindo Salgado @pablogsal <https://discuss.python.org/u/pablogsal> Łukasz Langa @ambv <https://discuss.python.org/u/ambv>

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March Steering Council update.
by Thomas Wouters June 7, 2021

June 7, 2021

The SC has just published the community update for March: https://github.com/python/steering-council/blob/main/updates/2021-03-steeri… We're still trying to get these done every month, but between the rush of PEPs and other issues before the 3.10b1 deadline, and PyCon US, we're delayed a little. (The April update hopefully won't be too long.) In the meantime, the SC keynote from PyCon US covers our longer-term plans and our points of view on a few other subjects, and that will hopefully be up on YouTube ( https://www.youtube.com/playlist?list=PL2Uw4_HvXqvYk1Y5P8kryoyd83L_0Uk5K) soon. (Since it's mentioned in the notes below, I just want to point out that we didn't record on April 19th; it was pushed back to May 3rd, the same day 3.10b1 was cut.) March 1 - Steering Council synced up on the rejection draft for PEP 651. Group discussed the importance of conveying that all aspects of the proposal were reviewed and the decision is a holistic one. Group will continue working on the draft and will sync up via Slack during the week so it can be sent out. - The Steering Council discussed PEP 648. Barry created a doc and the group will consolidate feedback+questions into this document. Then the Steering Council will post this on Discourse as well as to python-dev@. - The Steering Council extensively discussed PEP 637. The group decided that it would reject the PEP based on the PEPs costs not being worth the benefits. - The Steering Council also discussed typing in general and who should own it. - Next week the SC will vote on the Documentation Work Group's charter. <https://github.com/python/steering-council/blob/main/updates/2021-03-steeri…>March 8 - The Steering Council discussed Mark's response to the rejection of PEP 651. - The group also discussed the notification for PEP 637. - The group approved PEP 624 & PEP 597. - The Steering Council discussed PEP 644 and decided further communication was needed with Christian. - The Steering Council voted on and approved the Documentation Work Group. - The group discussed moving master to main and decided it needed to be done. The SC discussed communication around this change. <https://github.com/python/steering-council/blob/main/updates/2021-03-steeri…>March 15 - Thomas updated the notifications for PEP 597, PEP 624 and PEP 637, and sent out the notifications March 15th. - Group checked in on the draft for PEP 648. Thomas has more text to add to it. - The Steering Council discussed what kind of presentation they will give at PyCon US. The group decided on a combination of presentation and Q&A. Team is working on an outline. SC members were also reminded to register for PyCon US, and encourage others to do so. - Barry proposed to the SC that they create a Work Group with a subset of the Python Security Response Team members and that group can help scope the future of the PSRT group. Everyone is fine with this. - Steering Council discussed code of conduct situations around changing master to main. The group decided on a warning to S.D. that will be sent as a warning to all. Thomas is working on the initial draft. <https://github.com/python/steering-council/blob/main/updates/2021-03-steeri…>March 22 - Barry and Thomas checked-in on PEP 648's draft response, they will be sending it out soon. - The SC reviewed PEP 644 more. Pablo raised a concern around users that can be in an env without OpenSSL 1.1.1 or newer and then not being able to use wheels. Pablo will email Christian to get clarification and will keep the SC informed. - Steering Council discussed their keynote at PyCon US 2021. They would like to gather questions from the community. Ewa will create a Slido, which will be live from April 5 to 11th. SC will review questions on the 12th. The current plan is to record on April 19th. - Steering Council discussed the response to Debian. Carol's done with her draft. Pablo is going to take a look at it to see if anything else needs to be added. - SC discussed the behavior on python-dev@ pertaining to switching git from master to main. <https://github.com/python/steering-council/blob/main/updates/2021-03-steeri…>March 29 - The Steering Council accepted PEP 644 (Require OpenSSL 1.1.1 or newer) - SC accepted PEP 652 (Maintaining the Stable ABI) - SC checked in on the draft response for PEP 648 (Extensible customizations of the interpreter at startup), and the draft response to the Debian discussion. - SC met with Ezio, PM for the GitHub Issues migration, to talk about status, progress and next steps, including keeping python-dev up to date. -- Thomas Wouters <thomas(a)python.org> Hi! I'm an email virus! Think twice before sending your email to help me spread!

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GDB not breaking at the right place
by Skip Montanaro June 7, 2021

June 7, 2021

I'm having a hard time debugging some virtual machine code because GDB won't break where it's supposed to. Here's my breakpoint #2: 2 breakpoint keep y 0x00005555556914fd ceval_reg.h:_PyEval_EvalFrameDefault:TARGET_JUMP_IF_FALSE_REG breakpoint already hit 1 time p/x oparg p (oparg >> 16) & 0xff | (oparg >> 8) & 0xff p oparg & 0xff p *fastlocals@4 but when it breaks, it's not at the beginning of the case (that is, where the TARGET_JUMP_IF_FALSE_REG label is defined), but inside the SETLOCAL macro of the COMPAR_OP_REG case! (That is, it's not anywhere close to the correct place.) case TARGET(COMPARE_OP_REG): { int dst = REGARG4(oparg); int src1 = REGARG3(oparg); int src2 = REGARG2(oparg); int cmpop = REGARG1(oparg); assert(cmpop <= Py_GE); PyObject *left = GETLOCAL(src1); PyObject *right = GETLOCAL(src2); PyObject *res = PyObject_RichCompare(left, right, cmpop); *SETLOCAL(dst, res);* if (res == NULL) goto error; DISPATCH(); } It actually breaks in the Py_XDECREF which is part of the SETLOCAL macro: #define SETLOCAL(i, value) do { PyObject *tmp = GETLOCAL(i); \ GETLOCAL(i) = value; \ *Py_XDECREF(tmp)*; } while (0) (actually, in the Py_DECREF underneath the Py_XDECREF macro). I've configured like so: ./configure --with-pydebug --with-tracerefs --with-assertions Python/ceval.c is compiled with this GCC command: gcc -pthread -c -Wno-unused-result -Wsign-compare -g -Og -Wall -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -I. -I./Include -DPy_BUILD_CORE -o Python/ceval.o Python/ceval.c I don't know if this is a GCC problem, a GDB problem, or a Skip problem. Is there more I can do to help the tool chain break at the correct place? It seems that if I break at a hard line number, GDB does the right thing, but I'd kind of prefer to use the symbolic label instead. I rather like the notion of breaking at a label name, but if GCC/GDB can't figure things out, I guess I'll have to live with line numbers. Thanks, Skip

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name for new Enum decorator
by Ethan Furman June 6, 2021

June 6, 2021

Greetings! The Flag type in the enum module has had some improvements, but I find it necessary to move one of those improvements into a decorator instead, and I'm having a hard time thinking up a name. What is the behavior? Well, a name in a flag type can be either canonical (it represents one thing), or aliased (it represents two or more things). To use Color as an example: class Color(Flag): RED = 1 # 0001 GREEN = 2 # 0010 BLUE = 4 # 0100 PURPLE = RED | BLUE # 0101 WHITE = RED | GREEN | BLUE # 0111 The flags RED, GREEN, and BLUE are all canonical, while PURPLE and WHITE are aliases for certain flag combinations. But what if we have something like: class Color(Flag): RED = 1 # 0001 BLUE = 4 # 0100 WHITE = 7 # 0111 As you see, WHITE is an "alias" for a value that does not exist in the Flag (0010, or 2). That seems like it's probably an error. But what about this? class FlagWithMasks(IntFlag): DEFAULT = 0x0 FIRST_MASK = 0xF FIRST_ROUND = 0x0 FIRST_CEIL = 0x1 FIRST_TRUNC = 0x2 SECOND_MASK = 0xF0 SECOND_RECALC = 0x00 SECOND_NO_RECALC = 0x10 THIRD_MASK = 0xF00 THIRD_DISCARD = 0x000 THIRD_KEEP = 0x100 Here we have three flags (FIRST_MASK, SECOND_MASK, THIRD_MASK) that are aliasing values that don't exist, but it seems intentional and not an error. So, like the enum.unique decorator that can be used when duplicate names should be an error, I'm adding a new decorator to verify that a Flag has no missing aliased values that can be used when the programmer thinks it's appropriate... but I have no idea what to call it. Any nominations? -- ~Ethan~

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Need help to debug a ssl crash on Windows which prevents merging PRs
by Victor Stinner June 2, 2021

June 2, 2021

Hi, In the 3.10 branch, it became really hard to merge PRs because the following ssl crashs on Windows: https://bugs.python.org/issue44252 It has a failure rate 1/2 (on average) on the "Windows x86" and "Windows x64" jobs of GitHub Action and on the Win32 and Win64 jobs of the Azure Pipelines. I failed to reproduce it on an up to date Windows 10 with an up to date Visual Studio 2019. I cannot say if it's a race condition, if it's a bug in Python, if it's a bug in the tests (it sounds unlikely, it worked well previously and it's a hard crash, not a Python exception), if it's a bug in the C compiler or in Windows itself... Since there are other random test failures like test_asyncio, it now requires multiple "re-run jobs" on GitHub Actions. Example of test_asyncio test which fails frequently on Windows: https://bugs.python.org/issue41682 If someone can reproduce https://bugs.python.org/issue44252 crash on Windows, can you please provide me a SSH access to your machine so I can debug it? Here is my public SSH key: https://github.com/vstinner.keys Is there a way to get a SSH access to a machine of the GitHub Action CI job or of an Azure Pipelines CI job? Victor -- Night gathers, and now my watch begins. It shall not end until my death.

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Re: The repr of a sentinel
by Eric Nieuwland June 1, 2021

June 1, 2021

To add to the suggestions already given in this thread I dug into code I wrote some time ago. Offered as an inspiration. === missing.py === from typing import Any def MISSING(klass: Any) -> Any: """ create a sentinel to indicate a missing instance of a class :param klass: the class of which an instance is missing :return: missing class object """ g = globals() missing_klass_name = f"_MISSING_{klass.__module__}_{klass.__name__}_MISSING_" if missing_klass_name not in g: g[missing_klass_name] = type( missing_klass_name, (klass,), { "__repr__": lambda x: f"MISSING({klass.__name__})", } ) return g[missing_klass_name]() === and as a demo: === demo_missing.py === import pickle from missing import MISSING x = MISSING(str) y = "bar" print(f"{x!r} == {y!r}: {x == y}") print(f"{x!r} is {y!r}: {x is y}") # MISSING(str) == 'bar': False # MISSING(str) is 'bar': False with open("object.pickled", "wb") as f: pickle.dump(x, f) with open("object.pickled", "rb") as f: y = pickle.load(f) print(f"{x!r} == {y!r}: {x == y}") print(f"{x!r} is {y!r}: {x is y}") # MISSING(str) == MISSING(str): True # MISSING(str) is MISSING(str): False def foo(a: int = MISSING(int), b: int = MISSING(int)): print(f"{a=} {isinstance(a, int)}") print(f"{b=} {isinstance(b, int)}") print(f"{a!r} == {b!r}: {a == b}") print(f"{a!r} is {b!r}: {a is b}") foo() # a=MISSING(int) True # b=MISSING(int) True # MISSING(int) == MISSING(int): True # MISSING(int) is MISSING(int): False foo(1) # a=1 True # b=MISSING(int) True # 1 == MISSING(int): False # 1 is MISSING(int): False class Test: ... t = MISSING(Test) print(f"{t=}") # t=MISSING(Test) ===

2 1

The repr of a sentinel
by Irit Katriel June 1, 2021

June 1, 2021

Following a recent change, we now have in traceback.py: _sentinel = object() def print_exception(exc, /, value=_sentinel, tb=_sentinel, limit=None, file=None, chain=True): So now: >>> import traceback >>> help(traceback.print_exception) Help on function print_exception in module traceback: print_exception(exc, /, value=<object object at 0x000002825DF09650>, tb=<object object at 0x000002825DF09650>, limit=None, file=None, chain=True) Is there a convention on how such default sentinel values should appear in docs? https://bugs.python.org/issue43024

22 66

Farewell, for now :)
by Kyle Stanley May 31, 2021

May 31, 2021

Hi all, Last week, I started a new thread on discuss.python.org <https://discuss.python.org/t/farewell-for-now/8918?u=aeros> about my intention to take a further extended break from open source to continue my mental health healing process. Just wanted to announce it in the other channels as well since I know that not everyone has the bandwidth to keep up with more than just the MLs. In the thread, I discussed my intention to pursue the path of becoming a Buddhist monk for some time, and recently detailed my adventures at a local Thai temple. Check it out if you are interested. :) With Loving Regards, -- --Kyle R. Stanley, Python Core Developer (what is a core dev? <https://devguide.python.org/coredev/>) *Pronouns: they/them **(why is my pronoun here?* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-…> )

1 0

python-iterators mailing list on SourceForge
by Julien Palard May 31, 2021

May 31, 2021

Hi, PEP 234 mention https://sourceforge.net/p/python/mailman/python-iterators/ but the project mailing list archives are marked as "hidden". Looks like projects admin and developers can get the "hidden link", but I think it would be nice to "unhide" the archives if someone is still admin there and if it's possible, to "unbreak" the link from the PEP. Bests, -- [Julien Palard](https://mdk.fr)

6 14

Help with the grail browser
by Prakhar Sehgal May 31, 2021

May 31, 2021

The latest version of Grail is 0.6 which was released in 1999 was made for Python 1 but I want to make one compatible with Python 3. But I need help for that. Currently me and Guido van Rossum are working on this. Any help will be welcomed. This is the link for the GitHub repo: https://github.com/PrakharPythonProgrammer/Grail-0.6 Sincerely Prakhar

2 1

Implementing async enumerate
by Filipe Alves Caixeta May 30, 2021

May 30, 2021

Hello, Python 3.10 comes with the built-in *anext()* but I think we may be missing some other equivalent built-in functions like *list* and *enumerate*. I didn't discuss the idea of creating a PEP for this but I would like to get some help with the implementation. The equivalent Python code would be *async def aenumerate(sequence, start=0): n = start async for elem in sequence: yield n, elem n += 1* The code for enumerate if here https://github.com/python/cpython/blob/2f3a87856c7033227577b9ed0c77ed753114… The *next* function creates a tuple and return with (n, elem) *result = PyTuple_New(2);PyTuple_SET_ITEM(result, 0, next_index);PyTuple_SET_ITEM(result, 1, next_item);return result;* For the async implementation I would have to instead return an *async_generator_asend* object and that would resolve to the tuple. Calling *tp_as_async->am_anext* and getting the value doesn't seem like the solution because I should not get the result at this stage yet. I would like to have a hint on how to implement this =D

3 2

PEP 659: Specializing Adaptive Interpreter
by Mark Shannon May 28, 2021

May 28, 2021

Hi everyone, I would like to present PEP 659. This is an informational PEP about a key part of our plan to improve CPython performance for 3.11 and beyond. For those of you aware of the recent releases of Cinder and Pyston, PEP 659 might look similar. It is similar, but I believe PEP 659 offers better interpreter performance and is more suitable to a collaborative, open-source development model. As always, comments and suggestions are welcome. Cheers, Mark. Links: https://www.python.org/dev/peps/pep-0659/ https://github.com/facebookincubator/cinder https://github.com/pyston/pyston

