Mailman 3 February 2015 - docs

[issue13047] imp.find_module("") and imp.find_module(".")
by Arfrever Frehtes Taifersar Arahesis Oct. 22, 2020

Oct. 22, 2020

New submission from Arfrever Frehtes Taifersar Arahesis <Arfrever.FTA(a)GMail.Com>: It's undocumented that imp.find_module("") and imp.find_module(".") try to find __init__.py. There is also a small difference in behavior between them. sys.path by default contains "" as the first element, which is sufficient for imp.find_module("."), but not for imp.find_module(""): $ mkdir /tmp/imp_tests $ cd /tmp/imp_tests $ touch __init__.py $ python3.3 -c 'import imp, sys; print(repr(sys.path[0])); print(imp.find_module("."))' '' (None, '.', ('', '', 5)) $ python3.3 -c 'import imp, sys; print(repr(sys.path[0])); print(imp.find_module(""))' '' Traceback (most recent call last): File "<string>", line 1, in <module> ImportError: No module named '' If sys.path contains path (e.g. "." or absolute path) to directory with __init__.py file, then imp.find_module("") will succeed: $ PYTHONPATH="." python3.3 -c 'import imp, sys; print(repr(sys.path[0:2])); print(imp.find_module("."))' ['', '/tmp/imp_tests'] (None, '.', ('', '', 5)) $ PYTHONPATH="." python3.3 -c 'import imp, sys; print(repr(sys.path[0:2])); print(imp.find_module(""))' ['', '/tmp/imp_tests'] (None, '/tmp/imp_tests/', ('', '', 5)) $ python3.3 -c 'import imp, sys; sys.path.insert(1, "."); print(repr(sys.path[0:2])); print(imp.find_module("."))' ['', '.'] (None, '.', ('', '', 5)) $ python3.3 -c 'import imp, sys; sys.path.insert(1, "."); print(repr(sys.path[0:2])); print(imp.find_module(""))' ['', '.'] (None, './', ('', '', 5)) I think that imp.find_module(".") and imp.find_module("") should have the same behavior, and this behavior should be documented. ---------- assignee: docs@python components: Documentation, Interpreter Core messages: 144531 nosy: Arfrever, docs@python priority: normal severity: normal status: open title: imp.find_module("") and imp.find_module(".") versions: Python 2.7, Python 3.2, Python 3.3 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13047> _______________________________________

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[issue14979] pdb: Link to source
by anatoly techtonik Oct. 22, 2020

Oct. 22, 2020

New submission from anatoly techtonik <techtonik(a)gmail.com>: http://docs.python.org/library/pdb.html#pdb.Pdb Documentation for pdb says: "The debugger is extensible — it is actually defined as the class Pdb. This is currently undocumented but easily understood by reading the source." There should a link to the source. ---------- assignee: docs@python components: Documentation, Library (Lib) messages: 162074 nosy: docs@python, techtonik priority: normal severity: normal status: open title: pdb: Link to source _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue14979> _______________________________________

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[issue19438] Where is NoneType in Python 3?
by mpb Oct. 21, 2020

Oct. 21, 2020

New submission from mpb: types.NoneType seems to have disappeared in Python 3. This is probably intentional, but I cannot figure out how to test if a variable is of type NoneType in Python 3. Specifically, I want to write: assert type (v) in ( bytes, types.NoneType ) Yes, I could write: assert v is None or type (v) is bytes But the first assert statement is easier to read (IMO). Here are links to various Python 3 documentation about None: [1] http://docs.python.org/3/library/stdtypes.html#index-2 [2] http://docs.python.org/3/library/constants.html#None Link [2] says: "None The sole value of the type NoneType." However, NoneType is not listed in the Python 3 documentation index. (As compared with the Python 2 index, where NoneType is listed.) [3] http://docs.python.org/3/library/types.html If NoneType is gone in Python 3, mention of NoneType should probably be removed from link [2]. If NoneType is present in Python 3, the docs (presumably at least one of the above links, and hopefully also the index) should tell me how to use it. Here is another link: [4] http://docs.python.org/3/library/stdtypes.html#bltin-type-objects "The standard module types defines names for all standard built-in types." (Except <class 'NoneType'> ???) None is a built-in constant. It has a type. If None's type is not considered to be a "standard built-in type", then IMO this is surprising(!!) and should be documented somewhere (for example, at link [4], and possibly elsewhere as well.) Thanks! ---------- assignee: docs@python components: Documentation messages: 201666 nosy: docs@python, mpb priority: normal severity: normal status: open title: Where is NoneType in Python 3? versions: Python 3.3 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue19438> _______________________________________

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[issue18280] Documentation is too personalized
by Serhiy Storchaka Sept. 19, 2020

