- my $basedistro = access_basedistro();
- my $distro = $idistro || access_distro();
- my $value = cfg(map {
- ("dgit-distro.$distro.$_",
- "dgit-distro.$basedistro.$_",
- "dgit.default.$_")
- } @keys);
+ my @cfgs;
+ # The nesting of these loops determines the search order. We put
+ # the key loop on the outside so that we search all the distros
+ # for each key, before going on to the next key. That means that
+ # if access_cfg is called with a more specific, and then a less
+ # specific, key, an earlier distro can override the less specific
+ # without necessarily overriding any more specific keys. (If the
+ # distro wants to override the more specific keys it can simply do
+ # so; whereas if we did the loop the other way around, it would be
+ # impossible to for an earlier distro to override a less specific
+ # key but not the more specific ones without restating the unknown
+ # values of the more specific keys.
+ my @realkeys;
+ my @rundef;
+ # We have to deal with RETURN-UNDEF specially, so that we don't
+ # terminate the search prematurely.
+ foreach (@keys) {
+ if (m/RETURN-UNDEF/) { push @rundef, $_; last; }
+ push @realkeys, $_
+ }
+ foreach my $d (access_distros()) {
+ push @cfgs, map { "dgit-distro.$d.$_" } @realkeys;
+ }
+ push @cfgs, map { "dgit.default.$_" } @realkeys;
+ push @cfgs, @rundef;
+ my $value = cfg(@cfgs);