From: Paul Brannan <pbrannan@...>
Date: 2004-09-08T23:42:09+09:00
Subject: Re: Marshal and allocating objects

On Wed, Sep 08, 2004 at 11:31:04PM +0900, ts wrote:
> >>>>> "P" == Paul Brannan <pbrannan@atdesk.com> writes:
> 
> P> Even if allocate is used, this won't work.  The lookup for the class is
> P> failing before allocate is called.
> 
>  Well, if I've well understood he want that Marshal use the same algorithm
>  than ruby when it find a constant name.

That's the way I read it.

>  Actually marshal just look is the constant is defined, when ruby can call
>  #const_missing when he write `M.allocate'

Right, which is why const_missing never gets called.  Making Ruby call
allocate doesn't solve the problem, because Ruby is checking to see if
the constant exists (in rb_path2name) before trying to look it up.

> P>   class Foo
> P>     SOME_CONSTANT = 1
> P>     def foo
> P>       return SOME_CONSTATN
> P>     end
> P>   end
> 
> P> my code will no longer break, but will silently do the wrong thing.
> 
>  Not understood, sorry

In order to demonstrate why I do not think const_missing should be
defined for class Object, I intentionally misspelled "SOME_CONSTATN".
Before const_missing was defined I would get an exception here,
whereas after Stephen's version of const_missing is in place, I will
instead get a new class.  Even with well-written unit tests, finding
this misspelling can be a challenge.

Paul