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On 10.05.2013 16:13, Dirk Laurie wrote:

2013/5/10 Bernd Eggink <monoped@sudrala.de>:

I've just been struggling with a bug that caused my program to go into an
infinite loop at a certain point for no obvious reason. As I'm in the habit
of starting each source with "require strict", I didn't expect it to be
something as simple as the usage of an undefined (and undeclared) global. I
use the module from
http://metalua.luaforge.net/src/lib/strict.lua.html
It happens in the __index metafunction, which is defined like this:

mt.__index = function (t, n)
   if not mt.__declared[n] and debug.getinfo(2, "S").what ~= "C" then
      error("variable '"..n.."' is not declared", 2)
   end
   return rawget(t, n)
end

The baffling fact is that the function 'error' from the standard library
loops and eats up 100% CPU, instead of aborting the program. If the line is
replaced by os.exit(1), the program halts immediately.


`error` is local, I hope?


Well, to make sure I inserted
	local error = error
at the top of the module, which didn't help, and I also said:
	mt.__declared = { error }
so that "error" is considered declared, but that didn't help either.

Bernd

--
http://sudrala.de