Fixes heap-use-after-free:
==32046==ERROR: AddressSanitizer: heap-use-after-free on address 0x615000064d20 at pc 0x55571ce4d303 bp 0x7fff545c64c0 sp 0x7fff545c64b0
WRITE of size 8 at 0x615000064d20 thread T0
#0 0x55571ce4d302 in xdg_decoration_handle_destroy ../sway/xdg_decoration.c:13
#1 0x7f64009d6f36 in wlr_signal_emit_safe ../util/signal.c:29
#2 0x7f64009d3c46 in toplevel_decoration_handle_resource_destroy ../types/wlr_xdg_decoration_v1.c:65
#3 0x7f6400a19f8d (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x7f8d)
#4 0x7f6400a19fed in wl_resource_destroy (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x7fed)
#5 0x7f64009d3d1f in toplevel_decoration_handle_surface_destroy ../types/wlr_xdg_decoration_v1.c:82
#6 0x7f64009d6f36 in wlr_signal_emit_safe ../util/signal.c:29
#7 0x7f64009b059c in reset_xdg_surface ../types/xdg_shell/wlr_xdg_surface.c:453
#8 0x7f64009b0688 in destroy_xdg_surface ../types/xdg_shell/wlr_xdg_surface.c:483
#9 0x7f64009af08c in xdg_client_handle_resource_destroy ../types/xdg_shell/wlr_xdg_shell.c:71
#10 0x7f6400a19f8d (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x7f8d)
#11 0x7f6400a1e211 (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0xc211)
#12 0x7f6400a1e6fe (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0xc6fe)
#13 0x7f6400a1a0ec in wl_client_destroy (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x80ec)
#14 0x7f6400a1a1c4 (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x81c4)
#15 0x7f6400a1b941 in wl_event_loop_dispatch (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x9941)
#16 0x7f6400a1a569 in wl_display_run (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x8569)
#17 0x55571ce4c7fd in server_run ../sway/server.c:214
#18 0x55571ce4ad59 in main ../sway/main.c:405
#19 0x7f640071109a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a)
#20 0x55571ce2cfa9 in _start (/usr/local/bin/sway+0x35fa9)
0x615000064d20 is located 32 bytes inside of 504-byte region [0x615000064d00,0x615000064ef8)
freed by thread T0 here:
#0 0x7f6401531b70 in free (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xedb70)
#1 0x55571ce6c72b in destroy ../sway/desktop/xdg_shell.c:252
#2 0x55571cee3f7b in view_destroy ../sway/tree/view.c:60
#3 0x55571cee4090 in view_begin_destroy ../sway/tree/view.c:73
#4 0x55571ce6dd95 in handle_destroy ../sway/desktop/xdg_shell.c:464
#5 0x7f64009d6f36 in wlr_signal_emit_safe ../util/signal.c:29
#6 0x7f64009b059c in reset_xdg_surface ../types/xdg_shell/wlr_xdg_surface.c:453
#7 0x7f64009b0688 in destroy_xdg_surface ../types/xdg_shell/wlr_xdg_surface.c:483
#8 0x7f64009af08c in xdg_client_handle_resource_destroy ../types/xdg_shell/wlr_xdg_shell.c:71
#9 0x7f6400a19f8d (/usr/lib/x86_64-linux-gnu/libwayland-server.so.0+0x7f8d)
previously allocated by thread T0 here:
#0 0x7f6401532138 in calloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xee138)
#1 0x55571ce6df39 in handle_xdg_shell_surface ../sway/desktop/xdg_shell.c:485
#2 0x7f64009d6f36 in wlr_signal_emit_safe ../util/signal.c:29
#3 0x7f64009b0167 in handle_xdg_surface_commit ../types/xdg_shell/wlr_xdg_surface.c:350
#4 0x7f64009ce2a5 in surface_commit_pending ../types/wlr_surface.c:372
#5 0x7f64009ce523 in surface_commit ../types/wlr_surface.c:444
#6 0x7f63ff63ddad in ffi_call_unix64 (/usr/lib/x86_64-linux-gnu/libffi.so.6+0x5dad)
Fixes#3759