Debugging also seems to crash:
luke@stardust:~/src/Proton/dist$ /tmp/proton_luke/winedbg_run
WineDbg starting on pid 002a
winedbg: Internal crash at 0x42b25885
luke@stardust:~/src/Proton/dist$ /tmp/proton_luke/gdb_run
002a:002b: create process 'Z:\Users\luke\Downloads\vkquake-1.00.0_win64\vkQuake.exe'/0x10da0 @0x140084378 (0<0>)
winedbg: Internal crash at 0x43325885
luke@stardust:~/src/Proton/dist$
PROTON_DUMP_DEBUG_COMMANDS=1x1 2018-08PROTON_NO_ESYNC=1x1 2018-08PROTON_NO_ESYNC=1`x1 2018-08STEAM_COMPAT_DATA_PATH="/Users/luke/.wine"x1 2018-08
It appears that this only happens within the Valve modified sources:
This the same issue reported here.
When replacing the wine source in the Proton project with a fresh winehq version (devel or staging) this problem goes away.
PROTON_NO_ESYNC=1has no effect.