From: Peter Rabbitson <ribasushi@cpan.org>
Date: Tue, 4 Aug 2009 10:35:57 +0000 (+0000)
Subject: Fix how a distinct-induced group_by is calculated, taking in consideration the new... 
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=b5f4f62f2e5d756401c91f8eb6a5fbe1db28b95e;p=dbsrgits%2FDBIx-Class-Historic.git

Fix how a distinct-induced group_by is calculated, taking in consideration the new prefetch mechanism
---

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index b7ba496..cd62c34 100644
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -1264,7 +1264,7 @@ sub _count_subq_rs {
   my $sub_attrs = { %$attrs };
 
   # extra selectors do not go in the subquery and there is no point of ordering it
-  delete $sub_attrs->{$_} for qw/collapse prefetch_select select as order_by/;
+  delete $sub_attrs->{$_} for qw/collapse select _prefetch_select as order_by/;
 
   # if we prefetch, we group_by primary keys only as this is what we would get out of the rs via ->next/->all
   # clobber old group_by regardless
@@ -2875,6 +2875,12 @@ sub _resolved_attrs {
     $attrs->{group_by} = [ $attrs->{group_by} ];
   }
 
+  # generate the distinct induced group_by early, as prefetch will be carried via a
+  # subquery (since a group_by is present)
+  if (delete $attrs->{distinct}) {
+    $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
+  }
+
   $attrs->{collapse} ||= {};
   if ( my $prefetch = delete $attrs->{prefetch} ) {
     $prefetch = $self->_merge_attr( {}, $prefetch );
@@ -2886,19 +2892,16 @@ sub _resolved_attrs {
     my @prefetch =
       $source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
 
-    $attrs->{prefetch_select} = [ map { $_->[0] } @prefetch ];
-    push @{ $attrs->{select} }, @{$attrs->{prefetch_select}};
+    # we need to somehow mark which columns came from prefetch
+    $attrs->{_prefetch_select} = [ map { $_->[0] } @prefetch ];
+
+    push @{ $attrs->{select} }, @{$attrs->{_prefetch_select}};
     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}} ];
-  }
-
   # 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
diff --git a/lib/DBIx/Class/Storage/DBI.pm b/lib/DBIx/Class/Storage/DBI.pm
index 1d1e57b..ca0ee87 100644
--- a/lib/DBIx/Class/Storage/DBI.pm
+++ b/lib/DBIx/Class/Storage/DBI.pm
@@ -1430,7 +1430,7 @@ sub _select_args {
     ( $attrs->{rows} && keys %{$attrs->{collapse}} )
        ||
     ( $attrs->{group_by} && @{$attrs->{group_by}} &&
-      $attrs->{prefetch_select} && @{$attrs->{prefetch_select}} )
+      $attrs->{_prefetch_select} && @{$attrs->{_prefetch_select}} )
   ) {
     ($ident, $select, $where, $attrs)
       = $self->_adjust_select_args_for_complex_prefetch ($ident, $select, $where, $attrs);
@@ -1475,14 +1475,15 @@ sub _adjust_select_args_for_complex_prefetch {
   # separate attributes
   my $sub_attrs = { %$attrs };
   delete $attrs->{$_} for qw/where bind rows offset group_by having/;
-  delete $sub_attrs->{$_} for qw/for collapse prefetch_select _collapse_order_by select as/;
+  delete $sub_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/;
 
   my $alias = $attrs->{alias};
   my $sql_maker = $self->sql_maker;
 
   # create subquery select list - consider only stuff *not* brought in by the prefetch
   my $sub_select = [];
-  for my $i (0 .. @{$attrs->{select}} - @{$attrs->{prefetch_select}} - 1) {
+  my $sub_group_by;
+  for my $i (0 .. @{$attrs->{select}} - @{$attrs->{_prefetch_select}} - 1) {
     my $sel = $attrs->{select}[$i];
 
     # alias any functions to the dbic-side 'as' label
@@ -1595,13 +1596,15 @@ sub _adjust_select_args_for_complex_prefetch {
 
   # if a multi-type join was needed in the subquery ("multi" is indicated by
   # presence in {collapse}) - add a group_by to simulate the collapse in the subq
-  for my $alias (keys %inner_joins) {
-
-    # the dot comes from some weirdness in collapse
-    # remove after the rewrite
-    if ($attrs->{collapse}{".$alias"}) {
-      $sub_attrs->{group_by} ||= $sub_select;
-      last;
+  unless ($sub_attrs->{group_by}) {
+    for my $alias (keys %inner_joins) {
+
+      # the dot comes from some weirdness in collapse
+      # remove after the rewrite
+      if ($attrs->{collapse}{".$alias"}) {
+        $sub_attrs->{group_by} ||= $sub_select;
+        last;
+      }
     }
   }