Only set/save the inverse on a HABTM if the inverse is also HABTM

lib/active_fedora/associations/has_and_belongs_to_many_association.rb

@@ -18,13 +18,16 @@ def insert_record(record, force = true, validate = true)
         owner[reflection.foreign_key] ||= []
         owner[reflection.foreign_key] += [record.id]
 
-        if @owner.new_record? and @reflection.options[:inverse_of]
-          ActiveFedora::Base.logger.warn("has_and_belongs_to_many #{@reflection.inspect} is cowardly refusing to insert the inverse relationship into #{record}, because #{@owner} is not persisted yet.") if ActiveFedora::Base.logger
-        elsif @reflection.options[:inverse_of]
-          inverse = @reflection.inverse_of
-          record[inverse.foreign_key] ||= []
-          record[inverse.foreign_key] += [owner.id]
-          record.save
+        # Only if they've explicitly stated the inverse in the options
+        if reflection.options[:inverse_of]
+          inverse = reflection.inverse_of
+          if owner.new_record?
+            ActiveFedora::Base.logger.warn("has_and_belongs_to_many #{reflection.inspect} is cowardly refusing to insert the inverse relationship into #{record}, because #{owner} is not persisted yet.") if ActiveFedora::Base.logger
+          elsif inverse.has_and_belongs_to_many?
+            record[inverse.foreign_key] ||= []
+            record[inverse.foreign_key] += [owner.id]
+            record.save
+          end
         end
 
         return true

spec/integration/has_and_belongs_to_many_associations_spec.rb

@@ -364,6 +364,23 @@ class Component < ActiveFedora::Base
           expect(component.item_ids).to eq [item.id]
         end
       end
+
+      context "when the has_and_belongs_to_many provides an inverse_of" do
+        let(:reflection) { Component.reflect_on_association(:items) }
+        before do
+          reflection.options[:inverse_of] = :components
+        end
+
+        describe "shifting" do
+          let(:component) { Component.create }
+          let(:item) { Item.new }
+
+          it "should set item_ids" do
+            component.items << item
+            expect(component.item_ids).to eq [item.id]
+          end
+        end
+      end
     end
 
     describe "From the has_many side" do