17 37

Summary of Python tracker Issues
by Python tracker May 28, 2021

May 28, 2021

ACTIVITY SUMMARY (2021-05-21 - 2021-05-28) 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 7424 (-28) closed 48574 (+82) total 55998 (+54) Open issues with patches: 2945 Issues opened (38) ================== #44209: urllib.robotparser fail on Disallow: /? from google.com https://bugs.python.org/issue44209 opened by karl.pradene #44210: Make importlib.metadata._meta.PackageMetadata public https://bugs.python.org/issue44210 opened by FFY00 #44211: Duplicate '.bmp' key in mimetypes.py, maps to both 'image/bmp' https://bugs.python.org/issue44211 opened by andreasjansson #44212: asyncio overrides signal handlers https://bugs.python.org/issue44212 opened by Francisco Demartino #44213: LIST_TO_TUPLE placed below the sentence "all of the following https://bugs.python.org/issue44213 opened by glubs9 #44214: PyArg_Parse* for vectorcall? https://bugs.python.org/issue44214 opened by ronaldoussoren #44215: help() module listing displays import warnings from deprecated https://bugs.python.org/issue44215 opened by stefanor #44217: Tkinter/IDLE: literal astral char discombobulates text editing https://bugs.python.org/issue44217 opened by shreyanavigyan #44218: Possible Stack Based Buffer Overflow at Programs/_freeze_impor https://bugs.python.org/issue44218 opened by demonia #44219: Opening a file holds the GIL when it calls "isatty()" https://bugs.python.org/issue44219 opened by smurfix #44220: PyStructSequence_UnnamedField unavailable on Windows https://bugs.python.org/issue44220 opened by johnboy2 #44221: ImportError: sys.meta_path is None, Python is likely shutting https://bugs.python.org/issue44221 opened by luizoti #44225: stop() on a stopped loop inhibits the next run_forever https://bugs.python.org/issue44225 opened by mandolaerik #44226: Threads shutting down in Py 2.7 but not in Py 3.69 while makin https://bugs.python.org/issue44226 opened by muralidhar.bn #44229: Intermittent connection errors in ssl tests on macOS CI https://bugs.python.org/issue44229 opened by erlendaasland #44230: lookup extensions with the stable ABI under a platform specifi https://bugs.python.org/issue44230 opened by doko #44233: Provide Windows Terminal Fragment Extension https://bugs.python.org/issue44233 opened by mveril #44234: Debugging with LLDB doesn't work for universal2 installer on m https://bugs.python.org/issue44234 opened by ronaldoussoren #44235: Remove l*gettext() and related functions in the gettext module https://bugs.python.org/issue44235 opened by corona10 #44236: Define SOABI, LIBRARY, LDLIBRARY and LIBPL on Windows https://bugs.python.org/issue44236 opened by steve.dower #44237: test_ssl randomly fails on macOS GH Action: test_get_server_ce https://bugs.python.org/issue44237 opened by vstinner #44238: Unable to install Python 3.9.5 - Windows Server https://bugs.python.org/issue44238 opened by RFuentes #44239: Use platform defined data directories instead of ~/.python_his https://bugs.python.org/issue44239 opened by oxalica #44240: Incorrect behavior of LOAD_ATTR due to overflow in tp_version https://bugs.python.org/issue44240 opened by Mark.Shannon #44242: enum.IntFlag regression: missing values cause TypeError https://bugs.python.org/issue44242 opened by hroncok #44245: Cross-compilation of CPython 3.8 with _socket module using And https://bugs.python.org/issue44245 opened by laheller #44246: 3.10 beta 1: breaking change in importlib.metadata entry point https://bugs.python.org/issue44246 opened by Anthony Sottile #44249: Readme typo fix https://bugs.python.org/issue44249 opened by Ayushparikh-code #44251: ctypes '_get_soname' fails silently on missing objdump https://bugs.python.org/issue44251 opened by GuillaumeDesforges #44252: test_ssl and test_httplib.HTTPSTest crash randomly with "Windo https://bugs.python.org/issue44252 opened by vstinner #44254: Change turtledemo button colors https://bugs.python.org/issue44254 opened by terry.reedy #44255: strptime and week numbers without week days https://bugs.python.org/issue44255 opened by Jaap van der Velde #44257: typo and verbous grammar in the grammar spec https://bugs.python.org/issue44257 opened by orangebana15 #44258: Support PEP 515 for Fraction's initialization from string https://bugs.python.org/issue44258 opened by Sergey.Kirpichev #44259: lib2to3 does not accept "exec" as name https://bugs.python.org/issue44259 opened by mulugruntz #44260: _Random.seed() is called twice https://bugs.python.org/issue44260 opened by serhiy.storchaka #44261: SocketType documentation misleading https://bugs.python.org/issue44261 opened by srittau #44262: tarfile: some content different output https://bugs.python.org/issue44262 opened by yellowhat Most recent 15 issues with no replies (15) ========================================== #44262: tarfile: some content different output https://bugs.python.org/issue44262 #44261: SocketType documentation misleading https://bugs.python.org/issue44261 #44260: _Random.seed() is called twice https://bugs.python.org/issue44260 #44259: lib2to3 does not accept "exec" as name https://bugs.python.org/issue44259 #44257: typo and verbous grammar in the grammar spec https://bugs.python.org/issue44257 #44255: strptime and week numbers without week days https://bugs.python.org/issue44255 #44254: Change turtledemo button colors https://bugs.python.org/issue44254 #44251: ctypes '_get_soname' fails silently on missing objdump https://bugs.python.org/issue44251 #44249: Readme typo fix https://bugs.python.org/issue44249 #44245: Cross-compilation of CPython 3.8 with _socket module using And https://bugs.python.org/issue44245 #44239: Use platform defined data directories instead of ~/.python_his https://bugs.python.org/issue44239 #44238: Unable to install Python 3.9.5 - Windows Server https://bugs.python.org/issue44238 #44225: stop() on a stopped loop inhibits the next run_forever https://bugs.python.org/issue44225 #44221: ImportError: sys.meta_path is None, Python is likely shutting https://bugs.python.org/issue44221 #44220: PyStructSequence_UnnamedField unavailable on Windows https://bugs.python.org/issue44220 Most recent 15 issues waiting for review (15) ============================================= #44258: Support PEP 515 for Fraction's initialization from string https://bugs.python.org/issue44258 #44257: typo and verbous grammar in the grammar spec https://bugs.python.org/issue44257 #44249: Readme typo fix https://bugs.python.org/issue44249 #44246: 3.10 beta 1: breaking change in importlib.metadata entry point https://bugs.python.org/issue44246 #44239: Use platform defined data directories instead of ~/.python_his https://bugs.python.org/issue44239 #44235: Remove l*gettext() and related functions in the gettext module https://bugs.python.org/issue44235 #44230: lookup extensions with the stable ABI under a platform specifi https://bugs.python.org/issue44230 #44220: PyStructSequence_UnnamedField unavailable on Windows https://bugs.python.org/issue44220 #44212: asyncio overrides signal handlers https://bugs.python.org/issue44212 #44211: Duplicate '.bmp' key in mimetypes.py, maps to both 'image/bmp' https://bugs.python.org/issue44211 #44210: Make importlib.metadata._meta.PackageMetadata public https://bugs.python.org/issue44210 #44206: Add a version number to dict keys. https://bugs.python.org/issue44206 #44205: shutil.copystat can fail when copying to a file system with a https://bugs.python.org/issue44205 #44195: importlib.abc.TraversableReader is not implemented https://bugs.python.org/issue44195 #44188: ThreadPoolExecutor unbalanced semaphore count https://bugs.python.org/issue44188 Top 10 most discussed issues (10) ================================= #42972: [C API] Heap types (PyType_FromSpec) must fully implement the https://bugs.python.org/issue42972 42 msgs #44242: enum.IntFlag regression: missing values cause TypeError https://bugs.python.org/issue44242 16 msgs #44252: test_ssl and test_httplib.HTTPSTest crash randomly with "Windo https://bugs.python.org/issue44252 15 msgs #44217: Tkinter/IDLE: literal astral char discombobulates text editing https://bugs.python.org/issue44217 14 msgs #44229: Intermittent connection errors in ssl tests on macOS CI https://bugs.python.org/issue44229 13 msgs #43921: test_ssl fails on Windows buildbots https://bugs.python.org/issue43921 12 msgs #44246: 3.10 beta 1: breaking change in importlib.metadata entry point https://bugs.python.org/issue44246 10 msgs #44031: test_embed and test_tabnanny fails if the current directory is https://bugs.python.org/issue44031 9 msgs #37596: Reproducible pyc: frozenset is not serialized in a determinist https://bugs.python.org/issue37596 8 msgs #44206: Add a version number to dict keys. https://bugs.python.org/issue44206 8 msgs Issues closed (76) ================== #3702: test_urllib2.test_trivial fails when run from another Windows https://bugs.python.org/issue3702 closed by iritkatriel #8264: [doc] hasattr doesn't show private (double underscore) attribu https://bugs.python.org/issue8264 closed by kj #12463: Calling SocketServer.shutdown() when server_forever() was not https://bugs.python.org/issue12463 closed by iritkatriel #16533: HPUX: Unable to fork() in thread https://bugs.python.org/issue16533 closed by iritkatriel #20408: memoryview() constructor documentation error https://bugs.python.org/issue20408 closed by berker.peksag #21633: Argparse does not propagate HelpFormatter class to subparsers https://bugs.python.org/issue21633 closed by iritkatriel #23443: XMLRPCLIB Exception uses str not class or instance https://bugs.python.org/issue23443 closed by iritkatriel #23833: email.header.Header folding modifies headers that include semi https://bugs.python.org/issue23833 closed by iritkatriel #26503: argparse with required field , not having new line separator i https://bugs.python.org/issue26503 closed by iritkatriel #26740: tarfile: accessing (listing and extracting) tarball fails with https://bugs.python.org/issue26740 closed by iritkatriel #30757: pyinstaller can be added to docs, py2exe ref can be updated https://bugs.python.org/issue30757 closed by erlendaasland #30849: test_stress_delivery_dependent() of test_signal randomly fails https://bugs.python.org/issue30849 closed by vstinner #31790: double free or corruption (while using smem) https://bugs.python.org/issue31790 closed by iritkatriel #32084: [Security] http.server can be abused to redirect to (almost) a https://bugs.python.org/issue32084 closed by ned.deily #32983: UnicodeDecodeError 'ascii' codec can't decode byte in position https://bugs.python.org/issue32983 closed by iritkatriel #33809: Expose `capture_locals` parameter in `traceback` convenience f https://bugs.python.org/issue33809 closed by iritkatriel #35134: Add a new Include/cpython/ subdirectory for the "CPython API" https://bugs.python.org/issue35134 closed by vstinner #35197: graminit.h defines very generic names like 'stmt' or 'test' https://bugs.python.org/issue35197 closed by vstinner #36128: ResourceReader for FileLoader inconsistently handles path sepa https://bugs.python.org/issue36128 closed by jaraco #36560: test_functools leaks randomly 1 memory block https://bugs.python.org/issue36560 closed by vstinner #36940: Update Py_FrozenMain() for _PyCoreConfig (PEP 587) https://bugs.python.org/issue36940 closed by vstinner #36950: test.support: add an helper to wait for an event with a timeou https://bugs.python.org/issue36950 closed by vstinner #37228: UDP sockets created by create_datagram_endpoint() allow by def https://bugs.python.org/issue37228 closed by ned.deily #37903: IDLE Shell sidebar. https://bugs.python.org/issue37903 closed by terry.reedy #38575: Child process deadlock in subprocess.Popen https://bugs.python.org/issue38575 closed by iritkatriel #39995: test_concurrent_futures: ProcessPoolSpawnExecutorDeadlockTest. https://bugs.python.org/issue39995 closed by vstinner #39996: test_multiprocessing_fork hangs on AMD64 FreeBSD Shared 3.x https://bugs.python.org/issue39996 closed by vstinner #40237: Test code coverage (C) job of Travis CI fails on test_distutil https://bugs.python.org/issue40237 closed by vstinner #40551: PRs should be rebased on top of master before running the buil https://bugs.python.org/issue40551 closed by FFY00 #40695: hashlib: OpenSSL hash detection should obey security policy https://bugs.python.org/issue40695 closed by christian.heimes #40736: better message for re.search TypeError ("expected string or by https://bugs.python.org/issue40736 closed by iritkatriel #41147: Document that redirect_std{out,err} yield the new stream as th https://bugs.python.org/issue41147 closed by iritkatriel #41611: IDLE: problems with completions on Mac https://bugs.python.org/issue41611 closed by taleinat #41736: test_site: test_s_option() failed on AMD64 Windows8.1 Refleaks https://bugs.python.org/issue41736 closed by vstinner #41855: FastPath.zip_children can give duplicate results on Python 3.8 https://bugs.python.org/issue41855 closed by jaraco #42043: zipfile.Path should support inheritance https://bugs.python.org/issue42043 closed by jaraco #43063: zipfile.Path / importlib.resources raises KeyError if a file w https://bugs.python.org/issue43063 closed by jaraco #43109: When using Apple Clang, --with-lto builds should not check for https://bugs.python.org/issue43109 closed by vstinner #43167: Add a note to the macOS installer welcome window about customi https://bugs.python.org/issue43167 closed by ned.deily #43504: Site linked in docs, effbot.org, down https://bugs.python.org/issue43504 closed by mdk #43556: fix attr names for ast.expr and ast.stmt https://bugs.python.org/issue43556 closed by iritkatriel #43643: importlib.readers.MultiplexedPath.name is not a property https://bugs.python.org/issue43643 closed by jaraco #43667: Solaris: Fix broken Unicode encoding in non-UTF locales https://bugs.python.org/issue43667 closed by vstinner #43688: [C API] Support the limited C API in debug mode (Py_INCREF and https://bugs.python.org/issue43688 closed by vstinner #43774: [Doc] Document configure options in the Python documentation https://bugs.python.org/issue43774 closed by vstinner #43843: libregrtest: mark a test as failed if a thread logs an unexpec https://bugs.python.org/issue43843 closed by vstinner #43879: Add native_thread_id to PyThreadState https://bugs.python.org/issue43879 closed by vstinner #43927: Remove IOError references from the tutorial https://bugs.python.org/issue43927 closed by terry.reedy #43988: Add test.support.check_disallow_instantiation() https://bugs.python.org/issue43988 closed by erlendaasland #44010: IDLE: highlight soft keywords https://bugs.python.org/issue44010 closed by taleinat #44032: Function locals and evaluation stack should be stored in a con https://bugs.python.org/issue44032 closed by vstinner #44043: 3.10 b1 armhf Bus Error in hashlib test: test_gil https://bugs.python.org/issue44043 closed by christian.heimes #44120: logging.config.fileConfig/dictConfig can not import class https://bugs.python.org/issue44120 closed by vinay.sajip #44131: [C API] Add tests on Py_FrozenMain() https://bugs.python.org/issue44131 closed by pablogsal #44151: Improve parameter names and return value ordering for linear_r https://bugs.python.org/issue44151 closed by rhettinger #44184: crash on windows invoking flake8 https://bugs.python.org/issue44184 closed by vstinner #44190: Dictionary assignment shorthand https://bugs.python.org/issue44190 closed by terry.reedy #44196: Document that importlib.abc.Traversable's methods should raise https://bugs.python.org/issue44196 closed by FFY00 #44201: REPL requests another line despite syntax error https://bugs.python.org/issue44201 closed by pablogsal #44208: argparse: Accept option without needing to distinguish "-" fro https://bugs.python.org/issue44208 closed by rhettinger #44216: Bug in class method with optional parameter https://bugs.python.org/issue44216 closed by steven.daprano #44222: Improving _removeHandlerRef for a very long _handlerList https://bugs.python.org/issue44222 closed by Yonatan Goldschmidt #44223: := in comprehensions does not work https://bugs.python.org/issue44223 closed by serhiy.storchaka #44224: urllib.parse.urljoin behaves differently in Python 3.9.5 https://bugs.python.org/issue44224 closed by rushter #44227: help(bisect.bisect_left) https://bugs.python.org/issue44227 closed by rhettinger #44228: [urllib] Error with handling of urllib.parse.quote. Terminate https://bugs.python.org/issue44228 closed by martin.panter #44231: Remove _PyTuple_FromArray from the public API https://bugs.python.org/issue44231 closed by vstinner #44232: Crash in Objects/typeobject.c https://bugs.python.org/issue44232 closed by vstinner #44241: Sync importlib_metadata enhancements through 4.1. https://bugs.python.org/issue44241 closed by jaraco #44243: tkinter button colors on Mac https://bugs.python.org/issue44243 closed by terry.reedy #44244: protected members accessible in other modules https://bugs.python.org/issue44244 closed by iritkatriel #44247: bpo stacktrace linkifier does not understand 3.10+ https://bugs.python.org/issue44247 closed by zach.ware #44248: copy.deepcopy calls objdect's __deepcopy__ with incorrect argu https://bugs.python.org/issue44248 closed by zach.ware #44250: Link to ibera IRC goes to 404 page https://bugs.python.org/issue44250 closed by xtreak #44253: tkinter searches for tk.tcl in wrong directory https://bugs.python.org/issue44253 closed by ned.deily #44256: _functools._lru_list_elem is exposed unintentionally. https://bugs.python.org/issue44256 closed by methane

1 0

IRC #python-dev channel is now on Libera Chat (bye bye Freenode)
by Victor Stinner May 27, 2021

May 27, 2021

Hi, The #python-dev IRC channel moves from Freenode to Libera Chat: https://libera.chat/ I'm connected as vstinner, see you there ;-) Join the channel if you would like to talk about the development of Python itself (the VM, bytecode, stdlib, etc.)! Moreover, bots notifications (GitHub, buildbots, bugs.python.org) are now in a new dedicated channel #python-dev-notifs so humans can talk together again! :-) The migration is on-going, right now some notifications are still on Freenode. -- Yesterday evening, Freenode admins decided to take the control of the #python-fr channel on Freenode (which now redirects to a new ##python-fr channel), only because the channel topic contained "libera"! The french Python association ("AFPy") managing #python-fr lost control and decided to migrate to Libera Chat (libera.chat). Announcement in french: https://www.afpy.org/posts/actualites/1622023152 I'm disappointed by how the events are going. At least, it motivated me to move bots notfications ;-) Victor -- Night gathers, and now my watch begins. It shall not end until my death.

