サブクラスでも問題なしっぽ
% perl -MData::Dumper -MDBIx::Sunny -E 'my $dbh=DBIx::Sunny->connect("dbi:mysql:test"); say ref($dbh); my $dbh2=$dbh->clone; say ref($dbh2); say $dbh2->{mysql_enable_utf8}; say Dumper($dbh2->{private_connect_info})' DBIx::Sunny::db DBIx::Sunny::db 1 $VAR1 = [ 'dbi:mysql:test', undef, undef, { 'mysql_enable_utf8' => 1, 'ShowErrorStatement' => 1, 'RaiseError' => 1, 'AutoInactiveDestroy' => 1, 'PrintError' => 0 } ]; % perl -MData::Dumper -MDBIx::Sunny -E 'my $dbh=DBIx::Sunny->connect("dbi:mysql:test","","",{root_class=>"DBIx::Sunny"}); say ref($dbh); my $dbh2=$dbh->clone; say ref($dbh2); say $dbh2->{mysql_enable_utf8}; say Dumper($dbh2->{private_connect_info})' DBIx::Sunny::db DBIx::Sunny::db 1 $VAR1 = [ 'dbi:mysql:test', '', '', { 'mysql_enable_utf8' => 1, 'ShowErrorStatement' => 1, 'RaiseError' => 1, 'AutoInactiveDestroy' => 1, 'PrintError' => 0, 'root_class' => 'DBIx::Sunny' } ];