Add extra doc line expanding on the role of the prefetch attribute

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultSet.pm

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index 97dfe78..d15696d 100644 (file)
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -2248,6 +2248,8 @@ sub populate {
     my (@results, $guard);
 
     if (ref $data->[0] eq 'ARRAY') {
+      # column names only, nothing to do
+      return if @$data == 1;
 
       $guard = $self->result_source->schema->storage->txn_scope_guard
         if @$data > 2;
@@ -2290,6 +2292,8 @@ sub populate {
 
       # positional(!) explicit column list
       if ($i == 0) {
+        # column names only, nothing to do
+        return if @$data == 1;
 
         $colinfo->{$data->[0][$_]} = { pos => $_, name => $data->[0][$_] } and push @$colnames, $data->[0][$_]
           for 0 .. $#{$data->[0]};
@@ -4362,8 +4366,10 @@ For a more in-depth discussion, see L</PREFETCHING>.
 
 This attribute is a shorthand for specifying a L</join> spec, adding all
 columns from the joined related sources as L</+columns> and setting
-L</collapse> to a true value. For example, the following two queries are
-equivalent:
+L</collapse> to a true value. It can be thought of as a rough B<superset>
+of the L</join> attribute.
+
+For example, the following two queries are equivalent:
 
   my $rs = $schema->resultset('Artist')->search({}, {
     prefetch => { cds => ['genre', 'tracks' ] },