PyGtk App Core dumps

[Rick Spencer]

Steps:
1. expand the attached crash_repro directory that has the repro code
2. run the "grid_filter.py" file
(note that if you have quickly-widgets installed, you need to make sure that you point your python path to the directory that contains the code.
3. In the filter UI at the top, set ID < 5 (or whatever)

Result:
A couple of warnings are displayed, and then a crash
rick@rick-desktop:~/Projects/crash_repro$ PYTHONPATH="./" python grid_filter.py TypeError: can't convert return value to desired type
grid_filter.py:797: Warning: /build/buildd/glib2.0-2.25.15/gobject/gtype.c:4181: type id `0' is invalid
  gtk.main()
grid_filter.py:797: Warning: can't peek value table for type `<invalid>' which is not currently referenced
  gtk.main()
Segmentation fault (core dumped)

Expected:
The Grid is filtered properly

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: libglib2.0-0 2.25.15-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.35-20.29-generic 2.6.35.4
Uname: Linux 2.6.35-20-generic i686
Architecture: i386
Date: Tue Sep 14 14:57:05 2010
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
ProcEnviron:
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: glib2.0

[Krzysztof Klimonda (kklimonda)]

A smaller python script that reproduces this crash

[Krzysztof Klimonda (kklimonda)]

The crash is result of callback not returning expected value (or, as in our examples not returning nothing at all). Python should still handle it more gracefully.

[Barry Warsaw (barry)]

(gdb) bt
#0 0x00007ffff60d1953 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#1 0x00007ffff60d2353 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#2 0x00007ffff492380c in gtk_spin_button_update () from /usr/lib/libgtk-x11-2.0.so.0
#3 0x00007ffff4926008 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#4 0x00007ffff48a86e3 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#5 0x00007ffff60b7afe in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#6 0x00007ffff60cffc2 in ?? () from /usr/lib/libgobject-2.0.so.0
#7 0x00007ffff60d193c in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#8 0x00007ffff60d2353 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#9 0x00007ffff49dbc0f in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#10 0x00007ffff489f3b3 in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#11 0x00007ffff48a058b in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#12 0x00007ffff44fae9c in ?? () from /usr/lib/libgdk-x11-2.0.so.0
#13 0x00007ffff59fb7e2 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#14 0x00007ffff59ff748 in ?? () from /lib/libglib-2.0.so.0
#15 0x00007ffff59ffc55 in g_main_loop_run () from /lib/libglib-2.0.so.0
#16 0x00007ffff48a0a47 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#17 0x00007ffff5046268 in _wrap_gtk_main (self=0x0) at /build/buildd/pygtk-2.21.0/gtk/gtk.override:1239
#18 0x00000000004cf3c8 in call_function (pp_stack=0x7fffffffddd0, oparg=0) at ../Python/ceval.c:3734
#19 0x00000000004ca734 in PyEval_EvalFrameEx (f=Frame 0x9cbeb0, for file spin.py, line 14, in <module> (), throwflag=0) at ../Python/ceval.c:2412
#20 0x00000000004cd04c in PyEval_EvalCodeEx (co=0x7ffff7ec3970, globals={'__warningregistry__': {("can't peek value table for type `<invalid>' which is not currently referenced", <type at remote 0x9ce0f0>, 14): True, ("/build/buildd/glib2.0-2.25.15/gobject/gtype.c:4181: type id `0' is invalid", <type at remote 0x9ce0f0>, 14): True}, '__builtins__': <module at remote 0x7ffff7fb5e30>, '__file__': 'spin.py', 'gtk': <module at remote 0x7ffff7e64bc0>, '__package__': None, 'window': <gtk.Window at remote 0xf3e160>, 'test': <function at remote 0x7ffff7ece990>, '__name__': '__main__', 'spin': <gtk.SpinButton at remote 0xf3e6e0>, '__doc__': None}, locals={'__warningregistry__': {("can't peek value table for type `<invalid>' which is not currently referenced", <type at remote 0x9ce0f0>, 14): True, ("/build/buildd/glib2.0-2.25.15/gobject/gtype.c:4181: type id `0' is invalid", <type at remote 0x9ce0f0>, 14): True}, '__builtins__': <module at remote 0x7ffff7fb5e30>, '__file__': 'spin.py', 'gtk': <module at remote 0x7ffff7e64bc0>, '__package__': None, 'window': <gtk.Window at remote 0xf3e160>, 'test': <function at remote 0x7ffff7ece990>, '__name__': '__main__', 'spin': <gtk.SpinButton at remote 0xf3e6e0>, '__doc__': None}, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0, closure=0x0) at ../Python/ceval.c:3000
#21 0x00000000004c3ca6 in PyEval_EvalCode (co=0x7ffff7ec3970, globals={'__warningregistry__': {("can't peek value table for type `<invalid>' which is not currently referenced", <type at remote 0x9ce0f0>, 14): True, ("/build/buildd/glib2.0-2.25...

[Rick Spencer (rick-rickspencer3)]

ok, so you're not supposed to use "input" from Python ... according to the documentation:
The "input" signal is emitted when the value changes. The value_ptr is a GPointer to the value that cannot be accessed from PyGTK. This signal cannot be handled in PyGTK.

d'oh

[Rick Spencer (rick-rickspencer3)]

for future reference, 'value-changed' is the correct signal to use

[Barry Warsaw (barry)]

pygtk still shouldn't core dump the interpreter ;) but i guess this is a bug for upstream to fix. It should probably raise a ValueError on the .connect() call.

[Tomeu Vizoso (tomeu)]

What would mean that ValueError in connect?

The correct fix I guess is stop using the GObject API for discovering which signals a GObject subclass has and instead rely on the introspection API. Then we could mark as introspectable=0 all such signals and you would get a 'Signal not known' error on connect().