docs March 2018

docs@python.org

29 participants
543 discussions

[issue24650] Error in yield expression documentation

by swanson

New submission from swanson: https://docs.python.org/3/reference/expressions.html in 6.2.9. Yield expressions end of 1st paragraph: "Using a yield expression in a function’s body causes that function to be a generator." NO! As the very next sentence explains, a generator is what's returned by such a function, not the function itself. Basically, it should be sufficient to add the word "function" to the end of that sentence: "... generator function." However, this error does NOT exist in 3.0 to 3.2 - just in 3.3 to 3.6, so I suggest just using the same wording as 3.0 to 3.2: "Using a yield expression in a function definition is sufficient to cause that definition to create a generator function instead of a normal function." ---------- assignee: docs@python components: Documentation messages: 246841 nosy: docs@python, swanson priority: normal severity: normal status: open title: Error in yield expression documentation versions: Python 3.3, Python 3.4, Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue24650> _______________________________________

5 days, 4 hours

[issue24711] Document getpass.getpass behavior on ^C

by Markus Unterwaditzer

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: normal status: open title: Document getpass.getpass behavior on ^C 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/issue24711> _______________________________________

6 days

[issue15097] Improving wording on the thread-safeness of import

by Merlijn van Deen

New submission from Merlijn van Deen <valhallasw(a)gmail.com>: http://docs.python.org/library/threading.html#importing-in-threaded-code Currently, the documentation states "Firstly, other than in the main module, an import should not have the side effect of spawning a new thread and then waiting for that thread in any way. Failing to abide by this restriction can lead to a deadlock if the spawned thread directly or indirectly attempts to import a module." which, I think, fails to make the main point: a call to import acquires the import lock. A call to import from a second thread will thus block. As such, I would suggest rephrasing it to something like: "Firstly, an import acquires the import lock for that thread. Therefore, the import should not have the side effect of waiting for a different thread in any way, as this can lead to a deadlock if that thread directly or indirectly attempts to import a module." There are two additional points that might be interesting to note: (1) Any module can be imported. If the import causes a deadlock, that is a bad thing. Every module *will* be imported by tools such as nosetests. (1b) so: never, ever, have code that causes locks in a different thread in module level code witout 'if __name__=="__main__" ' blocks? (2) The lock is also acquired if a module has already been imported. For instance, in import sys # (1) def f(): import sys # (2) the import lock is acquired in (1) /and/ (2). Adding example code and/or a flow diagram might be a bit too much, but it does clarify how easy it is to make this mistake. See the attached for an example (both a simple example script, as well as a flow diagram explaining what happens). ---------- assignee: docs@python components: Documentation files: deadlock.py messages: 163068 nosy: docs@python, valhallasw priority: normal severity: normal status: open title: Improving wording on the thread-safeness of import type: enhancement Added file: http://bugs.python.org/file26037/deadlock.py _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue15097> _______________________________________

2 weeks, 3 days

[issue8595] Unexpected default timeout in http-client-related libraries

by Julian

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 would use a timeout in the 2-10 second range. This problem is propagated up to urllib2, which sits on httplib, and further obscures that the default might be unsuitable. >From an inspection of the manuals, Python 3.0.1 suffers from the same problem except, the names have changed. urllib.response sits on http.client. I, for one, made a brutal mistake of assuming that the "global default" would be some reasonable default for fetching web pages; I didn't have any specific timeout in mind, and was happy for the library to take care of it. Several million successful http downloads later, my server application thread froze waiting forever when talking to a recalcitrant web-server. I imagine others have fallen for the same trap. While an ideal solution would be for httplib and http.client to use a more generally acceptable default, I can see it might be far too late to make such a change without breaking existing applications. Failing that, I would recommend that the documentation for httplib, urllib, urllib2, http.client and urllib.request (+ any other similar libraries sitting on socket? FTP, SMTP?) be changed to highlight that the default global timeout, sans deliberate override, is to wait a surprisingly long time. ---------- assignee: docs@python components: Documentation, Library (Lib) messages: 104763 nosy: docs@python, oddthinking priority: normal severity: normal status: open title: Unexpected default timeout in http-client-related libraries type: behavior versions: Python 2.6, Python 2.7, Python 3.1 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue8595> _______________________________________

2 weeks, 5 days

[issue8822] datetime naive and aware types should have a well-defined definition that can be cross-referenced

by anatoly techtonik

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 troubleshooting datetims issues in Python projects. It needs a proper documentation. ---------- assignee: docs@python components: Documentation messages: 106524 nosy: docs@python, techtonik priority: normal severity: normal status: open title: datetime naive and aware types should have a well-defined definition that can be cross-referenced _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue8822> _______________________________________

2 weeks, 5 days

[issue32501] Documentation for dir([object])

by Vladislavs Burakovs

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> _______________________________________

3 weeks, 2 days

[issue23522] Misleading note in Statistics module documentation

by Jake

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> _______________________________________

4 weeks, 1 day

[issue14586] TypeError: truncate() takes no keyword arguments

by Guy Taylor

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> _______________________________________

1 month

[issue26515] Update extending/embedding docs to new way to build modules in C

by Brett Cannon

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> _______________________________________

1 month

[issue26451] CSV documentation doesn't open with an example

by Alex LordThorsen

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> _______________________________________

1 month

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docs March 2018