Killing the embedded Xwayland server aborted the compositor:
surface_handle_resource_destroy assert (non-empty map listener list)
via wl_client_destroy in the main loop's flush_clients.
Mechanism: the dead server's Wayland client connection is purged before
wlroots' xwm cascade dissociates anything, so wlr_surfaces die with our
map/unmap/commit listeners still attached.
Fix: watch the Xwayland Wayland client (its destroy signal fires before
its resources are purged) and proactively detach surface listeners only
-- across claimed windows, override-redirect windows and unclaimed
pendings -- leaving xsurface-level listeners for the later tab teardown.
Idempotent; later dissociate/xsurface-destroy find clean flags. The
restart test now also waits for the X11 window's map before killing, so
the crash path (listeners attached at death) is deterministically
exercised instead of raced.
Also re-mark output_mgmt_apply flaky (1 post-fix assertion under -n15;
budgets help but the modeset roundtrip stays load-sensitive).
Evidence: restart test 12/12 at the -n15 repro config (was ~2/9
crashing), detach handler firing on every server death, -n15 gate
clean, serial gate clean (148), flaky set green (11).
Andrew Hamilton
0babe8832e