Sept. 19, 2020

New submission from Serhiy Storchaka: Some documentation files contain a number of I/my/me. Looks like they grew from personal modules and personal articles. Perhaps the official documentation needs more depersonalized style. Here is full list of such files: Doc/c-api/exceptions.rst Doc/c-api/long.rst Doc/distutils/builtdist.rst Doc/extending/extending.rst Doc/extending/windows.rst Doc/howto/argparse.rst Doc/howto/curses.rst Doc/howto/functional.rst Doc/howto/regex.rst Doc/howto/sockets.rst Doc/howto/urllib2.rst Doc/install/index.rst Doc/library/audioop.rst Doc/library/ctypes.rst Doc/library/doctest.rst Doc/library/heapq.rst Doc/library/numbers.rst Doc/library/ossaudiodev.rst Doc/library/tk.rst Doc/library/unittest.mock-examples.rst Doc/library/unittest.mock.rst Doc/reference/introduction.rst Doc/tutorial/classes.rst The list doesn't include FAQs where it may be appropriate and whatsnew files. Andrew Kuchling recently has fixed Doc/howto/unicode.rst for this issue (as part of issue4153). ---------- assignee: docs@python components: Documentation messages: 191636 nosy: akuchling, docs@python, eric.araujo, ezio.melotti, georg.brandl, serhiy.storchaka priority: normal severity: normal status: open title: Documentation is too personalized versions: Python 2.7, Python 3.3, Python 3.4 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue18280> _______________________________________

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[issue13828] Further improve casefold documentation
by Jim Jewett Aug. 24, 2020

Aug. 24, 2020

New submission from Jim Jewett <jimjjewett(a)gmail.com>: > http://hg.python.org/cpython/rev/0b5ce36a7a24 > changeset: 74515:0b5ce36a7a24 > + Casefolding is similar to lowercasing but more aggressive because it is > + intended to remove all case distinctions in a string. For example, the German > + lowercase letter ``'ß'`` is equivalent to ``"ss"``. Since it is already > + lowercase, :meth:`lower` would do nothing to ``'ß'``; :meth:`casefold` > + converts it to ``"ss"``. Perhaps add the recommendation to canonicalize as well. A complete, but possibly too long, try is below: Casefolding is similar to lowercasing but more aggressive because it is intended to remove all case distinctions in a string. For example, the German lowercase letter ``'ß'`` is equivalent to ``"ss"``. Since it is already lowercase, :meth:`lower` would do nothing to ``'ß'``; :meth:`casefold` converts it to ``"ss"``. Note that most case-insensitive matches should also match compatibility equivalent characters. The casefolding algorithm is described in section 3.13 of the Unicode Standard. Per D146, a compatibility caseless match can be achieved by from unicodedata import normalize def caseless_compat(string): nfd_string = normalize("NFD", string) nfkd1_string = normalize("NFKD", nfd_string.casefold()) return normalize("NFKD", nfkd1_string.casefold()) ---------- assignee: docs@python components: Documentation messages: 151644 nosy: Jim.Jewett, benjamin.peterson, docs@python priority: normal severity: normal status: open title: Further improve casefold documentation versions: Python 3.3 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13828> _______________________________________

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[issue21333] Document recommended exception for objects that shouldn't be pickled
by Stefan Schwarzer July 5, 2020

July 5, 2020

New submission from Stefan Schwarzer: I recently was confused whether to raise a `PicklingError` or `TypeError` in `__getstate__` if objects of my class can't and shouldn't be pickled. [1] Terry Reedy advised I should use `TypeError`. [2] I wonder if the `pickle` module documention should explicitly recommend using `TypeError` if a class wants to say that its objects can't be pickled. What do you think? [1] https://mail.python.org/pipermail/python-list/2014-April/670987.html [2] https://mail.python.org/pipermail/python-list/2014-April/671002.html ---------- assignee: docs@python components: Documentation messages: 217054 nosy: docs@python, sschwarzer priority: normal severity: normal status: open title: Document recommended exception for objects that shouldn't be pickled type: enhancement versions: Python 3.5 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue21333> _______________________________________

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[issue17805] No such class: multiprocessing.pool.AsyncResult
by Takafumi Arakaki July 3, 2020

July 3, 2020

New submission from Takafumi Arakaki: Document mentions AsyncResult but there is no such class. http://docs.python.org/2/library/multiprocessing.html#multiprocessing.pool.… You can check it by simply running: python -c 'from multiprocessing.pool import AsyncResult' I think it means ApplyResult so I made a patch (attached). Note that there managers.py also uses name 'AsyncResult': % hg grep AsyncResult Doc/library/multiprocessing.rst:83232:.. class:: AsyncResult Lib/multiprocessing/managers.py:81039: 'apply_async': 'AsyncResult', Lib/multiprocessing/managers.py:81039: 'map_async': 'AsyncResult', Lib/multiprocessing/managers.py:81039: 'starmap_async': 'AsyncResult', Lib/multiprocessing/managers.py:81039:SyncManager.register('AsyncResult', create_method=False) Probably renaming them would be better? ---------- assignee: docs@python components: Documentation files: ApplyResult.patch keywords: patch messages: 187466 nosy: docs@python, tkf priority: normal severity: normal status: open title: No such class: multiprocessing.pool.AsyncResult versions: Python 2.6, Python 2.7, Python 3.1, Python 3.2, Python 3.3, Python 3.4, Python 3.5 Added file: http://bugs.python.org/file29954/ApplyResult.patch _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue17805> _______________________________________