9 11

IMPORTANT: Python 3.10b2 release blockers
by Pablo Galindo Salgado May 26, 2021

May 26, 2021

Hi, Tomorrow is the scheduled release of Python 3.10 beta 2 but unfortunately we have several release blockers: https://bugs.python.org/issue41282: Deprecate and remove distutils https://bugs.python.org/issue40222: "Zero cost" exception handling https://bugs.python.org/issue42972: [C API] Heap types (PyType_FromSpec) must fully implement the GC protocol https://bugs.python.org/issue44043: 3.10 b1 armhf Bus Error in hashlib test: test_gil We also have the address sanitizer buildbot failing : https://buildbot.python.org/all/#/builders/582/builds/165/steps/5/logs/stdio and some segmentation faults on the fedora stable buildbot: https://buildbot.python.org/all/#/builders/543/builds/190 Some of these issues have PRs but some of them have not. Please, if you are involved or you maintain one of the areas involved in these issues, take a look at them and act with one of the following: * Fix the issue making a PR * Review an existing PR and / or merge it * If you intend to mark it as a deferred blocker, please provide a rationale and contact me first by pinging me in the issue. Until these issues are fixed or deferred, the release team will not be able to make a new beta release. Thanks for your help, Regards from stormy London, Pablo Galindo Salgado

2 3

Question for potential python development contributions on Windows
by pjfarley3＠earthlink.net May 24, 2021

May 24, 2021

The Python Developers Guide specifically states to get VS2017 for developing or enhancing python on a Windows system. Is it still correct to specifically use VS2017 , or is VS2019 also acceptable? I ask this because I know that the *.vcproj files and other build-environment files have changed format pretty dramatically over the many releases of VS. If a potential new contribution targeted for current and future python will require new build environment files, I wouldn't want to have to "down release" those files (or expect core dev's to do it) at or after submission to the community for approval. Much better to use the same setup as core dev's use than to introduce up-level differences in the build environment. IOW, for new releases on Windows are core dev's still using VS2017 and so potential contributors should also use that version, or has the core dev's process for Windows releases been updated to use VS2019? Peter --

5 5

Summary of Python tracker Issues
by Python tracker May 21, 2021

May 21, 2021

ACTIVITY SUMMARY (2021-05-14 - 2021-05-21) 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 7452 (+23) closed 48492 (+51) total 55944 (+74) Open issues with patches: 2965 Issues opened (57) ================== #39950: Add pathlib.Path.hardlink_to() https://bugs.python.org/issue39950 reopened by barneygale #42834: [subinterpreters] Convert "global" static variable caches in _ https://bugs.python.org/issue42834 reopened by kj #44126: Support cross-compiling of cpython modules using setuptools https://bugs.python.org/issue44126 reopened by jmoguill2 #44135: issubclass documentation doesn't explain tuple semantic https://bugs.python.org/issue44135 opened by joaozinho #44136: Remove pathlib flavours https://bugs.python.org/issue44136 opened by barneygale #44138: multiprocessing documentation should note behavior when proces https://bugs.python.org/issue44138 opened by kushal-kumaran #44140: WeakKeyDictionary should support lookup by id instead of hash https://bugs.python.org/issue44140 opened by conchylicultor #44142: ast.unparse: visually better code generation https://bugs.python.org/issue44142 opened by BTaskaya #44145: hmac.update is not releasing the GIL when openssl's hmac is us https://bugs.python.org/issue44145 opened by gregory.p.smith #44147: [WinError 193] %1 is not a valid Win32 application https://bugs.python.org/issue44147 opened by bassel27 #44149: difflib.get_close_matches: Add `key` argument https://bugs.python.org/issue44149 opened by mustafaquraish #44151: Improve parameter names and return value ordering for linear_r https://bugs.python.org/issue44151 opened by rhettinger #44153: Signaling an asyncio subprocess might raise ProcessLookupError https://bugs.python.org/issue44153 opened by syntaxcoloring #44155: Race condition when using multiprocessing BaseManager and Pool https://bugs.python.org/issue44155 opened by chenzhuowansui #44156: [subinterpreters] Replace static string caches with subinterpr https://bugs.python.org/issue44156 opened by kj #44157: redirect_* should also redirect C-level streams https://bugs.python.org/issue44157 opened by xmorel #44158: Clarify documentation for redirected stdout/stderr when using https://bugs.python.org/issue44158 opened by tanty #44159: mimetypes - "strict" on Windows https://bugs.python.org/issue44159 opened by Norman Lorrain #44163: IDLE ValueError in HyperParser https://bugs.python.org/issue44163 opened by rhettinger #44164: Document what are resources in importlib.resources https://bugs.python.org/issue44164 opened by FFY00 #44165: [sqlite3] sqlite3_prepare_v2 micro optimisation: pass string s https://bugs.python.org/issue44165 opened by erlendaasland #44166: Make IndexError messages for list more informative https://bugs.python.org/issue44166 opened by miguendes #44167: ipaddress.IPv6Address.is_private makes redundant checks https://bugs.python.org/issue44167 opened by mjpieters #44170: ShareableList cannot safely handle multibyte utf-8 characters https://bugs.python.org/issue44170 opened by huwcbjones #44172: curses module may call delwin() on original window before subw https://bugs.python.org/issue44172 opened by michaelforney #44173: Stored (uncompressed) ZipExtFile in zipfile can be seekable at https://bugs.python.org/issue44173 opened by juniorjpdj #44174: Unclear meaning of _Private__names in enum docs. https://bugs.python.org/issue44174 opened by gregory.p.smith #44175: What do "cased" and "uncased" mean? https://bugs.python.org/issue44175 opened by otakutyrant #44176: asyncio.as_completed() raises TypeError when the first supplie https://bugs.python.org/issue44176 opened by alexdelorenzo #44178: Add an interpreter-level critical section construct https://bugs.python.org/issue44178 opened by xmorel #44180: SyntaxError misidentified in 3.10.0b1 when = used instead of : https://bugs.python.org/issue44180 opened by aroberge #44181: SyntaxError in Python 3.10.0b1: wrong token for missing comma https://bugs.python.org/issue44181 opened by aroberge #44182: python-config.sh vs python-config.py inconsistency https://bugs.python.org/issue44182 opened by millert #44183: Can't install certificates if GUI tools are not installed on m https://bugs.python.org/issue44183 opened by thetechconspiracy #44184: crash on windows invoking flake8 https://bugs.python.org/issue44184 opened by Anthony Sottile #44185: mock_open file handle __exit__ does not call close https://bugs.python.org/issue44185 opened by williamsjoblom #44186: TimedRotatingFileHandler overwrite log https://bugs.python.org/issue44186 opened by aeg #44187: Implement infrastructure for quickening and specializing https://bugs.python.org/issue44187 opened by Mark.Shannon #44188: ThreadPoolExecutor unbalanced semaphore count https://bugs.python.org/issue44188 opened by bennieswart #44189: multiprocessing AF_PIPE name format is slightly confusing in t https://bugs.python.org/issue44189 opened by Antony.Lee #44190: Dictionary assignment shorthand https://bugs.python.org/issue44190 opened by davidhariri #44191: Getting an ImportError DLL load failed while importing _ssl https://bugs.python.org/issue44191 opened by lnegger #44192: Annotations, Inheritance and Circular Reference https://bugs.python.org/issue44192 opened by reob-info #44193: socket line 46 import _socket Import Error https://bugs.python.org/issue44193 opened by Joshex #44194: Folding ''.join(<known number of elts>) into f-strings https://bugs.python.org/issue44194 opened by BTaskaya #44195: importlib.abc.TraversableReader is not implemented https://bugs.python.org/issue44195 opened by FFY00 #44196: Document that importlib.abc.Traversable's methods should raise https://bugs.python.org/issue44196 opened by FFY00 #44198: Add flags or function in pathlib.Path https://bugs.python.org/issue44198 opened by tetelevm #44200: Recommend importlib.abc.Traversable users to implement __fspat https://bugs.python.org/issue44200 opened by FFY00 #44201: REPL requests another line despite syntax error https://bugs.python.org/issue44201 opened by gvanrossum #44202: Add errors argument to importlib.abc.Traversable.read_text https://bugs.python.org/issue44202 opened by FFY00 #44203: test__xxsubinterpreters: heap-buffer-overflow in interp_is_run https://bugs.python.org/issue44203 opened by vstinner #44204: socket.connect ignores CTRL+C during timeout on Win https://bugs.python.org/issue44204 opened by mrx23dot #44205: shutil.copystat can fail when copying to a file system with a https://bugs.python.org/issue44205 opened by chrisburr #44206: Add a version number to dict keys. https://bugs.python.org/issue44206 opened by Mark.Shannon #44207: Add a version number to Python functions https://bugs.python.org/issue44207 opened by Mark.Shannon #44208: argparse: Accept option without needing to distinguish "-" fro https://bugs.python.org/issue44208 opened by wbarnha Most recent 15 issues with no replies (15) ========================================== #44208: argparse: Accept option without needing to distinguish "-" fro https://bugs.python.org/issue44208 #44207: Add a version number to Python functions https://bugs.python.org/issue44207 #44205: shutil.copystat can fail when copying to a file system with a https://bugs.python.org/issue44205 #44204: socket.connect ignores CTRL+C during timeout on Win https://bugs.python.org/issue44204 #44203: test__xxsubinterpreters: heap-buffer-overflow in interp_is_run https://bugs.python.org/issue44203 #44198: Add flags or function in pathlib.Path https://bugs.python.org/issue44198 #44196: Document that importlib.abc.Traversable's methods should raise https://bugs.python.org/issue44196 #44195: importlib.abc.TraversableReader is not implemented https://bugs.python.org/issue44195 #44192: Annotations, Inheritance and Circular Reference https://bugs.python.org/issue44192 #44188: ThreadPoolExecutor unbalanced semaphore count https://bugs.python.org/issue44188 #44187: Implement infrastructure for quickening and specializing https://bugs.python.org/issue44187 #44186: TimedRotatingFileHandler overwrite log https://bugs.python.org/issue44186 #44185: mock_open file handle __exit__ does not call close https://bugs.python.org/issue44185 #44183: Can't install certificates if GUI tools are not installed on m https://bugs.python.org/issue44183 #44182: python-config.sh vs python-config.py inconsistency https://bugs.python.org/issue44182 Most recent 15 issues waiting for review (15) ============================================= #44208: argparse: Accept option without needing to distinguish "-" fro https://bugs.python.org/issue44208 #44205: shutil.copystat can fail when copying to a file system with a https://bugs.python.org/issue44205 #44196: Document that importlib.abc.Traversable's methods should raise https://bugs.python.org/issue44196 #44195: importlib.abc.TraversableReader is not implemented https://bugs.python.org/issue44195 #44188: ThreadPoolExecutor unbalanced semaphore count https://bugs.python.org/issue44188 #44187: Implement infrastructure for quickening and specializing https://bugs.python.org/issue44187 #44184: crash on windows invoking flake8 https://bugs.python.org/issue44184 #44180: SyntaxError misidentified in 3.10.0b1 when = used instead of : https://bugs.python.org/issue44180 #44173: Stored (uncompressed) ZipExtFile in zipfile can be seekable at https://bugs.python.org/issue44173 #44172: curses module may call delwin() on original window before subw https://bugs.python.org/issue44172 #44167: ipaddress.IPv6Address.is_private makes redundant checks https://bugs.python.org/issue44167 #44166: Make IndexError messages for list more informative https://bugs.python.org/issue44166 #44165: [sqlite3] sqlite3_prepare_v2 micro optimisation: pass string s https://bugs.python.org/issue44165 #44164: Document what are resources in importlib.resources https://bugs.python.org/issue44164 #44156: [subinterpreters] Replace static string caches with subinterpr https://bugs.python.org/issue44156 Top 10 most discussed issues (10) ================================= #44184: crash on windows invoking flake8 https://bugs.python.org/issue44184 32 msgs #40452: Tkinter/IDLE: preserve clipboard on closure https://bugs.python.org/issue40452 19 msgs #44151: Improve parameter names and return value ordering for linear_r https://bugs.python.org/issue44151 13 msgs #44099: [C API] Introduce a new slot in PyModuleDef to hold the classe https://bugs.python.org/issue44099 10 msgs #44147: [WinError 193] %1 is not a valid Win32 application https://bugs.python.org/issue44147 10 msgs #28937: str.split(): allow removing empty strings (when sep is not Non https://bugs.python.org/issue28937 9 msgs #44180: SyntaxError misidentified in 3.10.0b1 when = used instead of : https://bugs.python.org/issue44180 8 msgs #43882: [security] urllib.parse should sanitize urls containing ASCII https://bugs.python.org/issue43882 7 msgs #44175: What do "cased" and "uncased" mean? https://bugs.python.org/issue44175 6 msgs #42109: Use hypothesis for testing the standard library, falling back https://bugs.python.org/issue42109 5 msgs Issues closed (48) ================== #22891: code removal from urllib.parse.urlsplit() https://bugs.python.org/issue22891 closed by gregory.p.smith #29639: test suite intentionally avoids referring to localhost, destro https://bugs.python.org/issue29639 closed by gregory.p.smith #30593: Document that sqlite3.Cursor.executescript disregards isolatio https://bugs.python.org/issue30593 closed by berker.peksag #32133: documentation: numbers module nitpick https://bugs.python.org/issue32133 closed by rhettinger #33433: ipaddress is_private misleading for IPv4 mapped IPv6 addresses https://bugs.python.org/issue33433 closed by gregory.p.smith #35765: Document references object x but doesn't show it in the exampl https://bugs.python.org/issue35765 closed by iritkatriel #35889: sqlite3.Row doesn't have useful repr https://bugs.python.org/issue35889 closed by berker.peksag #36160: Multiple errors in test_site.py on sysconfig._CONFIG_VARS.clea https://bugs.python.org/issue36160 closed by iritkatriel #36464: Python 2.7 build install fails intermittently with -j on MacOS https://bugs.python.org/issue36464 closed by willingc #38593: Python 3.7 does not catch infinite recursion for some values o https://bugs.python.org/issue38593 closed by iritkatriel #39924: pathlib handles missing `os.link`, `os.symlink` and `os.readli https://bugs.python.org/issue39924 closed by barneygale #40339: Instead of skipping, IPV6 test(s) fail on a non-IPV6 machine https://bugs.python.org/issue40339 closed by gregory.p.smith #40670: supplying an empty string to timeit causes an IndentationError https://bugs.python.org/issue40670 closed by iritkatriel #40975: contextlib.AsyncExitStack enter_async_context and aclose shoul https://bugs.python.org/issue40975 closed by iritkatriel #41318: Better error message of "Cannot recover from stack overflow." https://bugs.python.org/issue41318 closed by iritkatriel #42022: Allow ensurepip to work without bundled wheels https://bugs.python.org/issue42022 closed by FFY00 #42783: asyncio.sleep(0) idiom is not documented https://bugs.python.org/issue42783 closed by iritkatriel #43295: datetime.strptime emits IndexError on parsing 'z' as %z https://bugs.python.org/issue43295 closed by vstinner #43650: MemoryError on zip.read in shutil._unpack_zipfile https://bugs.python.org/issue43650 closed by gregory.p.smith #43753: [C API] Add Py_Is(x, y) and Py_IsNone(x) functions https://bugs.python.org/issue43753 closed by vstinner #44038: In documentation Section 8.6, the definition of parameter_list https://bugs.python.org/issue44038 closed by pablogsal #44072: Doc: power operator (`**`) present for numbers.Complex, not ad https://bugs.python.org/issue44072 closed by terry.reedy #44078: Output relative path when using PurePath.relative_to https://bugs.python.org/issue44078 closed by terry.reedy #44081: ast.unparse: dont use redundant space separator for lambdas wi https://bugs.python.org/issue44081 closed by BTaskaya #44086: py.svg not found on search result page https://bugs.python.org/issue44086 closed by jugmac00 #44106: [sqlite3] don't use politicians in examples/docs https://bugs.python.org/issue44106 closed by erlendaasland #44107: HTTPServer can't close http client completely https://bugs.python.org/issue44107 closed by gregory.p.smith #44132: Local import conflict with system import https://bugs.python.org/issue44132 closed by ned.deily #44137: importlib.resources.path raises RuntimeError when FileNotFound https://bugs.python.org/issue44137 closed by jaraco #44139: Unparenthesized tuple doc bug in what's new https://bugs.python.org/issue44139 closed by pablogsal #44141: Getting error while importing ssl "import _ssl ImportError: DL https://bugs.python.org/issue44141 closed by christian.heimes #44143: The parse crashes when raising tokenizer errors when an existi https://bugs.python.org/issue44143 closed by pablogsal #44144: Python window not opening https://bugs.python.org/issue44144 closed by christian.heimes #44146: Format string fill not handling brace char https://bugs.python.org/issue44146 closed by eric.smith #44148: Raise a SystemError if frame is NULL in PyEval_GetGlobals https://bugs.python.org/issue44148 closed by shreyanavigyan #44150: Add optional weights parameter to statistics.fmean() https://bugs.python.org/issue44150 closed by rhettinger #44152: [not a bug] .isupper() does not support Polytonic Greek (but . https://bugs.python.org/issue44152 closed by Jelle Zijlstra #44154: Optimize Fraction pickling https://bugs.python.org/issue44154 closed by Sergey.Kirpichev #44160: speed up searching for keywords by using a dictionary https://bugs.python.org/issue44160 closed by Dennis Sweeney #44161: free: invalid pointer on graph and photo.message imports https://bugs.python.org/issue44161 closed by christian.heimes #44162: importlib.resources.path no longer supports directories https://bugs.python.org/issue44162 closed by gitpushdashf #44168: Wrong syntax error hint when spurious colon present in functio https://bugs.python.org/issue44168 closed by pablogsal #44169: Add HTTPS support to http.server https://bugs.python.org/issue44169 closed by ned.deily #44171: Cython cannot compile 'a = 5/6' and return 'a = 0' https://bugs.python.org/issue44171 closed by pablogsal #44177: Unable to get the else while parsing through AST module https://bugs.python.org/issue44177 closed by eric.smith #44179: python3 �� range�� https://bugs.python.org/issue44179 closed by christian.heimes #44197: [request feature] Itertools extended combinations to limited n https://bugs.python.org/issue44197 closed by rhettinger #44199: code example index error in tutorial controlflow https://bugs.python.org/issue44199 closed by HVoltBb

