Don't pass frozen array of extensions

Author: rmosolgo

lib/graphql/schema/resolver.rb

@@ -307,10 +307,15 @@ def field_options
             arguments: arguments,
             null: null,
             complexity: complexity,
-            extensions: extensions,
             broadcastable: broadcastable?,
           }
 
+          # If there aren't any, then the returned array is `[].freeze`,
+          # but passing that along breaks some user code.
+          if (exts = extensions).any?
+            field_opts[:extensions] = exts
+          end
+
           if has_max_page_size?
             field_opts[:max_page_size] = max_page_size
           end

spec/graphql/schema/resolver_spec.rb

@@ -825,6 +825,12 @@ def load_input(input); end
         assert_equal 1, r1.extensions.size
         assert_equal 2, r2.extensions.size
       end
+
+      it "doesn't pass anything when there are no extensions" do
+        r1 = Class.new(GraphQL::Schema::Resolver)
+        assert_equal [], r1.extensions
+        refute r1.field_options.key?(:extensions)
+      end
     end
 
     describe "max_page_size" do