[asdf-devel] Looking for some help crafting a test case

[Faré]

On 10 February 2010 00:28, Robert Goldman <rpgoldman at sift.info> wrote:
> I believe my first ASDF patch had a minor buglet that could cause
> over-compilation.
>
> Here's the deal:  when new TRAVERSE detects that the components of a
> module need to have an operation performed on them, it binds a dynamic
> variable and calls itself on the components of the module.  The dynamic
> variable forces the components to be done even when they satisfy
> operation-done-p.  This has an effect equivalent to propagating the
> module's dependencies onto the children.
>
> However, this also means that the dynamic variable is in place when we
> call TRAVERSE recursively on the dependencies recorded on the children,
> then those dependencies are forced to happen as well.
>
> In /theory/ this could cause over-compilation, over-loading, etc.
> However, I cannot come up with a test case where this will /actually/
> occur.  Why is that?  It's because components of modules cannot "reach
> out" of the containing module to depend on anything in their
> surroundings.  E.g. if I have a module FOO, then components of FOO can
> record dependencies only onto other components of FOO.  This is a
> consequence of how name resolution works in ASDF.
>
> So I have what I think is a fix for performing unnecessary operations in
> ASDF, but I cannot figure out a way to craft a test case where
> unnecessary operations could actually occur.
>
> I feel like I should put the patch in anyway, in case we change the
> rules on name-lookup in ASDF, but this feels wrong.
>
> Any suggestions?  Have I missed something?  Is there any way, for
> example, a component of FOO could depend on an outside system?  I don't
> believe that this is possible, but I could be wrong.
>
Can't you work around the name resolution by using a defmethod?
Say, have a component type :foo-file
that depends on system :foo?
(Note that this case is rather artificial;
in practice, you'd have your .asd do a load-op of foo).

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]
Does artillery violate the natural rights of the target? I would say: the
entire *purpose* of artillery is to violate the natural rights of the target.