detach owner sanity check

lua/arccw/shared/sh_attachments.lua

@@ -4,6 +4,9 @@ function ArcCW:PlayerCanAttach(ply, wep, attname, slot, detach)
     -- The global variable takes priority over everything
     if !ArcCW.EnableCustomization then return false end
 
+    -- Attach and Detach require a player (usually the owner)
+    if !IsValid(ply) then return false end
+
     -- Spectators taking off your attachments is funny, but also cursed
     if wep:GetOwner() != ply then return false end
 

lua/weapons/arccw_base/sh_attach.lua

@@ -1293,12 +1293,11 @@ function SWEP:Detach(slot, silent, noadjust, nocheck)
 
         local ammo = atttbl.UBGL_Ammo or "smg1_grenade"
 
-        if SERVER then
+        if SERVER and IsValid(self:GetOwner()) then
             self:GetOwner():GiveAmmo(clip, ammo, true)
         end
 
         self:SetClip2(0)
-
         self:DeselectUBGL()
     end