Mailman 3 November 2020 - docs

[issue42317] Docs of `typing.get_args`: Mention that due to caching of typing generics the order of arguments for Unions can be different from the one of the returned tuple
by Dominik V. 16 Nov '20

16 Nov '20

New submission from Dominik V. <dominik.vilsmeier1123(a)gmail.com>: Due to caching of `__getitem__` for generic types, the order of arguments as returned by `get_args` might be different for Union: ```python >>> from typing import List, Union, get_args >>> get_args(get_args(List[Union[int, str]])[0]) (<class 'int'>, <class 'str'>) >>> get_args(get_args(List[Union[str, int]])[0]) (<class 'int'>, <class 'str'>) ``` This is because `List[Union[int, str]] is List[Union[str, int]]`. I understand that caching is useful to reduce the memory footprint of type hints, so I suggest to update the documentation of `get_args`. At the moment it reads: > For a typing object of the form X[Y, Z, ...] these functions return X and (Y, Z, ...). This seems to imply that the returned objects are identical to the ones in the form `X[Y, Z, ...]`. However that's not the case: ```python >>> U1 = Union[int, str] >>> U2 = Union[str, int] >>> get_args(List[U1])[0] is U1 True >>> get_args(List[U2])[0] is U2 False ``` I'm not so much concerned about the identity, but the fact that a subsequent call to `get_args` on the Union returns a different type seems to be relevant. So I propose to add the following sentence to the `get_args` docs: > [...], it gets normalized to the original class. > If `X` is a `Union`, the order of `(Y, Z, ...)` can be different from the one of the original arguments `[Y, Z, ...]`. Or alternatively: > [...], it gets normalized to the original class. > If `X` is a `Union`, the order of `(Y, Z, ...)` is arbitrary. The second version is shorter but it's not completely accurate (since the order is actually not arbitrary). ---------- assignee: docs@python components: Documentation messages: 380699 nosy: Dominik V., docs@python priority: normal severity: normal status: open title: Docs of `typing.get_args`: Mention that due to caching of typing generics the order of arguments for Unions can be different from the one of the returned tuple type: enhancement versions: Python 3.9 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue42317> _______________________________________

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[issue14338] urllib2 HowTo for overriding post/3xx behavior.
by beeNuts 16 Nov '20

16 Nov '20

New submission from beeNuts <jeff.adams(a)linux.com>: Issue #14144, with the title "urllib2 HTTPRedirectHandler not forwarding POST data in redirect" was recently closed with these comments: "This could be cookbook recipe style example, if it's utility value is high. I am closing this issue as I feel that the requirement may not be addressed by a change. If there is patch for HowTo, we can tackle that in another issue. Thank you for contribution." The decision that documents on this issue were preferable to a patch seems like a fair compromise, especially considering that the RFC is decidedly ambiguous.I was wondering if the HowTo would be forthcoming? It seems to me that the value/utility would certainly be high. I'd submit it myself but I'm so new to Python that I don't trust my ability to do it correctly. It's something I would find highly useful, though. ---------- assignee: docs@python components: Documentation messages: 156080 nosy: beerNuts, docs@python priority: normal severity: normal status: open title: urllib2 HowTo for overriding post/3xx behavior. versions: Python 3.3 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue14338> _______________________________________

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[issue17437] Difference between open and codecs.open
by Giampaolo Rodola' 15 Nov '20

15 Nov '20

New submission from Giampaolo Rodola': In Python 2 the distinction between open() and codes.open() was clear because 'encoding' and 'errors' args were provided by codecs.open only. This is no longer the case in Python 3 since both args are provided also by open(). I'm probably missing something but regardless I think codecs.open doc [1] should be more clear as to when and why (say) codecs.open(file, encoding='utf8', errors='ignore') should be preferred over open(file, encoding='utf8', errors='ignore'). [1] http://docs.python.org/3/library/codecs.html#codecs.open ---------- assignee: docs@python components: Documentation messages: 184303 nosy: docs@python, ezio.melotti, giampaolo.rodola priority: normal severity: normal status: open title: Difference between open and codecs.open versions: Python 3.2, Python 3.3, Python 3.4 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue17437> _______________________________________

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[issue38495] print built-in function docs bug
by Alex Mashianov 15 Nov '20

