Mailman 3 October 2015 - Python-Dev

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)

7 17

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

congrats on 3.5! Alas, windows 7 users are having problems installing it
by Laura Creighton Sept. 15, 2019

Sept. 15, 2019

webmaster has already heard from 4 people who cannot install it. I sent them to the bug tracker or to python-list but they seem not to have gone either place. Is there some guide I should be sending them to, 'how to debug installation problems'? Laura

5 6

PEP 506 secrets module
by Steven D'Aprano April 15, 2016

April 15, 2016

Hi, As extensively discussed on Python-Ideas, the secrets module and PEP 506 is (I hope) ready for pronouncement. https://www.python.org/dev/peps/pep-0506/ There is code and tests here: https://bitbucket.org/sdaprano/secrets or you can run hg clone https://sdaprano@bitbucket.org/sdaprano/secrets The code is written for and tested on Python 2.6, 2.7, 3.1 - 3.4. -- Steve

13 28

If you shadow a module in the standard library that IDLE depends on, bad things happen
by Laura Creighton Nov. 1, 2015

Nov. 1, 2015

see the following: lac@smartwheels:~/junk$ echo "print ('hello there')" >string.py lac@smartwheels:~/junk$ idle-python3.5 hello there Traceback (most recent call last): File "<string>", line 1, in <module> File "/usr/lib/python3.5/idlelib/run.py", line 10, in <module> from idlelib import CallTips File "/usr/lib/python3.5/idlelib/CallTips.py", line 16, in <module> from idlelib.HyperParser import HyperParser File "/usr/lib/python3.5/idlelib/HyperParser.py", line 14, in <module> _ASCII_ID_CHARS = frozenset(string.ascii_letters + string.digits + "_") AttributeError: module 'string' has no attribute 'ascii_letters' IDLE then produces a popup that says: IDLE's subprocess didn't make connection. Either IDLE can't stat a subprocess por personal firewall software is blocking the connection. <ok> -------- I think that life would be a whole lot easier for people if instead we got a message: Warning: local file /u/lac/junk/string.py shadows module named string in the Standard Library I think that it is python exec that would have to do this -- though of course the popup could also warn about shadowing in general, instead of sending people on wild goose chases over their firewalls. Would this be hard to do? Laura

10 20

Should PEP 498 specify if rf'...' is valid?
by Ryan Gonzalez Nov. 1, 2015

Nov. 1, 2015

It mentions fr'...' as a formatted raw string but doesn't say anything about rf'...'. Right now, in implementing PEP 498 support in Howl (https://github.com/howl-editor/howl/pull/118 and https://github.com/howl-editor/howl/commit/1e577da89efc1c1de780634b531f6434…), I assumed both were valid. Should the PEP be more specific? BTW, at the rate language-python is going, GitHub will get syntax highlighting for f-strings in 2050. :D -- Sent from my Nexus 5 with K-9 Mail. Please excuse my brevity.

