gistfile1.diff

From 166815cde49599cca0d7d69921abd533984a78d6 Mon Sep 17 00:00:00 2001
From: Emilio Tagua <miloops@gmail.com>
Date: Mon, 28 Dec 2009 17:07:47 -0300
Subject: [PATCH] Fix: count should look for projections in chained relations and perform the count on the given column.

---
 .../lib/active_record/relational_calculations.rb   |   19 +++++++++++++++++--
 activerecord/test/cases/relations_test.rb          |   10 +++++++++-
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/activerecord/lib/active_record/relational_calculations.rb b/activerecord/lib/active_record/relational_calculations.rb
index 10eb992..93457ff 100644
--- a/activerecord/lib/active_record/relational_calculations.rb
+++ b/activerecord/lib/active_record/relational_calculations.rb
@@ -31,10 +31,10 @@ module ActiveRecord
       # TODO : relation.projections only works when .select() was last in the chain. Fix it!
       case args.size
       when 0
-        column_name = @relation.send(:select_clauses).join(', ') if @relation.respond_to?(:projections) && @relation.projections.present?
+        column_name = get_projection_name_from_chained_relations
       when 1
         if args[0].is_a?(Hash)
-          column_name = @relation.send(:select_clauses).join(', ') if @relation.respond_to?(:projections) && @relation.projections.present?
+          column_name = get_projection_name_from_chained_relations
           options = args[0]
         else
           column_name = args[0]
@@ -48,5 +48,20 @@ module ActiveRecord
       [column_name || :all, options]
     end
 
+    def get_projection_name_from_chained_relations
+      name = nil
+      if @relation.respond_to?(:projections) && @relation.projections.present?
+        name = @relation.send(:select_clauses).join(', ')
+      elsif @relation.respond_to?(:relation) && relation = @relation.relation
+        while relation.respond_to?(:relation)
+          if relation.respond_to?(:projections) && relation.projections.present?
+            name = relation.send(:select_clauses).join(', ')
+          end
+          relation = relation.relation
+        end
+      end
+      name
+    end
+
   end
 end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index ded4f2f..5531edb 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -341,7 +341,7 @@ class RelationTest < ActiveRecord::TestCase
     relations = []
     relations << (Post.order('comments.id DESC') & Post.eager_load(:last_comment) & Post.scoped)
     relations << (Post.eager_load(:last_comment) & Post.order('comments.id DESC') & Post.scoped)
-    
+
     relations.each do |posts|
       post = posts.find { |p| p.id == 1 }
       assert_equal Post.find(1).last_comment, post.last_comment
@@ -383,9 +383,17 @@ class RelationTest < ActiveRecord::TestCase
     Post.update_all(:comments_count => nil)
     posts = Post.scoped
 
+    assert_equal 0, posts.select('comments_count').where('id is not null').order('id').count
+    assert_equal 0, posts.where('id is not null').select('comments_count').count
     assert_equal 7, posts.select('comments_count').count('id')
     assert_equal 0, posts.select('comments_count').count
     assert_equal 0, posts.count(:comments_count)
     assert_equal 0, posts.count('comments_count')
   end
+
+  def test_count_complex_chained_relations
+    posts = Post.scoped
+
+    assert_equal 2, posts.select('comments_count').where('id is not null').group("author_id").where("comments_count > 0").count
+  end
 end
-- 
1.6.5