system-config-printer.py crashed with Error in setlocale() in Jaunty BETA

[ramesh]

Binary package hint: system-config-printer

Dear Sir

This is happens when clicking in Printing in system-administration - printing menu.

Ram

ProblemType: Crash
Architecture: i386
DistroRelease: Ubuntu 9.04
ExecutablePath: /usr/share/system-config-printer/system-config-printer.py
InterpreterPath: /usr/bin/python2.6
Package: system-config-printer-gnome 1.1.3+git20090218-0ubuntu7
PackageArchitecture: all
ProcCmdline: python /usr/share/system-config-printer/system-config-printer.py
ProcEnviron:
 LANG=en_IN
 SHELL=/bin/bash
PythonArgs: ['/usr/share/system-config-printer/system-config-printer.py']
SourcePackage: system-config-printer
Title: system-config-printer.py crashed with Error in setlocale()
Uname: Linux 2.6.28-9-generic i686
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

The following is the verbose output on jaunty-beta-amd64 (fully updated).

Connected as user root
refresh
Created subscription 18
<monitor.Monitor instance at 0x2cee5a8>: printers and jobs lists provided
update_jobs
Authentication pass: 1
Authentication: password callback set
Authentication pass: 1
Authentication: password callback set
Traceback (most recent call last):
  File "/usr/share/system-config-printer/system-config-printer.py", line 6760, in <module>
    focus_on_map)
  File "/usr/share/system-config-printer/system-config-printer.py", line 6708, in main
    print_test_page, focus_on_map)
  File "/usr/share/system-config-printer/system-config-printer.py", line 819, in __init__
    self.populateList()
  File "/usr/share/system-config-printer/system-config-printer.py", line 1270, in populateList
    self.printers = cupshelpers.getPrinters(self.cups)
  File "/var/lib/python-support/python2.6/cupshelpers/cupshelpers.py", line 419, in getPrinters
    printer = Printer(name, connection, **printer)
  File "/var/lib/python-support/python2.6/cupshelpers/cupshelpers.py", line 40, in __init__
    self.update (**kw)
  File "/var/lib/python-support/python2.6/cupshelpers/cupshelpers.py", line 88, in update
    self._expand_flags()
  File "/var/lib/python-support/python2.6/cupshelpers/cupshelpers.py", line 68, in _expand_flags
    locale.setlocale (locale.LC_CTYPE, current_ctype)
  File "/usr/lib/python2.6/locale.py", line 513, in setlocale
    return _setlocale(category, locale)
locale.Error: unsupported locale setting
Exception AttributeError: "Printer instance has no attribute '_ppd'" in <bound method Printer.__del__ of <cupshelpers.Printer "epsonfx">> ignored

[sgtbug (sgtbug)]

I changed my default language to en_US [English (United States)], and it is working. Please fix it for en_IN

[Till Kamppeter (till-kamppeter)]

Tim, it seems that system-config-printer crashes on certain locales. Can you have a look into it? Perhaps one could do a "try .... except ..." or some kind of fallback chain (en_IN -> en -> C, pt_BR -> pt -> C, ...).

[Till Kamppeter (till-kamppeter)]

I can reproduce this bug by simply executing

LANG=en_IN system-config-printer

in a terminal window.

[Till Kamppeter (till-kamppeter)]

Tim, the problem somes from a place where the locale is temporarily set to "C" for using the lower() method and setting the locale back to the original makes s-c-p crash. Is there no less invasive way to use lower() (or something equivalent) in a locale-neutral way? For some users s-c-p is completely non-functional now, depending on their locale.

[Tim Waugh (twaugh)]

Till, have you tried with current 1.0.x?

[Till Kamppeter (till-kamppeter)]

No, I am using 1.1.x. Does 1.0.x contain another (better) fix for Trac #151?

[Till Kamppeter (till-kamppeter)]

The problem is the patch of Trac #151:

https://fedorahosted.org/system-config-printer/ticket/151

[Tim Waugh (twaugh)]

Well, have you tried with current 1.1.x?

If you are seeing this fail:

        current_ctype = locale.setlocale (locale.LC_CTYPE)
        locale.setlocale (locale.LC_CTYPE, "C")
        ...
        locale.setlocale (locale.LC_CTYPE, current_ctype)

then it is certainly a Python bug.

[Tim Waugh (twaugh)]

I don't much like the current approach anyway. If you like, rewrite that part so that has a static mapping between the two names, like:

flagmap = { cups.CUPS_PRINTER_AUTHENTICATED: 'authenticated',
                    cups.CUPS_PRINTER_BIND: 'bind',
                    ... }
for flag, name in flagmap.iteritems ():
  setattr(self, name, bool(self.type & flag))

Then you don't need the locale or blacklist handling.

[Till Kamppeter (till-kamppeter)]

I think this is not a good idea as the set of attributes can change in future CUPS versions and this way we will miss access to new attributes or get error if attributes get removed.

So I better move this to Python.

[Tim Waugh (twaugh)]

Well, you could use getattr for the actual flag values. Or, alternatively, it's very easy to write a locale-independent lower() function and use that instead.

Locale handling seems to be riddled with bugs in Python, so I'm in favour of avoiding it when possible.

[Till Kamppeter (till-kamppeter)]

Fixed upstream in the 1.1.x GIT branch, commit 33132c1.

[Till Kamppeter (till-kamppeter)]

Fixed in system-config-printer_1.1.3+git20090218-0ubuntu18 (Jaunty).

[Till Kamppeter (till-kamppeter)]

Tim, thanks for your good hints. They helped me to find this solution.

[Tim Waugh (twaugh)]

Neat fix. Thanks.

[Matthias Klose (doko)]

Re: comment #9

> then it is certainly a Python bug.

import locale
current_ctype = locale.setlocale (locale.LC_CTYPE)
locale.setlocale (locale.LC_CTYPE, "C")
locale.setlocale (locale.LC_CTYPE, current_ctype)

this doesn't fail for me; unsure what I am supposed to fix for python.

[Matthias Klose (doko)]

closing the python2.6 task as invalid