fixes configuration inside namespaced params scope (#2152)

Author: fsainz

CHANGELOG.md

@@ -13,6 +13,7 @@
 * [#2137](https://github.com/ruby-grape/grape/pull/2137): Fix typos - [@johnny-miyake](https://github.com/johnny-miyake).
 * [#2131](https://github.com/ruby-grape/grape/pull/2131): Fix Ruby 2.7 keyword deprecation warning in validators/coerce - [@K0H205](https://github.com/K0H205).
 * [#2132](https://github.com/ruby-grape/grape/pull/2132): Use #ruby2_keywords for correct delegation on Ruby <= 2.6, 2.7 and 3 - [@eregon](https://github.com/eregon).
+* [#2152](https://github.com/ruby-grape/grape/pull/2152): Fix configuration method inside namespaced params - [@fsainz](https://github.com/fsainz).
 
 ### 1.5.1 (2020/11/15)
 

lib/grape/validations/params_scope.rb

@@ -39,7 +39,7 @@ def initialize(opts, &block)
       end
 
       def configuration
-        @api.configuration.evaluate
+        @api.configuration.respond_to?(:evaluate) ? @api.configuration.evaluate : @api.configuration
       end
 
       # @return [Boolean] whether or not this entire scope needs to be

spec/grape/api_remount_spec.rb

@@ -340,19 +340,24 @@ def app
       context 'when the configuration is read within a namespace' do
         before do
           a_remounted_api.namespace 'api' do
+            params do
+              requires configuration[:required_param]
+            end
             get "/#{configuration[:path]}" do
               '10 votes'
             end
           end
-          root_api.mount a_remounted_api, with: { path: 'votes' }
-          root_api.mount a_remounted_api, with: { path: 'scores' }
+          root_api.mount a_remounted_api, with: { path: 'votes', required_param: 'param_key' }
+          root_api.mount a_remounted_api, with: { path: 'scores', required_param: 'param_key' }
         end
 
         it 'will use the dynamic configuration on all routes' do
-          get 'api/votes'
+          get 'api/votes', param_key: 'a'
           expect(last_response.body).to eql '10 votes'
-          get 'api/scores'
+          get 'api/scores', param_key: 'a'
           expect(last_response.body).to eql '10 votes'
+          get 'api/votes'
+          expect(last_response.status).to eq 400
         end
       end