sub prepare_assembly_render_vars {
my ($self) = @_;
+ croak("Need assembly item(s) to create a 'save as new' assembly.") unless $self->part->items;
+
my %vars = ( items_sellprice_sum => $self->part->items_sellprice_sum,
items_lastcost_sum => $self->part->items_lastcost_sum,
assembly_html => $self->render_assembly_items_to_html( \@{ $self->part->items } ),