Gtk::Application::get_default segfault on exit

[David Mugnai <dvd+gtk gnx it>]

According to the docs this code should be correct

   #include <gtkmm.h>

   class HelloWorld : public Gtk::Window {
     public:
        HelloWorld() : m_button("Hello World") {
                m_button.signal_clicked().connect(sigc::mem_fun(*this, &HelloWorld::on_button_clicked));
                add(m_button);
                m_button.show();
        }

     protected:
        void on_button_clicked() {
                Gtk::Application::get_default();
        }
        Gtk::Button m_button;
   };

   int main() {
        auto app = Gtk::Application::create();
        HelloWorld helloworld;
        app->run(helloworld);
        return 0;
   }

but it segfaults when closing the window (in app->run()) if "Gtk::Application::get_default();" has been 
called.

gtkmm version is 3.22.0 (as shipped by Ubuntu 17.04)
   ii  libgtk-3-0:amd64             3.22.11-0ubuntu3         amd64        GTK+ graphical user interface 
library
   ii  libgtk-3-bin                 3.22.11-0ubuntu3         amd64        programs for the GTK+ graphical 
user interface library
   ii  libgtk-3-common              3.22.11-0ubuntu3         all          common files for the GTK+ graphical 
user interface library
   ii  libgtk-3-dev:amd64           3.22.11-0ubuntu3         amd64        development files for the GTK+ 
library
   ii  libgtk-3-doc                 3.22.11-0ubuntu3         all          documentation for the GTK+ 
graphical user interface library
   ii  libgtkmm-3.0-1v5:amd64       3.22.0-1                 amd64        C++ wrappers for GTK+ (shared 
libraries)
   ii  libgtkmm-3.0-dev:amd64       3.22.0-1                 amd64        C++ wrappers for GTK+ (development 
files)
   ii  libgtkmm-3.0-doc             3.22.0-1                 all          C++ wrappers for GTK+ 
(documentation)


Valgrind reports several invalid reads, this is the first one:

   ==26534== Invalid read of size 8
   ==26534==    at 0x77CD5FB: g_application_run (in /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0.5200.0)
   ==26534==    by 0x5129081: Gtk::Application::run(Gtk::Window&) (in 
/usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1.1.0)
   ==26534==    by 0x44B032: main (main.cpp:25)
   ==26534==  Address 0x11c333c8 is 264 bytes inside a block of size 288 free'd
   ==26534==    at 0x4C2ED5B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
   ==26534==    by 0x8458321: g_type_free_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x845C09F: g_value_unset (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x844F8D2: g_signal_emit_valist (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x844FC6E: g_signal_emit (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x77CD5FA: g_application_run (in /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0.5200.0)
   ==26534==    by 0x5129081: Gtk::Application::run(Gtk::Window&) (in 
/usr/lib/x86_64-linux-gnu/libgtkmm-3.0.so.1.1.0)
   ==26534==    by 0x44B032: main (main.cpp:25)
   ==26534==  Block was alloc'd at
   ==26534==    at 0x4C2DB2F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
   ==26534==    by 0x86C7988: g_malloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.5200.0)
   ==26534==    by 0x86DFED2: g_slice_alloc (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.5200.0)
   ==26534==    by 0x86E04FD: g_slice_alloc0 (in /lib/x86_64-linux-gnu/libglib-2.0.so.0.5200.0)
   ==26534==    by 0x8458058: g_type_create_instance (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x8439EAA: ??? (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x843B8A7: g_object_newv (in /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0.5200.0)
   ==26534==    by 0x605EB89: Glib::Object::Object(Glib::ConstructParams const&) (in 
/usr/lib/x86_64-linux-gnu/libglibmm-2.4.so.1.3.0)
   ==26534==    by 0x5AFA741: Gio::Application::Application(Glib::ConstructParams const&) (in 
/usr/lib/x86_64-linux-gnu/libgiomm-2.4.s
   o.1.3.0)
   ==26534==    by 0x51293DD: Gtk::Application::Application(Glib::ustring const&, Gio::ApplicationFlags) (in 
/usr/lib/x86_64-linux-gnu
   /libgtkmm-3.0.so.1.1.0)
   ==26534==    by 0x51294ED: Gtk::Application::create(Glib::ustring const&, Gio::ApplicationFlags) (in 
/usr/lib/x86_64-linux-gnu/libg
   tkmm-3.0.so.1.1.0)
   ==26534==    by 0x44AFF6: main (main.cpp:23)

It's a bug in gtk, gtkmm or in the Ubuntu packages?

Regards,
david