File

util.jsonschema: Fix validation to not assume presence of "type" field MattJ reported a curious issue where validation did not work as expected. Primarily that the "type" field was expected to be mandatory, and thus leaving it out would result in no checks being performed. This was likely caused by misreading during initial development. Spent some time testing against https://github.com/json-schema-org/JSON-Schema-Test-Suite.git and discovered a multitude of issues, far too many to bother splitting into separate commits. More than half of them fail. Many because of features not implemented, which have been marked NYI. For example, some require deep comparisons e.g. when objects or arrays are present in enums fields. Some because of quirks with how Lua differs from JavaScript, e.g. no distinct array or object types. Tests involving fractional floating point numbers. We're definitely not going to follow references to remote resources. Or deal with UTF-16 sillyness. One test asserted that 1.0 is an integer, where Lua 5.3+ will disagree.

local enum ptr_error
	"invalid-table"
	"invalid-path"
end

local function unescape_token(escaped_token : string) : string
	local unescaped = escaped_token:gsub("~1", "/"):gsub("~0", "~")
	return unescaped
end

local function resolve_json_pointer(ref : table, path : string) : any, ptr_error
	local ptr_len = #path+1
	for part, pos in path:gmatch("/([^/]*)()") do
		local token = unescape_token(part)
		if not ref is table then
			return nil
		end
		local idx = next(ref)
		local new_ref : any

		if idx is string then
			new_ref = ref[token]
		elseif idx is integer then
			local i = tonumber(token)
			if token == "-" then i = #ref + 1 end
			new_ref = ref[i+1]
		else
			return nil, "invalid-table"
		end

		if pos as integer == ptr_len then
			return new_ref
		elseif new_ref is table then
			ref = new_ref
		elseif not ref is table then
			return nil, "invalid-path"
		end

	end
	return ref
end

return {
	resolve = resolve_json_pointer,
}