Mailman 3 September 2021 - Python-Dev

deprecated-removed
by Serhiy Storchaka Sept. 8, 2021

Sept. 8, 2021

I always thought that the "deprecated" directive is used if the term of removing the deprecated feature is not set yet, and the "deprecated-removed" directive is used if it is set. After removing the feature both directives are replaced with the "versionchanged" directive which only specifies the version of removing, not version of deprecation. But after reading the devguide [1] I am no longer so confident. The devguide clearly describes it as specifying version at which the feature "is" … [View More]

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[RELEASE] Python 3.10.0rc2 is available
by Pablo Galindo Salgado Sept. 7, 2021

Sept. 7, 2021

Python 3.10 is one month away, can you believe it? This snake is still trying to bite as it has been an interesting day of fighting fires, release blockers, and a bunch of late bugs but your friendly release team always delivers :) You can get this new release while is still fresh here: https://www.python.org/downloads/release/python-3100rc2/ This is the second release candidate of Python 3.10 This release, **3.10.0rc2** , is the last preview before the final release of Python 3.10.0 on … [View More]2021-10-04. Entering the release candidate phase, only reviewed code changes which are clear bug fixes are allowed between release candidates and the final release. There will be no ABI changes from this point forward in the 3.10 series and the goal is that there will be as few code changes as possible. *The next release will be the final release of Python 3.10.0, which is currently scheduled for Monday, 2021-10-04.* Call to action ⚠️⚠️⚠️⚠️⚠️⚠️⚠️ *The 3.10 branch is now accepting changes for 3.10.**1*. To maximize stability, the final release will be cut from the v3.10.0rc2 tag. If you need the release manager (me) to cherry-pick any critical fixes, mark issues as release blockers, and/or add me as a reviewer on a critical backport PR on GitHub. To see which changes are currently cherry-picked for inclusion in 3.10.0, look at the short-lived branch-v3.10.0 https://github.com/python/cpython/tree/branch-v3.10.0 on GitHub. ⚠️⚠️⚠️⚠️⚠️⚠️⚠️ *Core developers: all eyes on the docs now* - Are all your changes properly documented? - Did you notice other changes you know of to have insufficient documentation? *Community members* We strongly encourage maintainers of third-party Python projects to prepare their projects for 3.10 compatibilities during this phase. As always, report any issues to [the Python bug tracker ](https://bugs.python.org/). Please keep in mind that this is a preview release and its use is **not** recommended for production environments. And now for something completely different Maxwell's demon is a thought experiment that would hypothetically violate the second law of thermodynamics. It was proposed by the physicist James Clerk Maxwell in 1867. In the thought experiment, a demon controls a small massless door between two chambers of gas. As individual gas molecules (or atoms) approach the door, the demon quickly opens and closes the door to allow only fast-moving molecules to pass through in one direction, and only slow-moving molecules to pass through in the other. Because the kinetic temperature of a gas depends on the velocities of its constituent molecules, the demon's actions cause one chamber to warm up and the other to cool down. This would decrease the total entropy of the two gases, without applying any work, thereby violating the second law of thermodynamics. We hope you enjoy those new releases! Thanks to all of the many volunteers who help make Python Development and these releases possible! Please consider supporting our efforts by volunteering yourself or through organization contributions to the Python Software Foundation. Regards from a plane going to Malaga, Your friendly release team, Pablo Galindo @pablogsal Ned Deily @nad Steve Dower @steve.dower [View Less]

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Making code object APIs unstable
by Guido van Rossum Sept. 7, 2021

Sept. 7, 2021

In 3.11 we're changing a lot of details about code objects. Part of this is the "Faster CPython" work, part of it is other things (e.g. PEP 657 -- Fine Grained Error Locations in Tracebacks). As a result, the set of fields of the code object is changing. This is fine, the structure is part of the internal API anyway. But there's a problem with two public API functions, PyCode_New() and PyCode_NewWithPosArgs(). As we have them in the main (3.11) branch, their signatures are incompatible with … [View More]previous versions, and they have to be since the set of values needed to create a code object is different. (The types.CodeType constructor signature is also changed, and so is its replace() method, but these aren't part of any stable API). Unfortunately, PyCode_New() and PyCode_NewWithPosArgs() are part of the PEP 387 stable ABI. What should we do? A. We could deprecate them, keep (restore) their old signatures, and create crippled code objects (no exception table, no endline/column tables, qualname defaults to name). B. We could deprecate them, restore the old signatures, and always raise an error when they are called. C. We could just delete them. D. We could keep them, with modified signatures, and to heck with ABI compatibility for these two. E. We could get rid of PyCode_NewWithPosArgs(), update PyCode() to add the posonlyargcount (which is the only difference between the two), and d*mn the torpedoes. F. Like (E), but keep PyCode_NewWithPosArgs() as an alias for PyCode_New() (and deprecate it). If these weren't part of the stable ABI, I'd choose (E). But because they are, I think only (A) or (B) are our options. The problem with (C) is that if there's code that links to them but doesn't call them (except in some corner case that the user can avoid), the code won't link even though it would work fine. The problem with (D) is that if it *is* called by code expecting the old signature it will segfault. I'm not keen on (A) since it can cause broken code objects when used to copy a code object with some modified metadata (e.g. a different filename), since there's no way to pass the exception table (and several other fields, but the exception table is an integral part of the code now). Code wanting to make slight modifications to code objects such as changing co_name or co_filename should switch to the .replace() API, which is much better at this (though calling it from C is a pain, it's possible). Code wanting to synthesize code should be updated for each release; we should probably require such code to be built with the internal API and use _PyCode_New(), which takes a struct argument containing all the necessary fields. Thoughts? I'm especially interested in Petr's opinion given that this is a case where we'd like to deprecate something in the stable ABI. See also discussion in https://bugs.python.org/issue40222 (esp. near the end). -- --Guido van Rossum (python.org/~guido) *Pronouns: he/him **(why is my pronoun here?)* <http://feministing.com/2015/02/03/how-using-they-as-a-singular-pronoun-can-…> [View Less]

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[RELEASE] Python 3.7.12 and 3.6.15 security updates now available
by nad＠python.org Sept. 6, 2021

Sept. 6, 2021

The content of this message was lost. It was probably cross-posted to multiple lists and previously handled on another list.

