Re: Confused by Lua garbage collection tear down order when there are references between objects

[Philipp Janda <siffiejoe@...>]

Am 21.05.2014 11:43 schröbte Eric Wing:
> Thank you for all the responses. That clears a lot up. Thanks for
> mentioning the lua_close case too. That insight was also valuable.
>
> So I went with a luaL_ref/luaL_unref workaround which solves
> everything but the lua_close case.
>
> I had the idea of iterating through the _G table and setting all the
> references to nil and forcing garbage collection before close, but in
> testing, I noticed there were a lot of local "global" variables in use
> in my programs which I can't reach. Any other ideas along these lines,
> perhaps using the debug library?

A weak table where all A objects register themselves?

I have another idea: What about splitting the A objects into two objects 
A and A_finalizer. The A_finalizer only lives in A's uservalue table, so 
it usually will become garbage at the same time as A. Whenever you 
associate a B object with the A object, you "disarm" the old 
A_finalizer, create a new one, and put both the B object and the new 
A_finalizer in A's uservalue table. Since the A_finalizer was created 
after the B object, it will be finalized before it.

> Thanks,
> Eric

Philipp