1 0

Critique of PEP 657 -- Include Fine Grained Error Locations in Tracebacks
by Mark Shannon May 21, 2021

May 21, 2021

Hi everyone, I fully agree with the rationale for the PEP, better error messages always help. However, I think the proposed implementation could be misleading in some cases and wastes memory. Use one position, not one-and-a-half positions. ----------------------------------------------- The main problem with PEP 657, IMO, is that it wants to present the location of an error as a pair of positions, but without the line number of the second position. Consequently it ends up with one and a half positions, not two. This does not work well for a number of reasons. 1. Errors spanning multiple lines. Consider: (i1 + i2 + s1 ) Where i1, i2 are integers and s1 is a string. With a single location, the error points to the second `+`. PEP 657 would highlight the whole line, `i1 + i2 +`, making it unclear where the error occurred. 2. Repeated binary operations on the same line. A single location can also be clearer when all the code is on one line. i1 + i2 + s1 PEP 657: i1 + i2 + s1 ^^^^^^^^^^^^ Using a single location: i1 + i2 + s1 ^ 3. Tracking locations in the compiler. While nicer locations for errors is great, it won't be popular if it has a negative impact on performance. Locations need to tracked through the compiler. The simpler the location, the easier this is to do correctly without a negative performance impact. It is already tricky to do this correctly with just line numbers because we have both source that compiles to no bytecodes (try, pass) and bytecodes that have no source (implicit return None and except cleanups). A single location can still be presented as a whole token, as tokenizing a single line of code is easy and fast. So when presenting an error, the whole token can be highlighted. E.g: NameError name ^^^^ Compression ----------- PEP 657 proposes that no compression be used, but also mandates the use of a lossy compression scheme (truncating all offsets over 255). I think it would be better to provide an API like PEP 626 and not restrict the internal format used. In fact, extending or replacing the API of PEP 626 seems the best approach to me. I wouldn't worry about memory consumption. The code object layout and unmarshalling process needs to be re-implemented for reduced memory use and faster startup: https://github.com/markshannon/faster-cpython/blob/master/tiers.md#tier-0 A few bytes more or less in the location table(s) is inconsequential. Cheers, Mark.

8 19

Speeding up CPython
by Mark Shannon May 18, 2021

May 18, 2021

Hi everyone, CPython is slow. We all know that, yet little is done to fix it. I'd like to change that. I have a plan to speed up CPython by a factor of five over the next few years. But it needs funding. I am aware that there have been several promised speed ups in the past that have failed. You might wonder why this is different. Here are three reasons: 1. I already have working code for the first stage. 2. I'm not promising a silver bullet. I recognize that this is a substantial amount of work and needs funding. 3. I have extensive experience in VM implementation, not to mention a PhD in the subject. My ideas for possible funding, as well as the actual plan of development, can be found here: https://github.com/markshannon/faster-cpython I'd love to hear your thoughts on this. Cheers, Mark.

33 77

PEP 1, PEP Purpose and Guidelines
by barry＠zope.com May 18, 2021

May 18, 2021

It has been a while since I posted a copy of PEP 1 to the mailing lists and newsgroups. I've recently done some updating of a few sections, so in the interest of gaining wider community participation in the Python development process, I'm posting the latest revision of PEP 1 here. A version of the PEP is always available on-line at http://www.python.org/peps/pep-0001.html Enjoy, -Barry -------------------- snip snip -------------------- PEP: 1 Title: PEP Purpose and Guidelines Version: $Revision: 1.36 $ Last-Modified: $Date: 2002/07/29 18:34:59 $ Author: Barry A. Warsaw, Jeremy Hylton Status: Active Type: Informational Created: 13-Jun-2000 Post-History: 21-Mar-2001, 29-Jul-2002 What is a PEP? PEP stands for Python Enhancement Proposal. A PEP is a design document providing information to the Python community, or describing a new feature for Python. The PEP should provide a concise technical specification of the feature and a rationale for the feature. We intend PEPs to be the primary mechanisms for proposing new features, for collecting community input on an issue, and for documenting the design decisions that have gone into Python. The PEP author is responsible for building consensus within the community and documenting dissenting opinions. Because the PEPs are maintained as plain text files under CVS control, their revision history is the historical record of the feature proposal[1]. Kinds of PEPs There are two kinds of PEPs. A standards track PEP describes a new feature or implementation for Python. An informational PEP describes a Python design issue, or provides general guidelines or information to the Python community, but does not propose a new feature. Informational PEPs do not necessarily represent a Python community consensus or recommendation, so users and implementors are free to ignore informational PEPs or follow their advice. PEP Work Flow The PEP editor, Barry Warsaw <peps(a)python.org>, assigns numbers for each PEP and changes its status. The PEP process begins with a new idea for Python. It is highly recommended that a single PEP contain a single key proposal or new idea. The more focussed the PEP, the more successfully it tends to be. The PEP editor reserves the right to reject PEP proposals if they appear too unfocussed or too broad. If in doubt, split your PEP into several well-focussed ones. Each PEP must have a champion -- someone who writes the PEP using the style and format described below, shepherds the discussions in the appropriate forums, and attempts to build community consensus around the idea. The PEP champion (a.k.a. Author) should first attempt to ascertain whether the idea is PEP-able. Small enhancements or patches often don't need a PEP and can be injected into the Python development work flow with a patch submission to the SourceForge patch manager[2] or feature request tracker[3]. The PEP champion then emails the PEP editor <peps(a)python.org> with a proposed title and a rough, but fleshed out, draft of the PEP. This draft must be written in PEP style as described below. If the PEP editor approves, he will assign the PEP a number, label it as standards track or informational, give it status 'draft', and create and check-in the initial draft of the PEP. The PEP editor will not unreasonably deny a PEP. Reasons for denying PEP status include duplication of effort, being technically unsound, not providing proper motivation or addressing backwards compatibility, or not in keeping with the Python philosophy. The BDFL (Benevolent Dictator for Life, Guido van Rossum) can be consulted during the approval phase, and is the final arbitrator of the draft's PEP-ability. If a pre-PEP is rejected, the author may elect to take the pre-PEP to the comp.lang.python newsgroup (a.k.a. python-list(a)python.org mailing list) to help flesh it out, gain feedback and consensus from the community at large, and improve the PEP for re-submission. The author of the PEP is then responsible for posting the PEP to the community forums, and marshaling community support for it. As updates are necessary, the PEP author can check in new versions if they have CVS commit permissions, or can email new PEP versions to the PEP editor for committing. Standards track PEPs consists of two parts, a design document and a reference implementation. The PEP should be reviewed and accepted before a reference implementation is begun, unless a reference implementation will aid people in studying the PEP. Standards Track PEPs must include an implementation - in the form of code, patch, or URL to same - before it can be considered Final. PEP authors are responsible for collecting community feedback on a PEP before submitting it for review. A PEP that has not been discussed on python-list(a)python.org and/or python-dev(a)python.org will not be accepted. However, wherever possible, long open-ended discussions on public mailing lists should be avoided. Strategies to keep the discussions efficient include, setting up a separate SIG mailing list for the topic, having the PEP author accept private comments in the early design phases, etc. PEP authors should use their discretion here. Once the authors have completed a PEP, they must inform the PEP editor that it is ready for review. PEPs are reviewed by the BDFL and his chosen consultants, who may accept or reject a PEP or send it back to the author(s) for revision. Once a PEP has been accepted, the reference implementation must be completed. When the reference implementation is complete and accepted by the BDFL, the status will be changed to `Final.' A PEP can also be assigned status `Deferred.' The PEP author or editor can assign the PEP this status when no progress is being made on the PEP. Once a PEP is deferred, the PEP editor can re-assign it to draft status. A PEP can also be `Rejected'. Perhaps after all is said and done it was not a good idea. It is still important to have a record of this fact. PEPs can also be replaced by a different PEP, rendering the original obsolete. This is intended for Informational PEPs, where version 2 of an API can replace version 1. PEP work flow is as follows: Draft -> Accepted -> Final -> Replaced ^ +----> Rejected v Deferred Some informational PEPs may also have a status of `Active' if they are never meant to be completed. E.g. PEP 1. What belongs in a successful PEP? Each PEP should have the following parts: 1. Preamble -- RFC822 style headers containing meta-data about the PEP, including the PEP number, a short descriptive title (limited to a maximum of 44 characters), the names, and optionally the contact info for each author, etc. 2. Abstract -- a short (~200 word) description of the technical issue being addressed. 3. Copyright/public domain -- Each PEP must either be explicitly labelled as placed in the public domain (see this PEP as an example) or licensed under the Open Publication License[4]. 4. Specification -- The technical specification should describe the syntax and semantics of any new language feature. The specification should be detailed enough to allow competing, interoperable implementations for any of the current Python platforms (CPython, JPython, Python .NET). 5. Motivation -- The motivation is critical for PEPs that want to change the Python language. It should clearly explain why the existing language specification is inadequate to address the problem that the PEP solves. PEP submissions without sufficient motivation may be rejected outright. 6. Rationale -- The rationale fleshes out the specification by describing what motivated the design and why particular design decisions were made. It should describe alternate designs that were considered and related work, e.g. how the feature is supported in other languages. The rationale should provide evidence of consensus within the community and discuss important objections or concerns raised during discussion. 7. Backwards Compatibility -- All PEPs that introduce backwards incompatibilities must include a section describing these incompatibilities and their severity. The PEP must explain how the author proposes to deal with these incompatibilities. PEP submissions without a sufficient backwards compatibility treatise may be rejected outright. 8. Reference Implementation -- The reference implementation must be completed before any PEP is given status 'Final,' but it need not be completed before the PEP is accepted. It is better to finish the specification and rationale first and reach consensus on it before writing code. The final implementation must include test code and documentation appropriate for either the Python language reference or the standard library reference. PEP Template PEPs are written in plain ASCII text, and should adhere to a rigid style. There is a Python script that parses this style and converts the plain text PEP to HTML for viewing on the web[5]. PEP 9 contains a boilerplate[7] template you can use to get started writing your PEP. Each PEP must begin with an RFC822 style header preamble. The headers must appear in the following order. Headers marked with `*' are optional and are described below. All other headers are required. PEP: <pep number> Title: <pep title> Version: <cvs version string> Last-Modified: <cvs date string> Author: <list of authors' real names and optionally, email addrs> * Discussions-To: <email address> Status: <Draft | Active | Accepted | Deferred | Final | Replaced> Type: <Informational | Standards Track> * Requires: <pep numbers> Created: <date created on, in dd-mmm-yyyy format> * Python-Version: <version number> Post-History: <dates of postings to python-list and python-dev> * Replaces: <pep number> * Replaced-By: <pep number> The Author: header lists the names and optionally, the email addresses of all the authors/owners of the PEP. The format of the author entry should be address(a)dom.ain (Random J. User) if the email address is included, and just Random J. User if the address is not given. If there are multiple authors, each should be on a separate line following RFC 822 continuation line conventions. Note that personal email addresses in PEPs will be obscured as a defense against spam harvesters. Standards track PEPs must have a Python-Version: header which indicates the version of Python that the feature will be released with. Informational PEPs do not need a Python-Version: header. While a PEP is in private discussions (usually during the initial Draft phase), a Discussions-To: header will indicate the mailing list or URL where the PEP is being discussed. No Discussions-To: header is necessary if the PEP is being discussed privately with the author, or on the python-list or python-dev email mailing lists. Note that email addresses in the Discussions-To: header will not be obscured. Created: records the date that the PEP was assigned a number, while Post-History: is used to record the dates of when new versions of the PEP are posted to python-list and/or python-dev. Both headers should be in dd-mmm-yyyy format, e.g. 14-Aug-2001. PEPs may have a Requires: header, indicating the PEP numbers that this PEP depends on. PEPs may also have a Replaced-By: header indicating that a PEP has been rendered obsolete by a later document; the value is the number of the PEP that replaces the current document. The newer PEP must have a Replaces: header containing the number of the PEP that it rendered obsolete. PEP Formatting Requirements PEP headings must begin in column zero and the initial letter of each word must be capitalized as in book titles. Acronyms should be in all capitals. The body of each section must be indented 4 spaces. Code samples inside body sections should be indented a further 4 spaces, and other indentation can be used as required to make the text readable. You must use two blank lines between the last line of a section's body and the next section heading. You must adhere to the Emacs convention of adding two spaces at the end of every sentence. You should fill your paragraphs to column 70, but under no circumstances should your lines extend past column 79. If your code samples spill over column 79, you should rewrite them. Tab characters must never appear in the document at all. A PEP should include the standard Emacs stanza included by example at the bottom of this PEP. A PEP must contain a Copyright section, and it is strongly recommended to put the PEP in the public domain. When referencing an external web page in the body of a PEP, you should include the title of the page in the text, with a footnote reference to the URL. Do not include the URL in the body text of the PEP. E.g. Refer to the Python Language web site [1] for more details. ... [1] http://www.python.org When referring to another PEP, include the PEP number in the body text, such as "PEP 1". The title may optionally appear. Add a footnote reference that includes the PEP's title and author. It may optionally include the explicit URL on a separate line, but only in the References section. Note that the pep2html.py script will calculate URLs automatically, e.g.: ... Refer to PEP 1 [7] for more information about PEP style ... References [7] PEP 1, PEP Purpose and Guidelines, Warsaw, Hylton http://www.python.org/peps/pep-0001.html If you decide to provide an explicit URL for a PEP, please use this as the URL template: http://www.python.org/peps/pep-xxxx.html PEP numbers in URLs must be padded with zeros from the left, so as to be exactly 4 characters wide, however PEP numbers in text are never padded. Reporting PEP Bugs, or Submitting PEP Updates How you report a bug, or submit a PEP update depends on several factors, such as the maturity of the PEP, the preferences of the PEP author, and the nature of your comments. For the early draft stages of the PEP, it's probably best to send your comments and changes directly to the PEP author. For more mature, or finished PEPs you may want to submit corrections to the SourceForge bug manager[6] or better yet, the SourceForge patch manager[2] so that your changes don't get lost. If the PEP author is a SF developer, assign the bug/patch to him, otherwise assign it to the PEP editor. When in doubt about where to send your changes, please check first with the PEP author and/or PEP editor. PEP authors who are also SF committers, can update the PEPs themselves by using "cvs commit" to commit their changes. Remember to also push the formatted PEP text out to the web by doing the following: % python pep2html.py -i NUM where NUM is the number of the PEP you want to push out. See % python pep2html.py --help for details. Transferring PEP Ownership It occasionally becomes necessary to transfer ownership of PEPs to a new champion. In general, we'd like to retain the original author as a co-author of the transferred PEP, but that's really up to the original author. A good reason to transfer ownership is because the original author no longer has the time or interest in updating it or following through with the PEP process, or has fallen off the face of the 'net (i.e. is unreachable or not responding to email). A bad reason to transfer ownership is because you don't agree with the direction of the PEP. We try to build consensus around a PEP, but if that's not possible, you can always submit a competing PEP. If you are interested assuming ownership of a PEP, send a message asking to take over, addressed to both the original author and the PEP editor <peps(a)python.org>. If the original author doesn't respond to email in a timely manner, the PEP editor will make a unilateral decision (it's not like such decisions can be reversed. :). References and Footnotes [1] This historical record is available by the normal CVS commands for retrieving older revisions. For those without direct access to the CVS tree, you can browse the current and past PEP revisions via the SourceForge web site at http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi/python/nondist/peps/?cvsroot=… [2] http://sourceforge.net/tracker/?group_id=5470&atid=305470 [3] http://sourceforge.net/tracker/?atid=355470&group_id=5470&func=browse [4] http://www.opencontent.org/openpub/ [5] The script referred to here is pep2html.py, which lives in the same directory in the CVS tree as the PEPs themselves. Try "pep2html.py --help" for details. The URL for viewing PEPs on the web is http://www.python.org/peps/ [6] http://sourceforge.net/tracker/?group_id=5470&atid=305470 [7] PEP 9, Sample PEP Template http://www.python.org/peps/pep-0009.html Copyright This document has been placed in the public domain. Local Variables: mode: indented-text indent-tabs-mode: nil sentence-end-double-space: t fill-column: 70 End:

