Segfault in mn_mail_icon_set_tip_widget after gnome-shell restart

[John Schanck]

Version 5.4, debian testing.

mail-notification segfaults in mn_mail_icon_set_tip_widget
shortly after a gnome-shell restart. Presumably the mail
check thread tries to update the tooltip using a reference
to a gtk widget which was destroyed during the gnome-shell
restart.

Application does not crash in "debug" mode. To reproduce,
disable debug mode or compile with -DG_DISABLE_CHECKS.

Backtrace:

(mail-notification:11978): Gtk-CRITICAL **: gtk_widget_show: assertion `GTK_IS_WIDGET (widget)' failed

** (mail-notification:11978): CRITICAL **: mn_mail_icon_set_tip_widget: assertion `self != NULL' failed

Program received signal SIGTRAP, Trace/breakpoint trap.
[Switching to Thread 0x7ffff7fb5920 (LWP 11978)]
0x00007ffff3dec491 in g_logv () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
(gdb) bt
#0 0x00007ffff3dec491 in g_logv () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1 0x00007ffff3dec622 in g_log () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2 0x000000000042faca in mn_shell_update_tooltip (self=0x6d6f40) at src/mn-shell.gob:713
#3 0x00007ffff40a46e0 in g_closure_invoke () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#4 0x00007ffff40b5750 in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#5 0x00007ffff40bc8bb in g_signal_emitv () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#6 0x00000000004298cc in mn_mailboxes_error_changed (self=0x7c7240) at mn-mailboxes.c:917
#7 0x00007ffff40a46e0 in g_closure_invoke () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#8 0x00007ffff40b5750 in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#9 0x00007ffff40bd6bc in g_signal_emit_valist () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#10 0x00007ffff40bd852 in g_signal_emit () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#11 0x00007ffff40a9085 in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#12 0x00007ffff40a8ace in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff40abc3d in g_object_set_valist () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007ffff40ac3e7 in g_object_set () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x0000000000420e35 in mn_mailbox_set_error (self=self@entry=0x7ef360, format=format@entry=0x0) at src/mn-mailbox.gob:518
#16 0x000000000045468f in ___5_mn_reentrant_mailbox_check (mailbox=0x7ef360) at src/mn-reentrant-mailbox.gob:95
#17 0x00000000004544fc in mn_reentrant_mailbox_queue_check_cb (data=0x7ef360) at src/mn-reentrant-mailbox.gob:81
#18 0x00007ffff6f30980 in ?? () from /usr/lib/x86_64-linux-gnu/libgdk-3.so.0
#19 0x00007ffff3de5355 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007ffff3de5688 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007ffff3de5a82 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007ffff73153b5 in gtk_main () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#23 0x000000000041aff0 in main (argc=1, argv=0x7fffffffdff8) at src/mn-main.c:546