Re: Order of *CENTRAL-REGISTRY* traversal

On Wed, 7 Dec 2005 10:00:29 +0200 (EET), Nikodemus Siivola <[email protected]> wrote:

> (This is parallel to my earlier note about
> SB-EXT:*MODULE-PROVIDER-FUNCTIONS* traversal.)
>
> Currently ASDF traverses *CENTRAL-REGISTRY* head-to-tail: new
> locations pushed to the front take precendence and older ones serve
> as fallbacks. The behaviour undocumented.
>
> I believe that this is an unfortunate design as it means that a
> seemingly innocent PUSH can lead to totally different set of
> libraries being loaded as would be without. The system is unstable:
> a single idiomatic operation can have large and impossible to
> predict consequences.
>
> I would like to change ASDF to traverse it tail to head instead, so
> that (PUSH <DIR> *CENTRAL-REGISTRY*) can only make a previously
> failing (OOS 'LOAD-OP :FOO) succeed, but not alter the behaviour of
> a succeeding operation.
>
> This _would_ cause migration work for people whose setups
> deliberately operate on the head or tail already. However, I doubt
> this is much depended on outside personal initialization files since
> the current behaviour is not only undocumented but unstable.

Sounds acceptable to me.  I think /if/ you change it you should
document it this time so that one can finally rely on defined
behaviour.

Cheers,
Edi.


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