From: Calamitas <calamitates@...>
Date: 2008-07-23T22:12:26+09:00
Subject: Re: circular 'require'

On Wed, Jul 23, 2008 at 3:02 PM, Stefano Crocco <stefano.crocco@alice.it> wrote:
> Regarding why your code doesn't work, I think Peter is almost correct in his
> analisys, except when he states that the name of the file is stored in $"
> before being loaded, in the require case. After actually testing your code
> (which I should have done before sending my first mail), I went looking in the
> ruby source code to try to understand why the behavior I described wasn't the
> observed one. From what I understand (I'm not very good at reading C code), it
> seems that ruby has a mechanism which avoids exactly this kind of endless
> loop: when it starts requiring a file, it stores it in some kind of table
> (which as nothing to do with $"), where it remains until it's been 'fully'
> required (that is, until the code it contains, including other requires, has
> been executed). While the file is in the table, attempts to require it again
> fail, just as it had been put in $". Only at the end of this process, the file
> is added to $". For those interested, the involved C functions are
> rb_require_safe and load_lock, both in eval.c in the ruby distribution.

Good to know it works this way. I wanted to test whether it was
actually stored in $", but I was too lazy. Dang! ;-) But either way,
something had to break the infinite loop because there was none.

Peter