Mailman 3 February 2014 - docs

[issue16891] Fix docs about module search order
by Dmitry Mugtasimov May 31, 2020

May 31, 2020

New submission from Dmitry Mugtasimov: http://docs.python.org/2/tutorial/modules.html should be rewritten. AS IS 6.1.2. The Module Search Path When a module named spam is imported, the interpreter first searches for a built-in module with that name. If not found, it then searches for a file named spam.py in a list of directories given by the variable sys.path. sys.path is initialized from these locations: TO BE 6.1.2. The Module Search Path When a module named spam is imported, the interpreter first searches for a built-in module with that name. If not found, it looks in the containing package (the package of which the current module is a submodule). If not found, it then searches for a file named spam.py in a list of directories given by the variable sys.path. sys.path is initialized from these locations: ------ Note that now "6.1.2. The Module Search Path" and "6.4.2. Intra-package References" are contradictary since in 6.4.2 it is said: "In fact, such references are so common that the import statement first looks in the containing package before looking in the standard module search path.", but this is not reflected in 6.1.2. ------ EXAMPLE (for more information see http://stackoverflow.com/questions/14183541/why-python-finds-module-instead… ): /home/dmugtasimov/tmp/name-res3/xyz __init__.py a.py b.py t.py xyz.py Files init.py, b.py and xyz.py are empty File a.py: import os, sys ROOT_DIRECTORY = os.path.abspath(os.path.join(os.path.dirname(__file__), '..')) if not sys.path or ROOT_DIRECTORY not in sys.path: print 'sys.path is modified in a.py' sys.path.insert(0, ROOT_DIRECTORY) else: print 'sys.path is NOT modified in a.py' print 'sys.path:', sys.path print 'BEFORE import xyz.b' import xyz.b print 'AFTER import xyz.b' File t.py: import os, sys ROOT_DIRECTORY = os.path.abspath(os.path.join(os.path.dirname(__file__), '..')) if not sys.path or ROOT_DIRECTORY not in sys.path: print 'sys.path is modified in t.py' sys.path.insert(0, ROOT_DIRECTORY) else: print 'sys.path is NOT modified in t.py' import xyz.a Run: python a.py Output: sys.path is modified in a.py sys.path: ['/home/dmugtasimov/tmp/name-res3', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/local/lib/python2.7/dist-packages/tornado-2.3-py2.7.egg', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/local/lib/python2.7/dist-packages/setuptools-0.6c11-py2.7.egg-info', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PIL', '/usr/lib/python2.7/dist-packages/gst-0.10', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client'] BEFORE import xyz.b AFTER import xyz.b Run: python -vv a.py Output: import xyz # directory /home/dmugtasimov/tmp/name-res3/xyz # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__.so # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__module.so # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__.py # /home/dmugtasimov/tmp/name-res3/xyz/__init__.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/__init__.py import xyz # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/__init__.pyc # trying /home/dmugtasimov/tmp/name-res3/xyz/b.so # trying /home/dmugtasimov/tmp/name-res3/xyz/bmodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/b.py # /home/dmugtasimov/tmp/name-res3/xyz/b.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/b.py import xyz.b # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/b.pyc Run: python t.py Output: sys.path is modified in t.py sys.path is NOT modified in a.py sys.path: ['/home/dmugtasimov/tmp/name-res3', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/local/lib/python2.7/dist-packages/tornado-2.3-py2.7.egg', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/local/lib/python2.7/dist-packages/setuptools-0.6c11-py2.7.egg-info', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PIL', '/usr/lib/python2.7/dist-packages/gst-0.10', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client'] BEFORE import xyz.b Traceback (most recent call last): File "t.py", line 9, in <module> import xyz.a File "/home/dmugtasimov/tmp/name-res3/xyz/a.py", line 11, in <module> import xyz.b ImportError: No module named b Run: python -vv t.py Output: import xyz # directory /home/dmugtasimov/tmp/name-res3/xyz # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__.so # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__module.so # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__.py # /home/dmugtasimov/tmp/name-res3/xyz/__init__.