pass, and is apparently the Right Thing To Do. (See mailing list 09/06/2009)
my $class = $schema->class('Artist');
$class->belongs_to('rank' => $schema->class('Lyrics'));
+# Re-register the source:
+$schema->register_extra_source(
+ Artist => $schema->class('Artist')->new->result_source_instance
+);
+
# Now check we have the relationship:
my $source = $schema->source('Artist');