[Exim] question on when address_data is expanded

according to spec.txt address_data is expanded "just before the router is
run, after all the pre-condition tests have succeeded." Because I can't
use the $address_data variable in the expansion of router_home_directory,
this leads me to believe that router_home_directory is being expanded
before address_data, which implies router_home_directory is a
pre-condition item. Is this true, and is this intentional?

hmmm... looking at the source, router_home_directory is expanded in the
check_router_conditions function. It looks like it was placed there not
because it's a condition, but because $home is expected to be defined at
that point. This comment is right after router_home_directory is
expanded:

/* This is the point at which we print out the router's debugging string
if it is set. We wait till here so as to have $home available for local
users (and anyway, we don't want too much stuff for skipped routers). */

It seems like it makes more sense to have this expanded elsewhere, or at
least after $address_data is available. (OK, I'm not sure if it makes
more sense or not, but I want it to be that way =)).

--John