Difference between revisions of "Module:No globals"
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import>Minorax m (7 revisions imported from meta:Module:No_globals) |
none>MusikAnimal (Undid revision 948472525 by [[Special:Contributions/w>DiBabelYurikBot|w>DiBabelYurikBot]] ([[User talk:w>DiBabelYurikBot|talk]])) |
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| Line 2: | Line 2: | ||
function mt.__index (t, k) | function mt.__index (t, k) | ||
if k ~= 'arg' then | if k ~= 'arg' then | ||
| − | + | error('Tried to read nil global ' .. tostring(k), 2) | |
| − | error | ||
end | end | ||
return nil | return nil | ||
| Line 9: | Line 8: | ||
function mt.__newindex(t, k, v) | function mt.__newindex(t, k, v) | ||
if k ~= 'arg' then | if k ~= 'arg' then | ||
| − | error | + | error('Tried to write global ' .. tostring(k), 2) |
end | end | ||
rawset(t, k, v) | rawset(t, k, v) | ||
end | end | ||
setmetatable(_G, mt) | setmetatable(_G, mt) | ||
Revision as of 23:28, 31 March 2020
| 40px | This Lua module is used on 8,000,000+ pages, or roughly 98099% of all pages. To avoid major disruption and server load, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Consider discussing changes on the talk page before implementing them. |
| 40x40px | 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 causes an error if any nil global is read or if any global is written to, with the exception of arg. To use, add <syntaxhighlight lang="lua" inline>require('Module:No globals')</syntaxhighlight> to the top of the module using it. The arg variable is excluded because it is necessary for Scribunto's require function to work properly. (See the Scribunto source code here.)
local mt = getmetatable(_G) or {}
function mt.__index (t, k)
if k ~= 'arg' then
error('Tried to read nil global ' .. tostring(k), 2)
end
return nil
end
function mt.__newindex(t, k, v)
if k ~= 'arg' then
error('Tried to write global ' .. tostring(k), 2)
end
rawset(t, k, v)
end
setmetatable(_G, mt)