Mailman 3 November 2018 - docs

[issue32501] Documentation for dir([object])
by Vladislavs Burakovs 24 Dec '20

24 Dec '20

New submission from Vladislavs Burakovs <solomonchild(a)gmail.com>: Documentation page [1] says "If the object has a method named __dir__(), this method will be called and must return the list of attributes.". It seems that on Python 3.6 it only works if the *class* has a method named __dir__. Should the documentation be changed? Microsoft Windows [Version 10.0.16299.192] (c) 2017 Microsoft Corporation. All rights reserved. D:\Users\wlad>python Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> class C: pass ... >>> x = C() >>> import types >>> x.__dir__ = types.MethodType(lambda _:[], x) >>> dir(x) ['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__'] >>> C.__dir__ = types.MethodType(lambda _:[], x) >>> dir(x) [] [1] https://docs.python.org/3/library/functions.html ---------- assignee: docs@python components: Documentation messages: 309544 nosy: Vladislavs Burakovs, docs@python priority: normal severity: normal status: open title: Documentation for dir([object]) type: enhancement versions: Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue32501> _______________________________________

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[issue23522] Misleading note in Statistics module documentation
by Jake 19 Dec '20

19 Dec '20

New submission from Jake: In the statistics module documentation, there is a note that states that "The mean is strongly affected by outliers and is not a robust estimator for central location: the mean is not necessarily a typical example of the data points. For more robust, although less efficient, measures of central location, see median() and mode()" https://docs.python.org/3/library/statistics.html While I appreciate the intention, this is quite misleading. The implication is that the mean, median and mode are different ways to estimate one "central location", however, in reality they are very different things (albeit which refer to a similar notion). The sample mean is an unbiased estimator of the true mean but it need not be unbiased as an estimator of the true median or modes and vice versa for the median and mode. To make this clearer I would rephrase to "The mean is strongly affected by outliers and is not necessarily representative of the central tendency of the data. For cases with large outliers or very low sample size, see median() and mode()" Apologies if this is seen as frivolous, but statistics can be hard enough to remain very clear about even when the words are used precisely. ---------- assignee: docs@python components: Documentation messages: 236612 nosy: Journeyman08, docs@python priority: normal severity: normal status: open title: Misleading note in Statistics module documentation type: enhancement versions: Python 3.4 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue23522> _______________________________________

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[issue14586] TypeError: truncate() takes no keyword arguments
by Guy Taylor 15 Dec '20

15 Dec '20

New submission from Guy Taylor <thebigguy.co.uk(a)gmail.com>: The Python docs suggest that io.IOBase.truncate' should take a keyword argument of 'size'. However this causes a 'TypeError': TypeError: truncate() takes no keyword arguments Suggest that the docs are changed to 'truncate(size)' or CPython is changed to allow the keyword. http://docs.python.org/py3k/library/io.html?highlight=truncate#io.IOBase.tr… http://docs.python.org/library/io.html?highlight=truncate#io.IOBase.truncate ---------- assignee: docs@python components: Documentation, Interpreter Core files: test.py messages: 158308 nosy: TheBiggerGuy, docs@python priority: normal severity: normal status: open title: TypeError: truncate() takes no keyword arguments type: behavior versions: Python 2.7, Python 3.2 Added file: http://bugs.python.org/file25219/test.py _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue14586> _______________________________________

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[issue26515] Update extending/embedding docs to new way to build modules in C
by Brett Cannon 15 Dec '20

15 Dec '20

New submission from Brett Cannon: https://docs.python.org/3/extending/extending.html#a-simple-example uses PyModule_Create() instead of PyModuleDef_Init(). ---------- assignee: docs@python components: Documentation messages: 261398 nosy: brett.cannon, docs@python, eric.snow, ncoghlan priority: normal severity: normal stage: needs patch status: open title: Update extending/embedding docs to new way to build modules in C versions: Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue26515> _______________________________________

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[issue35083] Fix documentation for __instancecheck__
by Joy Diamond 15 Dec '20

15 Dec '20

New submission from Joy Diamond <python.gem(a)gmail.com>: This is a request to fix the documentation for __instancecheck__. Please add the following: """ (Note that any object `x` is always considered to be an instance of `type(x)`, and this cannot be overridden.) """ Consider the following program: class M(type): def __instancecheck__(m, t): print('instancecheck(%s, %s)' % (m, t)) return False # LIE! Test = M('Test', ((object,)), {}) something = Test() print('Does *NOT* call __instancecheck__:') print('isinstance(something, Test): %s' % isinstance(something, Test)) print() print('Does call __instancecheck__:') print('isinstance(0, Test): %s' % isinstance(0, Test)) Under python 2, python 3, and pypy, in all cases, the first examples does *NOT* call __instancecheck__. You can see the optimization here: https://github.com/python/cpython/blob/master/Objects/abstract.c#L2397-L2405 Which reads: int PyObject_IsInstance(PyObject *inst, PyObject *cls) { _Py_IDENTIFIER(__instancecheck__); PyObject *checker; /* Quick test for an exact match */ if (Py_TYPE(inst) == (PyTypeObject *)cls) return 1; I'm fine with the optimization -- I am not suggesting to get rid of it. I just want the documentation to match the actual implementation. The following documentation needs to be fixed: https://docs.python.org/2/reference/datamodel.html https://docs.python.org/3/reference/datamodel.html https://www.python.org/dev/peps/pep-3119/ It took me half an hour to figure out why my version of __instancecheck__ was not working, as I tried to test it using the super simple code above ... One of the best things about python is how accurate and consistent the documentation is. This request is to keep these high standards. ---------- assignee: docs@python components: Documentation messages: 328658 nosy: docs@python, joydiamond priority: normal severity: normal status: open title: Fix documentation for __instancecheck__ type: enhancement versions: Python 2.7, Python 3.8 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue35083> _______________________________________