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[issue23427] Python should expose command when invoked with -c
by Jan-Philip Gehrcke June 29, 2020

June 29, 2020

New submission from Jan-Philip Gehrcke: When Python is invoked with the `-c command` switch, the command string does not get exposed in sys.argv: $ python -c "import sys; print(sys.argv)" ['-c'] $ python -c "import sys; print(sys.argv)" arg1 ['-c', 'arg1'] The command string does not get exposed anywhere, AFAIK, so it is inaccessible from within Python programs. There might be application scenarios in which it is useful to access the command string, such as for debugging purposes. One scenario is when a Python session should be able to "re-spawn" itself in a subprocess (I came across this question on StackOverflow: http://stackoverflow.com/q/28412903/145400) I propose to make the command string accessible. If you agree that it might make sense, the question is *how/where* to expose it. One possible way is to retain it in sys.argv, as in this example: $ python -c "import sys; print(sys.argv)" "arg1" ['-c', 'import sys; print(sys.argv)', 'arg1'] The current sys.argv docs say > If the command was executed using the -c command line option to > the interpreter, argv[0] is set to the string '-c'. This sentence could then be adjusted to "[...], argv[0] is set to the string '-c', and argv[1] contains the command." This method breaks existing applications that are started with the -c method and that consume command line arguments in a sys.argv[1:] fashion. The tests in Lib/test/test_cmd_line.py all pass, however. A second method would be to change sys.argv[0] from '-c' to '-c command'. This would break existing applications that check for sys.argv[0] == 'c'. A third method would be to leave sys.argv as it is, and expose the command with a new attribute in the sys module. I have attached a patch for variant 1 (passes all tests in Lib/test/test_cmd_line.py), to demonstrate which code is affected: the translation from the "real" argv to sys' argv is triggered in Modules/main.c. The patch does not change behavior of '-m' (it's funny, however, that the current version of main.c at first replaces the module string with '-m', whereas the runpy module later on replaces '-m' with the path to the module file anyway.). As a side node, I figure that the sys.argv documentation should be adjusted to properly reflect the -m behavior, which is: $ ./python -m testmodule foo testmodule sys.argv: ['/data/local/pythondev/pythontip/cpython/testmodule.py', 'foo'] Let me hear your comments, and I am willing to work on code and doc patches, thanks! ---------- assignee: docs@python components: Documentation, Interpreter Core files: sys_argv_cmd.patch keywords: patch messages: 235633 nosy: docs@python, georg.brandl, haypo, jgehrcke, pitrou priority: normal severity: normal status: open title: Python should expose command when invoked with -c type: enhancement versions: Python 3.5, Python 3.6 Added file: http://bugs.python.org/file38065/sys_argv_cmd.patch _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue23427> _______________________________________

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[issue17589] Make documentation about macros in C API explicit about rvalue vs statement
by Larry Hastings June 25, 2020

June 25, 2020

New submission from Larry Hastings: CPython API "functions" implemented as macros can expand into either rvalues or statements. Most expand into statements (often using the do {} while (0) syntactic sugar trick), but occasionally they're legal as rvalues. As of this writing Py_INCREF works as an rvalue. But discussion on another tracker issue (#17206) proposes changing the implementation in such a way that it will only be usable as a statement. Although it's mildly unlikely, it's certainly possible that this will break somebody's code. I propose that the documentation make an explicit ruling on whether macros are usable as rvalues or as statements. Perhaps a blanket statement would suffice, "all macros are only supported for use as statements except where explicitly noted", then annotate specific macros that are supported for use as rvalues. Though that raises the question of acknowledging in the documentation that some things are macros--I think the documentation glosses over that fact right now. Note: I added you three (Georg, Mark, Martin) as I thought you might have an opinion on this one way or the other. If you're not interested, my apologies. ---------- assignee: docs@python components: Documentation messages: 185646 nosy: Mark.Shannon, docs@python, georg.brandl, larry, loewis priority: normal severity: normal stage: needs patch status: open title: Make documentation about macros in C API explicit about rvalue vs statement type: enhancement versions: Python 3.4 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue17589> _______________________________________

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[issue21508] C API PyArg_ParseTuple doc is innacurate
by Steve June 25, 2020

June 25, 2020

New submission from Steve: PyArg_ParseTuple is defined as returning an "int", but the documentation talks about returning a true/false value, and failling on false. In addition to being inaccurate, considering that most other functions fail on !=0 ("true"), it can lead to confusion. Doc: int PyArg_ParseTuple(PyObject *args, const char *format, ...) Parse the parameters of a function that takes only positional parameters into local variables. Returns true on success; on failure, it returns false and raises the appropriate exception. ---------- assignee: docs@python components: Documentation messages: 218536 nosy: Banger, docs@python priority: normal severity: normal status: open title: C API PyArg_ParseTuple doc is innacurate type: enhancement versions: Python 3.3, Python 3.4, Python 3.5 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue21508> _______________________________________

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