On Sun, 2003-01-05 at 01:59, D'Arcy J.M. Cain wrote:

> Here is what I am proposing.
> 
> Build C (Note 1)
> Remove C

  Unfortunately, it's a little bit mor complicated.  Since A and B
depend on C, removing C also means removing A and B.  This is actually
what 'make update' currently does (A and B are never explicitly removed,
they are simply removed implicitly by 'Remove C').

> Install C (Note 2)
> Build B (Note 1)

  Here, things get even more complicated.  B might depend on a package D
as well, which might need updating.  There might be a whole new subtree
depending on D, which in turn then needs updating.

  At the moment, this is simple: because the subtree depending on C has
already been removed, all packages that depend on D (excluding B) get
updated first, before building of B resumes.  This is recursive, of
course, so there might be other subtrees as well that might need
updating.

  If the corresponding packages have not been removed yet, tracking the
order in which packages need to be rebuilt becomes quite complicated.

  Please note that this does not only apply to B but any other package
of the updated subtree (including C).

  Cheers
      ,
   Rene