12 24

Summary of Python tracker Issues
by Python tracker Oct. 30, 2015

Oct. 30, 2015

ACTIVITY SUMMARY (2015-10-23 - 2015-10-30) Python tracker at http://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 5204 (+23) closed 32073 (+30) total 37277 (+53) Open issues with patches: 2298 Issues opened (37) ================== #25467: Put “deprecated” warnings first http://bugs.python.org/issue25467 opened by Tony R. #25468: PyTraceBack_Print()/_Py_DisplaySourceLine() should take custom http://bugs.python.org/issue25468 opened by shiz #25469: multiprocessing .Condition.notify(_all) function has O(N) time http://bugs.python.org/issue25469 opened by vilnis.termanis #25470: Random Malloc error raised http://bugs.python.org/issue25470 opened by augustin rieunier #25472: Typing: Specialized subclasses of generics cannot be unpickled http://bugs.python.org/issue25472 opened by maatt #25474: Weird behavior when setting f_trace in a context manager http://bugs.python.org/issue25474 opened by Fred Gansevles #25476: close() behavior on non-blocking BufferedIO objects with socke http://bugs.python.org/issue25476 opened by dabeaz #25477: text mode for pkgutil.get_data http://bugs.python.org/issue25477 opened by Antony.Lee #25478: Consider adding a normalize() method to collections.Counter() http://bugs.python.org/issue25478 opened by rhettinger #25479: Increase unit test coverage for abc.py http://bugs.python.org/issue25479 opened by szymon #25481: PermissionError in subprocess.check_output() when an inaccessi http://bugs.python.org/issue25481 opened by jaystrict #25482: signal.set_wakeup_fd() doesn't work if the signal don't have h http://bugs.python.org/issue25482 opened by ishimoto #25483: Improve f-string implementation: FORMAT_VALUE opcode http://bugs.python.org/issue25483 opened by eric.smith #25485: Add a context manager to telnetlib.Telnet http://bugs.python.org/issue25485 opened by desbma #25486: Resurrect inspect.getargspec() in 3.6 http://bugs.python.org/issue25486 opened by yselivanov #25487: imp module DeprecationWarning in test suite http://bugs.python.org/issue25487 opened by martin.panter #25488: IDLE: Remove idlelib from sys.path when added http://bugs.python.org/issue25488 opened by terry.reedy #25489: sys.exit() caught in exception handler http://bugs.python.org/issue25489 opened by jinty #25491: ftplib.sendcmd only accepts string http://bugs.python.org/issue25491 opened by wozlaf #25492: subprocess with redirection fails after FreeConsole http://bugs.python.org/issue25492 opened by George Prekas #25493: warnings.warn: wrong stacklevel causes import of local file "s http://bugs.python.org/issue25493 opened by bevan #25495: binascii documentation incorrect http://bugs.python.org/issue25495 opened by mouse07410 #25496: tarfile: Default value for compresslevel is not documented http://bugs.python.org/issue25496 opened by Sworddragon #25497: Rewrite test_robotparser http://bugs.python.org/issue25497 opened by berker.peksag #25498: Python 3.4.3 core dump with simple sample code http://bugs.python.org/issue25498 opened by JakeMont #25500: docs claim __import__ checked for in globals, but IMPORT_NAME http://bugs.python.org/issue25500 opened by superbobry #25505: undefined name 'window' in Tools/scripts/fixdiv.py http://bugs.python.org/issue25505 opened by John.Mark.Vandenberg #25507: IDLE: user code 'import tkinter; tkinter.font' should fail http://bugs.python.org/issue25507 opened by terry.reedy #25508: LogRecord attributes are not tuple, when logging only dict http://bugs.python.org/issue25508 opened by sejvlond #25509: PyImport_ImportModule inaccurately described http://bugs.python.org/issue25509 opened by memeplex #25510: fileinput.FileInput.readline() always returns str object at th http://bugs.python.org/issue25510 opened by Ryosuke Ito #25511: multiprocessing pool blocks SIGTERM from being handled http://bugs.python.org/issue25511 opened by djones #25514: better startup error messages in IDLE when stdlib modules shad http://bugs.python.org/issue25514 opened by markroseman #25516: threading.Condition._is_owned() is wrong when using threading. http://bugs.python.org/issue25516 opened by nirs #25517: regex howto example in "Lookahead Assertions" http://bugs.python.org/issue25517 opened by Pavel #25518: Investigate implementation of PyOS_CheckStack on OSX http://bugs.python.org/issue25518 opened by ronaldoussoren #25519: Minor difflib documentation bug http://bugs.python.org/issue25519 opened by lurchman Most recent 15 issues with no replies (15) ========================================== #25519: Minor difflib documentation bug http://bugs.python.org/issue25519 #25518: Investigate implementation of PyOS_CheckStack on OSX http://bugs.python.org/issue25518 #25511: multiprocessing pool blocks SIGTERM from being handled http://bugs.python.org/issue25511 #25505: undefined name 'window' in Tools/scripts/fixdiv.py http://bugs.python.org/issue25505 #25497: Rewrite test_robotparser http://bugs.python.org/issue25497 #25491: ftplib.sendcmd only accepts string http://bugs.python.org/issue25491 #25487: imp module DeprecationWarning in test suite http://bugs.python.org/issue25487 #25486: Resurrect inspect.getargspec() in 3.6 http://bugs.python.org/issue25486 #25479: Increase unit test coverage for abc.py http://bugs.python.org/issue25479 #25477: text mode for pkgutil.get_data http://bugs.python.org/issue25477 #25474: Weird behavior when setting f_trace in a context manager http://bugs.python.org/issue25474 #25468: PyTraceBack_Print()/_Py_DisplaySourceLine() should take custom http://bugs.python.org/issue25468 #25462: Avoid repeated hash calculation in C implementation of Ordered http://bugs.python.org/issue25462 #25458: ftplib: command response shift - mismatch http://bugs.python.org/issue25458 #25455: Some repr implementations don't check for self-referential str http://bugs.python.org/issue25455 Most recent 15 issues waiting for review (15) ============================================= #25516: threading.Condition._is_owned() is wrong when using threading. http://bugs.python.org/issue25516 #25510: fileinput.FileInput.readline() always returns str object at th http://bugs.python.org/issue25510 #25505: undefined name 'window' in Tools/scripts/fixdiv.py http://bugs.python.org/issue25505 #25498: Python 3.4.3 core dump with simple sample code http://bugs.python.org/issue25498 #25497: Rewrite test_robotparser http://bugs.python.org/issue25497 #25495: binascii documentation incorrect http://bugs.python.org/issue25495 #25489: sys.exit() caught in exception handler http://bugs.python.org/issue25489 #25485: Add a context manager to telnetlib.Telnet http://bugs.python.org/issue25485 #25483: Improve f-string implementation: FORMAT_VALUE opcode http://bugs.python.org/issue25483 #25479: Increase unit test coverage for abc.py http://bugs.python.org/issue25479 #25469: multiprocessing .Condition.notify(_all) function has O(N) time http://bugs.python.org/issue25469 #25467: Put “deprecated” warnings first http://bugs.python.org/issue25467 #25464: Tix HList header_exists should be "exist" http://bugs.python.org/issue25464 #25462: Avoid repeated hash calculation in C implementation of Ordered http://bugs.python.org/issue25462 #25461: Unclear language (the word ineffective) in the documentation f http://bugs.python.org/issue25461 Top 10 most discussed issues (10) ================================= #25489: sys.exit() caught in exception handler http://bugs.python.org/issue25489 17 msgs #8231: Unable to run IDLE without write-access to home directory http://bugs.python.org/issue8231 12 msgs #25482: signal.set_wakeup_fd() doesn't work if the signal don't have h http://bugs.python.org/issue25482 11 msgs #25467: Put “deprecated” warnings first http://bugs.python.org/issue25467 10 msgs #25481: PermissionError in subprocess.check_output() when an inaccessi http://bugs.python.org/issue25481 10 msgs #25483: Improve f-string implementation: FORMAT_VALUE opcode http://bugs.python.org/issue25483 8 msgs #25485: Add a context manager to telnetlib.Telnet http://bugs.python.org/issue25485 8 msgs #25156: shutil.copyfile should internally use os.sendfile when possibl http://bugs.python.org/issue25156 6 msgs #25495: binascii documentation incorrect http://bugs.python.org/issue25495 6 msgs #25498: Python 3.4.3 core dump with simple sample code http://bugs.python.org/issue25498 6 msgs Issues closed (28) ================== #16785: Document the fact that constructing OSError with erron returns http://bugs.python.org/issue16785 closed by martin.panter #21160: incorrect comments in nturl2path.py http://bugs.python.org/issue21160 closed by serhiy.storchaka #21827: textwrap.dedent() fails when largest common whitespace is a su http://bugs.python.org/issue21827 closed by serhiy.storchaka #23391: Documentation of EnvironmentError (OSError) arguments disappea http://bugs.python.org/issue23391 closed by martin.panter #24765: Move .idlerc to %APPDATA%\IDLE on Windows http://bugs.python.org/issue24765 closed by terry.reedy #25193: itertools.accumulate should have an optional initializer argum http://bugs.python.org/issue25193 closed by rhettinger #25311: Add f-string support to tokenize.py http://bugs.python.org/issue25311 closed by eric.smith #25356: Idle (Python 3.4 on Ubuntu) does not allow typing accents http://bugs.python.org/issue25356 closed by terry.reedy #25425: white-spaces encountered in 3.4 http://bugs.python.org/issue25425 closed by terry.reedy #25432: isinstance documentation: explain behavior when type is a tupl http://bugs.python.org/issue25432 closed by terry.reedy #25447: TypeError invoking deepcopy on lru_cache http://bugs.python.org/issue25447 closed by serhiy.storchaka #25466: offer "from __future__ import" option for "raise... from" http://bugs.python.org/issue25466 closed by terry.reedy #25471: socket.recv() blocks while it's gettimeout() returns 0.0 http://bugs.python.org/issue25471 closed by python-dev #25473: socket.recv() raises correct code with the misleading descript http://bugs.python.org/issue25473 closed by benjamin.peterson #25475: use argparse instead of getopt http://bugs.python.org/issue25475 closed by SilentGhost #25480: string format in large number http://bugs.python.org/issue25480 closed by eric.smith #25484: Operator issue with "in" on same level and preceding == http://bugs.python.org/issue25484 closed by ezio.melotti #25490: small mistake in example for random.choice() http://bugs.python.org/issue25490 closed by serhiy.storchaka #25494: Four quotes used to begin docstring http://bugs.python.org/issue25494 closed by python-dev #25499: use argparse for the calendar module http://bugs.python.org/issue25499 closed by serhiy.storchaka #25501: Use async/await through asyncio docs http://bugs.python.org/issue25501 closed by brett.cannon #25502: unnecessary re-imports http://bugs.python.org/issue25502 closed by python-dev #25503: inspect.getdoc does find inherited property __doc__ http://bugs.python.org/issue25503 closed by serhiy.storchaka #25504: undefined name 'modules' in Tools/freeze/checkextensions_win32 http://bugs.python.org/issue25504 closed by benjamin.peterson #25506: test_pprint reuses test_user_dict http://bugs.python.org/issue25506 closed by serhiy.storchaka #25512: apparent memory leak using ctypes http://bugs.python.org/issue25512 closed by blindgoat #25513: collections.abc.Iterable don't implement __bool__ http://bugs.python.org/issue25513 closed by r.david.murray #25515: Always use os.urandom for generating uuid4s http://bugs.python.org/issue25515 closed by python-dev

