Revert "Fix rails#5667. Preloading should ignore scoping."

Causes a subtle regression where record.reload includes the default
scope. Hard to reproduce in isolation. Seems like the relation is
getting infected by some previous usage.

This reverts commit dffbb52.

activerecord/CHANGELOG.md

@@ -1,9 +1,3 @@
-## Rails 3.2.4 (unreleased) ##
-
-*   Association preloading shouldn't be affected by the current scoping.
-    This could cause infinite recursion and potentially other problems.
-    See GH #5667. *Jon Leighton*
-
 ## Rails 3.2.3 (unreleased) ##
 
 *   Added find_or_create_by_{attribute}! dynamic method. *Andrew White*

activerecord/lib/active_record/associations/preloader/association.rb

@@ -77,7 +77,7 @@ def associated_records_by_owner
             # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
             # Make several smaller queries if necessary or make one query if the adapter supports it
             sliced  = owner_keys.each_slice(model.connection.in_clause_length || owner_keys.size)
-            records = sliced.map { |slice| records_for(slice).to_a }.flatten
+            records = sliced.map { |slice| records_for(slice) }.flatten
           end
 
           # Each record may have multiple owners, and vice-versa
@@ -93,8 +93,7 @@ def associated_records_by_owner
         end
 
         def build_scope
-          scope = klass.unscoped
-          scope.default_scoped = true
+          scope = klass.scoped
 
           scope = scope.where(process_conditions(options[:conditions]))
           scope = scope.where(process_conditions(preload_options[:conditions]))

activerecord/test/cases/associations/eager_test.rb

@@ -1095,15 +1095,4 @@ def test_join_eager_with_nil_order_should_generate_valid_sql
       Post.includes(:comments).order(nil).where(:comments => {:body => "Thank you for the welcome"}).first
     end
   end
-
-  test "scoping with a circular preload" do
-    assert_equal Comment.find(1), Comment.preload(:post => :comments).scoping { Comment.find(1) }
-  end
-
-  test "preload ignores the scoping" do
-    assert_equal(
-      Comment.find(1).post,
-      Post.where('1 = 0').scoping { Comment.preload(:post).find(1).post }
-    )
-  end
 end