8 14

Using FutureWarning for last version before deletion.
by Inada Naoki May 16, 2021

May 16, 2021

Hi, folks. Now Python 3.11 development is open and I am removing some deprecated stuffs carefully. I am considering `configparser.ParseError.filename` property that is deprecated since Python 3.2. https://github.com/python/cpython/blob/8e8307d70bb9dc18cfeeed3277c076309b27… My random thoughts about it: * It has been deprecated long enough. * But the maintenance burden is low enough. * If we don't remove long deprecated stuff like this, Python 4.0 will be a big breaking change. My proposal: * Change DeprecationWarning to FutureWarning and wait one more version. * DeprecationWarning is suppressed by default to hide noise from end users. * But sudden breaking change is more annoying to end users. I am not proposing to change PEP 387 "Backwards Compatibility Policy". This is just a new convention. Another idea: * Stop suppressing DeprecationWarning by default * Use at least one PendingDeprecationWarning and one DeprecationWarning. * More than two PendingDeprecationWarning periods is preferred. How do you think? -- Inada Naoki <songofacandy(a)gmail.com>

4 5

Re: The repr of a sentinel
by Eric Nieuwland May 15, 2021

May 15, 2021

To add to the suggestions already given in this thread I dug into code I wrote some time ago. Offered as an inspiration. === missing.py === from typing import Any def MISSING(klass: Any) -> Any: """ create a sentinel to indicate a missing instance of a class :param klass: the class of which an instance is missing :return: missing class object """ g = globals() missing_klass_name = f"_MISSING_{klass.__module__}_{klass.__name__}_MISSING_" if missing_klass_name not in g: g[missing_klass_name] = type( missing_klass_name, (klass,), { "__repr__": lambda x: f"MISSING({klass.__name__})", } ) return g[missing_klass_name]() === and as a demo: === demo_missing.py === import pickle from missing import MISSING x = MISSING(str) y = "bar" print(f"{x!r} == {y!r}: {x == y}") print(f"{x!r} is {y!r}: {x is y}") # MISSING(str) == 'bar': False # MISSING(str) is 'bar': False with open("object.pickled", "wb") as f: pickle.dump(x, f) with open("object.pickled", "rb") as f: y = pickle.load(f) print(f"{x!r} == {y!r}: {x == y}") print(f"{x!r} is {y!r}: {x is y}") # MISSING(str) == MISSING(str): True # MISSING(str) is MISSING(str): False def foo(a: int = MISSING(int), b: int = MISSING(int)): print(f"{a=} {isinstance(a, int)}") print(f"{b=} {isinstance(b, int)}") print(f"{a!r} == {b!r}: {a == b}") print(f"{a!r} is {b!r}: {a is b}") foo() # a=MISSING(int) True # b=MISSING(int) True # MISSING(int) == MISSING(int): True # MISSING(int) is MISSING(int): False foo(1) # a=1 True # b=MISSING(int) True # 1 == MISSING(int): False # 1 is MISSING(int): False class Test: ... t = MISSING(Test) print(f"{t=}") # t=MISSING(Test) ===

1 0

Summary of Python tracker Issues
by Python tracker May 14, 2021

May 14, 2021

ACTIVITY SUMMARY (2021-05-07 - 2021-05-14) 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 7429 ( +1) closed 48441 (+64) total 55870 (+65) Open issues with patches: 2949 Issues opened (41) ================== #41730: Show deprecation warnings for tkinter.tix https://bugs.python.org/issue41730 reopened by pablogsal #44072: Doc: power operator (`**`) present for numbers.Complex, not ad https://bugs.python.org/issue44072 opened by roryyorke #44073: [sqlite3] drop statement in_use field in favour of sqlite3_stm https://bugs.python.org/issue44073 opened by erlendaasland #44075: Add a PEP578 audit hook for Asyncio loop stalls https://bugs.python.org/issue44075 opened by orf #44077: IP_RECVTOS option is missing from socket module https://bugs.python.org/issue44077 opened by gms #44078: Output relative path when using PurePath.relative_to https://bugs.python.org/issue44078 opened by mhammondr #44079: [sqlite3] remove superfluous statement weak ref list from conn https://bugs.python.org/issue44079 opened by erlendaasland #44081: ast.unparse: dont use redundant space separator for lambdas wi https://bugs.python.org/issue44081 opened by BTaskaya #44082: Add a method to check interpolation errors in configparser https://bugs.python.org/issue44082 opened by munircontractor #44085: Remaining invalid rules in simplified grammar https://bugs.python.org/issue44085 opened by quentel #44086: py.svg not found on search result page https://bugs.python.org/issue44086 opened by jugmac00 #44087: [sqlite3] consider adding Py_TPFLAGS_DISALLOW_INSTANTIATION to https://bugs.python.org/issue44087 opened by erlendaasland #44090: Add class binding to unbound super objects for allowing autosu https://bugs.python.org/issue44090 opened by maggyero #44091: traceback & inspect modules should verify that the .py source https://bugs.python.org/issue44091 opened by gregory.p.smith #44092: [sqlite3] consider removing special rollback handling https://bugs.python.org/issue44092 opened by erlendaasland #44093: compiler detection on macOS seems to be incorrect https://bugs.python.org/issue44093 opened by xrisk #44096: Bad clang detection in configure script https://bugs.python.org/issue44096 opened by xrisk #44097: add configure option to control the groups of .pyc files to in https://bugs.python.org/issue44097 opened by pxinwr #44099: [c-api] Introduce a new slot in PyModuleDef to hold the classe https://bugs.python.org/issue44099 opened by shreyanavigyan #44100: test__xxsubinterpreters: test_one() fails in AMD64 Fedora Stab https://bugs.python.org/issue44100 opened by pablogsal #44101: Generation of an executable's library file when python is buil https://bugs.python.org/issue44101 opened by lakor64 #44102: mock_open does not support the use of 'seek()' https://bugs.python.org/issue44102 opened by nikle #44105: tempfile.TemporaryDirectory deleted after sleep in threads https://bugs.python.org/issue44105 opened by colas.le.guernic #44106: [sqlite3] don't use politicians in examples/docs https://bugs.python.org/issue44106 opened by erlendaasland #44107: HTTPServer can't close http client completely https://bugs.python.org/issue44107 opened by ueJone #44109: missing dataclass decorator in match-statement example https://bugs.python.org/issue44109 opened by ahmetveburak #44110: Improve string's __getitem__ error message https://bugs.python.org/issue44110 opened by miguendes #44112: [buildbot] test_asyncio hangs (killed after 3 hours) on Reflea https://bugs.python.org/issue44112 opened by vstinner #44115: Improve conversions for fractions https://bugs.python.org/issue44115 opened by Martin.Teichmann #44117: [C API] Remove deprecated PyEval_InitThreads() https://bugs.python.org/issue44117 opened by vstinner #44120: logging.config.fileConfig/dictConfig can not import class https://bugs.python.org/issue44120 opened by akihiro #44121: Missing implementation for formatHeader and formatFooter metho https://bugs.python.org/issue44121 opened by Harmouch101 #44123: make function parameter sentinel value true singletons https://bugs.python.org/issue44123 opened by taleinat #44124: Unhelpful error messages with mis-ordering of f-string specifi https://bugs.python.org/issue44124 opened by angus-lherrou #44127: urllib.parse.ParseResult._replace() does not allow replacing u https://bugs.python.org/issue44127 opened by AstraLuma #44128: zipfile: Deduplicate ZipExtFile code for init and resetting wh https://bugs.python.org/issue44128 opened by dhillier #44129: zipfile: Add descriptive global variables for general purpose https://bugs.python.org/issue44129 opened by dhillier #44131: [C API] Add tests on Py_FrozenMain() https://bugs.python.org/issue44131 opened by vstinner #44132: Local import conflict with system import https://bugs.python.org/issue44132 opened by otrejoso #44133: "Py_FrozenMain" symbol is not exported https://bugs.python.org/issue44133 opened by vstinner #44134: lzma: stream padding in xz files https://bugs.python.org/issue44134 opened by rogdham Most recent 15 issues with no replies (15) ========================================== #44134: lzma: stream padding in xz files https://bugs.python.org/issue44134 #44132: Local import conflict with system import https://bugs.python.org/issue44132 #44131: [C API] Add tests on Py_FrozenMain() https://bugs.python.org/issue44131 #44129: zipfile: Add descriptive global variables for general purpose https://bugs.python.org/issue44129 #44128: zipfile: Deduplicate ZipExtFile code for init and resetting wh https://bugs.python.org/issue44128 #44127: urllib.parse.ParseResult._replace() does not allow replacing u https://bugs.python.org/issue44127 #44121: Missing implementation for formatHeader and formatFooter metho https://bugs.python.org/issue44121 #44120: logging.config.fileConfig/dictConfig can not import class https://bugs.python.org/issue44120 #44110: Improve string's __getitem__ error message https://bugs.python.org/issue44110 #44101: Generation of an executable's library file when python is buil https://bugs.python.org/issue44101 #44099: [c-api] Introduce a new slot in PyModuleDef to hold the classe https://bugs.python.org/issue44099 #44093: compiler detection on macOS seems to be incorrect https://bugs.python.org/issue44093 #44091: traceback & inspect modules should verify that the .py source https://bugs.python.org/issue44091 #44087: [sqlite3] consider adding Py_TPFLAGS_DISALLOW_INSTANTIATION to https://bugs.python.org/issue44087 #44086: py.svg not found on search result page https://bugs.python.org/issue44086 Most recent 15 issues waiting for review (15) ============================================= #44133: "Py_FrozenMain" symbol is not exported https://bugs.python.org/issue44133 #44131: [C API] Add tests on Py_FrozenMain() https://bugs.python.org/issue44131 #44129: zipfile: Add descriptive global variables for general purpose https://bugs.python.org/issue44129 #44128: zipfile: Deduplicate ZipExtFile code for init and resetting wh https://bugs.python.org/issue44128 #44121: Missing implementation for formatHeader and formatFooter metho https://bugs.python.org/issue44121 #44117: [C API] Remove deprecated PyEval_InitThreads() https://bugs.python.org/issue44117 #44115: Improve conversions for fractions https://bugs.python.org/issue44115 #44110: Improve string's __getitem__ error message https://bugs.python.org/issue44110 #44106: [sqlite3] don't use politicians in examples/docs https://bugs.python.org/issue44106 #44101: Generation of an executable's library file when python is buil https://bugs.python.org/issue44101 #44092: [sqlite3] consider removing special rollback handling https://bugs.python.org/issue44092 #44090: Add class binding to unbound super objects for allowing autosu https://bugs.python.org/issue44090 #44082: Add a method to check interpolation errors in configparser https://bugs.python.org/issue44082 #44081: ast.unparse: dont use redundant space separator for lambdas wi https://bugs.python.org/issue44081 #44079: [sqlite3] remove superfluous statement weak ref list from conn https://bugs.python.org/issue44079 Top 10 most discussed issues (10) ================================= #40222: "Zero cost" exception handling https://bugs.python.org/issue40222 16 msgs #43760: The DISPATCH() macro is not as efficient as it could be (move https://bugs.python.org/issue43760 14 msgs #44123: make function parameter sentinel value true singletons https://bugs.python.org/issue44123 11 msgs #43350: [sqlite3] Active statements are reset twice in _pysqlite_query https://bugs.python.org/issue43350 8 msgs #43804: "Building C and C++ Extensions on Windows" docs are very out-o https://bugs.python.org/issue43804 8 msgs #44045: canonicalize "upper-case" -> "uppercase"; "lower-case" -> "low https://bugs.python.org/issue44045 7 msgs #40938: urllib.parse.urlunsplit makes relative path to absolute (http: https://bugs.python.org/issue40938 6 msgs #42109: Use hypothesis for testing the standard library, falling back https://bugs.python.org/issue42109 5 msgs #43882: [security] urllib.parse should sanitize urls containing ASCII https://bugs.python.org/issue43882 5 msgs #37658: In some cases asyncio.wait_for can lead to socket leak. https://bugs.python.org/issue37658 4 msgs Issues closed (61) ================== #1662: [patch] assert tp_traverse in PyType_GenericAlloc() https://bugs.python.org/issue1662 closed by iritkatriel #10548: document (lack of) interaction between @expectedFailure on a t https://bugs.python.org/issue10548 closed by iritkatriel #13657: IDLE doesn't recognize resetting sys.ps1. https://bugs.python.org/issue13657 closed by terry.reedy #16866: libainstall doesn't create $(BINDIR) directory https://bugs.python.org/issue16866 closed by orsenthil #21381: Python 3.4+ interpreter built on/with OS X 10.7 deployment tar https://bugs.python.org/issue21381 closed by ned.deily #22953: Windows installer configures system PATH also when installing https://bugs.python.org/issue22953 closed by iritkatriel #23750: doc: Clarify difference between os.system/subprocess.call in s https://bugs.python.org/issue23750 closed by orsenthil #24871: freeze.py doesn't work on x86_64 Linux out of the box https://bugs.python.org/issue24871 closed by vstinner #25479: Increase unit test coverage for abc.py https://bugs.python.org/issue25479 closed by iritkatriel #25821: Documentation for threading.enumerate / threading.Thread.is_al https://bugs.python.org/issue25821 closed by iritkatriel #28146: Confusing error messages in str.format() https://bugs.python.org/issue28146 closed by pitrou #28528: Pdb.checkline() attribute error when 'curframe' is None https://bugs.python.org/issue28528 closed by iritkatriel #31604: unittest.TestLoader().loadTestsFromTestCase(...) fails when ad https://bugs.python.org/issue31604 closed by iritkatriel #32725: Instance of _multiprocessing.PipeConnection-subtype crash on d https://bugs.python.org/issue32725 closed by iritkatriel #34367: AsyncResult.get() only notifies one thread https://bugs.python.org/issue34367 closed by iritkatriel #35663: webbrowser.py firefox bug [python3, windows 10] https://bugs.python.org/issue35663 closed by gregory.p.smith #37891: Exceptions tutorial page does not mention raise from https://bugs.python.org/issue37891 closed by rhettinger #38552: Colored Prompt broken in REPL in Windows in 3.8 https://bugs.python.org/issue38552 closed by MinchinWeb #38908: Troubles with @runtime_checkable protocols https://bugs.python.org/issue38908 closed by kj #39228: traceback.FrameSummary does not handle exceptions from `repr() https://bugs.python.org/issue39228 closed by iritkatriel #40640: Tutorial for Continue missing ... line https://bugs.python.org/issue40640 closed by iritkatriel #42725: PEP 563: Should the behavior change for yield/yield from's https://bugs.python.org/issue42725 closed by BTaskaya #43389: Cancellation ignored by asyncio.wait_for can hang application https://bugs.python.org/issue43389 closed by nmatravolgyi #43417: ast.unparse: Simplify buffering logic https://bugs.python.org/issue43417 closed by BTaskaya #43558: The dataclasses documentation should mention how to call super https://bugs.python.org/issue43558 closed by eric.smith #43656: StackSummary.format fails if repr(value) fails https://bugs.python.org/issue43656 closed by iritkatriel #43992: Unable to get external dependencies for CPython on Ubuntu Linu https://bugs.python.org/issue43992 closed by ned.deily #44002: Use functools.lru_cache in urllib.parse instead of 1996 custom https://bugs.python.org/issue44002 closed by gregory.p.smith #44026: IDLE: print "Did you mean?" for AttributeError and NameError https://bugs.python.org/issue44026 closed by terry.reedy #44030: Markup with_traceback code example https://bugs.python.org/issue44030 closed by iritkatriel #44057: Inconsitencies in `__init_subclass__` in a generic class https://bugs.python.org/issue44057 closed by kj #44061: Regression in pkgutil: iter_modules stopped taking Path argume https://bugs.python.org/issue44061 closed by steve.dower #44063: compiler: does not revert back the end_* locations https://bugs.python.org/issue44063 closed by BTaskaya #44066: Conflicts while using Py_LIMITED_API https://bugs.python.org/issue44066 closed by erlendaasland #44068: Possible divide by zero problems https://bugs.python.org/issue44068 closed by vstinner #44070: __file__ is now fully qualified in 3.8 and 3.9 https://bugs.python.org/issue44070 closed by steve.dower #44071: Syntax error in Python3 documentation https://bugs.python.org/issue44071 closed by evolvah #44074: patchcheck checks against branch "master" not "main" https://bugs.python.org/issue44074 closed by pablogsal #44076: issue with list in Python 3.8.5 https://bugs.python.org/issue44076 closed by zach.ware #44080: Bias in random.choices(long_sequence) https://bugs.python.org/issue44080 closed by rhettinger #44083: problem with updated 3.9.5 https://bugs.python.org/issue44083 closed by eric.smith #44084: Can't mark match, case, _ as keywords in docs https://bugs.python.org/issue44084 closed by taleinat #44088: traced line number can be None https://bugs.python.org/issue44088 closed by Mark.Shannon #44089: csv.Error can't be subclassed https://bugs.python.org/issue44089 closed by orsenthil #44094: Remove PyErr_Set...WithUnicodeFilename APIs https://bugs.python.org/issue44094 closed by pitrou #44095: Add suffix property to zipfile.Path https://bugs.python.org/issue44095 closed by jaraco #44098: Remove ParamSpec from __parameters__ of most typing generics https://bugs.python.org/issue44098 closed by kj #44103: Python 3.10 docs are visually broken https://bugs.python.org/issue44103 closed by zach.ware #44104: http.cookies.CookieError: Illegal key https://bugs.python.org/issue44104 closed by ra1nb0w #44108: [sqlite3] normalise SQL quoted literals in sqlite3 test suite https://bugs.python.org/issue44108 closed by corona10 #44111: 404 link on python webpage https://bugs.python.org/issue44111 closed by christian.heimes #44113: [C API] Deprecate legacy API for configure Python initializati https://bugs.python.org/issue44113 closed by vstinner #44114: Incorrect function signatures in dictobject.c https://bugs.python.org/issue44114 closed by pitrou #44116: The _csv module can't be garbage-collected after _csv.register https://bugs.python.org/issue44116 closed by pablogsal #44118: cython compiler error https://bugs.python.org/issue44118 closed by mlucool #44119: Use glob.glob() to implement pathlib.Path.glob() https://bugs.python.org/issue44119 closed by barneygale #44122: let linter allow defining attribute outside __init__ if called https://bugs.python.org/issue44122 closed by lys.nikolaou #44125: "make patchcheck" fails https://bugs.python.org/issue44125 closed by pitrou #44126: Cross Compile Cython Modules https://bugs.python.org/issue44126 closed by ned.deily #44130: GIL Improvement https://bugs.python.org/issue44130 closed by shreyanavigyan #1606233: readline on popen3 file returns empty string before end https://bugs.python.org/issue1606233 closed by iritkatriel

