[Python-modules-team] Bug#556943: Bug#556943: python-matplotlib: Segfaults with Qt4Agg backend

Sandro Tosi morph at debian.org
Fri Nov 27 10:14:55 UTC 2009

severity 556943 minor

On Sun, Nov 22, 2009 at 14:03, Benjamin Drung <bdrung at ubuntu.com> wrote:
> Am Mittwoch, den 18.11.2009, 15:01 +0100 schrieb Teemu Ikonen:
>> >>> import matplotlib.pyplot as plt
>> >>> plt.plot([1,2])
>> Segmentation fault
> I enabled Qt4Agg backend and tried this example code without an
> segmentation fault in an up-to-date squeeze environment.
>> This is could be a bug in python-qt4, which was updated recently, but other
>> PyQt4 applications work fine here.
> That's possible. Is your system up-to-date? Where there any PyQt4
> updates since you reported this bug? Do you still experience the bug?

I just created a fresh squeeze chroot, then

# apt-get install python-matplotlib
# apt-get install python-qt4
# export DISPLAY=:0.0
# python
Python 2.5.4 (r254:67916, Sep 26 2009, 10:32:22)
[GCC 4.3.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import matplotlib as mpl
>>> mpl.use('Qt4Agg')
>>> import matplotlib.pyplot as plt
>>> plt.plot([1,2])
QGtkStyle cannot be used together with the GTK_Qt engine.
[<matplotlib.lines.Line2D object at 0x2275590>]
>>> plt.show()

So there should be something broken on your machine (hence the
severity downgrade).

Versions of packages python-matplotlib depends on:
ii  libatk1.0-0            1.28.0-1          The ATK accessibility toolkit
ii  libc6                  2.10.1-7          GNU C Library: Shared libraries
ii  libcairo2              1.8.8-2           The Cairo 2D vector graphics libra
ii  libfontconfig1         2.6.0-4           generic font configuration library
ii  libfreetype6           2.3.11-1          FreeType 2 font engine, shared lib
ii  libgcc1                1:4.4.2-3         GCC support library
ii  libglib2.0-0           2.22.2-2          The GLib library of C routines
ii  libgtk2.0-0            2.18.3-1          The GTK+ graphical user interface
ii  libpango1.0-0          1.26.0-1          Layout and rendering of internatio
ii  libpng12-0             1.2.40-1          PNG library - runtime
ii  libstdc++6             4.4.2-3           The GNU Standard C++ Library v3
ii  python                 2.5.4-2           An interactive high-level object-o
ii  python-cairo           1.8.6-1           Python bindings for the Cairo vect
ii  python-dateutil        1.4.1-3           powerful extensions to the standar
ii  python-gobject         2.20.0-1          Python bindings for the GObject li
ii  python-matplotlib-data        Python based plotting system (data
ii  python-numpy           1:1.3.0-3         Numerical Python adds a fast array
ii  python-pyparsing       1.5.2-1           Python parsing module
ii  python-support         1.0.4             automated rebuilding support for P
ii  python-tz              2009p-1           Python version of the Olson timezo
ii  tcl8.5                 8.5.7-1           Tcl (the Tool Command Language) v8
ii  tk8.5                  8.5.7-2           Tk toolkit for Tcl and X11, v8.5 -
ii  zlib1g                 1: compression library - runtime

Versions of packages python-matplotlib recommends:
ii  python-glade2                 2.16.0-1   GTK+ bindings: Glade support
ii  python-gtk2                   2.16.0-1   Python bindings for the GTK+ widge
ii  python-qt4                    4.6-1      Python bindings for Qt4

Could you please look at these deps and see if upgrading/downgrading
some of this packages helps?

Sandro Tosi (aka morph, morpheus, matrixhasu)
My website: http://matrixhasu.altervista.org/
Me at Debian: http://wiki.debian.org/SandroTosi

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