Mailman 3 September 2018 - docs

[issue22401] argparse: 'resolve' conflict handler damages the actions of the parent parser
by paul j3 Jan. 27, 2021

Jan. 27, 2021

New submission from paul j3: When there's a conflict involving an argument that was added via 'parents', and the conflict handler is 'resolve', the action in the parent parser may be damaged, rendering that parent unsuitable for further use. In this example, 2 parents have the same '--config' argument: parent1 = argparse.ArgumentParser(add_help=False) parent1.add_argument('--config') parent2 = argparse.ArgumentParser(add_help=False) parent2.add_argument('--config') … [View More]parser = argparse.ArgumentParser(parents=[parent1,parent2], conflict_handler='resolve') The actions of the 3 parsers are (from the ._actions list): (id, dest, option_strings) parent1: [(3077384012L, 'config', [])] # empty option_strings parent2: [(3076863628L, 'config', ['--config'])] parser: [(3076864428L, 'help', ['-h', '--help']), (3076863628L, 'config', ['--config'])] # same id The 'config' Action from 'parent1' is first copied to 'parser' by reference (this is important). When 'config' from 'parent2' is copied, there's a conflict. '_handle_conflict_resolve()' attempts to remove the first Action, so it can add the second. But in the process it ends up deleting the 'option_strings' values from the original action. So now 'parent1' has an action in its 'optionals' argument group with an empty option_strings list. It would display as an 'optionals' but parse as a 'positionals'. 'parent1' can no longer be safely used as a parent for another (sub)parser, nor used as a parser itself. The same sort of thing would happen, if, as suggested in the documentation: "Sometimes (e.g. when using parents_) it may be useful to simply override any older arguments with the same option string." In test_argparse.py, 'resolve' is only tested once, with a simple case of two 'add_argument' statements. The 'parents' class tests a couple of cases of conflicting actions (for positionals and optionals), but does nothing with the 'resolve' handler. ------------------------------ Possible fixes: - change the documentation to warn against reusing such a parent parser - test the 'resolve' conflict handler more thoroughly - rewrite this conflict handler so it does not modify the action in the parent - possibly change the 'parents' mechanism so it does a deep copy of actions. References: http://stackoverflow.com/questions/25818651/argparse-conflict-resolver-for-… http://bugs.python.org/issue15271 argparse: repeatedly specifying the same argument ignores the previous ones http://bugs.python.org/issue19462 Add remove_argument() method to argparse.ArgumentParser http://bugs.python.org/issue15428 add "Name Collision" section to argparse docs ---------- assignee: docs@python components: Documentation, Library (Lib), Tests messages: 226862 nosy: docs@python, paul.j3 priority: normal severity: normal status: open title: argparse: 'resolve' conflict handler damages the actions of the parent parser type: behavior versions: Python 3.5 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue22401> _______________________________________ [View Less]

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[issue24711] Document getpass.getpass behavior on ^C
by Markus Unterwaditzer Jan. 11, 2021

Jan. 11, 2021

New submission from Markus Unterwaditzer: getpass.getpass doesn't enter a newline when the user aborts input with ^C, while input/raw_input does. This behavior is surprising and can lead to mis-formatting of subsequent output. However, since this behavior exists since 2.7 and applications may have started to rely on it, I'd add a note to the documentation. ---------- assignee: docs@python components: Documentation messages: 247302 nosy: docs@python, untitaker priority: normal severity: … [View More]

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[issue34804] Repetition of 'for example' in documentation
by Aydin Jan. 10, 2021

Jan. 10, 2021

New submission from Aydin <bagiyevaydin(a)gmail.com>: In the documentation of Python 3.7.0 there is an error in the usage of the world 'for example'. ---------- assignee: docs@python components: Documentation files: Functional Programming HOWTO — Python 3.7.0 documentation.png messages: 326418 nosy: docs@python, rarblack priority: normal severity: normal status: open title: Repetition of 'for example' in documentation versions: Python 3.7 Added file: https://bugs.python.org/file47825/… [View More]

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[issue34451] docs: tutorial/introduction doesn't mention toggle of prompts
by Jonathan Fine Jan. 6, 2021

Jan. 6, 2021

New submission from Jonathan Fine <jfine2358(a)gmail.com>: Interactive code examples need the prompt to be stripped, before copy-and-paste. This is explained in https://docs.python.org/3/tutorial/introduction.html But this page does not tell us about the [>>>] prompt-toggle at top of each interactive code example. This caused a user error, reported in https://mail.python.org/pipermail/python-ideas/2018-August/052869.html. The [>>>] toggle isn't in the Python 2.7 docs,… [View More]

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[issue8595] Unexpected default timeout in http-client-related libraries
by Julian Dec. 29, 2020

Dec. 29, 2020

New submission from Julian <python_org(a)somethinkodd.com>: Since Python 2.6, httplib has offered a timeout parameter for fetches. As the documentation explains, if this parameter is not provided, it uses the global default. What the document doesn't explain is httplib builds on top of the socket library. The socket library has a default timeout of None (i.e. forever). This may be an appropriate default for general sockets, but it is a poor default for httplib; typical http clients … [View More]

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[issue8822] datetime naive and aware types should have a well-defined definition that can be cross-referenced
by anatoly techtonik Dec. 29, 2020

Dec. 29, 2020

New submission from anatoly techtonik <techtonik(a)gmail.com>: 'naive' and 'aware' are key datetime types - they need a proper definition and anchor for crossrefences. If you take a look at http://docs.python.org/library/datetime.html - the definition of distinction between them is too vague and this seeds of uncertainty grow through the rest of the doc. It is not said how to make non-naive object, how to detect if object of naive or aware. All this stuff is very important for … [View More]

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[issue32501] Documentation for dir([object])
by Vladislavs Burakovs Dec. 24, 2020

Dec. 24, 2020

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 … [View More]

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[issue23522] Misleading note in Statistics module documentation
by Jake Dec. 19, 2020

Dec. 19, 2020

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 … [View More]

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[issue14586] TypeError: truncate() takes no keyword arguments
by Guy Taylor Dec. 15, 2020

Dec. 15, 2020

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.… [View More]

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[issue26515] Update extending/embedding docs to new way to build modules in C
by Brett Cannon Dec. 15, 2020

Dec. 15, 2020

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 _______________________________________ … [View More]

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