GNOME Bugzilla – Bug 459004
Parsing OptionContext with Gnome::Main::Main causes failed assertion
Last modified: 2018-08-17 19:27:13 UTC
Steps to reproduce: 1. Build this test case // g++ main.cc -o main_test `pkg-config libgnomemm-2.6 --libs --cflags` #include <libgnomemm/main.h> #include <libgnomemm/init.h> int main(int argc, char* argv[]) { Glib::OptionGroup options("foo", "bar"); Glib::OptionContext context; context.set_main_group(options); Gnome::Main app("foobar", "0.1", Gnome::module_info_get(), argc, argv, context); } 2. run ./main_test 3. see it crash Stack trace: (gdb) run Starting program: /tmp/main_test [Thread debugging using libthread_db enabled] [New Thread -1208629536 (LWP 14536)] (main_test:14536): GLib-CRITICAL **: g_option_group_free: assertion `group != NULL' failed Program received signal SIGSEGV, Segmentation fault.
+ Trace 149599
Thread NaN (LWP 14536)
Other information: Using context.parse(argc, argv) instead of Gnome::Main::Main works fine.
You can actually just do this, it will produce the same result int main(int argc, char* argv[]) { Glib::OptionContext context; Gnome::Main app("foobar", "0.1", Gnome::module_info_get(), argc, argv, context); }
The Gnome::Main constructor passes the context along to gnome_program_init(), and according to the documentation [1], gnome_program_init() takes ownership of the option context. So it looks like when main() exits, the option context is getting destroyed by the OptionContext destructor and also by libgnome. Re-writing the program like this 'solves' the issue, but it's not obvious that it's necessary. This should either be clearly documented somewhere, or it should be changed so that the Gnome::Main cosntructor creates a copy of the passed context so that we don't get double-free problems (but I'm not sure if that's possible without breaking the spirit of a stable API) // g++ main.cc -g -o main_test `pkg-config libgnomemm-2.6 libgnomeuimm-2.6 --libs --cflags` #include <libgnomemm/main.h> #include <libgnomemm/init.h> #include <libgnomeuimm/init.h> int main(int argc, char* argv[]) { Glib::OptionGroup options("foo", "bar"); Glib::OptionContext* context = new Glib::OptionContext();; context->set_main_group(options); Gnome::Main app("foobar", "0.1", Gnome::UI::module_info_get(), argc, argv, *context); } [1] http://developer.gnome.org/doc/API/2.0/libgnome/libgnome-gnome-program.html#gnome-program-init
> gnome_program_init() takes ownership of the option context That is unusual. I guess we need some way to give ownership. OptionContext might be able to do this already.
libgnomemm is not under active development anymore since 2010. Its codebase has been archived: https://gitlab.gnome.org/Archive/libgnomemm/commits/master Closing this report as WONTFIX as part of Bugzilla Housekeeping to reflect reality. Please feel free to reopen this ticket (or rather transfer the project to GNOME Gitlab, as GNOME Bugzilla is deprecated) if anyone takes the responsibility for active development again.