Reset @full_path to nil when cache expires

app/models/concerns/routable.rb

@@ -108,6 +108,7 @@ module Routable
 
   def expires_full_path_cache
     RequestStore.delete(full_path_key) if RequestStore.active?
+    @full_path = nil
   end
 
   def build_full_path

spec/models/concerns/routable_spec.rb

@@ -135,11 +135,12 @@ describe Group, 'Routable' do
   describe '#expires_full_path_cache' do
     context 'with RequestStore active', :request_store do
       it 'expires the full_path cache' do
-        expect(group).to receive(:uncached_full_path).twice.and_call_original
+        expect(group.full_path).to eq('foo')
 
-        3.times { group.full_path }
+        group.route.update(path: 'bar', name: 'bar')
         group.expires_full_path_cache
-        3.times { group.full_path }
+
+        expect(group.full_path).to eq('bar')
       end
     end
   end