From: Peter Rabbitson <ribasushi@cpan.org>
Date: Sat, 25 Dec 2010 03:38:41 +0000 (+0100)
Subject: Fail early on literal-ordered complex prefetch without explicit group_by clause
X-Git-Tag: v0.08125~6
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits%2FDBIx-Class.git;a=commitdiff_plain;h=14e26c5f3516e39d9191ca9b2a9d460f8f495654

Fail early on literal-ordered complex prefetch without explicit group_by clause
---

diff --git a/Changes b/Changes
index 132c4e5..d14c03c 100644
--- a/Changes
+++ b/Changes
@@ -34,6 +34,9 @@ Revision history for DBIx::Class
         - Fix regressions in IC::DT registration logic
         - Fix regression in select-associated bind value handling (RT#61025)
         - Simplify SQL generated by some LIMITed prefetching queries
+        - Throw an exception when a required group_by on a complex prefetch
+          can not be auto-constructed, instead of continuing to eventually
+          produce invalid SQL
         - Fix infinite loops on old perls with a recent Try::Tiny
         - Improve "fork()" on Win32 by reimplementing a more robust DBIC
           thread support (still problematic, pending a DBI fix)
diff --git a/lib/DBIx/Class/Storage/DBIHacks.pm b/lib/DBIx/Class/Storage/DBIHacks.pm
index 41ca371..ba1faa4 100644
--- a/lib/DBIx/Class/Storage/DBIHacks.pm
+++ b/lib/DBIx/Class/Storage/DBIHacks.pm
@@ -129,9 +129,16 @@ sub _adjust_select_args_for_complex_prefetch {
         ! $inner_aliastypes->{selecting}{$_}
       } ( keys %{$inner_aliastypes->{multiplying}||{}} )
     ) {
-      $inner_attrs->{group_by} = $self->_group_over_selection (
+      my $unprocessed_order_chunks;
+      ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection (
         $inner_from, $inner_select, $inner_attrs->{order_by}
       );
+
+      $self->throw_exception (
+        'A required group_by clause could not be constructed automatically due to a complex '
+      . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable '
+      . 'group_by by hand'
+      )  if $unprocessed_order_chunks;
     }
 
     # we already optimized $inner_from above
@@ -367,17 +374,27 @@ sub _group_over_selection {
   # add any order_by parts that are not already present in the group_by
   # we need to be careful not to add any named functions/aggregates
   # i.e. order_by => [ ... { count => 'foo' } ... ]
+  my @leftovers;
   for ($self->_extract_order_criteria($order_by)) {
     # only consider real columns (for functions the user got to do an explicit group_by)
-    next if @$_ != 1;
+    if (@$_ != 1) {
+      push @leftovers, $_;
+      next;
+    }
     my $chunk = $_->[0];
-    my $colinfo = $rs_column_list->{$chunk} or next;
+    my $colinfo = $rs_column_list->{$chunk} or do {
+      push @leftovers, $_;
+      next;
+    };
 
     $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./;
     push @group_by, $chunk unless $group_index{$chunk}++;
   }
 
-  return \@group_by;
+  return wantarray
+    ? (\@group_by, (@leftovers ? \@leftovers : undef) )
+    : \@group_by
+  ;
 }
 
 sub _resolve_ident_sources {
diff --git a/t/746mssql.t b/t/746mssql.t
index 674046a..6584050 100644
--- a/t/746mssql.t
+++ b/t/746mssql.t
@@ -336,6 +336,7 @@ for my $dialect (
       {
         prefetch => 'books',
         order_by => { -asc => \['name + ?', [ test => 'xxx' ]] }, # test bindvar propagation
+        group_by => [ map { "me.$_" } $schema->source('Owners')->columns ], # the literal order_by requires an explicit group_by
         rows     => 3,  # 8 results total
         unsafe_subselect_ok => 1,
       },
diff --git a/t/prefetch/with_limit.t b/t/prefetch/with_limit.t
index bc035de..4acdcab 100644
--- a/t/prefetch/with_limit.t
+++ b/t/prefetch/with_limit.t
@@ -84,6 +84,15 @@ throws_ok (
   'single() with multiprefetch is illegal',
 );
 
+throws_ok (
+  sub {
+    $use_prefetch->search(
+      {'tracks.title' => { '!=' => 'foo' }},
+      { order_by => \ 'some oddball literal sql', join => { cds => 'tracks' } }
+    )->next
+  }, qr/A required group_by clause could not be constructed automatically/,
+);
+
 my $artist = $use_prefetch->search({'cds.title' => $artist_many_cds->cds->first->title })->next;
 is($artist->cds->count, 1, "count on search limiting prefetched has_many");