MONGOID-5895 Make Reload Properly Update new_record (#6034) (#6037)

* Ensure reload properly handles instances where we create a new document, but set the ID to an existing one

* Fix misplaced spec

Co-authored-by: Matthew Livingstone <matthew.livingstone@clio.com>

Author: jamis

lib/mongoid/reloadable.rb

@@ -17,6 +17,12 @@ def reload
       reloaded = _reload
       check_for_deleted_document!(reloaded)
 
+      # In an instance where we create a new document, but set the ID to an existing one,
+      #   when the document is reloaded, we want to set new_record to false.
+      #   This is necessary otherwise saving will fail, as it will try to insert the document,
+      #   instead of attempting to update the existing document.
+      @new_record = false unless reloaded.nil? || reloaded.empty?
+
       reset_object!(reloaded)
 
       run_callbacks(:find) unless _find_callbacks.empty?

spec/mongoid/reloadable_spec.rb

@@ -134,6 +134,16 @@
 
           agent.title.should == '007'
         end
+
+        it 'sets new_record to false' do
+          expect(agent.new_record?).to be true
+
+          lambda do
+            agent.reload
+          end.should_not raise_error
+
+          expect(agent.new_record?).to be false
+        end
       end
     end
 
@@ -596,6 +606,20 @@
           band.id.should_not == original_id
         end
       end
+
+      context 'when there is no document matching our id' do
+        let(:agent) { Agent.new(id: BSON::ObjectId.new) }
+
+        it 'does not set new_record to false' do
+          expect(agent.new_record?).to be true
+
+          lambda do
+            agent.reload
+          end.should_not raise_error
+
+          expect(agent.new_record?).to be true
+        end
+      end
     end
 
     context 'when document has referenced associations' do