GtkStatsMonitor crashes when closing session about panda3d HOT 4 CLOSED

I suspect a reference counting issue.

If one tell me how to rebuild pstats with debug symbols without rebuilding the whole Panda3D source I will provide a more useful stack trace.

With makepanda, you can just delete the files containing "pstatserver" as well as "pstats_composite1.o" in built/tmp (don't delete the client related files) and then rebuild with export CXXFLAGS=-ggdb set.

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With makepanda, you can just delete the files containing "pstatserver" as well as "pstats_composite1.o" in built/tmp (don't delete the client related files) and then rebuild with export CXXFLAGS=-ggdb set.

Thanks, it's much faster using that !

I suspect a reference counting issue.

With the debugger I see the code crashes when the first label is removed from the _status_bar container :

But the widget instance seems still referenced :

(gdb) p *label
$5 = {parent_instance = {g_type_instance = {Python Exception  No type named TypeNode.: 
g_class = }, ref_count = 1, qdata = 0x555555cc7300}, priv = 0x555555891970}

I also noticed a log error when the "Wating for connection" label is removed :

(pstats:38272): GLib-CRITICAL **: 21:53:56.852: g_sequence_remove: assertion 'iter != NULL' failed

Digging a bit, it seems this is a bug in GTK, see https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/2029, but Ubuntu 20.04 is still shipping with version 3.24.20-0ubuntu1.1 which does not include it.

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So, could we work around it by retaining a reference ourselves? That means, whenever we add it to _status_bar_labels, we do this:

_status_bar_labels.push_back(label);
g_object_ref(label);

And then, in the destructor:

  for (GtkWidget *label : _status_bar_labels) {
    gtk_container_remove(GTK_CONTAINER(_status_bar), label);
    g_object_unref(label);
  }

Could you try this?

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It does not work directly as GtkFlowBox can not contain GtkWidgetbut only GtkFlowBoxChild instances. If one call gtk_container_add on a GtkFlowBox instance, it will creates a hidden instance of GtkFlowBoxChild and add the received widget as child (See https://docs.gtk.org/gtk3/class.FlowBox.html)

So I have modified the code to explicitly create a GtkFlowBoxChild instance for each label created and increased the ref count as you suggested and it worked :)

I'm cleaning up the code and will submit a PR shortly.

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