Avoid writing to routes.rb when no models exist.

This closes: thoughtbot#502, thoughtbot#516, thoughtbot#555, thoughtbot#649, thoughtbot#583, thoughtbot#601, thoughtbot#613.

lib/generators/administrate/routes/routes_generator.rb

@@ -8,7 +8,7 @@ class RoutesGenerator < Rails::Generators::Base
       source_root File.expand_path("../templates", __FILE__)
 
       def insert_dashboard_routes
-        unless File.read(rails_routes_file_path).include?(dashboard_routes)
+        if should_route_dashboard?
           route(dashboard_routes)
         end
       end
@@ -66,13 +66,21 @@ def dashboard_routes
         ERB.new(File.read(routes_file_path)).result(binding)
       end
 
+      def routes_includes_resources?
+        File.read(rails_routes_file_path).include?(dashboard_routes)
+      end
+
       def rails_routes_file_path
         Rails.root.join("config/routes.rb")
       end
 
       def routes_file_path
         File.expand_path(find_in_source_paths("routes.rb.erb"))
       end
+
+      def should_route_dashboard?
+        routes_includes_resources? || valid_dashboard_models.any?
+      end
     end
   end
 end

spec/generators/routes_generator_spec.rb

@@ -17,6 +17,16 @@
       expect(routes).not_to contain("Delayed::Backend::ActiveRecord::Job")
     end
 
+    it "does not populate routes when no models exist" do
+      stub_generator_dependencies
+      routes = file("config/routes.rb")
+      allow(ActiveRecord::Base).to receive(:descendants).and_return([])
+
+      run_generator
+
+      expect(routes).not_to contain("namespace :admin")
+    end
+
     it "skips namespaced models with a warning" do
       stub_generator_dependencies
       routes = file("config/routes.rb")