Lua client.getconfig object indexing issues

Summary

As of 2.5.0 the client.getconfig().CoreSettings or CoreSyncSettings objects do not accept 'BizHawk.Emulation.Cores.Sony.PSX.Octoshock' as a valid index. Looking at config.ini the structure remains the same and it is listed the same way as before, so it seems like it should work just fine. I am using this to detect the display mode automatically for my script. Furthermore attempting to index CommonToolSettings with 'BizHawk.Client.EmuHawk.LuaConsole' does work without issues, so the problem seems to only be with CoreSettings or at least not all properties inside the settings object.

Note: In 2.4 and 2.3 a few users had the following issue, though the majority did not. I was not able to replicate that issue on both my Win7 and Win10 systems.

NLua.Exceptions.LuaScriptException: [string "main"]:34: attempt to call field 'getconfig' (a nil value)

Repro

client.getconfig().CoreSettings['BizHawk.Emulation.Cores.Sony.PSX.Octoshock'].ResolutionMode

Output

NLua.Exceptions.LuaScriptException: attempt to index field 'BizHawk.Emulation.Cores.Sony.PSX.Octoshock' (a nil value)

Problematic Build

• BizHawk 2.5.0; Win7 Pro ; Intel/NVIDIA
• BizHawk 2.4 Developer-2020-04-16-172542

Working Builds

• BizHawk 2.4
• BizHawk 2.3.2

Start at the Lua API entry point for client.getconfig() and trace how CoreSettings indexes BizHawk.Emulation.Cores.Sony.PSX.Octoshock. Compare the behavior in the problematic BizHawk 2.5.0 build with the working 2.4 and 2.3.2 builds. Done means the reproduced expression returns ResolutionMode instead of raising a nil-index error.