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Fixing sys.platlibdir usages in sysconfig on Python 3.10
by Tzu-ping Chung Sept. 5, 2021

Sept. 5, 2021

Hi I’d like to raise awareness to the two b.p.o. entries I recently created and their corresponding PRs: sysconfig's posix_user scheme has different platlib value to distutils's unix_user https://bugs.python.org/issue44860 sysconfig's posix_home scheme has different platlib value to distutils's unix_home https://bugs.python.org/issue45035 Since Python 3.10 switches from distutils to sysconfig as the canonical location to discover/install packages, I’d very much want these two to be included … [View More]

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API's to interface python with Eclipse to execute and debug C/C++ Source files.
by Chandrakant Shrimantrao Sept. 4, 2021

Sept. 4, 2021

Hi, We would like to know if there is any option available to execute and debug( setting break point and delete break point) C/C++ Source files Python API's inside Eclipse IDE after interfacing Pydev with Eclipse. Please let us know. Thanks and regards. Chandrakant shrimantrao. L&T Technology Services Ltd www.LTTS.com L&T Technology Services Limited (LTTS) is committed to safeguard your data privacy. For more information to view our commitment towards data privacy under GDPR, … [View More]

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Summary of Python tracker Issues
by Python tracker Sept. 3, 2021

Sept. 3, 2021

ACTIVITY SUMMARY (2021-08-27 - 2021-09-03) 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 7409 ( -4) closed 49419 (+67) total 56828 (+63) Open issues with patches: 2945 Issues opened (38) ================== #20658: os.environ.clear() fails with empty keys (posix.unsetenv) https://bugs.python.org/issue20658 reopened by iritkatriel #37330: open(): … [View More]

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Is anyone relying on new-bugs-announce/python-bugs-list/bugs.python.org summaries
by Ammar Askar Sept. 3, 2021

Sept. 3, 2021

Hey everyone, As part of PEP 588, migrating bugs.python.org issues to Github, there are two current mailing list related items that need a replacement or need to be turned down. 1. Weekly summary emails with bug counts and issues from the week, example: https://mail.python.org/archives/list/python-dev@python.org/thread/JRFJ4QH7… 2. Emails sent to the new-bugs-announce and python-bugs-list for new issues and comments to existing issues. I wanted to quickly gauge if anyone is relying on … [View More]

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PEP-535 (Rich comparison chaining) Discussion?
by Angus Hollands Sept. 2, 2021

Sept. 2, 2021

Hi all, PEP 535 was deferred until Python 3.8. I would like to discuss the PEP given that some time has passed, and I _personally_ would benefit from its acceptance. ## A little about me: As a reasonably long-time Python user (well, 16 years), I have gradually moved from using only the core language to working within the DSLs (NumPy et al.) of the Scientific Python ecosystem. Most recently, I've been using Awkward Arrray (https://github.com/scikit-hep/awkward-1.0), which generalises the … [View More]regular NumPy array programming paradigm into "jagged" data structures, and was initially aimed at the High Energy Physics (HEP) domain. ## TL;DR of the PEP's Motivations: Various aspects of NumPy's API have become a "lingua-franca" in the Scientific Python domain, such as strongly-overloaded index operations. One such overload allows "mask arrays" — arrays with boolean entries corresponding to a per-element mask — to select a subset of the array. These mask arrays are conveniently built from the rich comparison operators that Python supports, e.g. ```python x = np.array(...) y = x[(2 < x) & (x < 8)] ``` As discussed in PEP 535, the limitation on comparison chaining (namely that it is not possible for rich comparisons) makes the above syntax more clunky than it might otherwise be. The main repercussion of this limitation is lower readability: - operator precedence of bitwise and/or requires a reasonable number of parentheses (https://docs.python.org/3/reference/expressions.html#operator-precedence) - repetition of the rich-object (array) With PEP 535 (and the necessary library changes), this would look more like ```python x = np.array(...) y = x[2 < x < 8] ``` This is already well described in the PEP, so I'll leave the example there! ## Community Survey The Oct 2020 Python Developers Survey (https://www.jetbrains.com/lp/python-developers-survey-2020/) suggests that 62% of respondents use NumPy. Additionally, 37% of respondents list "Simple syntax, syntactic sugar, easy to learn" and 30% list "Easy to write & read code, high-level language" amongst their three most liked features in the Python language (to clarify, these answers may overlap by respondent!) From these results, I would make a tentative case that this PEP would have a reasonable impact on the Python community, given that libraries benefitting from this proposal (e.g. NumPy) are used by a "majority" of those surveyed. ## Conclusion This is a bit of a long opener to this list (apologies!). Is there any interest in pushing this PEP along? Thanks, Angus Hollands [View Less]

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