docs February 2012

docs@python.org

30 participants
340 discussions

[issue8557] subprocess portability issue

by Dave Abrahams

New submission from Dave Abrahams <dave(a)boostpro.com>: On POSIX systems, the PATH environment variable is always used to look up directory-less executable names passed as the first argument to Popen(...), but on Windows, PATH is only considered when shell=True is also passed. Actually I think it may be slightly weirder than that when shell=False, because the following holds for me: C:\>rem ##### Prepare minimal PATH ##### C:\>set "PATH=C:\Python26\Scripts;C:\Python26;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem" C:\>rem ##### Prepare a minimal, clean environment ##### C:\>virtualenv --no-site-packages e:\zzz New python executable in e:\zzz\Scripts\python.exe Installing setuptools................done. C:\>rem ##### Show that shell=True makes the difference in determining whether PATH is respected ##### C:\>python Python 2.6.5 (r265:79096, Mar 19 2010, 18:02:59) [MSC v.1500 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import subprocess >>> subprocess.Popen(['python', '-c', 'import sys; print sys.executable']) <subprocess.Popen object at 0x0000000001DBE080> >>> C:\Python26\python.exe >>> subprocess.Popen(['python', '-c', 'import sys; print sys.executable'], env={'PATH':r'e:\zzz\Scripts'}) <subprocess.Popen object at 0x0000000001F05A90> >>> C:\Python26\python.exe >>> subprocess.Popen(['python', '-c', 'import sys; print sys.executable'], env={'PATH':r'e:\zzz\Scripts'}, shell=True) <subprocess.Popen object at 0x0000000001F05B00> >>> e:\zzz\Scripts\python.exe That is, it looks like the environment at the time Python is invoked is what counts unless I pass shell=True. I don't even seem to be able to override this behavior by changing os.environ: you can clear() it and pass env={} and subprocess.Popen(['python']) still succeeds. This is a very important problem for portable code and one that took me hours to suss out. I think: a) the current behavior needs to be documented b) it needs to be fixed if possible c) otherwise, shell=True should be the default ---------- assignee: docs@python components: Documentation messages: 104422 nosy: dabrahams, docs@python priority: normal severity: normal status: open title: subprocess portability issue type: behavior versions: Python 2.6 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue8557> _______________________________________

1 month, 1 week

[issue12594] Docs for py3k still refer to "MacPython 2.5 folder"

by Christoph Schindler

New submission from Christoph Schindler <hop(a)30hopsmax.at>: In http://docs.python.org/py3k/using/mac.html#getting-and-installing-macpython and http://docs.python.org/py3k/using/mac.html#distributing-python-applications… . ---------- assignee: docs@python components: Documentation messages: 140744 nosy: docs@python, hop priority: normal severity: normal status: open title: Docs for py3k still refer to "MacPython 2.5 folder" versions: Python 3.1, Python 3.2 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue12594> _______________________________________

1 month, 1 week

[issue13368] Possible problem in documentation of module subprocess, method send_signal

by Eli Bendersky

New submission from Eli Bendersky <eliben(a)gmail.com>: docs@ list report by Daniel Dieterle: in the documentation (http://docs.python.org/library/subprocess.html#subprocess.Popen.send_signal) is a bug. CTRL_C_EVENT can not be sent to processes started with a creationflags parameter which includes CREATE_NEW_PROCESS_GROUP. Why can be read in the msdn documentation http://msdn.microsoft.com/en-us/library/windows/desktop/ms683155%28v=vs.85%… . A workaround using CTRL_C_EVENT nevertheless is described here: http://stackoverflow.com/questions/7085604/sending-c-to-python-subprocess-o… -- I do not know why the subprocess.CREATE_NEW_PROCESS_GROUP parameter was introduced. But it is useless for terminating a process with os.kill() in combination with signal.SIGTERM, which corresponds to a CTRL-C-EVENT. A CTRL-C-EVENT is only forwarded to the process if the process group is zero. Therefore the Note in the documentation on Popen.send_signal() is wrong. ---------- assignee: docs@python components: Documentation messages: 147272 nosy: docs@python, eli.bendersky priority: normal severity: normal status: open title: Possible problem in documentation of module subprocess, method send_signal versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13368> _______________________________________

