Mailman 3 May 2018 - docs

[issue6673] Uncaught comprehension SyntaxError eats up all memory
by Serhiy Storchaka May 9, 2018

May 9, 2018

Serhiy Storchaka <storchaka+cpython(a)gmail.com> added the comment: "yield" in comprehensions is deprecated in 3.7: ../issue6673.py:22: DeprecationWarning: 'yield' inside list comprehension target.send([ (yield) for i in range(chunk_size) ]) and an error in 3.8: File "../issue6673.py", line 22 target.send([ (yield) for i in range(chunk_size) ]) ^ SyntaxError: 'yield' inside list comprehension ---------- nosy: +serhiy.storchaka resolution: -> duplicate stage: needs patch -> resolved status: open -> closed superseder: -> yield expression inside generator expression does nothing _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue6673> _______________________________________

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frozenset.copy() does not create a copy
by Mihail Temelkov May 8, 2018

May 8, 2018

Tried it in Python 2.7 and found that it just creates an alias to the original set.

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add explain about where to set use_builtin_types when use customTransport
by peng yu May 8, 2018

May 8, 2018

I'm using xmlrpc, and I'm using a custom Transport, follow the "21.26.8. Example of Client Usage" section of below document: https://docs.python.org/3/library/xmlrpc.client.html I found if I use a custom transport, set use_builtin_types parameter to xmlrpc.client.ServerProxy will have no effect. After read the source code, I found if I use a custom transport, I should set the use_builtin_types parameter in the transport. I think it is better to describe this behavior in the document. best regards.

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[issue33426] Behavior of os.path.join does not match documentation
by Michael Klatt May 5, 2018

May 5, 2018

New submission from Michael Klatt <michael.d.klatt(a)gmail.com>: The behavior of os.path.join() regarding path separators does not match the documentation. This affects Python 3.6, and goes back to at least Python 2.7. >From the documenation: "The return value is the concatenation of path and any members of *paths with exactly one directory separator (os.sep) following each non-empty part except the last, meaning that the result will only end in a separator if the last part is empty." To me, this means that join will remove extraneous separators from the path, and that the only way to produce a trailing separator is to use join "" as the final path segment. I expect `os.path.join("/abc//", "def/")` to produce the string "/abc/def" based on the documentation, but what it actually produces is "abc//def/". ---------- assignee: docs@python components: Documentation, Library (Lib) messages: 316184 nosy: Michael Klatt, docs@python priority: normal severity: normal status: open title: Behavior of os.path.join does not match documentation type: behavior versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue33426> _______________________________________

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[issue32362] multiprocessing.connection.Connection misdocumented as multiprocessing.Connection
by Mark May 5, 2018

May 5, 2018

New submission from Mark <markamery(a)btinternet.com>: https://docs.python.org/3/library/multiprocessing.html#multiprocessing.Conn… purports to document the multiprocessing.Connection class. There's no such thing: Python 3.6.1 (v3.6.1:69c0db5050, Mar 21 2017, 01:21:04) [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> import multiprocessing >>> multiprocessing.Connection Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: module 'multiprocessing' has no attribute 'Connection' I think it should be multiprocessing.connection.Connection? ---------- assignee: docs@python components: Documentation messages: 308539 nosy: Amery, docs@python priority: normal severity: normal status: open title: multiprocessing.connection.Connection misdocumented as multiprocessing.Connection versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue32362> _______________________________________

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[issue33431] Change description about doc in programming, faq.
by lvhuiyang May 5, 2018

May 5, 2018

Change by lvhuiyang <ilvhuiyang(a)gmail.com>: ---------- keywords: +patch pull_requests: +6398 stage: -> patch review _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue33431> _______________________________________

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[issue33431] Change description about doc in programming, faq.
by lvhuiyang May 5, 2018

May 5, 2018

Change by lvhuiyang <ilvhuiyang(a)gmail.com>: ---------- assignee: docs@python components: Documentation nosy: docs@python, lvhuiyang priority: normal severity: normal status: open title: Change description about doc in programming, faq. type: performance versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue33431> _______________________________________

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[issue33417] Isinstance() behavior is not consistent with the document
by weapon May 4, 2018

May 4, 2018

New submission from weapon <hongweichen8888(a)sina.com>: In the PEP 3119(https://www.python.org/dev/peps/pep-3119/),it introduce about Customizing instance and subclass checks. >The primary mechanism proposed here is to allow overloading the built-in functions isinstance() and issubclass(). The overloading works as follows: The call isinstance(x, C) first checks whether C.__instancecheck__ exists, and if so, calls C.__instancecheck__(x) instead of its normal implementation. but my code doesn't works. ``` class Sizeable(object): def __instancecheck__(cls, instance): print("__instancecheck__ call") return hasattr(instance, "__len__") class B(object): pass b = B() print(isinstance(b, Sizeable)) # output:False ``` The __instancecheck__ function is not called. In PyObject_IsInstance,when isinstance(x, C) the following three conditions are reached, __instancecheck__ will take effect: 1. x can not be directly instantiated by C; 2. The C class specifies the metaclass; 3. The __instancecheck__ in the specified metaclass class is defined. This code can work: ``` class MetaSizeable(type): def __instancecheck__(cls, instance): print("__instancecheck__ call") return hasattr(instance, "__len__") class Sizeable(metaclass=MetaSizeable): pass class B(object): pass b = B() print(isinstance(b, Sizeable)) # output: False print(isinstance([], Sizeable)) # output: True ``` So,the problem is that the document does not conform to the reality.Can it be guaranteed that __instancecheck__ is always called? If yes: PyObject_IsInstance should be tweaked. If no: document should be tweaked. ---------- assignee: docs@python components: Documentation, Interpreter Core messages: 316118 nosy: docs@python, hongweipeng priority: normal severity: normal status: open title: Isinstance() behavior is not consistent with the document type: behavior versions: Python 3.7 _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue33417> _______________________________________

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[issue26256] Fast decimalisation and conversion to other bases
by Cheryl Sabella May 4, 2018

May 4, 2018

Cheryl Sabella <chekat2(a)gmail.com> added the comment: ping ---------- _______________________________________ Python tracker <report(a)bugs.python.org> <https://bugs.python.org/issue26256> _______________________________________

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