my $attrs = $new_parent_rs->_resolved_attrs;
$new_parent_rs->{attrs}->{$_} = undef for qw(prefetch include_columns +select +as); # prefetch, include_columns, +select, +as cause additional columns to be fetched
+ # If $column can be found in the 'as' list of the parent resultset, use the
+ # corresponding element of its 'select' list (to keep any custom column
+ # definition set up with 'select' or '+select' attrs), otherwise use $column
+ # (to create a new column definition on-the-fly).
my $as_list = $attrs->{as} || [];
my $select_list = $attrs->{select} || [];
my $as_index = List::Util::first { ($as_list->[$_] || "") eq $column } 0..$#$as_list;
-
my $select = defined $as_index ? $select_list->[$as_index] : $column;
my $new = bless { _select => $select, _as => $column, _parent_resultset => $new_parent_rs }, $class;