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Re: [Python-Dev] If you shadow a module in the standard library that IDLE depends on, bad things happen
by Mark Roseman Oct. 30, 2015

Oct. 30, 2015

Laura, I think what you want should actually be more-or-less doable in IDLE. The main routine that starts IDLE should be able to detect if it starts correctly (something unlikely to happen if a significant stdlib module is shadowed), watch for an attribute error of that form and try to determine if shadowing is the cause, and if so, reissue a saner error message. The subprocess/firewall error is occurring because the ‘string’ problem in your example isn’t being hit right away so a few startup things already are happening. The point where we’re showing that error (as a result of a timeout) should be able to check as per the above that IDLE was able to start alright, and if not, change or ignore the timeout error. There’ll probably be some cases (depending on exactly what gets shadowed) that may be difficult to get to work, but it should be able to handle most things. Mark

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Intended Usage of collections.abc for Custom Collections
by jab＠math.brown.edu Oct. 28, 2015

Oct. 28, 2015

Dear Python-Dev, I am the author of bidict, a bidirectional map implementation for Python. A user recently filed a bug that bidict should be a subclass of dict, so that isinstance(mybidict, dict) would return True. I replied that the user should instead use isinstance(mybidict, collections.abc.Mapping), which does already return True, and is more polymorphic to boot. But before I put the issue to bed, I want to make sure I'm correctly understanding the intended usage of collections.abc, as well as any relevant interfaces I'm not currently using (collections.UserDict? __subclasshook__?), since the documentation leaves me with some doubt. Could any collections experts on this list please confirm whether bidict is implemented as the language intends it should be? Some quick references: https://bidict.readthedocs.org/en/latest/other-bidict-types.html#bidict-typ… https://github.com/jab/bidict/blob/master/bidict/_bidict.py I would be happy to try to capture what I learn from this thread and write up a guide for collections library authors in the future, or otherwise pay your help forward however I can. Thanks and best wishes. -jab

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Bytcode "magic tag"
by Eric V. Smith Oct. 28, 2015

Oct. 28, 2015

In issue 25483 I'm adding an opcode to make f-string formatting more robust and faster. As part of that, I'm bumping the .pyc magic number. While doing that, I notice Lib/importlib/_bootstrap_external.h includes this comment: # Starting with the adoption of PEP 3147 in Python 3.2, every bump in magic # number also includes a new "magic tag", i.e. a human readable string used # to represent the magic number in __pycache__ directories. When you change # the magic number, you must also set a new unique magic tag. Generally this # can be named after the Python major version of the magic number bump, but # it can really be anything, as long as it's different than anything else # that's come before. The tags are included in the following table, starting # with Python 3.2a0. The "following table" is a comment, that contains a few references to the tag "cpython-<version>", specifically cpython-32. It doesn't seem that the tag is routinely updated in the comment. sys.implementation.cache_tag returns 'cpython-36', and is in fact implemented as 'cpython-{PY_MAJOR_VERSION}{PY_MINOR_VERSION}'. Do I need to do anything else? Unlike what the comment in _boostrap_external.py suggests, this "magic tag" will not change every time a bytecode is added, but only on every minor release. Which implies that if we have a micro release that adds an opcode, we'll in fact break the promise in the comment. >From my understanding on how this tag is used, this wouldn't be a problem (because the magic number in the file also changes). But I want to make sure I'm not misunderstanding something. I think the comment above is probably just misleading. Eric.

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