gpu.lua:195: attempt to index a nil value

[cheapie]

I'm not entirely sure what triggered this, although I imagine an invalid command was probably sent to the GPU at some point:

2026-02-15 21:19:30: ERROR[Main]: ServerError: AsyncErr: Lua: Runtime error from mod 'mesecons' in callback environment_Step(): /home/medic/worlds/creative/worldmods/digistuff/gpu.lua:195: attempt to index a nil value
2026-02-15 21:19:30: ERROR[Main]: stack traceback:
2026-02-15 21:19:30: ERROR[Main]:       [C]: in function '__index'
2026-02-15 21:19:30: ERROR[Main]:       /home/medic/worlds/creative/worldmods/digistuff/gpu.lua:195: in function 'unpack_color_with_cache'
2026-02-15 21:19:30: ERROR[Main]:       /home/medic/worlds/creative/worldmods/digistuff/gpu.lua:434: in function 'interpolate'
2026-02-15 21:19:30: ERROR[Main]:       /home/medic/worlds/creative/worldmods/digistuff/gpu.lua:913: in function 'runcommand'
2026-02-15 21:19:30: ERROR[Main]:       /home/medic/worlds/creative/worldmods/digistuff/gpu.lua:995: in function 'action'
<snip a bunch of spew from the message getting to the GPU in the first place>