I got this in FNEI while trying to figure out how to make red chips (Advanced Circuit). My own modding skills don't allow me to know if this is a bug in Sea Block, FNEI, Bobs, Angels, etc., etc.

For background, that little status list with the red/green lights that show suggested mods are all green.

This is not the first Unknown Key that I have encountered but this IS the first one that I have reported...unless you say otherwise, I will start listing them as I come across them.

Oh, and thanks for keeping up with bugs. I am going thru enough agony as it is in playing this mod solo.

Ok, found out the "fix". It's the Reverse Factory mod. When I removed the mod, both this AND some other Unknown Keys disappeared. I will try to alert that modder at his portal.

Just to clarify, the unknown key issue stems from a non-default setting, which is labelled as "experimental" in its description. The issue does not arise when both mods are at stock settings.

Yes and no. When looking in FNEI at the recycling recipe for green circuits, I can see the issue even with default settings.

Ah, I see now.. I don't normally use FNEI. I guess it must be looking for the recipe name, since each reverse recipe technically produces multiple products, it won't have a name by default. I guess I might actually have to look into that localized names thing. Even though I would consider this more of a cosmetic issue...

Adding something like this in function makeRecipe should do it:

    Recipe(nrec):set_field("localised_name", { "recipe-name.reverse-factory-recycling", { itemType == "fluid" and "fluid" or "item" .. "-name." .. item.name }})

And in \en\base.cfg:

[recipe-name]
reverse-factory-recycling=Recycling of __1__

Yeah, I talked to a coder friend at the Discord server and he said the problem is actually FNEI. It just APPEARS to be a problem with Reverse Factory to a non-coder like me. I meant to tell you sooner, sorry. I have submitted a bug report to the FNEI portal. My skill with playing Factorio almost REQUIRES me to get help from FNEI and to be able to undo my booboos with Reverse Factory. And yes, I also use Simple Landfill Mining. I might also have to install Factory Search too.

I don't use Helmod's mod because I can't figure it out.

Yeah, I talked to a coder friend at the Discord server and he said the problem is actually FNEI. It just APPEARS to be a problem with Reverse Factory to a non-coder like me. I meant to tell you sooner, sorry. I have submitted a bug report to the FNEI portal. My skill with playing Factorio almost REQUIRES me to get help from FNEI and to be able to undo my booboos with Reverse Factory. And yes, I also use Simple Landfill Mining. I might also have to install Factory Search too.

Your friend is mistaken. The issue is definitely with Reverse Factory.

I don't use Helmod's mod because I can't figure it out.

I've always used Factory Planner myself; looking up what one singular recipe does isn't the most helpful for me, I like to plan out the entire chain before I build it. For that mod, recipes that are hidden from the player are also hidden from the interface (by default), so I've never been exposed to the internal names.

Adding something like this in function makeRecipe should do it:

Thanks very much for the specific code! I don't think I would have been able to figure it out by myself. That being said, I added it and tested it out, but a lot of recipes still seem a bit weird.

I'm testing with a minimal modlist (bare minimum for SeaBlock, Reverse Factory, and FNEI), and while some of them appear properly (Recycling of Air filter 1, Recycling of Electrolyser 1, Recycling of Lab, etc), a lot of them still mention unknown keys (Recycling of Unknown key: "item-name.assembling-machine-1", Recycling of Unknown key: "item-name.splitter"). I'm not entirely sure what the pattern is for what works and what doesn't. Some vanilla items work, and some don't; some modded items work, and some don't. My recycling machines all appear properly, but I don't know why.

I tried checking what the localized_name variable looks like for the broken item names, and they don't seem any different? Same category (recipe-name.reverse-factory-recycling), same item name format (item-name.splitter), same bracket format. I don't quite get it. Maybe something to do with normal/expensive recipes? I'm not sure.

I believe this code should cover all cases:

local localised_name
if itemType == "fluid" then
  localised_name = "fluid-name." .. item.name
elseif item.place_result then
  localised_name = "entity-name." .. item.place_result
elseif item.place_as_tile then
  localised_name = "tile-name." .. item.place_as_tile.result
elseif item.placed_as_equipment_result then
  localised_name = "equipment-name." .. item.placed_as_equipment_result
else
  localised_name = "item-name." .. item.name
end
Recipe(nrec):set_field("localised_name", { "recipe-name.reverse-factory-recycling", { localised_name }})

Looks liked it worked, and I was also able to fix the issue with the fluid items not having names, so many thanks for the code!

Happy to help! The documentation pages are very useful.

https://lua-api.factorio.com/latest/prototypes/ItemPrototype.html
https://lua-api.factorio.com/latest/types/LocalisedString.html
https://wiki.factorio.com/Tutorial:Localisation

I did try reading through some of the documentation, but I couldn't really.. understand how to use it for my specific use case, at least within 5-10 minutes of searching. It would have taken a lot longer for me to figure out what the issue was with the original code too lol. I'm a lot less used to this part of the code, compared to the standard prototype stuff.