mail archive List which receives bug reports on Python
python-bugs-list.python.org
(List home) (Recent threads) (97 other Python lists)
Subscription Options
- RSS or Atom: Read-only subscription using a browser or aggregator. This is the recommended way if you don't need to send messages to the list. You can learn more about feed syndication and clients here.
- Conventional: All messages are delivered to your mail address, and you can reply. To subscribe, send an email to the list's subscribe address with "subscribe" in the subject line, or visit the list's homepage here.
- High traffic list: 30+ messages per day
- This list contains about 204,940 messages, beginning May 1999
- 61 messages added yesterday
Report the Spam
This button sends a spam report to the moderator. Please use it sparingly. For other removal requests, read this.
Are you sure? yes no
Fatal LookupError: unknown encoding: cp0 on Windows embedded startup.
Ad
New submission from Graham Dumpleton : When using Python 3.1 for Apache/mod_wsgi (3.0c4) on Windows, Apache will crash on startup because Python is forcing the process to exit with: Fatal Python error: Py_Initialize: can't initialize sys standard streams LookupError: unknown encoding: cp0 I first mentioned this on issue6393, but have now created it as a separate issue as appears to be distinct from the issue on MacOS X, athough possibly related. In the Windows case there is actually an encoding, that of 'cp0' where as on MacOS X, the encoding name was empty. The same mod_wsgi code works fine under Python 3.1 on MacOS X. ---------- components: Interpreter Core, Windows messages: 90616 nosy: grahamd severity: normal status: open title: Fatal LookupError: unknown encoding: cp0 on Windows embedded startup. type: crash versions: Python 3.1
Amaury Forgeot d'Arc added the comment: - Apache is not a Console application, so the Windows GetConsoleCP() function returns zero (and os.device_encoding(1) returns 'cp0'). - pythonw.exe has no console either; but in pythonrun.c, the test (fileno(stdin) < 0) is true, and the standard streams are all set to None. - It is probable that Apache has redefined stdin & co, so the previous test does not work there. As a workaround, I suggest to set the environment variable PYTHONIOENCODING before starting Apache, or before the call to Py_Initialize. ---------- nosy: +amaury.forgeotdarc
Graham Dumpleton added the comment: Yes, Apache remaps stdout and stderr to the Apache error log to still capture anything that errant modules don't log via the Apache error log functions. In mod_wsgi it replaces sys.stdout and sys.stderr with special file like objects that redirect via Apache error logging functions. This though obviously happens after Python first initialises sys.stdout and sys.stderr. What would be an appropriate value to set PYTHONIOENCODING to on Windows as a workaround? ----------
Amaury Forgeot d'Arc added the comment:
On a Western Windows, I suggest
PYTHONIOENCODING=cp1252:backslashreplace
But
PYTHONIOENCODING=mbcs
is also OK, except that characters outside the Windows code page will be
replaced with '?'
----------
Graham Dumpleton added the comment:
The workaround of using:
#if defined(WIN32) && PY_MAJOR_VERSION >= 3
_wputenv(L"PYTHONIOENCODING=cp1252:backslashreplace");
#endif
Py_Initialize();
gets around the crash on startup.
I haven't done sufficient testing to know if this may introduce any other
problems given that one is overriding default I/O encoding for whole
process.
----------
Antoine Pitrou added the comment: Graham, is the workaround ok for you or do you think this is something Python itself should handle? ---------- nosy: +pitrou
Graham Dumpleton added the comment: Python should be as robust as possible and thus should be fixed, but I am happy with using the workaround so if this is more a question of what priority to mark this, I wouldn't see it as being urgent. ----------
Florent Xicluna added the comment: Patch to prevent crash when PYTHONIOENCODING is invalid: ~ $ PYTHONIOENCODING= ./python Fatal Python error: Py_Initialize: can't initialize sys standard streams LookupError: unknown encoding: Abandon ---------- keywords: +patch nosy: +flox versions: +Python 3.2 Added file: http://bugs.python.org/file15623/issue6501_PY...
Antoine Pitrou added the comment: Well, this might prevent the crash but how does the system behave afterwards? Do the standard streams use utf-8 by default? At the minimum, we should still output a warning on stderr. ----------
Alexander Belopolsky added the comment:
The issue is not Windows specific, so I am changing the title to reflect that. On OSX, for example, I get
$ PYTHONIOENCODING=xyz ./python.exe
Fatal Python error: Py_Initialize: can't initialize sys standard streams
LookupError: unknown encoding: xyz
Abort trap
I agree that abort() is too drastic for a typo in the environment variable setting, but ignoring it silently is not a good option either. Someone setting PYTHONIOENCODING most likely does it for a reason and giving him or her some sort of default behavior for mistyped encoding is not helpful. (Note that this is how many C libraries treat TZ environment variable setting and this is often very frustrating.)
