warn compatibility function causes write guard warning in OpenResty

[piotrp]

Loading Penlight in OpenResty gives me a warning on stdout:

[warn] 19#19: *2 [lua] _G write guard:12: __newindex(): writing a global Lua variable ('warn') which may lead to race conditions between concurrent requests, so prefer the use of 'local' va
riables
stack traceback:
        /usr/lib/openresty/luajit/share/lua/5.1/pl/compat.lua:230: in main chunk
        [C]: in function 'require'
        /usr/lib/openresty/luajit/share/lua/5.1/pl/utils.lua:9: in main chunk
        [C]: in function 'require'
        /usr/lib/openresty/luajit/share/lua/5.1/pl/pretty.lua:12: in main chunk
        [C]: in function 'require'

Would it be possible to set it using rawset, i.e. change its definition from

Penlight/lua/pl/compat.lua

Line 230 in 16743e9

function warn(arg1, ...) -- luacheck: ignore

to

local function warn(arg1, ...)
...
end
rawset(_G, "warn", warn)

? It would make it compatible with current versions of OpenResty.

[Tieske]

can you sent a PR please?

2 caveats;

• make sure the docs still render properly
• please add a comment that it's a workaround for OpenResty

[piotrp]

Done, it doesn't change anything in docs as the change is contained within enclosing code block (and I verified it by generating docs in my branch)