1 month, 2 weeks

[issue13433] String format documentation contains error regarding %g

by Christian Iversen

New submission from Christian Iversen <ci(a)sikkerhed.org>: The documentation for string format options state that both %f, %g and %e default to 6 digits after the decimal point. In fact, %g always seems to use 5 digits by default: >>> "%g" % 2.1234567 '2.12346' >>> "%f" % 2.1234567 '2.123457' >>> "%e" % 2.1234567 '2.123457e+00' But something much more insidious is wrong, because even when explicitly told how many digits to have, %g is one off: >>> "%.6g" % 2.1234567 '2.12346' >>> "%.6f" % 2.1234567 '2.123457' >>> "%.6e" % 2.1234567 '2.123457e+00' This can't be right? ---------- assignee: docs@python components: Documentation messages: 147940 nosy: Christian.Iversen, docs@python priority: normal severity: normal status: open title: String format documentation contains error regarding %g type: behavior versions: Python 2.6, Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13433> _______________________________________

1 month, 3 weeks

[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> _______________________________________

3 months, 2 weeks

[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> _______________________________________

3 months, 2 weeks

[issue13341] Incorrect documentation for "u" PyArg_Parse format unit

by Ilya Novoselov

New submission from Ilya Novoselov <ilya.novoselov(a)gmail.com>: Documentation states that u format unit returns "buffer of 16-bit Unicode (UTF-16) data" while it returns pointer to internal buffer of unicode data, which is either UCS-16 or UCS-32 http://docs.python.org/c-api/arg.html ---------- assignee: docs@python components: Documentation, Unicode messages: 147002 nosy: Ilya.Novoselov, docs@python, ezio.melotti priority: normal severity: normal status: open title: Incorrect documentation for "u" PyArg_Parse format unit type: behavior versions: Python 2.7 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13341> _______________________________________

4 months, 2 weeks

[issue13875] cmd: no user documentation

by anatoly techtonik

New submission from anatoly techtonik <techtonik(a)gmail.com>: http://docs.python.org/library/cmd.html# Documentation for cmd module is poor to explain the value of this module to users. Intro is too abstract - phrase "simple framework for writing line-oriented command interpreters" doesn't mean much. Perhaps word "interactive" is missing? So, there is no part explaining the what cmd does exactly (intro fails) and no part explaining the main principle - How exactly does this framework allows to do this in a simple way? (I guess reference part under 'Cmd objects -> Cmd.cmdloop([intro]) -> p[4]` does that, but it is not the place you'd usually expect this info. At the very least what could be done is a link to Doug's tutorial http://www.doughellmann.com/PyMOTW/cmd/ ---------- assignee: docs@python components: Documentation messages: 152010 nosy: docs@python, techtonik priority: normal severity: normal status: open title: cmd: no user documentation _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13875> _______________________________________

4 months, 4 weeks

[issue9538] Replace confusing pseudoname 'object' in special methods section.

by Terry J. Reedy

New submission from Terry J. Reedy <tjreedy(a)udel.edu>: In 3.3. Special method names, 'object' is used as a pseudo class name to prefix all the special method entries. This conflicts with the usual two Python meanings. 1. 'object' is the name of a specific class. So the entry for object.__getattribute__(self, name) says to avoid circularity by calling object.__getattribute__(self, name), which looks circular and requires a bit a mental work by the reader to properly understand. Ditto for object.__setattr__(self, name, value) calling object.__setattr__(self, name, value) 2. Non-specifically, 'object' is usually understood to mean any Python object, not just a class. But the signatures as written require that 'object' specifically be a class and 'object' does not convey that. So for both reasons, I propose that the pseudoname 'object' be replaces with 'class' or 'someclass' ---------- assignee: docs@python components: Documentation messages: 113194 nosy: docs@python, georg.brandl, terry.reedy priority: normal severity: normal stage: needs patch status: open title: Replace confusing pseudoname 'object' in special methods section. versions: Python 3.2 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue9538> _______________________________________

4 months, 4 weeks

[issue13561] os.listdir documentation should mention surrogateescape

by Michael Foord

New submission from Michael Foord <michael(a)voidspace.org.uk>: Where os.listdir encounters undecodable bytes from the filesystem it uses the surrogateescape handler. As the resulting strings are invalid they can't be encoded without an errorhandler, and so can't be printed (for example). This should be documented. ---------- assignee: docs@python components: Documentation messages: 149070 nosy: docs@python, michael.foord priority: normal severity: normal stage: needs patch status: open title: os.listdir documentation should mention surrogateescape versions: Python 3.3 _______________________________________ Python tracker <report(a)bugs.python.org> <http://bugs.python.org/issue13561> _______________________________________

5 months

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docs February 2012