Merge 'trunk' into 'mssql_top_fixes'

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

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index cfb736b..74940eb 100644 (file)
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -698,10 +698,14 @@ a warning:
 
   Query returned more than one row
 
-In this case, you should be using L</first> or L</find> instead, or if you really
+In this case, you should be using L</next> or L</find> instead, or if you really
 know what you are doing, use the L</rows> attribute to explicitly limit the size
 of the resultset.
 
+This method will also throw an exception if it is called on a resultset prefetching
+has_many, as such a prefetch implies fetching multiple rows from the database in
+order to assemble the resulting object.
+
 =back
 
 =cut
@@ -714,6 +718,12 @@ sub single {
 
   my $attrs = $self->_resolved_attrs_copy;
 
+  if (keys %{$attrs->{collapse}}) {
+    $self->throw_exception(
+      'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
+    );
+  }
+
   if ($where) {
     if (defined $attrs->{where}) {
       $attrs->{where} = {
@@ -1144,7 +1154,7 @@ sub count {
   return $self->search(@_)->count if @_ and defined $_[0];
   return scalar @{ $self->get_cache } if $self->get_cache;
 
-  my $meth = $self->_has_attr (qw/prefetch collapse distinct group_by/)
+  my $meth = $self->_has_resolved_attr (qw/collapse group_by/)
     ? 'count_grouped'
     : 'count'
   ;
@@ -1276,15 +1286,15 @@ sub _rs_update_delete {
 
   my $rsrc = $self->result_source;
 
-  my $needs_group_by_subq = $self->_has_attr (qw/prefetch distinct join seen_join group_by/);
-  my $needs_subq = $self->_has_attr (qw/row offset page/);
+  my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/);
+  my $needs_subq = $self->_has_resolved_attr (qw/row offset/);
 
   if ($needs_group_by_subq or $needs_subq) {
 
     # make a new $rs selecting only the PKs (that's all we really need)
     my $attrs = $self->_resolved_attrs_copy;
 
-    delete $attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns/;
+    delete $attrs->{$_} for qw/collapse select as/;
     $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
 
     if ($needs_group_by_subq) {
@@ -1808,14 +1818,14 @@ sub _is_deterministic_value {
   return 0;
 }
 
-# _has_attr
+# _has_resolved_attr
 #
 # determines if the resultset defines at least one
 # of the attributes supplied
 #
 # used to determine if a subquery is neccessary
 
-sub _has_attr {
+sub _has_resolved_attr {
   my ($self, @attr_names) = @_;
 
   my $attrs = $self->_resolved_attrs;
@@ -1823,7 +1833,7 @@ sub _has_attr {
   my $join_check_req;
 
   for my $n (@attr_names) {
-    ++$join_check_req if $n =~ /join/;
+    ++$join_check_req if $n eq '-join';
 
     my $attr =  $attrs->{$n};
 
@@ -1840,7 +1850,7 @@ sub _has_attr {
     }
   }
 
-  # a join can be expressed as a multi-level from
+  # a resolved join is expressed as a multi-level from
   return 1 if (
     $join_check_req
       and
@@ -2600,30 +2610,35 @@ sub _resolved_attrs {
     map { $prefix . $_ } ($source->primary_columns)
   ];
 
-  my $collapse = $attrs->{collapse} || {};
+  $attrs->{collapse} ||= {};
   if ( my $prefetch = delete $attrs->{prefetch} ) {
     $prefetch = $self->_merge_attr( {}, $prefetch );
-    my @pre_order;
-    foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
-
-      # bring joins back to level of current class
-      my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
-      my @prefetch =
-        $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
-      push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
-      push( @{ $attrs->{as} },     map { $_->[1] } @prefetch );
-    }
-    push( @{ $attrs->{order_by} }, @pre_order );
+
+    my $prefetch_ordering = [];
+
+    my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
+
+    my @prefetch =
+      $source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
+
+    push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
+    push( @{ $attrs->{as} },     map { $_->[1] } @prefetch );
+
+    push( @{ $attrs->{order_by} }, @$prefetch_ordering );
+    $attrs->{_collapse_order_by} = \@$prefetch_ordering;
   }
 
+
   if (delete $attrs->{distinct}) {
     $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
   }
 
-  $attrs->{collapse} = $collapse;
-
-  if ( $attrs->{page} and not defined $attrs->{offset} ) {
-    $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
+  # if both page and offset are specified, produce a combined offset
+  # even though it doesn't make much sense, this is what pre 081xx has
+  # been doing
+  if (my $page = delete $attrs->{page}) {
+    $attrs->{offset} = ($attrs->{rows} * ($page - 1)) +
+      ($attrs->{offset} || 0);
   }
 
   return $self->{_attrs} = $attrs;