I think errors in environment variables that can be detected on startup should be treated the same way as the command line typos: a descriptive message on C stderr and exit(1).
Currently different environment variables are treated differently. For example, mistakes in PYTHONHOME and PYTHONIOENCODING cause fatal error while an error in PYTHONSTARTUP is reported but does not terminate python:
$ PYTHONSTARTUP=xyz.py ./python.exe
Python 3.2rc2+ (py3k:88320, Feb 2 2011, 14:07:18)
[GCC 4.2.1 (Apple Inc. build 5646) (dot 1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
Could not open PYTHONSTARTUP
IOError: [Errno 2] No such file or directory: 'xyz.py'
>>>
----------
nosy: +belopolsky
title: Fatal LookupError: unknown encoding: cp0 on Windows embedded startup. -> Fatal error on startup with invalid PYTHONIOENCODING
Changes by Éric Araujo :
----------
nosy: +haypo
Daniel Goertzen added the comment:
I run into this problem when I start a Python app as a subprocess from Erlang (open_port() function). The PYTHONIOENCODING fix works when I launch my py app via pythonw.exe, but it does *not* work when I use the cx-freeze version of the app.
I am using the Win32GUI base for cx-freeze which appears to be a thin WinMain() wrapper around Py_Initialize(). I am going to continue investigating the cx-freeze related problems.
I am using Python 3.2 under Windows. The failure is basically silent under Windows (generic MSVC runtime error), so I wasted a lot time figuring out what the problem actually was. Python 2 doesn't seem to have this problem.
----------
nosy: +Daniel.Goertzen
Changes by Anthony Tuininga :
----------
nosy: +atuining
Daniel Goertzen added the comment:
It turns out that cx-freeze deliberately sets Py_IgnoreEnvironmentFlag to ensure that the final executable is really an isolated, standalone executable (ie, it can't be subverted by setting PYTHONPATH.) Therefore the PYTHONIOENCODING work-around does not work in this situation.
I am currently using a cx-freeze work-around from the author to enable the PYTHONIOENCODING work-around. Altogether not that pleasant.
Could Python 3 could just default to some reasonable encoding and keep on chugging?
----------
STINNER Victor added the comment: > Fatal Python error: Py_Initialize: can't initialize sys standard streams > LookupError: unknown encoding: cp0That's a bug in os.device_encoding(): os.device_encoding(sys.stdout.fileno()) should return None if the application has no console (if sys.stdout is not a Windows console stream). Attached device_encoding.patch should fix this issue. (I didn't test the patch yet.) ---------- Added file: http://bugs.python.org/file21849/device_encod...
STINNER Victor added the comment: > On a Western Windows, I suggest > PYTHONIOENCODING=cp1252:backslashreplaceWhy using this very small charset whereas a web server can use UTF-8? I don't think that using backslashreplace on stdout is a good idea.> But > PYTHONIOENCODING=mbcs > is also OK, except that characters outside the Windows code > page will be replaced with '?'Starting at Python 3.2, you should use mbcs:replace to replace unencodable characters by '?'. The strict error handler is now strict: it raises a UnicodeEncodeError if a character is not encodable to mbcs. Note: mbcs is the ANSI code page. -- Using device_encoding.patch, I suppose that sys.std* streams will use the ANSI code page (mbcs, which is the code page 1252 on a Western Windows setup) in grahamd's usecase (Python program running in Apache). ----------
Roundup Robot <devnull@devnull> added the comment: New changeset 5783a55a2418 by Victor Stinner in branch 'default': Issue #6501: os.device_encoding() returns None on Windows if the application http://hg.python.org/cpython/rev/5783a55a2418 ---------- nosy: +python-dev
STINNER Victor added the comment:
@grahamd: Can you try the development version of Python 3.3, or try to patch your version using device_encoding.patch? You will not get cp0 encoding anymore.
If the patch fixes your issue, I will backport it. I don't see anything interesting to do for this issue.
----------
Éric Araujo added the comment: > Currently different environment variables are treated differently. For example, > mistakes in PYTHONHOME and PYTHONIOENCODING cause fatal error while an error in > PYTHONSTARTUP is reported but does not terminate python:If PYTHONSTARTUP is the only envvar with non-fatal errors, I think it’s okay. PYTHONHOME contains vital information, PYTHONIOENCODING is set by the programmer/admin and their code probably depends on it, but PYTHONSTARTUP is just niceties for the interactive interpreter, so non-vital IMO. ---------- nosy: +eric.araujo versions: +Python 2.7, Python 3.3 -Python 3.1
Ad