Fix use-after-free in the lua object management #77
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Wlroots does not call `wl_list_remove(&destroy.listener_list)` after the destroy signal fires. It is the responsibility of the subscriber to handle their own wl_listener being left with an invalid link. This was an issue because it might happen that the kiwmi_object is not destroyed immediately, but only later by a lua gc handler that finally decrements the refcount to zero. We have to ensure that `kiwmi_object_destroy` can succeed. Here we first use `wl_list_remove` to unsubscribe from the signal, and then `wl_list_init` to leave the link in a valid state for `kiwmi_object_destroy`.
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Wlroots does not call
wl_list_remove(&destroy.listener_list)after the destroy signal fires. It is the responsibility of the subscriber to handle their own wl_listener being left with an invalid link.This was an issue because it might happen that the kiwmi_object is not destroyed immediately, but only later by a lua gc handler that finally decrements the refcount to zero. We have to ensure that
kiwmi_object_destroycan succeed.Here we first use
wl_list_removeto unsubscribe from the signal, and thenwl_list_initto leave the link in a valid state forkiwmi_object_destroy.