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 (… [View More]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) [View Less]

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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 … [View More]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! [View Less]

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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 … [View More]

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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.… [View More]

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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 … [View More]

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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://… [View More]

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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 … [View More]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> [View Less]

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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 … [View More]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! [View Less]

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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 … [View More]

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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 # … [View More]

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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 … [View More]

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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 … [View More]

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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 … [View More]

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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 … [View More]

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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)

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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

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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/… [View More]

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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.… [View More]

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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 … [View More]

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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. -- … [View More]

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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 : … [View More]

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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 … [View More]

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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" … [View More]

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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 … [View More]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. [View Less]

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 … [View More]

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: … [View More]$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: [View Less]

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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: … [View More]

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 … [View More]

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 (`**`)… [View More]

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 ^^^^^^^ … [View More] 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 [View Less]

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 … [View More]

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.… [View More]

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 … [View More]

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 … [View More]

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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 (… [View More]

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 … [View More]

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: … [View More]

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

2 2

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" … [View More]

14 45

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: … [View More]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/ > [View Less]

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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 … [View More]

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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 … [View More]

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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 … [View More]

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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 … [View More]

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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 … [View More]

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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

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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 … [View More]

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