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[issue26451] CSV documentation doesn't open with an example
by Alex LordThorsen 13 Dec '20

13 Dec '20

New submission from Alex LordThorsen: Had a friend get stuck on the CSV documentation. They didn't know what a CSV was (to start with) and couldn't find an example that made sense to them. they went to other sources to figure out how to read CSV files in the end. I made this patch in the hope that starting out with a very minimal example file format followed by an example python read will make landing on the CSV docs easier to follow for new programmers. ---------- assignee: docs@python components: Documentation files: csv_documentation.patch keywords: patch messages: 260960 nosy: Alex.LordThorsen, docs@python priority: normal severity: normal status: open title: CSV documentation doesn't open with an example versions: Python 3.6 Added file: http://bugs.python.org/file42040/csv_documentation.patch _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue26451> _______________________________________

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[issue24110] zipfile.ZipFile.write() does not accept bytes arcname
by July Tikhonov 08 Dec '20

08 Dec '20

New submission from July Tikhonov: In documentation of zipfile.ZipFile.write() there is following notice: "There is no official file name encoding for ZIP files. If you have unicode file names, you must convert them to byte strings in your desired encoding before passing them to write()." I understand it as that 'arcname' argument to write() shouldn't be of type str, but rather bytes. But it is str that works, and bytes that does not: $ ./python Python 3.5.0a4+ (default:6f6e78931875, May 1 2015, 23:18:40) [GCC 4.8.4] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import zipfile >>> zf = zipfile.ZipFile('foo.zip', 'w') >>> zf.write('python', 'a') >>> zf.write('python', b'b') Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/home/july/source/python/Lib/zipfile.py", line 1442, in write zinfo = ZipInfo(arcname, date_time) File "/home/july/source/python/Lib/zipfile.py", line 322, in __init__ null_byte = filename.find(chr(0)) TypeError: a bytes-like object is required, not 'str' (ZipInfo ostensibly attempts to find a zero byte in the filename, but searches instead for a unicode character chr(0). There are several other places in ZipInfo class that assume filename being str rather than bytes.) I consider this a documentation issue: the notice is misleading. Although maybe there is someone who wants to fix the behavior of ZipInfo to allow bytes filename. ---------- assignee: docs@python components: Documentation messages: 242355 nosy: docs@python, july priority: normal severity: normal status: open title: zipfile.ZipFile.write() does not accept bytes arcname type: behavior versions: Python 3.4, Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue24110> _______________________________________

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[issue25573] traceback documentation example is lying about FrameSummary repr()
by Alexandre Macabies 08 Dec '20

08 Dec '20

New submission from Alexandre Macabies: https://docs.python.org/3.5/library/traceback.html#traceback-examples See second code sample and its sample output. According to the docs, the call: print(repr(traceback.extract_tb(exc_traceback))) is supposed to print something that looks like an array with only strings; that is what the doc sample output states: [('<doctest...>', 10, '<module>', 'lumberjack()'), But actually, in 3.5+, this call outputs the repr() of a list of FrameSummary instances that do not go further in repr()esenting their state: [<FrameSummary file <ipython-input-61-3e63d7daea82>, line 10 in <module>>, By looking at the docs I thought I was able to get a nice string representation of a FrameSummary. I actually have to format it myself. It should be reflected in the doc sample output. ---------- assignee: docs@python components: Documentation messages: 254224 nosy: Alexandre Macabies, docs@python priority: normal severity: normal status: open title: traceback documentation example is lying about FrameSummary repr() versions: Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue25573> _______________________________________

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[issue26582] asyncio documentation links to wrong CancelledError
by awilfox 04 Dec '20

04 Dec '20

New submission from awilfox: In the 3.5 and 3.6a0 documentation for asyncio, "CancelledError" is linked to the concurrent.futures.CancelledError. This led me to try catching that exception and finding that it did not work correctly at all. Only after searching for asyncio example code and seeing how other people caught asyncio.CancelledError did I realise the issue. The fact asyncio.CancelledError even exists isn't actually documented, and I believe that is why the :exc: reference is linking to the wrong module. ---------- assignee: docs@python components: Documentation messages: 261911 nosy: awilfox, docs@python priority: normal severity: normal status: open title: asyncio documentation links to wrong CancelledError versions: Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue26582> _______________________________________

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[issue32830] tkinter documentation suggests "from tkinter import *", contradicting PEP8
by ChrisRands 01 Dec '20

01 Dec '20

New submission from ChrisRands <chrisrands0(a)gmail.com>: Issue arose from this SO post: https://stackoverflow.com/questions/48746351/documentation-is-contradicting… The tkinter documentation suggests: from tkinter import * https://docs.python.org/3/library/tkinter.html But this obviously contradicts PEP8: "Wildcard imports (from <module> import *) should be avoided" https://www.python.org/dev/peps/pep-0008/#imports Is tkinter a valid exception or is this a documentation bug? The commit of this line to the documentation is >10 years old (at least Python 2.4 I think): https://github.com/python/cpython/commit/116aa62bf54a39697e25f21d6cf6799f7f… ---------- assignee: docs@python components: Documentation messages: 312045 nosy: ChrisRands, docs@python priority: normal severity: normal status: open title: tkinter documentation suggests "from tkinter import *", contradicting PEP8 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue32830> _______________________________________

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