Guard enum_for's pluralized accessor with respond_to?

lib/permittable/generator.rb

@@ -507,15 +507,23 @@ def default_literal(value)
     # can be CALLED as `Model.name`: a `first-status` enum's
     # `Order.first-statuses.keys` parses as `Order.first - statuses.keys`,
     # which runs a query when the draft loads. defined_enums reaches the
-    # same mapping by name.
+    # same mapping by name. The model is also checked for the accessor
+    # itself (mirrors ColumnGuard.enum_keys_expr): a name can pluralize to a
+    # valid identifier that the model does not actually answer to — renamed
+    # or otherwise excluded — and calling it would raise NoMethodError when
+    # the draft loads.
     def enum_for(model, name)
       return nil unless model.respond_to?(:defined_enums)
 
       mapping = model.defined_enums[name]
       return nil unless mapping
 
       plural = name.pluralize
-      accessor = METHOD_NAME.match?(plural) ? "#{model.name}.#{plural}" : "#{model.name}.defined_enums[#{name.inspect}]"
+      accessor = if METHOD_NAME.match?(plural) && model.respond_to?(plural)
+                   "#{model.name}.#{plural}"
+                 else
+                   "#{model.name}.defined_enums[#{name.inspect}]"
+                 end
       { mapping: mapping, accessor: accessor }
     end
 

spec/generator_spec.rb

@@ -484,6 +484,29 @@ def lock_default
         expect(violations(klass, { gen_odd_enum: { "first-status" => "ajar" } }, action: "update"))
           .to eq([{ param: "gen_odd_enum.first-status", code: "inclusion" }])
       end
+
+      it "reaches an enum whose pluralized accessor the model does not answer to, so the draft loads" do
+        stub_const("GenOrderNoReader", Class.new(TestModel) do
+          self.table_name = "gen_orders"
+          if ActiveRecord.version >= Gem::Version.new("7.0")
+            enum :status, { pending: 0, shipped: 1 }
+          else
+            enum status: { pending: 0, shipped: 1 }
+          end
+          # Simulate an accessor renamed or excluded out from under the enum:
+          # "statuses" matches the identifier regex, but the model no longer
+          # responds to it.
+          singleton_class.send(:undef_method, :statuses)
+        end)
+
+        draft = described_class.draft(model: GenOrderNoReader)
+        expect(draft).to include('optional :status, :string, in: GenOrderNoReader.defined_enums["status"].keys')
+
+        klass = load_draft(draft)
+        expect(violations(klass, { gen_order_no_reader: { status: "shipped" } }, action: "update")).to eq([])
+        expect(violations(klass, { gen_order_no_reader: { status: "lost" } }, action: "update"))
+          .to eq([{ param: "gen_order_no_reader.status", code: "inclusion" }])
+      end
     end
 
     context "with defaults the model declares rather than the database" do