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

[Robert Goldman]

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.

thanks,
r