Fix: regression from ruby-grape#1263, closes ruby-grape#1307.

lib/grape/api.rb

@@ -131,11 +131,14 @@ def add_head_not_allowed_methods_and_options_methods
       self.class.endpoints.each do |endpoint|
         routes = endpoint.routes
         routes.each do |route|
-          methods_per_path[route.route_path] ||= []
-          methods_per_path[route.route_path] << route.route_method
+          # ignore any optional portions of the path
+          route_path = route.route_path.gsub(/\(.*\)/, '')
+
+          methods_per_path[route_path] ||= []
+          methods_per_path[route_path] << route.route_method
 
           # using the :any shorthand produces [nil] for route methods, substitute all manually
-          methods_per_path[route.route_path] = %w(GET PUT POST DELETE PATCH HEAD OPTIONS) if methods_per_path[route.route_path].compact.empty?
+          methods_per_path[route_path] = %w(GET PUT POST DELETE PATCH HEAD OPTIONS) if methods_per_path[route_path].compact.empty?
         end
       end
 

spec/grape/api/optional_parameters_in_route_spec.rb

@@ -0,0 +1,43 @@
+require 'spec_helper'
+
+describe Grape::Endpoint do
+  subject { Class.new(Grape::API) }
+
+  def app
+    subject
+  end
+
+  before do
+    subject.namespace :api do
+      get ':id(/:ext)' do
+        [params[:id], params[:ext]].compact.join('/')
+      end
+
+      put ':id' do
+        params[:id]
+      end
+    end
+  end
+
+  context 'get' do
+    it 'responds without ext' do
+      get '/api/foo'
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq 'foo'
+    end
+
+    it 'responds with ext' do
+      get '/api/foo/bar'
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq 'foo/bar'
+    end
+  end
+
+  context 'put' do
+    it 'responds' do
+      put '/api/foo'
+      expect(last_response.status).to eq 200
+      expect(last_response.body).to eq 'foo'
+    end
+  end
+end