Don't include fixed named captures as route params

lib/grape/router/route.rb

@@ -8,6 +8,7 @@ class Router
     class Route
       ROUTE_ATTRIBUTE_REGEXP = /route_([_a-zA-Z]\w*)/.freeze
       SOURCE_LOCATION_REGEXP = /^(.*?):(\d+?)(?::in `.+?')?$/.freeze
+      FIXED_NAMED_CAPTURES = %w[format version].freeze
 
       attr_accessor :pattern, :translator, :app, :index, :regexp
 
@@ -81,7 +82,7 @@ def params(input = nil)
           default = pattern.named_captures.keys.each_with_object({}) do |key, defaults|
             defaults[key] = ''
           end
-          default.delete_if { |key, _| key == 'format' }.merge(translator.params)
+          default.delete_if { |key, _| FIXED_NAMED_CAPTURES.include?(key) }.merge(translator.params)
         else
           parsed = pattern.params(input)
           parsed ? parsed.delete_if { |_, value| value.nil? }.symbolize_keys : {}

spec/grape/api_spec.rb

@@ -2257,6 +2257,13 @@ def static
       expect(route.route_foo).to be_nil
       expect(route.params).to eq({})
     end
+    it 'has params which does not include format and version as named captures' do
+      subject.version :v1, using: :path
+      subject.get :first do; end
+      param_keys = subject.routes.first.params.keys
+      expect(param_keys).not_to include('format')
+      expect(param_keys).not_to include('version')
+    end
     it 'describes methods separately' do
       subject.desc 'first method'
       subject.get :first do; end