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/__init__.py import xyz # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/__init__.pyc # trying /home/dmugtasimov/tmp/name-res3/xyz/a.so # trying /home/dmugtasimov/tmp/name-res3/xyz/amodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/a.py # /home/dmugtasimov/tmp/name-res3/xyz/a.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/a.py import xyz.a # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/a.pyc # trying /home/dmugtasimov/tmp/name-res3/xyz/os.so # trying /home/dmugtasimov/tmp/name-res3/xyz/osmodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/os.py # trying /home/dmugtasimov/tmp/name-res3/xyz/os.pyc # trying /home/dmugtasimov/tmp/name-res3/xyz/sys.so # trying /home/dmugtasimov/tmp/name-res3/xyz/sysmodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/sys.py # trying /home/dmugtasimov/tmp/name-res3/xyz/sys.pyc # trying /home/dmugtasimov/tmp/name-res3/xyz/xyz.so # trying /home/dmugtasimov/tmp/name-res3/xyz/xyzmodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/xyz.py # /home/dmugtasimov/tmp/name-res3/xyz/xyz.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/xyz.py import xyz.xyz # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/xyz.pyc # clear[2] __file__ # clear[2] __package__ # clear[2] sys # clear[2] ROOT_DIRECTORY # clear[2] __name__ # clear[2] os sys.path is modified in t.py sys.path is NOT modified in a.py sys.path: ['/home/dmugtasimov/tmp/name-res3', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/local/lib/python2.7/dist-packages/tornado-2.3-py2.7.egg', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/local/lib/python2.7/dist-packages/setuptools-0.6c11-py2.7.egg-info', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PIL', '/usr/lib/python2.7/dist-packages/gst-0.10', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client'] BEFORE import xyz.b Traceback (most recent call last): File "t.py", line 9, in <module> import xyz.a File "/home/dmugtasimov/tmp/name-res3/xyz/a.py", line 11, in <module> import xyz.b ImportError: No module named b As you see sys.path is the same for both cases: sys.path: ['/home/dmugtasimov/tmp/name-res3', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/local/lib/python2.7/dist-packages/tornado-2.3-py2.7.egg', '/home/dmugtasimov/tmp/name-res3/xyz', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/local/lib/python2.7/dist-packages/setuptools-0.6c11-py2.7.egg-info', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PIL', '/usr/lib/python2.7/dist-packages/gst-0.10', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client'] But the behaviour is different. For a.py python searches for package xyz first, and them for module b in it: import xyz # directory /home/dmugtasimov/tmp/name-res3/xyz # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__.so # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__module.so # trying /home/dmugtasimov/tmp/name-res3/xyz/__init__.py # /home/dmugtasimov/tmp/name-res3/xyz/__init__.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/__init__.py import xyz # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/__init__.pyc # trying /home/dmugtasimov/tmp/name-res3/xyz/b.so # trying /home/dmugtasimov/tmp/name-res3/xyz/bmodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/b.py # /home/dmugtasimov/tmp/name-res3/xyz/b.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/b.py import xyz.b # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/b.pyc In other words: Search PACKAGE xyz in directory sys.path[0] -> FOUND Search module b in PACKAGE xyz -> FOUND Continue execution For t.py it searches for moduel xyz in the same directory as a.py itself and then fails to find module b in module xyz: # trying /home/dmugtasimov/tmp/name-res3/xyz/xyz.so # trying /home/dmugtasimov/tmp/name-res3/xyz/xyzmodule.so # trying /home/dmugtasimov/tmp/name-res3/xyz/xyz.py # /home/dmugtasimov/tmp/name-res3/xyz/xyz.pyc matches /home/dmugtasimov/tmp/name-res3/xyz/xyz.py import xyz.xyz # precompiled from /home/dmugtasimov/tmp/name-res3/xyz/xyz.pyc In other words: Search MODULE xyz in directory in the same directory as a.py (or sys.path[1] ?) -> FOUND Search MODULE b in MODULE xyz -> NOT FOUND ImportError So it looks like if "import xyz.b" bahaves different depending on how a.py was initially loaded as a script or imported from another module. ---------- assignee: docs@python components: Documentation messages: 179321 nosy: dmugtasimov, docs@python priority: normal severity: normal status: open title: Fix docs about module search order type: behavior versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue16891> _______________________________________

