Module:No globals
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| warning Lua error: bad argument #1 to "get" (not a valid title). | Lua error: bad argument #1 to "get" (not a valid title). Lua error: bad argument #1 to "get" (not a valid title). | 
| File:Green check.svg | This module is rated as ready for general use. It has reached a mature form and is thought to be relatively bug-free and ready for use wherever appropriate. It is ready to mention on help pages and other Wikipedia resources as an option for new users to learn. To reduce server load and bad output, it should be improved by sandbox testing rather than repeated trial-and-error editing. | 
| File:Full-protection-shackle.svg | This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing. | 
This module is deprecated in most use cases, use strict library: require( "strict" ).
Usage
Include this module at the top of your code. An error will be raised any time your code tries to read or write to a non-local (undeclared) variable.
Tests
| Module:No globals | success: 0, error: 1, skipped: 0 | 
| Module:No globals/sandbox | success: 0, error: 1, skipped: 0 | 
- Lua error: bad argument #1 to "get" (not a valid title).
- Lua error: bad argument #1 to "get" (not a valid title).
[[Category:Modules{{#translation:}}]]
local mt = getmetatable(_G) or {}
function mt.__index (t, k)
	if k ~= 'arg' then
		-- perf optimization here and below: do not load Module:TNT unless there is an error
		error(require('Module:TNT').format('I18n/No globals', 'err-read', tostring(k)), 2)
	end
	return nil
end
function mt.__newindex(t, k, v)
	if k ~= 'arg' then
		error(require('Module:TNT').format('I18n/No globals', 'err-write', tostring(k)), 2)
	end
	rawset(t, k, v)
end
setmetatable(_G, mt)