1 0

Future PEP: Include Fine Grained Error Locations in Tracebacks
by Pablo Galindo Salgado May 13, 2021

May 13, 2021

Hi there, We are preparing a PEP and we would like to start some early discussion about one of the main aspects of the PEP. The work we are preparing is to allow the interpreter to produce more fine-grained error messages, pointing to the source associated to the instructions that are failing. For example: Traceback (most recent call last): File "test.py", line 14, in <module> lel3(x) ^^^^^^^ File "test.py", line 12, in lel3 return lel2(x) / 23 ^^^^^^^ File "test.py", line 9, in lel2 return 25 + lel(x) + lel(x) ^^^^^^ File "test.py", line 6, in lel return 1 + foo(a,b,c=x['z']['x']['y']['z']['y'], d=e) ^^^^^^^^^^^^^^^^^^^^^ TypeError: 'NoneType' object is not subscriptable The cost of this is having the start column number and end column number information for every bytecode instruction and this is what we want to discuss (there is also some stack cost to re-raise exceptions but that's not a big problem in any case). Given that column numbers are not very big compared with line numbers, we plan to store these as unsigned chars or unsigned shorts. We ran some experiments over the standard library and we found that the overhead of all pyc files is: * If we use shorts, the total overhead is ~3% (total size 28MB and the extra size is 0.88 MB). * If we use chars. the total overhead is ~1.5% (total size 28 MB and the extra size is 0.44MB). One of the disadvantages of using chars is that we can only report columns from 1 to 255 so if an error happens in a column bigger than that then we would have to exclude it (and not show the highlighting) for that frame. Unsigned short will allow the values to go from 0 to 65535. Unfortunately these numbers are not easily compressible, as every instruction would have very different offsets. There is also the possibility of not doing this based on some build flag on when using -O to allow users to opt out, but given the fact that these numbers can be quite useful to other tools like coverage measuring tools, tracers, profilers and the such adding conditional logic to many places would complicate the implementation considerably and will potentially reduce the usability of those tools so we prefer not to have the conditional logic. We believe this is extra cost is very much worth the better error reporting but we understand and respect other points of view. Does anyone see a better way to encode this information **without complicating a lot the implementation**? What are people thoughts on the feature? Thanks in advance, Regards from cloudy London, Pablo Galindo Salgado

26 69

Necessary or not for enhancement of issue44097: “add configure option to control the groups of .pyc files to install”
by Xin, Peixing May 12, 2021

May 12, 2021

Hi , I created issue44097 for build enhancement: “add configure option to control the groups of .pyc files to install” and PR 23920 for the solution. From the only a few of comments I’ve got, someone thinks this enhancement makes sense. However, someone expressed opposition to this. So what is your opinion on this PR? Necessary or not? I want to hear more views on this. Thanks. https://bugs.python.org/issue44097 https://github.com/python/cpython/pull/23920 Thanks, Peixing

2 2

Important: Python3.10 what's new
by Pablo Galindo Salgado May 10, 2021

May 10, 2021

Hi everyone, Now that we are in the beta period for 3.10 is very important that we make sure that all improvements, new APIs and deprecations are reflected in the 3.10 what's New document. IMPORTANT!! If you have worked on: * Make a PEP that affects Python 3.10. * A new feature/class/function/argument/option... * Deprecating something. * Remove something. * Improve something important. Please, make sure is reflected on the What's new document for Python 3.10. Users normally don't read the changelog directly and learn about what's available from the What's New document so you *absolutely* want your work to be reflected there. *Small* tutorials and small code samples and descriptions are a fantastic thing to add as well. Specially for deprecations and removals, this is our public window to the world so that learn what's coming or how to port code to Python 3.10. Thanks for helping to make Python3.10 a great release. Regards from sunny London, Pablo Galindo Salgado

1 0

The importance of mental health
by Kyle Stanley May 10, 2021

May 10, 2021

Hey all, In these last few months, I have been in the process of healing from some pretty heavy past trauma. And now that I am on the road to recovery, I want to share my journey with the Python community in hopes that it may reach those that are struggling with their own mental health battles, as many of us are during these dark and difficult times. Trigger warning that it includes a decent amount of highly personal content, so only check it out if you are okay with that: https://discuss.python.org/t/break-from-open-source/6372/7?u=aeros. To anyone that would limit my employment opportunities as a result of having had these struggles, *that's perfectly okay*. I kept the post in the private section because I was originally in fear of discriminate. However, I have reached an important conclusion: *I would not want to work for your company if you discriminate against people who have overcome past struggles* . -- --Kyle R. Stanley, Python Core Developer (what is a core dev? <https://devguide.python.org/coredev/>) *Pronouns: they/them **(why is my pronoun here?* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-…> )

2 1

a name for the ExceptHandler.type when it is a literal tuple of types
by Thomas Grainger May 10, 2021

May 10, 2021

That's this bit: ``` except (A, B): ^^^^^^ ``` bpo-43149 currently calls it an "exception group", but that conflicts with PEP 654 -- Exception Groups and except* ``` >>> try: ... pass ... except A, B: ... pass Traceback (most recent call last): SyntaxError: exception group must be parenthesized ``` some alternatives: exception classinfo must be parenthesized (classinfo so named from the parameter to issubclass) exception sequence must be parenthesized see also: - https://github.com/python/cpython/pull/24467#discussion_r628756347 - https://www.python.org/dev/peps/pep-0654/

3 6

On the migration from master to main
by Python Steering Council May 10, 2021

May 10, 2021

From Thomas Wouters, on behalf of and with full support of the Python Steering Council: This discussion seems to have died down a little, but I still want to make a few things clear: Yes, this is a political decision. Very many decisions are political. The existence of an open-source project is inherently political. The decision to try and make python-dev more welcoming, more open, more helpful is also a political decision -- one that the SC feels is absolutely necessary for the long-term health of the Python language. Not wanting to be bothered by political decisions is a political decision; it’s a decision that you’re happy with politics as they are. I’m afraid you can’t avoid politics. This isn’t just about ‘master’ being rooted in slavery. This is about what the community sees and does. As I mentioned before, we’re not leading the pack in this, we’re merely following along with others (like, say, Django). There are undoubtedly other terms and practices that are genuinely offensive, and the decision on how to handle them will be taken on a case-by-case basis, weighing the cost and the benefit in each case. While you may feel the benefit of this change is small and that it has no real impact, we believe that there is little cost to making this change. We believe this change, while a minor inconvenience to some, helps demonstrate our commitment to acting in the best interests of Python's future. Failure to make a small sacrifice, such as this, signals that the Python core development community would be unlikely to undertake real change for greater benefits. This isn’t happening because GitHub/Microsoft made a political decision. It’s happening because it is incredibly easy to make this move, many projects have already done this, and it reflects badly on any project not making this change. Speaking for the whole SC in this, Thomas.

14 15

Release of a responsive python-docs-theme 2021.5
by Carol Willing May 9, 2021

May 9, 2021

It’s with great pleasure that I announce that python-docs-theme has been released to PyPI. Thanks to the hard work and patience of Olga Bulat, @obulat, Python’s doc theme is now responsive. Many thanks to everyone who has contributed to this release by filing issues, writing PRs, reviewing PRs, and testing the theme. It was a great team effort. Here are the highlights from the CHANGELOG.rst: - Make the theme responsive (#46) Contributed by Olga Bulat. - Use Python 3.8 for the Github Actions (#71) Contributed by Stéphane Wirtel. - Use default pygments theme (#68) Contributed by Aaron Carlisle. - Test Github action to validate the theme against docsbuild scripts. (#69) Contributed by Julien Palard. - Add the copy button to pycon3 highlighted code blocks. (#64) Contributed by Julien Palard.

3 2

PEP 657 – Include Fine Grained Error Locations in Tracebacks
by Pablo Galindo Salgado May 9, 2021

May 9, 2021

Hi, We have prepared a PEP with our proposal for fine-grained error locations in tracebacks. You can find the PEP here: https://www.python.org/dev/peps/pep-0657/ The discussion is happening in the discourse server: https://discuss.python.org/t/pep-657-include-fine-grained-error-locations-i… To avoid splitting the discussion, *please redirect your comments there* instead of replying to this thread. Thanks! Regards from sunny London, Pablo Galindo Salgado

1 0

Can't sync cpython main to my fork
by Skip Montanaro May 8, 2021

May 8, 2021

(Sorry, this is probably not really python-dev material, but I'm stuck trying to bring my fork into sync with python/cpython.) I don't know if I did something to my fork or if the master->main change did something to me, but I am unable to sync my smontanaro/cpython main with the python/cpython main. The dev guide gives this simple recipe: git checkout main git pull upstream main git push origin main Here's how that goes: (python39) rvm% git co main Already on 'main' Your branch is up to date with 'upstream/main'. (python39) rvm% git pull upstream main From git://github.com/python/cpython * branch main -> FETCH_HEAD Already up to date. (python39) rvm% git push origin main To github.com:smontanaro/cpython.git ! [rejected] main -> main (non-fast-forward) error: failed to push some refs to 'github.com:smontanaro/cpython.git' hint: Updates were rejected because the tip of your current branch is behind hint: its remote counterpart. Integrate the remote changes (e.g. hint: 'git pull ...') before pushing again. hint: See the 'Note about fast-forwards' in 'git push --help' for details. I looked at the fast-forward stuff in 'git push --help' but couldn't decipher what it told me, or more importantly, how it related to my problem. It's not clear to me how python/cpython:main can be behind smontanaro/cpython:main. I've attached my .git/config file in case that provides clues to the Git aficionados. Thx... Skip

