Light userdata and destroyed objects

[Dmitry Maluka <dmitrymaluka@...>]

Hello!

Suppose that we have a Lua function foo() that creates a foo object,
stores it in application's internal data structures and returns a light
userdata pointer to it. The unfoo() function destroys that object and
frees the corresponding data structures. After that, all the light
userdata references to it are broken and may crash the application.

Any approaches to this problem?