Merge pull request afair#51 from simi/do-not-load-association

Do not load association during initialization of cursor.

Rakefile

@@ -21,4 +21,5 @@ desc "Setup testing database and table"
 task :setup do
   sh %q(createdb postgresql_cursor_test)
   sh %Q<echo "create table products ( id serial primary key, data varchar);" | psql postgresql_cursor_test>
+  sh %Q<echo "create table prices ( id serial primary key, data varchar, product_id integer);" | psql postgresql_cursor_test>
 end

lib/postgresql_cursor/cursor.rb

@@ -50,11 +50,14 @@ def initialize(sql, options={})
       @batched    = false
     end
 
-    # Specify the type to instantiate, or reset to return a Hash
+    # Specify the type to instantiate, or reset to return a Hash.
+    #
+    # Explicitly check for type class to prevent calling equality
+    # operator on active record relation, which will load it.
     def iterate_type(type=nil)
-      if type.nil? || type == Hash
+      if type.nil? || (type.class == Class && type == Hash)
         @iterate = :each_row
-      elsif type == Array
+      elsif type.class == Class && type == Array
         @iterate = :each_array
       else
         @iterate = :each_instance

test/helper.rb

@@ -10,6 +10,8 @@
   username: ENV['TEST_USER']     || ENV['USER'] || 'postgresql_cursor')
 
 class Product < ActiveRecord::Base
+  has_many :prices
+
   # create table records (id serial primary key);
   def self.generate(max=1_000)
     max.times do |i|
@@ -18,5 +20,9 @@ def self.generate(max=1_000)
   end
 end
 
+class Price < ActiveRecord::Base
+  belongs_to :product
+end
+
 Product.destroy_all
 Product.generate(1000)

test/test_postgresql_cursor.rb

@@ -191,4 +191,9 @@ def test_bad_sql
       assert_match(/bad_table/, e.message)
     end
   end
+
+  def test_relation_association_is_not_loaded
+    cursor = Product.first.prices.each_instance
+    refute cursor.instance_variable_get(:@type).loaded?
+  end
 end