8 10

Summary of Python tracker Issues
by Python tracker May 7, 2021

May 7, 2021

ACTIVITY SUMMARY (2021-04-30 - 2021-05-07) 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 7428 (-25) closed 48377 (+104) total 55805 (+79) Open issues with patches: 2946 Issues opened (48) ================== #40943: PEP 353: Drop support for PyArg_ParseTuple() "#" formats when https://bugs.python.org/issue40943 reopened by methane #43001: python3.8.9, python3.9.2 test_embed test_tabnanny failed https://bugs.python.org/issue43001 reopened by asholomitskiy84 #43176: Dataclasses derived from empty frozen bases skip immutability https://bugs.python.org/issue43176 reopened by eric.smith #43882: [security] urllib.parse should sanitize urls containing ASCII https://bugs.python.org/issue43882 reopened by gregory.p.smith #43992: Unable to get external dependencies for CPython on Ubuntu Linu https://bugs.python.org/issue43992 opened by shreyanavigyan #43994: change representation of match as / capture as `Name(..., ctx= https://bugs.python.org/issue43994 opened by Anthony Sottile #44002: Use functools.lru_cache in urllib.parse instead of 1996 custom https://bugs.python.org/issue44002 opened by gregory.p.smith #44005: multiple socket bind failure on Mac OS X with SO_REUSEADDR https://bugs.python.org/issue44005 opened by giangipy #44010: IDLE: highlight soft keywords https://bugs.python.org/issue44010 opened by epaine #44011: Borrow asyncio ssl implementation from uvloop https://bugs.python.org/issue44011 opened by asvetlov #44012: IPv6Address.exploded does not support interface name (scope id https://bugs.python.org/issue44012 opened by ohwgiles #44013: tempfile.TemporaryFile: name of file descriptor cannot be reus https://bugs.python.org/issue44013 opened by zhongxiang117 #44016: Enum related deprecation warnings in test_httpservers and test https://bugs.python.org/issue44016 opened by xtreak #44019: operator.call/operator.__call__ https://bugs.python.org/issue44019 opened by Antony.Lee #44021: enum docs in 3.10: missing "New in version 3.10" https://bugs.python.org/issue44021 opened by Akuli #44023: "tarfile" library will lead to "write any content to any file https://bugs.python.org/issue44023 opened by leveryd #44024: Improve the TypeError message for non-string second arguments https://bugs.python.org/issue44024 opened by maggyero #44025: Match doc: Clarify '_' as a soft keyword https://bugs.python.org/issue44025 opened by terry.reedy #44026: IDLE: print "Did you mean?" for AttributeError and NameError https://bugs.python.org/issue44026 opened by Dennis Sweeney #44028: Request for locals().update() to work, it is https://bugs.python.org/issue44028 opened by xuancong84 #44030: Markup with_traceback code example https://bugs.python.org/issue44030 opened by terry.reedy #44031: python3.8.9, python3.9.2 test_embed test_tabnanny failed https://bugs.python.org/issue44031 opened by asholomitskiy84 #44032: Function locals and evaluation stack should be stored in a con https://bugs.python.org/issue44032 opened by Mark.Shannon #44035: Regenerating the configure script fails even if dependencies a https://bugs.python.org/issue44035 opened by pablogsal #44036: asyncio SSL server can be DOSed, event loop gets blocked: busy https://bugs.python.org/issue44036 opened by ghost43 #44037: Broad performance regression from 3.10a7 to 3.10b1 with python https://bugs.python.org/issue44037 opened by rhettinger #44038: In documentation Section 8.6, the definition of parameter_list https://bugs.python.org/issue44038 opened by webbnh #44041: [sqlite3] optimisation: only call sqlite3_column_count when ne https://bugs.python.org/issue44041 opened by erlendaasland #44042: [sqlite3] _pysqlite_connection_begin() optimisations https://bugs.python.org/issue44042 opened by erlendaasland #44043: 3.10 b1 armhf Bus Error in hashlib test: test_gil https://bugs.python.org/issue44043 opened by Anthony Sottile #44044: ConfigParser: cannot link to ConfigParser.optionxform(option) https://bugs.python.org/issue44044 opened by jugmac00 #44045: canonicalize "upper-case" -> "uppercase"; "lower-case" -> "low https://bugs.python.org/issue44045 opened by jugmac00 #44048: test_hashlib failure for "AMD64 RHEL8 FIPS Only Blake2 Builtin https://bugs.python.org/issue44048 opened by cstratak #44050: Exceptions in a subinterpreter are changed by another subinter https://bugs.python.org/issue44050 opened by trygveaa #44052: patch object as argument should be explicit https://bugs.python.org/issue44052 opened by CendioOssman #44053: Can't connect to a server also not showing any type of output https://bugs.python.org/issue44053 opened by muqadasrasheed652 #44055: NamedTemporaryFile opened twice on Windows https://bugs.python.org/issue44055 opened by frenzy #44057: Inconsitencies in `__init_subclass__` in a generic class https://bugs.python.org/issue44057 opened by erezinman #44058: 'master' refs in 3.10 version of .azure-pipelines https://bugs.python.org/issue44058 opened by skip.montanaro #44060: Define TARGET macro the same even when computed goto support i https://bugs.python.org/issue44060 opened by skip.montanaro #44061: Regression in pkgutil: iter_modules stopped taking Path argume https://bugs.python.org/issue44061 opened by rikard.nordgren #44062: cross: wrong interpreter returned when no python available https://bugs.python.org/issue44062 opened by vfazio #44063: compiler: does not revert back the end_* locations https://bugs.python.org/issue44063 opened by BTaskaya #44065: "configure: error: internal configure error for the platform t https://bugs.python.org/issue44065 opened by sberg #44066: Conflicts while using Py_LIMITED_API https://bugs.python.org/issue44066 opened by shreyanavigyan #44067: Zipfile lib overwrites the extra field during closing when the https://bugs.python.org/issue44067 opened by shaanbhaya #44068: Possible divide by zero problems https://bugs.python.org/issue44068 opened by yiyuaner #44069: pathlib.Path.glob's generator is not a real generator https://bugs.python.org/issue44069 opened by Elijah Rippeth Most recent 15 issues with no replies (15) ========================================== #44069: pathlib.Path.glob's generator is not a real generator https://bugs.python.org/issue44069 #44063: compiler: does not revert back the end_* locations https://bugs.python.org/issue44063 #44062: cross: wrong interpreter returned when no python available https://bugs.python.org/issue44062 #44060: Define TARGET macro the same even when computed goto support i https://bugs.python.org/issue44060 #44058: 'master' refs in 3.10 version of .azure-pipelines https://bugs.python.org/issue44058 #44053: Can't connect to a server also not showing any type of output https://bugs.python.org/issue44053 #44042: [sqlite3] _pysqlite_connection_begin() optimisations https://bugs.python.org/issue44042 #44041: [sqlite3] optimisation: only call sqlite3_column_count when ne https://bugs.python.org/issue44041 #44038: In documentation Section 8.6, the definition of parameter_list https://bugs.python.org/issue44038 #44036: asyncio SSL server can be DOSed, event loop gets blocked: busy https://bugs.python.org/issue44036 #44032: Function locals and evaluation stack should be stored in a con https://bugs.python.org/issue44032 #44024: Improve the TypeError message for non-string second arguments https://bugs.python.org/issue44024 #44023: "tarfile" library will lead to "write any content to any file https://bugs.python.org/issue44023 #44019: operator.call/operator.__call__ https://bugs.python.org/issue44019 #44013: tempfile.TemporaryFile: name of file descriptor cannot be reus https://bugs.python.org/issue44013 Most recent 15 issues waiting for review (15) ============================================= #44063: compiler: does not revert back the end_* locations https://bugs.python.org/issue44063 #44062: cross: wrong interpreter returned when no python available https://bugs.python.org/issue44062 #44061: Regression in pkgutil: iter_modules stopped taking Path argume https://bugs.python.org/issue44061 #44060: Define TARGET macro the same even when computed goto support i https://bugs.python.org/issue44060 #44042: [sqlite3] _pysqlite_connection_begin() optimisations https://bugs.python.org/issue44042 #44041: [sqlite3] optimisation: only call sqlite3_column_count when ne https://bugs.python.org/issue44041 #44030: Markup with_traceback code example https://bugs.python.org/issue44030 #44026: IDLE: print "Did you mean?" for AttributeError and NameError https://bugs.python.org/issue44026 #44025: Match doc: Clarify '_' as a soft keyword https://bugs.python.org/issue44025 #44024: Improve the TypeError message for non-string second arguments https://bugs.python.org/issue44024 #44016: Enum related deprecation warnings in test_httpservers and test https://bugs.python.org/issue44016 #44012: IPv6Address.exploded does not support interface name (scope id https://bugs.python.org/issue44012 #44011: Borrow asyncio ssl implementation from uvloop https://bugs.python.org/issue44011 #44010: IDLE: highlight soft keywords https://bugs.python.org/issue44010 #44002: Use functools.lru_cache in urllib.parse instead of 1996 custom https://bugs.python.org/issue44002 Top 10 most discussed issues (10) ================================= #43882: [security] urllib.parse should sanitize urls containing ASCII https://bugs.python.org/issue43882 25 msgs #43976: Allow Python distributors to add custom site install schemes https://bugs.python.org/issue43976 19 msgs #44026: IDLE: print "Did you mean?" for AttributeError and NameError https://bugs.python.org/issue44026 16 msgs #43916: Mark static types newly converted to heap types as immutable: https://bugs.python.org/issue43916 15 msgs #44011: Borrow asyncio ssl implementation from uvloop https://bugs.python.org/issue44011 12 msgs #43983: Can't install Python v3.9.4 / 0x80070643 / windows 10 64bit https://bugs.python.org/issue43983 10 msgs #44010: IDLE: highlight soft keywords https://bugs.python.org/issue44010 10 msgs #37903: IDLE Shell sidebar. https://bugs.python.org/issue37903 9 msgs #43994: change representation of match as / capture as `Name(..., ctx= https://bugs.python.org/issue43994 9 msgs #44043: 3.10 b1 armhf Bus Error in hashlib test: test_gil https://bugs.python.org/issue44043 8 msgs Issues closed (99) ================== #9725: urllib.request.FancyURLopener won't connect to pages requiring https://bugs.python.org/issue9725 closed by orsenthil #11466: getpass.getpass doesn't close tty file https://bugs.python.org/issue11466 closed by orsenthil #12441: _GLOBAL_DEFAULT_TIMEOUT remains as an object() in HTTPConnecti https://bugs.python.org/issue12441 closed by orsenthil #27823: Change bare AttributeError messages to be more informative https://bugs.python.org/issue27823 closed by abarry #28556: typing.py upgrades https://bugs.python.org/issue28556 closed by Jelle Zijlstra #29753: [Linux] ctypes packs bitfields Incorrectly https://bugs.python.org/issue29753 closed by jaraco #30164: Testing FTP support in urllib shouldn't use Debian FTP server https://bugs.python.org/issue30164 closed by orsenthil #32745: ctypes string pointer fields should accept embedded null chara https://bugs.python.org/issue32745 closed by lukasz.langa #32752: no information about accessing typing.Generic type arguments https://bugs.python.org/issue32752 closed by Jelle Zijlstra #34568: Types in `typing` not anymore instances of `type` or subclasse https://bugs.python.org/issue34568 closed by Jelle Zijlstra #36515: unaligned memory access in the _sha3 extension https://bugs.python.org/issue36515 closed by christian.heimes #38135: Depth first search in compile.c creates wrong BB order for cer https://bugs.python.org/issue38135 closed by Mark.Shannon #38352: In typing docs, note explicit import needed for IO and Pattern https://bugs.python.org/issue38352 closed by lukasz.langa #39934: Fatal Python error "XXX block stack overflow" when exception s https://bugs.python.org/issue39934 closed by iritkatriel #40297: test_socket.CANTest is broken at HEAD on master https://bugs.python.org/issue40297 closed by zach.ware #40397: Refactor typing._GenericAlias https://bugs.python.org/issue40397 closed by Jelle Zijlstra #40617: sqlite3: expose sqlite3_create_window_function https://bugs.python.org/issue40617 closed by erlendaasland #41100: Support macOS 11 and Apple Silicon Macs https://bugs.python.org/issue41100 closed by ned.deily #41116: build on macOS 11 (beta) does not find system-supplied third-p https://bugs.python.org/issue41116 closed by ned.deily #41277: documentation: os.setxattr() errno EEXIST and ENODATA https://bugs.python.org/issue41277 closed by eric.smith #41730: Show deprecation warnings for tkinter.tix https://bugs.python.org/issue41730 closed by wyz23x2 #42001: Deprecate `typing.io` Wrapper Namespace https://bugs.python.org/issue42001 closed by Jelle Zijlstra #42067: Type annotation in for-loops https://bugs.python.org/issue42067 closed by kj #42083: PyStructSequence_NewType broken in 3.8 https://bugs.python.org/issue42083 closed by kj #42235: [macOS] Use --enable-optimizations in build-installer.py https://bugs.python.org/issue42235 closed by ned.deily #42269: Add ability to set __slots__ in dataclasses https://bugs.python.org/issue42269 closed by eric.smith #42362: Switch to clang as default compiler in build-installer.py https://bugs.python.org/issue42362 closed by ned.deily #42504: Failure to build with MACOSX_DEPLOYMENT_TARGET=11 on Big Sur https://bugs.python.org/issue42504 closed by ned.deily #42686: include built-in Math functions in SQLite to 3.35.0 of march 2 https://bugs.python.org/issue42686 closed by lukasz.langa #42688: ctypes memory error on Apple Silicon with external libffi https://bugs.python.org/issue42688 closed by ned.deily #42800: Traceback objects allow accessing frame objects without trigge https://bugs.python.org/issue42800 closed by steve.dower #43006: Changed behaviour of inspect.signature() in Python 3.10 https://bugs.python.org/issue43006 closed by Zac Hatfield-Dodds #43054: What does the existence of a struct in a header file imply abo https://bugs.python.org/issue43054 closed by Mark.Shannon #43075: ReDoS in urllib.request https://bugs.python.org/issue43075 closed by ned.deily #43354: xmlrpc.client: Fault.faultCode erroneously documented to be a https://bugs.python.org/issue43354 closed by jugmac00 #43434: sqlite3.Connection(...) bypasses 'sqlite3.connect' audit hooks https://bugs.python.org/issue43434 closed by steve.dower #43490: IDLE freezes at random https://bugs.python.org/issue43490 closed by ned.deily #43568: Drop support for Mac OS X < 10.3 module linking https://bugs.python.org/issue43568 closed by ned.deily #43733: PEP 597: netrc uses locale encoding. https://bugs.python.org/issue43733 closed by methane #43743: BlockingIOError: [Errno 11] Resource temporarily unavailable: https://bugs.python.org/issue43743 closed by gregory.p.smith #43754: Eliminate bindings for partial pattern matches https://bugs.python.org/issue43754 closed by brandtbucher #43794: OpenSSL 3.0.0: Handle UNEXPECTED_EOF_WHILE_READING / wrap SSL_ https://bugs.python.org/issue43794 closed by christian.heimes #43815: documentation for types.new_class() mention misleading default https://bugs.python.org/issue43815 closed by eric.smith #43878: ./configure fails on Apple Silicon with coreutils uname https://bugs.python.org/issue43878 closed by keith #43880: 3.10 SSL module deprecations https://bugs.python.org/issue43880 closed by christian.heimes #43888: GitHub Actions CI/CD `Coverage` job is broken on master https://bugs.python.org/issue43888 closed by ammar2 #43926: Clean metadata (importlib_metadata 4.0) https://bugs.python.org/issue43926 closed by jaraco #43930: Update bundled pip to 21.1 and setuptools to 56.0.0 https://bugs.python.org/issue43930 closed by sbidoul #43935: Fix typo in Turtle.back docstring https://bugs.python.org/issue43935 closed by terry.reedy #43937: Turtle uses the default root window https://bugs.python.org/issue43937 closed by terry.reedy #43942: RawDescriptionHelpFormatter seems to be ignored for argument d https://bugs.python.org/issue43942 closed by rrt #43953: InitVar should not be available on a @dataclass-decorated clas https://bugs.python.org/issue43953 closed by eric.smith #43957: [Enum] update __contains__ to return True for valid values https://bugs.python.org/issue43957 closed by ethan.furman #43971: documentation: no spacing around default args in annotated fun https://bugs.python.org/issue43971 closed by mdk #43972: Simple HTTP Request Handler in http.server does not set a cont https://bugs.python.org/issue43972 closed by orsenthil #43977: Implement the latest semantics for PEP 634 for matching collec https://bugs.python.org/issue43977 closed by Mark.Shannon #43978: Incorrect "versionadded" info in typing.NoReturn documentation https://bugs.python.org/issue43978 closed by kj #43979: Simplify urllib.parse_qsl https://bugs.python.org/issue43979 closed by corona10 #43981: test_idle is leaking references https://bugs.python.org/issue43981 closed by pablogsal #43982: Code coverage on the CI: validate codecov shell script checksu https://bugs.python.org/issue43982 closed by ammar2 #43985: lib2to3 fails on a slash('/') after positional_only paramter i https://bugs.python.org/issue43985 closed by cloud-yu #43987: Add "Annotations Best Practices" to HOWTO https://bugs.python.org/issue43987 closed by larry #43989: Enum deprecation breaks SSL tests https://bugs.python.org/issue43989 closed by christian.heimes #43990: In documentation Section 6.17, Operator precedence, footnotes https://bugs.python.org/issue43990 closed by rhettinger #43991: asyncio lock does not get released after task is canceled https://bugs.python.org/issue43991 closed by a.niederbuehl #43993: Update bundled pip to 21.1.1 https://bugs.python.org/issue43993 closed by sbidoul #43995: test_grammar fails if run sequentially https://bugs.python.org/issue43995 closed by pablogsal #43996: Doc for mutable sequence pop() method implies argument is a sl https://bugs.python.org/issue43996 closed by rhettinger #43997: dataclasses documentation needs version added for match_args, https://bugs.python.org/issue43997 closed by eric.smith #43998: Increase security of TLS settings in 3.10 https://bugs.python.org/issue43998 closed by christian.heimes #43999: Cannot pickle frozen dataclasses with slots https://bugs.python.org/issue43999 closed by eric.smith #44000: Current PY_VERSION 3.10.0a7+ does not conform to PEP 440 https://bugs.python.org/issue44000 closed by Cyril Jouve #44001: typing.Literal: args must be hashable, not immutable https://bugs.python.org/issue44001 closed by kj #44003: functools.lru_cache omits __defaults__ attribute from wrapped https://bugs.python.org/issue44003 closed by gregory.p.smith #44004: test_nntplib is failing in all buildbots https://bugs.python.org/issue44004 closed by christian.heimes #44006: symbol documentation still exists https://bugs.python.org/issue44006 closed by mdk #44007: urlparse("host:123", "http") inconsistent between 3.8 and 3.9 https://bugs.python.org/issue44007 closed by arcivanov #44008: os.walk and other directory traversal does not handle recursiv https://bugs.python.org/issue44008 closed by eryksun #44009: Provide "python3.x-intel64" command with macOS universal2 fram https://bugs.python.org/issue44009 closed by ned.deily #44014: Fix error in Enum documentation. https://bugs.python.org/issue44014 closed by lukasz.langa #44015: dataclasses: it should be an error to specify KW_ONLY twice https://bugs.python.org/issue44015 closed by eric.smith #44017: Deprecation warning in tests over no current event loop https://bugs.python.org/issue44017 closed by corona10 #44018: random.seed mutates input bytearray https://bugs.python.org/issue44018 closed by rhettinger #44020: test_ssl fails in the macos CI https://bugs.python.org/issue44020 closed by terry.reedy #44022: urllib http client possible infinite loop on a 100 Continue re https://bugs.python.org/issue44022 closed by gregory.p.smith #44027: Python 3.9 UWP does not create key in PythonCore https://bugs.python.org/issue44027 closed by steve.dower #44029: PEP 624: Remove Py_UNICODE APIs https://bugs.python.org/issue44029 closed by methane #44033: Adding multiple keys of the same name to a dict doesn't raise https://bugs.python.org/issue44033 closed by shreyanavigyan #44034: Incorrect type casting of float into int https://bugs.python.org/issue44034 closed by tim.peters #44039: Duplicated assignment in Modules/_randommodule.c https://bugs.python.org/issue44039 closed by rhettinger #44040: Update broken link in pathlib source https://bugs.python.org/issue44040 closed by matrixise #44046: When writing to the Registry using winreg, it currently allows https://bugs.python.org/issue44046 closed by eryksun #44047: [sqlite3] remove unused argument from _pysqlite_seterror() https://bugs.python.org/issue44047 closed by berker.peksag #44049: Use C99 Variable-length array if possible https://bugs.python.org/issue44049 closed by corona10 #44051: Virtualalloc wrong return type https://bugs.python.org/issue44051 closed by eryksun #44054: 2**53+1 != float(2**53+1) https://bugs.python.org/issue44054 closed by mark.dickinson #44056: Incorrect line number for syntax error. https://bugs.python.org/issue44056 closed by Mark.Shannon #44059: Support SerenityOS Browser in webbrowser module https://bugs.python.org/issue44059 closed by gregory.p.smith #44064: Python39/lib/logging/__init__.py SyntaxError: cannot delete st https://bugs.python.org/issue44064 closed by kathleenwest