6 10

[issue13649] termios.ICANON is not documented
by anatoly techtonik May 31, 2020

May 31, 2020

New submission from anatoly techtonik <techtonik(a)gmail.com>: http://docs.python.org/library/termios.html is missing documentation for ICANON flag used to put terminal to "raw" mode. It is also worth to place `termios` raw/canonical mode equivalent on `tty` pages, so that people porting C code to Python could understand the hidden magic. ---------- assignee: docs@python components: Documentation, IO, Library (Lib) messages: 150098 nosy: docs@python, techtonik priority: normal severity: normal status: open title: termios.ICANON is not documented versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13649> _______________________________________

3 3

[issue16700] Document that bytes OS API can returns unusable results on Windows
by Serhiy Storchaka May 31, 2020

May 31, 2020

New submission from Serhiy Storchaka: Some OS functions which returns bytes (os.environb, os.getenvb(), os.getcwdb(), os.listdir(), os.readlink(), os.walk(), os.path.abspath(), os.path.expanduser(), os.path.expandvars(), os.path.realpath() and may be other) can return unusable result on Windows (see for example issue13247 and issue16656). The documentation should contains strong warnings about this. ---------- assignee: docs@python components: Documentation, Windows messages: 177613 nosy: docs@python, serhiy.storchaka priority: normal severity: normal stage: needs patch status: open title: Document that bytes OS API can returns unusable results on Windows type: enhancement versions: Python 2.7, Python 3.2, Python 3.3, Python 3.4 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue16700> _______________________________________

6 12

[issue20296] PyArg_ParseTuple 2.X docs mention int for "t#", but "Py_ssize_t" for "w#", etc.
by Rob Browning May 31, 2020

May 31, 2020

New submission from Rob Browning: Here (http://docs.python.org/2/c-api/arg.html), the documentation for "t#" says: t# (read-only character buffer) [char *, int]... while the documentation for "w#" says: w# (read-write character buffer) [char *, Py_ssize_t]... However, from getargs.c, it looks like they're handled the same with respect to the size type. At a minimum, it seems like it might make sense to change these docs to match, and if "w#" and "t#" are actually handled similarly to "s#", it would be even better to just change their docs to match (or refer to) "s#"'s which are more detailed, i.e. they mention the PY_SSIZE_T_CLEAN issues, etc. Thanks ---------- assignee: docs@python components: Documentation messages: 208410 nosy: docs@python, rlb priority: normal severity: normal status: open title: PyArg_ParseTuple 2.X docs mention int for "t#", but "Py_ssize_t" for "w#", etc. versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue20296> _______________________________________

3 3

[issue9196] Improve docs for string interpolation "%s" re Unicode strings
by Craig McQueen May 31, 2020

May 31, 2020

New submission from Craig McQueen <python(a)craig.mcqueen.id.au>: I have just been trying to figure out how string interpolation works for "%s", when Unicode strings are involved. It seems it's a bit complicated, but the Python documentation doesn't really describe it. It just says %s "converts any Python object using str()". Here is what I have found (I think), and it could be worth improving the documentation of this somehow. Example 1: "%s" % test_object >From what I can tell, in this case: 1. test_object.__str__() is called. 2. If test_object.__str__() returns a string object, then that is substituted. 3. If test_object.__str__() returns a Unicode object (for some reason), then test_object.__unicode__() is called, then _that_ is substituted instead. The output string is turned into Unicode. This behaviour is surprising. [Note that the call to test_object.__str__() is not the same as str(test_object), because the former can return a Unicode object without causing an error, while the latter, if it gets a Unicode object, will then try to encode('ascii') to a string, possibly generating a UnicodeEncodeError exception.] Example 2: u"%s" % test_object In this case: 1. test_object.__unicode__() is called, if it exists, and the result is substituted. The output string is Unicode. 2. If test_object.__unicode__() doesn't exist, then test_object.__str__() is called instead, converted to Unicode, and substituted. The output string is Unicode. Example 3: "%s %s" % (u'unicode', test_object) In this case: 1. The first substitution causes the output string to be Unicode. 2. It seems that (1) causes the second substitution to follow the same rules as Example 2. This is a little surprising. ---------- assignee: docs@python components: Documentation messages: 109516 nosy: cmcqueen1975, docs@python priority: normal severity: normal status: open title: Improve docs for string interpolation "%s" re Unicode strings versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue9196> _______________________________________