15 Nov '20

New submission from Alex Mashianov <mashianov(a)gmail.com>: Python docs says print() function default sep='': http://joxi.ru/EA44JnfonNwLAb.png While in reality sep=' ': http://joxi.ru/n2YXyRsbw6oYm6.png Probably it's a bug with space not being escaped in html to prevent trimming. ---------- assignee: docs@python components: Documentation messages: 354778 nosy: Alex Mashianov, docs@python priority: normal severity: normal status: open title: print built-in function docs bug type: enhancement versions: Python 3.5, Python 3.6, Python 3.7, Python 3.8, Python 3.9 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue38495> _______________________________________

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[issue27119] `compile` doesn't compile into an AST object as specified
by Franklin? Lee 15 Nov '20

15 Nov '20

New submission from Franklin? Lee: >From `compile`'s doc: "Compile the source into a code or AST object." The docs don't say how to compile into an AST object with `compile`, though. As it says later: "If you want to parse Python code into its AST representation, see ast.parse()." I checked 3.4-3.2, 3.0, 2.7, and 2.6. Versions before 3.4, and version 2.6, are missing the `ast.parse` line, but still have the first line. ---------- assignee: docs@python components: Documentation messages: 266311 nosy: docs@python, leewz priority: normal severity: normal status: open title: `compile` doesn't compile into an AST object as specified type: behavior versions: Python 2.7, Python 3.2, Python 3.3, Python 3.4, Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue27119> _______________________________________

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Python 3.9.0 documentation's mistake
by UchidaKoichi 15 Nov '20

15 Nov '20

Hello My name is Koichi Uchida. I’m a University student. I’m sorry to not good at English. I suppose Image 1 in line 8(-6 -5 -4 …) is not true. I think it have to be written ‘-7 -6 -5 -4 -3 … -1’ because, Image 2 is said. Image 1 3.1.2. Strings(https://docs.python.org/3/tutorial/introduction.html#strings <https://docs.python.org/3/tutorial/introduction.html#strings>) Image 2

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[issue42316] Walrus Operator in list index
by Terry J. Reedy 15 Nov '20

15 Nov '20

Change by Terry J. Reedy <tjreedy(a)udel.edu>: ---------- keywords: +patch pull_requests: +22182 stage: -> patch review pull_request: https://github.com/python/cpython/pull/23291 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue42316> _______________________________________

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[issue42343] threading.local documentation should be on the net...
by Antti Haapala 15 Nov '20

15 Nov '20

New submission from Antti Haapala <antti(a)haapala.name>: The current documentation of `thread.local` is ---- Thread-Local Data Thread-local data is data whose values are thread specific. To manage thread-local data, just create an instance of local (or a subclass) and store attributes on it: mydata = threading.local() mydata.x = 1 The instance’s values will be different for separate threads. class threading.local A class that represents thread-local data. For more details and extensive examples, see the documentation string of the _threading_local module. ---- There is no link to the `_threading_local` module docs in the documentation and none of the content from the modules docstrings appear anywhere on docs.python.org website. This is rather annoying because the docstring contains completely non-trivial information including that threading.local can be subclassed and that the __init__ will be run once for each thread for each instance where attributes are accessed. ---------- assignee: docs@python components: Documentation messages: 380875 nosy: docs@python, ztane priority: normal severity: normal status: open title: threading.local documentation should be on the net... type: enhancement _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue42343> _______________________________________

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[issue42359] tutorial: list is a class
by Andy Harrington 15 Nov '20

15 Nov '20

New submission from Andy Harrington <aharrin(a)luc.edu>: Documentation in Tutorial section 9.3.3 seems to be stuck in Python 2: "In Python, the term method is not unique to class instances: other object types can have methods as well. For example, list objects have methods called append, insert, remove, sort, and so on." In Python 3 built-in types are derived from Object, so list is now a class, right? ---------- assignee: docs@python components: Documentation messages: 380997 nosy: andyharrington, docs@python priority: normal severity: normal status: open title: tutorial: list is a class versions: Python 3.9 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue42359> _______________________________________

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[issue42357] Wrong Availability for signal.SIGCHLD
by Maiyun Zhang 14 Nov '20

14 Nov '20

New submission from Maiyun Zhang <myzhang1029(a)hotmail.com>: The availability for `signal.SIGCHLD` is not correct. This seems to be present since Python 3.7 ---------- assignee: docs@python components: Documentation messages: 380981 nosy: docs@python, myzhang1029 priority: normal severity: normal status: open title: Wrong Availability for signal.SIGCHLD versions: Python 3.10 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue42357> _______________________________________

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