Just keep helpers method in the public scope.

CHANGELOG.md

@@ -15,6 +15,7 @@
 
 #### Fixes
 
+* [#2586](https://github.com/ruby-grape/grape/pull/2586): Limit helpers DSL public scope - [@ericproulx](https://github.com/ericproulx).
 * [#2588](https://github.com/ruby-grape/grape/pull/2588): Fix defaut format regression on */* - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 

lib/grape/dsl/helpers.rb

@@ -34,7 +34,7 @@ def helpers(*new_modules, &block)
         include_all_in_scope if !block && new_modules.empty?
       end
 
-      protected
+      private
 
       def include_new_modules(modules)
         return if modules.empty?

spec/grape/dsl/helpers_spec.rb

@@ -113,5 +113,11 @@ def test
         expect { api_class }.not_to raise_exception
       end
     end
+
+    context 'public scope' do
+      it 'returns helpers only' do
+        expect(Class.new { extend Grape::DSL::Helpers }.singleton_methods - Class.methods).to contain_exactly(:helpers)
+      end
+    end
   end
 end