Crash in send_delete_event()
To reproduce: open two Epiphany windows (3.34 or master, either will do), then close one of them with Ctrl+W. (The window you close must have only one tab for Ctrl+W to close it.) This crash occurs with both tip of GTK 3.24 branch and with GTK 3.24.13:
(gdb) bt
#0 _g_log_abort (breakpoint=1) at ../../../../Projects/glib/glib/gmessages.c:557
#1 0x00007f2ecee2ca15 in g_logv (log_domain=0x7f2ecef5286f "GLib-GObject", log_level=G_LOG_LEVEL_CRITICAL,
format=0x7f2ecee8e92d "%s: assertion '%s' failed", args=0x7fff07214a08)
at ../../../../Projects/glib/glib/gmessages.c:1373
#2 0x00007f2ecee2cb06 in g_log (log_domain=0x7f2ecef5286f "GLib-GObject", log_level=G_LOG_LEVEL_CRITICAL,
format=0x7f2ecee8e92d "%s: assertion '%s' failed") at ../../../../Projects/glib/glib/gmessages.c:1415
#3 0x00007f2ecee2e9c0 in g_return_if_fail_warning (log_domain=0x7f2ecef5286f "GLib-GObject",
pretty_function=0x7f2ecef540c0 <__func__.15232> "g_object_ref", expression=0x7f2ecef52da9 "G_IS_OBJECT (object)")
at ../../../../Projects/glib/glib/gmessages.c:2771
#4 0x00007f2ecef29a8a in g_object_ref (_object=0x0) at ../../../../Projects/glib/gobject/gobject.c:3365
#5 0x00007f2ecf62dfc1 in send_delete_event (data=0x2bd8aa0) at /home/mcatanzaro/Projects/gtk/gtk/gtkwindow.c:1323
#6 0x00007f2ece78dd75 in gdk_threads_dispatch (data=0x20f7360) at /home/mcatanzaro/Projects/gtk/gdk/gdk.c:777
#7 0x00007f2ecee252c1 in g_idle_dispatch (source=0x3a38b00, callback=0x7f2ece78dd30 <gdk_threads_dispatch>,
user_data=0x20f7360) at ../../../../Projects/glib/glib/gmain.c:5718
#8 0x00007f2ecee2262b in g_main_dispatch (context=0x1f030c0) at ../../../../Projects/glib/glib/gmain.c:3272
#9 0x00007f2ecee23488 in g_main_context_dispatch (context=0x1f030c0) at ../../../../Projects/glib/glib/gmain.c:3937
#10 0x00007f2ecee2366c in g_main_context_iterate (context=0x1f030c0, block=1, dispatch=1, self=0x1f08920)
at ../../../../Projects/glib/glib/gmain.c:4010
#11 0x00007f2ecee23730 in g_main_context_iteration (context=0x1f030c0, may_block=1)
at ../../../../Projects/glib/glib/gmain.c:4071
#12 0x00007f2ecf074c06 in g_application_run (application=0x1efa720, argc=1, argv=0x7fff07214f48)
at ../../../../Projects/glib/gio/gapplication.c:2559
#13 0x0000000000404bda in main (argc=1, argv=0x7fff07214f48) at ../../../../Projects/epiphany/src/ephy-main.c:427
Maybe Epiphany is doing something wrong, but I think there's at least two GTK bugs: (a) no protection for the GtkWindow passed from gtk_window_close() to send_delete_event(), (b) no protection for _gtk_widget_get_window() to return NULL in send_delete_event().