[Client Crash] - Modding: AddPlayerPostInit(...) crashes if EnableModDebugPrint() is active.

[Sarcen]

Bug Submission:

Category: Client Crash

Issue Title: Modding: AddPlayerPostInit(...) crashes if EnableModDebugPrint() is active.

Issue Description: AddPlayerPostInit(...) crashes if EnableModDebugPrint() is active.

Cause:

Line 46 of modutil.lua assumes mod is at stack level 3, but in AddPlayerPostInit its at 4 (AddPlayerPostInit calls AddPrefabPostInitAny that calls initprint)

Relevant Log:

[string "scripts/modutil.lua"]:46: variable 'modname' is not declared

LUA ERROR stack traceback:

=[C] in function 'error'

scripts/strict.lua(23,1)

scripts/modutil.lua(46,1) in function 'initprint'

scripts/modutil.lua(236,1) in function 'AddPrefabPostInitAny'

scripts/modutil.lua(242,1) in function 'AddPlayerPostInit'

../mods/workshop-373991022/modmain.lua(51,1) in main chunk

=[C] in function 'xpcall'

scripts/util.lua(455,1) in function 'RunInEnvironment'

scripts/mods.lua(319,1) in function 'InitializeModMain'

scripts/mods.lua(300,1) in function 'LoadMods'

scripts/main.lua(244,1) in function 'ModSafeStartup'

scripts/main.lua(292,1)

=[C] in function 'SetPersistentString'

scripts/mainfunctions.lua(24,1) in function 'SavePersistentString'

scripts/modindex.lua(76,1)

=[C] in function 'GetPersistentString'

scripts/modindex.lua(63,1) in function 'BeginStartupSequence'

scripts/main.lua(291,1) in function 'callback'

scripts/modindex.lua(342,1)

=[C] in function 'GetPersistentString'

scripts/modindex.lua(322,1) in function 'Load'

scripts/main.lua(290,1) in main chunk

Steps to Reproduce: EnableModDebugPrint() in modsettings.lua

AddPlayerPostInit(...) in a modmain.lua

[PeterA]

@Sarcen, thanks for reporting this! I don't have a fix for this yet, but it may have helped me uncover another issue that I'd been tracking down.

[Muche]

Maybe something like this would help?

--- modutil.lua
+++ modutil.patch.lua
@@ -70,9 +70,20 @@ local function RemoveDefaultCharacter(name)
 	end
 end
 
+local function getfenvminfield(level, fieldname)
+	level = level + 1 -- increase level due to this function call
+	-- tail call doesn't have full debug info, its func is nil
+	-- use rawget to circumvent strict.lua's checks of _G that we might hit
+	while debug.getinfo(level) ~= nil and (debug.getinfo(level).func == nil or rawget(getfenv(level), fieldname) == nil) do
+		level = level + 1
+	end
+	assert(debug.getinfo(level) ~= nil, "Field " .. tostring(fieldname) .. " not found in callstack's functions' environments")
+	return getfenv(level)[fieldname]
+end
+
 local function initprint(...)
 	if KnownModIndex:IsModInitPrintEnabled() then
-		local modname = getfenv(3).modname
+		local modname = getfenvminfield(3, "modname")
 		print(ModInfoname(modname), ...)
 	end
 end

[Muche]

Patch reformatted (added newlines lost during forum upgrade).

[Ipsquiggle]

Thanks for the fix, @Muche. This will be in the next update.