5 10

[issue20686] Confusing statement
by Daniel U. Thibault May 31, 2020

May 31, 2020

New submission from Daniel U. Thibault: Near the end of 3.1.3 http://docs.python.org/2/tutorial/introduction.html#unicode-strings you can read: "When a Unicode string is printed, written to a file, or converted with str(), conversion takes place using this default encoding." This can be interpreted as stating that stating that printing a Unicode string (using the print function or the shell's default print behaviour) results in ASCII printout. It can likewise be interpreted as stating that any write of a Unicode string to a file converts the string to ASCII. Experimentation shows this is not true. Perhaps you meant something like this: "When a Unicode string is converted with str() in order to be printed or written to a file, conversion takes place using this default encoding." Grammatical comments: In the statement "When a Unicode string is printed, written to a file, or converted with str(), conversion takes place using this default encoding.", the ", or" puts the three elements of the enumeration on the same level (respectively "printed", "written to a file", and "converted with str()"). The confusion seems to arise because "with str()" was meant to apply to the list as a whole, not just its last element. ---------- assignee: docs@python components: Documentation messages: 211627 nosy: Daniel.U..Thibault, docs@python priority: normal severity: normal status: open title: Confusing statement type: enhancement _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue20686> _______________________________________

4 9

[issue17387] Error in C API documentation of PySequenceMethods
by Alex Orange May 31, 2020

May 31, 2020

New submission from Alex Orange: The documentation at http://docs.python.org/2/c-api/typeobj.html#PySequenceMethods is missing sq_slice between sq_item and sq_ass_item. This will mess up anyone trying to use anything after sq_item (that isn't using designated initializers). ---------- assignee: docs@python components: Documentation messages: 183779 nosy: Alex.Orange, docs@python priority: normal severity: normal status: open title: Error in C API documentation of PySequenceMethods versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue17387> _______________________________________

5 10

[issue15952] format(value) and value.__format__() behave differently with unicode format
by Chris Jerdonek May 31, 2020

May 31, 2020

New submission from Chris Jerdonek: format(value) and value.__format__() behave differently even though the documentation says otherwise: "Note: format(value, format_spec) merely calls value.__format__(format_spec)." (from http://docs.python.org/library/functions.html?#format ) The difference happens when the format string is unicode. For example: >>> format(10, u'n') u'10' >>> (10).__format__(u'n') # parentheses needed to prevent SyntaxError '10' So either the documentation should be changed, or the behavior should be changed to match. Related to this: neither the "Format Specification Mini-Language" documentation nor the string.Formatter docs seem to say anything about the effect that a unicode format string should have on the return value (in particular, should it cause the return value to be unicode or not): http://docs.python.org/library/string.html#formatspec http://docs.python.org/library/string.html#string-formatting See also issue 15276 (int formatting), issue 15951 (empty format string), and issue 7300 (unicode arguments). ---------- assignee: docs@python components: Documentation messages: 170575 nosy: cjerdonek, docs@python priority: normal severity: normal status: open title: format(value) and value.__format__() behave differently with unicode format type: behavior versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue15952> _______________________________________

5 8

[issue18262] ZipInfo.external_attr are not documented
by anatoly techtonik May 17, 2020

May 17, 2020

New submission from anatoly techtonik: zipfile doesn't restore file attributes when extracting. Documentation should at least contain example how to do this manually, because the ony way to do this - through ZipInfo.external_attr is too cryptic. ---------- assignee: docs@python components: Documentation messages: 191447 nosy: docs@python, techtonik priority: normal severity: normal status: open title: ZipInfo.external_attr are not documented versions: Python 2.6, Python 2.7, Python 3.1, Python 3.2, Python 3.3, Python 3.4, Python 3.5 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue18262> _______________________________________

6 12

[issue11425] Cleanup sample codes in tutorial.
by INADA Naoki May 13, 2020

May 13, 2020

New submission from INADA Naoki <songofacandy(a)gmail.com>: * Insert spaces around operators and after commas. * Split one liner blocks (ex. def foo(x, y): return x + y) to multi-line blocks. * Insert empty line after def block for scripts (not interactive mode). * Use new-style raise (s/ralse KeyboardInterrupt/raise KeyboardInterrupt()/) * Use x ** 3 instead of x * x * x. Attached patch is for Python 2.6. I'll make same changes for Python 3.1 if this patch is accepted. ---------- assignee: docs@python components: Documentation files: cleanup_tutorial_codes.patch keywords: patch messages: 130225 nosy: docs@python, naoki priority: normal severity: normal status: open title: Cleanup sample codes in tutorial. versions: Python 2.6, Python 2.7, Python 3.1, Python 3.2, Python 3.3 Added file: http://bugs.python.org/file21027/cleanup_tutorial_codes.patch _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue11425> _______________________________________

5 5