From a35488c7125f62069fa02a0bb26c94164aa86eab Mon Sep 17 00:00:00 2001
From: John Devine <johnjdevine@gmail.com>
Date: Sat, 3 May 2008 22:49:18 -0500
Subject: [PATCH] Added logic to associations.rb to make sure select_for_limited_ids
includes joins that are needed to reach tables listed in the :order
or :conditions options if they are not joined directly to the main
active_record table.
---
 activerecord/lib/active_record/associations.rb |   25 +++++++++++++++++++++++-
 activerecord/test/cases/finder_test.rb         |    9 ++++++++
 2 files changed, 33 insertions(+), 1 deletions(-)
 mode change 100755 => 100644 activerecord/lib/active_record/associations.rb

diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
old mode 100755
new mode 100644
index 7d27b06..83f83c3
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1446,6 +1446,12 @@ module ActiveRecord
           tables_from_conditions = conditions_tables(options)
           tables_from_order      = order_tables(options)
           all_tables             = tables_from_conditions + tables_from_order
+          distinct_join_associations = all_tables.uniq.map{|table| 
+            join_dependency.joins_for_table_name(table)
+          }.flatten.compact.uniq
+
+
+
 
           is_distinct = !options[:joins].blank? || include_eager_conditions?(options, tables_from_conditions) || include_eager_order?(options, tables_from_order)
           sql = "SELECT "
@@ -1457,7 +1463,7 @@ module ActiveRecord
           sql << " FROM #{connection.quote_table_name table_name} "
 
           if is_distinct
-            sql << join_dependency.join_associations.reject{ |ja| !all_tables.include?(ja.table_name) }.collect(&:association_join).join
+            sql << distinct_join_associations.collect(&:association_join).join           
             add_joins!(sql, options, scope)
           end
 
@@ -1617,6 +1623,23 @@ module ActiveRecord
             end
           end
 
+          def join_for_table_name(table_name)
+            @joins.select{|j|j.aliased_table_name == table_name.gsub(/^\"(.*)\"$/){$1} }.first rescue nil
+          end
+
+          def joins_for_table_name(table_name)
+            join = join_for_table_name(table_name)            
+            result = nil            
+            if join && join.is_a?(JoinAssociation)
+              result = [join]
+              if join.parent && join.parent.is_a?(JoinAssociation)
+                result = joins_for_table_name(join.parent.aliased_table_name) +             
+                         result
+              end
+            end
+            result
+          end
+
           protected
             def build(associations, parent = nil)
               parent ||= @joins.last
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index b7f87fe..2acfe9b 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -8,6 +8,7 @@ require 'models/entrant'
 require 'models/developer'
 require 'models/post'
 require 'models/customer'
+require 'models/job'
 
 class FinderTest < ActiveRecord::TestCase
   fixtures :companies, :topics, :entrants, :developers, :developers_projects, :posts, :comments, :accounts, :authors, :customers
@@ -857,6 +858,14 @@ class FinderTest < ActiveRecord::TestCase
       Company.connection.select_rows("SELECT id, name FROM companies WHERE id IN (1,2,3) ORDER BY id").map! {|i| i.map! {|j| j.to_s unless j.nil?}}
   end
 
+  def test_find_with_order_on_included_associations_with_construct_finder_sql_for_association_limiting_and_is_distinct
+    assert_equal 2, Post.find(:all,:include=>{:authors=>:author_address},:order=>' author_addresses.id DESC ', :limit=>2).size
+
+    assert_equal 3, Post.find(:all,:include=>{:author=>:author_address,:authors=>:author_address},
+                              :order=>' author_addresses_authors.id DESC ', :limit=>3).size
+  end
+
+
   protected
     def bind(statement, *vars)
       if vars.first.is_a?(Hash)
-- 
1.5.2.5