No 'STEAM_COMPAT_CLIENT_INSTALL_PATH' Causes Launch Fail

[SStatZX]

Operating System Version:
    "Manjaro Linux" (64 bit)
    Kernel Name:  Linux
    Kernel Version:  5.16.14-1-MANJARO

Launch fails on arma3-unix launcher (arma3-unix-launcher-bin 355.8e10137-1)

[2022-04-09 14:42:46.286] [info] Steam path: /home/user/.local/share/Steam
found: proton_7
[2022-04-09 14:42:46.287] [info] Install path: /home/user/.local/share/Steam
[2022-04-09 14:42:46.287] [info] Install path: /run/media/user/Storage/Steamapps
[2022-04-09 14:42:46.288] [info] Running Arma:
env  SteamGameId=107410 LD_PRELOAD=/home/user/.local/share/Steam/ubuntu12_64/gameoverlayrenderer.so STEAM_COMPAT_DATA_PATH="/run/media/user/Storage/Steamapps/steamapps/compatdata/107410"   "/run/media/user/Storage/Steamapps/steamapps/common/Proton 7.0/proton" run "/run/media/user/Storage/Steamapps/steamapps/common/Arma 3/arma3_x64.exe"   -noSplash -skipIntro

Traceback (most recent call last):
  File "/run/media/user/Storage/Steamapps/steamapps/common/Proton 7.0/proton", line 1365, in <module>
    g_session.init_session(sys.argv[1] != "runinprefix")
  File "/run/media/user/Storage/Steamapps/steamapps/common/Proton 7.0/proton", line 1170, in init_session
    g_compatdata.setup_prefix()
  File "/run/media/user/Storage/Steamapps/steamapps/common/Proton 7.0/proton", line 722, in setup_prefix
    steamdir = os.environ["STEAM_COMPAT_CLIENT_INSTALL_PATH"]
  File "/usr/lib/python3.10/os.py", line 679, in __getitem__
    raise KeyError(key) from None
KeyError: 'STEAM_COMPAT_CLIENT_INSTALL_PATH'

I found a workaround, if Arma 3 is launched with STEAM_COMPAT_CLIENT_INSTALL_PATH=Steam Path (/home/user/.local/share/Steam) Then the game will launch without any issues, however it has to be directly after the STEAM_COMPAT_DATA_PATH Which from what I've tested is not possible with the Custom parameters setting as it is after all the env command

So the command that works on my system is: env SteamGameId=107410 LD_PRELOAD=/home/user/.local/share/Steam/ubuntu12_64/gameoverlayrenderer.so STEAM_COMPAT_DATA_PATH="/run/media/user/Storage/Steamapps/steamapps/compatdata/107410" STEAM_COMPAT_CLIENT_INSTALL_PATH="/home/user/.local/share/Steam" "/run/media/user/Storage/Steamapps/steamapps/common/Proton 7.0/proton" run "/run/media/user/Storage/Steamapps/steamapps/common/Arma 3/arma3_x64.exe" -noSplash -skipIntro I'm not entirely sure whether this is a bug on arma3-unix-launcher or an issue with my system however this workaround works for me.