$self->throw_exception(
"Can't prefetch has_many ${pre} (join cond too complex)")
unless ref($rel_info->{cond}) eq 'HASH';
+ my $dots = @{[$as_prefix =~ m/\./g]} + 1; # +1 to match the ".${as_prefix}"
+ if (my ($fail) = grep { @{[$_ =~ m/\./g]} == $dots }
+ keys %{$collapse}) {
+ my ($last) = ($fail =~ /([^\.]+)$/);
+ $self->throw_exception(
+ "Can't prefetch multiple has_many rels ${last} and ${pre}"
+ .(length($as_prefix) ? "at the same level (${as_prefix})"
+ : "at top level"
+ ));
+ }
#my @col = map { (/^self\.(.+)$/ ? ("${as_prefix}.$1") : ()); }
# values %{$rel_info->{cond}};
$collapse->{".${as_prefix}${pre}"} = [ $rel_source->primary_columns ];