Re: [Lua5.4] lua_toclose will close the wrong value

[Roberto Ierusalimschy <roberto@...>]

> It was thus said that the Great Roberto Ierusalimschy once stated:
> > >   The manual states for lua_toclose():
> > > 
> > > 	[...] AN INDEX MARKED AS TO-BE-CLOSED SHOULD NOT BE REMOVED FROM
> > > 	THE STACK BY ANY OTHER FUNCTION IN THE API EXCEPT LUA_SETTOP OR
> > > 	LUA_POP.
> > > 
> > > 	[...]
> > > 
> > >   [...] It might be that moving the item to be
> > > cleaned is disallowed as well and the manual doesn't mention it.
> >                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > It seems it does.
> 
>   No, it wasn't removed, it was *moved*.  As I stated in the email
> (switching the comments to use a Forth-like stack notation):
> 
> 				// before -- after | stack
> 	lua_pushinteger(L,1);	// -- i	           | i
> 	lua_newtable(L);	// -- t            | t i
> 	luaL_newlib(L,mt);	// -- t            | t2 t i
> 	lua_setmetatable(L,-2);	// t2 x -- x       | t i
> 	lua_toclose(L,-1);	// --              | t i
> 	lua_remove(L,-2);	// ? -- ?          | t
> 
>   When lua_tclose() was called, the stack looked like:
> 
> 		-1	table marked as to-close
> 		-2	integer
> 
>   The lua_remove(L,-2) is removing the integer, not the variable marked as
> "to-close".  It's *moved*, not *removed*, unless the act of "moving" is the
> same as "remove, then insert".  

What is marked to be closed is the index, not its value (see manual).
An index cannot be moved.

-- Roberto