X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSetColumn.pm;h=60d08c76cba86fb24aec624039f8f900740c4482;hb=0c11ad0ee5c8407f6b87d6e15c62a1b445076dc0;hp=0057abf84912ae3648b404a7269746d7d1a4ae3a;hpb=6dfbe2f861ff0d52f5b370a9059334ba8339be51;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm
index 0057abf..60d08c7 100644
--- a/lib/DBIx/Class/ResultSetColumn.pm
+++ b/lib/DBIx/Class/ResultSetColumn.pm
@@ -4,10 +4,11 @@ use strict;
 use warnings;
 
 use base 'DBIx::Class';
-
-use Carp::Clan qw/^DBIx::Class/;
+use DBIx::Class::Carp;
 use DBIx::Class::Exception;
-use List::Util;
+
+# not importing first() as it will clash with our own method
+use List::Util ();
 
 =head1 NAME
 
@@ -42,51 +43,64 @@ sub new {
   my ($class, $rs, $column) = @_;
   $class = ref $class if ref $class;
 
-  $rs->throw_exception("column must be supplied") unless $column;
+  $rs->throw_exception('column must be supplied') unless $column;
 
   my $orig_attrs = $rs->_resolved_attrs;
-  my $new_parent_rs = $rs->search_rs;
-
-  # prefetch causes additional columns to be fetched, but we can not just make a new
-  # rs via the _resolved_attrs trick - we need to retain the separation between
-  # +select/+as and select/as. At the same time we want to preserve any joins that the
-  # prefetch would otherwise generate.
-
-  my $new_attrs = $new_parent_rs->{attrs} ||= {};
-  $new_attrs->{join} = $rs->_merge_attr( delete $new_attrs->{join}, delete $new_attrs->{prefetch} );
+  my $alias = $rs->current_source_alias;
+  my $rsrc = $rs->result_source;
 
   # If $column can be found in the 'as' list of the parent resultset, use the
   # corresponding element of its 'select' list (to keep any custom column
   # definition set up with 'select' or '+select' attrs), otherwise use $column
   # (to create a new column definition on-the-fly).
-
   my $as_list = $orig_attrs->{as} || [];
   my $select_list = $orig_attrs->{select} || [];
   my $as_index = List::Util::first { ($as_list->[$_] || "") eq $column } 0..$#$as_list;
   my $select = defined $as_index ? $select_list->[$as_index] : $column;
 
-  # {collapse} would mean a has_many join was injected, which in turn means
-  # we need to group *IF WE CAN* (only if the column in question is unique)
-  if (!$new_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) {
+  my ($new_parent_rs, $colmap);
+  for ($rsrc->columns, $column) {
+    if ($_ =~ /^ \Q$alias\E \. ([^\.]+) $ /x) {
+      $colmap->{$_} = $1;
+    }
+    elsif ($_ !~ /\./) {
+      $colmap->{"$alias.$_"} = $_;
+      $colmap->{$_} = $_;
+    }
+  }
 
-    # scan for a constraint that would contain our column only - that'd be proof
-    # enough it is unique
-    my $constraints = { $rs->result_source->unique_constraints };
-    for my $constraint_columns ( values %$constraints ) {
+  # analyze the order_by, and see if it is done over a function/nonexistentcolumn
+  # if this is the case we will need to wrap a subquery since the result of RSC
+  # *must* be a single column select
+  if (
+    scalar grep
+      { ! exists $colmap->{$_->[0]} }
+      ( $rsrc->schema->storage->_extract_order_criteria ($orig_attrs->{order_by} ) )
+  ) {
+    # nuke the prefetch before collapsing to sql
+    my $subq_rs = $rs->search;
+    $subq_rs->{attrs}{join} = $subq_rs->_merge_joinpref_attr( $subq_rs->{attrs}{join}, delete $subq_rs->{attrs}{prefetch} );
+    $new_parent_rs = $subq_rs->as_subselect_rs;
+  }
 
-      next unless @$constraint_columns == 1;
+  $new_parent_rs ||= $rs->search_rs;
+  my $new_attrs = $new_parent_rs->{attrs} ||= {};
 
-      my $col = $constraint_columns->[0];
-      my $fqcol = join ('.', $new_attrs->{alias}, $col);
+  # prefetch causes additional columns to be fetched, but we can not just make a new
+  # rs via the _resolved_attrs trick - we need to retain the separation between
+  # +select/+as and select/as. At the same time we want to preserve any joins that the
+  # prefetch would otherwise generate.
+  $new_attrs->{join} = $rs->_merge_joinpref_attr( $new_attrs->{join}, delete $new_attrs->{prefetch} );
 
-      if ($col eq $select or $fqcol eq $select) {
-        $new_attrs->{group_by} = [ $select ];
-        delete $new_attrs->{distinct}; # it is ignored when group_by is present
-        last;
-      }
-    }
+  # {collapse} would mean a has_many join was injected, which in turn means
+  # we need to group *IF WE CAN* (only if the column in question is unique)
+  if (!$orig_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) {
 
-    if (!$new_attrs->{group_by}) {
+    if ($colmap->{$select} and $rsrc->_identifying_column_set([$colmap->{$select}])) {
+      $new_attrs->{group_by} = [ $select ];
+      delete $new_attrs->{distinct}; # it is ignored when group_by is present
+    }
+    else {
       carp (
           "Attempting to retrieve non-unique column '$column' on a resultset containing "
         . 'one-to-many joins will return duplicate results.'
@@ -129,7 +143,7 @@ sub as_query { return shift->_resultset->as_query(@_) }
 Returns the next value of the column in the resultset (or C<undef> if
 there is none).
 
-Much like L<DBIx::Class::ResultSet/next> but just returning the 
+Much like L<DBIx::Class::ResultSet/next> but just returning the
 one value.
 
 =cut
@@ -421,7 +435,7 @@ sub func_rs {
 
 See L<DBIx::Class::Schema/throw_exception> for details.
 
-=cut 
+=cut
 
 sub throw_exception {
   my $self=shift;
@@ -458,11 +472,9 @@ sub _resultset {
 
 1;
 
-=head1 AUTHORS
-
-Luke Saunders <luke.saunders@gmail.com>
+=head1 AUTHOR AND CONTRIBUTORS
 
-Jess Robinson
+See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
 
 =head1 LICENSE