Do not reindex type automatically.

When doing a partial reindex (to index a new field, for example), searchkick was
reindexing `type`  even when not asked to.

This is a problem because maybe you want to reindex `type` with a different value, and after
doing a partial index, you need to call the `reindex` again by type — mainly because searchkick
has overridden the type using the `document_type` method.

Performance is a concern here. Imagine doing that for millions of rows;
it will take more time to finish the reindexing.

lib/searchkick/record_data.rb

@@ -80,7 +80,7 @@ def search_data(method_name = nil)
       end
 
       if index.options[:inheritance]
-        if !TYPE_KEYS.any? { |tk| source.key?(tk) }
+        if !partial_reindex || TYPE_KEYS.any? { |tk| method_name.equal?(tk) }
           source[:type] = document_type(true)
         end
       end

test/inheritance_test.rb

@@ -81,6 +81,32 @@ def test_child_models_option
     assert_equal 2, Searchkick.search("bear", models: [Cat, Dog]).size
   end
 
+  def test_partial_reindex
+    store_names ["Buddy"], Dog
+
+    assert_equal ["Buddy"], Animal.search("budd", type: [Dog], load: false).map(&:name)
+
+    # Update the record to change the type to mess with the record
+    # and do not call the callbacks to avoid reindexing
+    animal = Dog.first
+    animal.name = "Charlie"
+    animal.type = "Cat"
+    Searchkick.callbacks(false) do
+      animal.save!
+    end
+
+    # Reindex records to have the `full_name` available
+    Animal.reindex(:full_name_data)
+
+    # full_name works now
+    assert_equal ["Charlie the Cat"], Animal.search("charlie", load: false).map(&:full_name)
+
+    # Does not change the original index (name still Buddy and type still Dog)
+    assert_equal ["Buddy"], Animal.search("buddy", type: [Dog], load: false).map(&:name)
+    assert_equal ["dog"], Animal.search("buddy", type: [Dog], load: false).map(&:type)
+  end
+
+
   def test_missing_records
     store_names ["Bear A"], Cat
     store_names ["Bear B"], Dog

test/models/animal.rb

@@ -3,4 +3,8 @@ class Animal
     inheritance: true,
     text_start: [:name],
     suggest: [:name]
+
+  def full_name_data
+    { full_name: "#{name} the #{type}" }
+  end
 end