If two X11 windows were the last two, we'd remove them from the stack
while unmanaging them. That'd hit an assert in
meta_stack_tracker_restack_managed(), resulting in the following crash
when Xwayland exited unexpectedly with two or more X11 windows being the
only windows on the stack:
#1 g_assertion_message() at ../glib/gtestutils.c:3256
#2 g_assertion_message_expr() at ../glib/gtestutils.c:3282
#3 meta_stack_tracker_restack_managed() at ../src/core/stack-tracker.c:1210
#4 on_stack_changed() at ../src/core/stack.c:142
#5 _g_closure_invoke_va() at ../gobject/gclosure.c:895
#6 g_signal_emit_valist() at ../gobject/gsignal.c:3456
#7 g_signal_emit() at ../gobject/gsignal.c:3606
#8 meta_stack_changed() at ../src/core/stack.c:265
#9 meta_stack_remove() at ../src/core/stack.c:324
#10 meta_window_unmanage() at ../src/core/window.c:1542
#11 meta_x11_display_unmanage_windows() at ../src/x11/meta-x11-display.c:111
#12 meta_x11_display_dispose() at ../src/x11/meta-x11-display.c:141
#13 g_object_run_dispose() at ../gobject/gobject.c:1448
#14 meta_display_shutdown_x11() at ../src/core/display.c:831
The added test specifically checks that this scenario is handled
gracefully.
Related: https://bugzilla.redhat.com/show_bug.cgi?id=2143637
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2704>
Instead of having users of the test client manually deal with alarm
filters, let the test client automatically add itself as filters. This
changes the MetaX11Display a bit, to handle an array of filters instead
of a single filter.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2704>
The test aims to test that trying to fetch X11 clipboard content after
Xwayland went away doesn't cause issues. What happens though is that
sometimes the clipboard content doesn't have time to settle (i.e. fetch
mime types etc) before Xwayland gets terminated, which causes flakyness.
Fix this by waiting for the compositor side clipboard owners to finish
setting up before continuing.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2484>
It works by using an X11 client to set the clipboard content, using a
mimetype that on purpose is not handled by the clipboard manager. The
test then makes sure we don't crash when trying to transfer data from
the old X11 selection source.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2364>
