Make source_reflection return nil when no name

Author: theodorton

activerecord/lib/active_record/reflection.rb

@@ -1007,6 +1007,8 @@ def klass
       #   # => <ActiveRecord::Reflection::BelongsToReflection: @name=:tag, @active_record=Tagging, @plural_name="tags">
       #
       def source_reflection
+        return unless source_reflection_name
+
         through_reflection.klass._reflect_on_association(source_reflection_name)
       end
 

activerecord/test/cases/reflection_test.rb

@@ -607,6 +607,18 @@ def test_reflect_on_association_accepts_strings
     end
   end
 
+  def test_reflect_on_missing_source_assocation
+    assert_nothing_raised do
+      assert_nil Hotel.reflect_on_association(:lost_items).source_reflection
+    end
+  end
+
+  def test_reflect_on_missing_source_assocation_raise_exception
+    assert_raises(ActiveRecord::HasManyThroughSourceAssociationNotFoundError) do
+      Hotel.reflect_on_association(:lost_items).check_validity!
+    end
+  end
+
   def test_name_error_from_incidental_code_is_not_converted_to_name_error_for_association
     UserWithInvalidRelation.stub(:const_missing, proc { oops }) do
       reflection = UserWithInvalidRelation.reflect_on_association(:not_a_class)

activerecord/test/models/hotel.rb

@@ -10,4 +10,6 @@ class Hotel < ActiveRecord::Base
   has_many :mocktail_designers, through: :chef_lists, source: :employable, source_type: "MocktailDesigner"
 
   has_many :recipes, through: :chefs
+
+  has_many :lost_items, through: :departments
 end