modlib/doc/schema.md

Schema

Place a file schema.lua in your mod, returning a schema table.

Non-string entries and minetest.conf

Suppose you have the following schema:

return {
	type = "table",
	entries = {
		[42] = {
			type = "boolean",
			description = "The Answer"
			default = true
		}
	}
}

And a user sets the following config:

mod.42 = false

It won't work, as the resulting table will be {["42"] = false} instead of {[42] = false}. In order to make this work, you have to convert the keys yourself:

return {
	type = "table",
	keys = {
		-- this will convert all keys to numbers
		type = "number"
	},
	entries = {
		[42] = {
			type = "boolean",
			description = "The Answer"
			default = true
		}
	}
}

This is best left explicit. First, you shouldn't be using numbered field keys if you want decent minetest.conf support, and second, modlib's schema module could only guess in this case, attempting conversion to number / boolean. What if both number and string field were set as possible entries? Should the string field be deleted? And so on.