1 0

Documenting collections.abc __class_getitem__ type hints
by Paul Bryan May 6, 2021

May 6, 2021

I'm looking through the documentation, and not finding any good reference for type hints for __class_getitem__ in the collections.abc module. I do see some of it covered in the typing module documentation, but those are deprecated, and some are somewhat cryptic (e.g. Coroutine). Make sense to open a BPO and start a PR for doc updates? Paul

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PEP 654: Exception Groups and except* [REPOST]
by Irit Katriel May 6, 2021

May 6, 2021

We would like to present for feedback a new version of PEP 654, which incorporates the feedback we received in the discussions so far: https://www.python.org/dev/peps/pep-0654/ The reference implementation has also been updated along with the PEP. The changes we made since the first post are: 1. Instead of ExceptionGroup(BaseException), we will have two new builtin types: BaseExceptionGroup(BaseException) and ExceptionGroup(BaseExceptionGroup, Exception). This is so that "except Exception" catches ExceptionGroups (but not BaseExceptionGroups). BaseExceptionGroup.__new__ inspects the wrapped exceptions, and if they are all Exception subclasses, it creates an ExceptionGroup instead of a BaseExceptionGroup. 2. The exception group classes are not final - they can be subclassed and split()/subgroup() work correctly if the subclass overrides the derive() instance method as described here: https://www.python.org/dev/peps/pep-0654/#subclassing-exception-groups 3. We had some good suggestions on formatting exception groups, which we have implemented as you can see in the output shown for the examples in the PEP. 4. We expanded the section on handling Exception Groups, to show how subgroup can be used (with side effects) to do something for each leaf exception, and how to iterate correctly when the tracebacks of leaf exceptions are needed: https://www.python.org/dev/peps/pep-0654/#handling-exception-groups 5. We expanded the sections on rationale and backwards compatibility to explain our premise and expectations regarding how exception groups will be used and how the transition to using them will be managed. 6. We added several items to the rejected ideas section. We did not receive any comments (or make any changes) to the proposed semantics of except*, hopefully this is because everyone thought they are sensible. Irit, Yury and Guido

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Anyone else gotten bizarre personal replies to mailing list posts?
by Nathaniel Smith May 4, 2021

May 4, 2021

I just got the reply below sent directly to my personal account, and I'm confused about what's going on. If it's just a one off I'll chalk it up to random internet weirdness, but if other folks are getting these too it might be something the list admins should look into? Or... something? ---------- Forwarded message --------- From: Hoi lam Poon <gillcovid19(a)gmail.com> Date: Fri, Apr 23, 2021, 02:01 Subject: Re: [Python-Dev] Re: PEP 654: Exception Groups and except* [REPOST] To: Nathaniel Smith <njs(a)pobox.com> Stop pretending, I can definitely get the key control file, your working group, all past actions and instructions cannot be cleared in front of me at all. You have been playing around for a few days, and I won’t stop you. Your face? I won’t, you know, you can’t drive me away, and that file is all, after I get it, you will be convicted even if you disband, I swear 在 2021年4月23日週五 16:23，Nathaniel Smith <njs(a)pobox.com> 寫道： > On Wed, Apr 21, 2021 at 4:50 PM Guido van Rossum <guido(a)python.org> wrote: > > On Wed, Apr 21, 2021 at 3:26 PM Nathaniel Smith <njs(a)pobox.com> wrote: > >> Sure. This was in my list of reasons why the backwards compatibility > >> tradeoffs are forcing us into awkward compromises. I only elaborated > >> on it b/c in your last email you said you didn't understand why this > >> was a problem :-). And except* is definitely useful. But I think there > >> are options for 'except' that haven't been considered fully. > > > > Do you have any suggestions, or are you just telling us to think harder? > Because we've already thought as hard as we could and within all the > constraints (backwards compatibility and otherwise) we just couldn't think > of a better one. > > The main possibility that I don't think we've examined fully is to > make 'except' blocks fire multiple times when there are multiple > exceptions. We ruled it out early b/c it's incompatible with nested > EGs, but if flat EGs are better anyway, then the balance shifts around > and it might land somewhere different. it's a tricky discussion > though, b/c both the current proposal and the alternative have very > complex implications and downsides. So we probably shouldn't get too > distracted by that until after the flat vs nested discussion has > settled down more. > > I'm not trying to filibuster here -- I really want some form of EGs to > land. I think python has the potential to be the most elegant and > accessible language around for writing concurrent programs, and EGs > are a key part of that. I don't want to fight about anything; I just > want to work together to make sure we have a full picture of our > options, so we can be confident we're making the best choice. > > > The real cost here is that we would need a new "TracebackGroup" concept, > since the internal data structures and APIs keep the traceback chain and > the exception object separated until the exception is caught. In our early > design stages we actually explored this and the complexity of the data > structures was painful. We eventually realized that we didn't need this > concept at all, and the result is much clearer, despite what you seem to > think. > > I'm not talking about TracebackGroups (at least, I think I'm not?). I > think it can be done with exactly our current data structures, nothing > new. > > - When an EG is raised, build the traceback for just that EG while > it's unwinding. This means if any C code peeks at exc_info while it's > in flight, it'll only see the current branch of the traceback tree, > but that seems fine. > - When the exception is caught and we go to write back the traceback > to its __traceback__ attribute, instead "peek through" the EG and > append the built-up traceback entries onto each of the constituent > exceptions. > > You could get cleverer for efficiency, but that basic concept seems > pretty simple and viable to me. What am I missing? > > -n > > -- > Nathaniel J. Smith -- https://vorpus.org > _______________________________________________ > Python-Dev mailing list -- python-dev(a)python.org > To unsubscribe send an email to python-dev-leave(a)python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/VOBOWZG… > Code of Conduct: http://python.org/psf/codeofconduct/ >

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github and dependabot
by Ethan Furman May 4, 2021

May 4, 2021

I have two pull requests against my cpython fork from a dependabot -- what is that, and should I merge them? -- ~Ethan~

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[Release manager team communication] master blocked until 3.10 beta 1 is released
by Pablo Galindo Salgado May 3, 2021

May 3, 2021

Hi everyone, Unfortunately, the CI for master is currently quite unstable and he had some problems that we have been fixing all weekend and today. We are doing our best to stabilize the test suite and making sure that everything is ready to go for the release with no issues, but this will take some time (also bear in mind that today is a bank holiday in the UK, so I am doing my best to get the release ready in a holiday). Given this and the fact that we need to do a branch rename, **we have decided to block the master branch** until we can stabilize the test suite. In the meantime, if you have some urgent fix or PR that you absolutely need to get merge before feature freeze, you can add me as a reviewer to said PR so we can evaluate the merge. Thanks for your understanding. I will update once master is unblocked again. Regards from cloudy London, Pablo Galindo Salgado

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Re: Announcing the CPython Docs Workgroup
by Raymond Hettinger May 3, 2021

May 3, 2021

That seems exclusionary. Right now, anyone can contribute to documentation, anyone can comment on proposals, and any core dev can accept their patches. In the interest of transparency, can you explain why the other initial members did not need to go through an application process? ISTM the initial group excludes our most active documentation contributors and includes people who have only minimal contributions to existing documentation and mostly have not participated in any documentation reviews on the issue tracker. Did the SC approve all the initial members? Raymond

2 1

Existing asyncio features scheduled for removal in Python 3.9 and 3.10
by Illia Volochii May 2, 2021

May 2, 2021

Hi everyone, There are a couple of uncompleted asyncio feature removals scheduled for 3.9 and 3.10 releases. It will be great if we either complete them or reschedule before the 3.10 feature freeze. There are two stale pull requests related to this. Removal of @asyncio.coroutine in version 3.10 deprecated since version 3.8 Documentation: https://docs.python.org/3.10/library/asyncio-task.html#asyncio.coroutine Issue deprecating the decorator: https://bugs.python.org/issue36921 Issue for the removal: https://bugs.python.org/issue43216 There is no pull request yet, mainly because of an unclarified question regarding types.coroutine in 36921. Prohibiting non-ThreadPoolExecutor in loop.set_default_executor Warning scheduling the prohibiting in version 3.9: https://github.com/python/cpython/blob/425434dadc30d96dc1c0c628f954f9b6f5ed… Issue: https://bugs.python.org/issue43234 Stale pull request: https://github.com/python/cpython/pull/24540 Prohibiting previously deprecated operations on asyncio.trsock.TransportSocket Warning scheduling the prohibiting in version 3.9: https://github.com/python/cpython/blob/425434dadc30d96dc1c0c628f954f9b6f5ed… Issue: https://bugs.python.org/issue43232 Stale pull request: https://github.com/python/cpython/pull/24538 Thanks, Illia

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Re: Python release timeline plot
by Irit Katriel May 2, 2021

May 2, 2021

This is just what I needed, thanks! I’m in the process of preparing a presentation for my team at Bank of America about how the dev lifecycle of our system (Quartz risk platform) interplays with the dev lifecycle of Python (and how we can do better). I will use this. > On 2 May 2021, at 08:33, Michał Górny <mgorny(a)gentoo.org> wrote: > > Hi, > > I've been working on visualizing some data on Python in Gentoo, and made > a timeline of Python releases as a side result. I've figured some of > you might be interested, so I've decided to share it. The result: > > https://mgorny.pl/python-timeline.html > > Script: https://github.com/mgorny/gpyutils/blob/master/timeline.py > Data: https://github.com/mgorny/gpyutils/blob/master/timeline.toml > > I've (roughly) covered the versions between 2.5 and 3.10 (2.5 is > the oldest I've seen during my time in Gentoo, also the timeline's > gotten narrow already). > > dev covers the period between start of development and first alpha. > alpha goes from a1 to b1, beta from b1 to rc1, rc from rc1 to final. > stable goes to the last bugfix release, and security from that until > the last security release. > > A few notes: > > 1. The data is cut off to the right, and for technical reasons this > means tooltips will display early end dates. > > 2. The right-most data is based on approximate dates where schedules > aren't precise, esp. 3.10 assumes 'approximately 18 months' for stable > status. > > 3. Start of development is only mentioned in the newest schedules. For > older versions, I've took the data of the commit changing PYTHON_VERSION > in configure.{ac,in} (which seems to match start of development in newer > schedules). > > 4. Where data on last bugfix release wasn't available in schedules, I've > looked through release notes. > > 5. I've deliberately skipped dev period for 2.5 not to overstretch it to > the left. > > If you see any mistakes, please let me know. > > -- > Best regards, > Michał Górny > > > _______________________________________________ > Python-Dev mailing list -- python-dev(a)python.org > To unsubscribe send an email to python-dev-leave(a)python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/CLSHKQA… > Code of Conduct: http://python.org/psf/codeofconduct/

1 0

Python release timeline plot
by Michał Górny May 2, 2021

May 2, 2021

Hi, I've been working on visualizing some data on Python in Gentoo, and made a timeline of Python releases as a side result. I've figured some of you might be interested, so I've decided to share it. The result: https://mgorny.pl/python-timeline.html Script: https://github.com/mgorny/gpyutils/blob/master/timeline.py Data: https://github.com/mgorny/gpyutils/blob/master/timeline.toml I've (roughly) covered the versions between 2.5 and 3.10 (2.5 is the oldest I've seen during my time in Gentoo, also the timeline's gotten narrow already). dev covers the period between start of development and first alpha. alpha goes from a1 to b1, beta from b1 to rc1, rc from rc1 to final. stable goes to the last bugfix release, and security from that until the last security release. A few notes: 1. The data is cut off to the right, and for technical reasons this means tooltips will display early end dates. 2. The right-most data is based on approximate dates where schedules aren't precise, esp. 3.10 assumes 'approximately 18 months' for stable status. 3. Start of development is only mentioned in the newest schedules. For older versions, I've took the data of the commit changing PYTHON_VERSION in configure.{ac,in} (which seems to match start of development in newer schedules). 4. Where data on last bugfix release wasn't available in schedules, I've looked through release notes. 5. I've deliberately skipped dev period for 2.5 not to overstretch it to the left. If you see any mistakes, please let me know. -- Best regards, Michał Górny

1 0

Re: Announcing the CPython Docs Workgroup
by Raymond Hettinger May 2, 2021

May 2, 2021

Please add me to the list of members for the initial workgroup. Thank you, Raymond

2 1

In what tense should the changelog be written?
by Larry Hastings May 1, 2021

May 1, 2021

When one writes one's "blurb" for the changelog, in what tense should it be? I mostly see entries in present tense: bpo-43660: Fix crash that happens when replacing sys.stderr with a callable that can remove the object while an exception is being printed. Patch by Pablo Galindo. bpo-41561: Add workaround for Ubuntu’s custom OpenSSL security level policy. But occasionally I see entries in past tense: bpo-26053: Fixed bug where the pdb interactive run command echoed the args from the shell command line, even if those have been overridden at the pdb prompt. bpo-40630: Added tracemalloc.reset_peak() to set the peak size of traced memory blocks to the current size, to measure the peak of specific pieces of code. I couldn't find any guidance in the Python Dev Guide after sixty seconds of poking around. Obviously this isn't a big deal. But it might be nice to try and nudge everybody in the same direction. It'd be pleasant if the changelog read in a more unified voice, and using the same tense and sentence structure would help towards that goal. If we arrived at a firm decision, maybe "blurb" et al could add a little text suggesting the proper style. Cheers, //arry/

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