Nil Guard

Guard checks prevent invalid values from reaching code that expects real data.

nil_guard.lua

local user = 
local status = "missing"

if user ~= "" then
  status = "ready"
end

print("user=" .. user)
print("status=" .. status)

local user = 
local status = "missing"

if user ~= "" then
  status = "ready"
end

print("user=" .. user)
print("status=" .. status)

local user = 
local status = "missing"

if user ~= "" then
  status = "ready"
end

print("user=" .. user)
print("status=" .. status)

guard before failing A simple guard often keeps error handling local and easier to explain.