Association preloading no longer stops if it hits a nil object [#1630 state:resolved]

Signed-off-by: Frederick Cheung <frederick.cheung@gmail.com>

2 files changed, 10 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb
index 7b1b2d9ad9..0bcf50c167 100644
--- a/activerecord/lib/active_record/association_preload.rb
+++ b/activerecord/lib/active_record/association_preload.rb
@@ -94,8 +94,8 @@ module ActiveRecord
             raise "parent must be an association name" unless parent.is_a?(String) || parent.is_a?(Symbol)
             preload_associations(records, parent, preload_options)
             reflection = reflections[parent]
-            parents = records.map {|record| record.send(reflection.name)}.flatten
-            unless parents.empty? || parents.first.nil?
+            parents = records.map {|record| record.send(reflection.name)}.flatten.compact
+            unless parents.empty?
               parents.first.class.preload_associations(parents, child)
             end
           end
diff --git a/activerecord/test/cases/associations/cascaded_eager_loading_test.rb b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
index 8c9ae8a031..45e74ea024 100644
--- a/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
+++ b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
@@ -104,6 +104,14 @@ class CascadedEagerLoadingTest < ActiveRecord::TestCase
       authors.first.posts.first.special_comments.first.post.very_special_comment
     end
   end
+  
+  def test_eager_association_loading_where_first_level_returns_nil
+    authors = Author.find(:all, :include => {:post_about_thinking => :comments}, :order => 'authors.id DESC')
+    assert_equal [authors(:mary), authors(:david)], authors
+    assert_no_queries do
+      authors[1].post_about_thinking.comments.first
+    end
+  end
 end
 
 require 'models/vertex'