modified it so it doesn't create a new scope for each input

lib/grape/dsl/parameters.rb

@@ -168,8 +168,8 @@ def all_or_none_of(*attrs)
       def given(*attrs, &block)
         attrs.each do |attr|
           fail Grape::Exceptions::UnknownParameter.new(attr) unless declared_param?(attr)
-          new_lateral_scope(dependent_on: attr, &block)
         end
+        new_lateral_scope(dependent_on: attrs, &block)
       end
 
       # Test for whether a certain parameter has been defined in this params

lib/grape/validations/params_scope.rb

@@ -36,7 +36,11 @@ def initialize(opts, &block)
       #   validated
       def should_validate?(parameters)
         return false if @optional && params(parameters).respond_to?(:all?) && params(parameters).all?(&:blank?)
-        return false if @dependent_on && params(parameters).try(:[], @dependent_on).blank?
+        if @dependent_on
+          @dependent_on.each do |dependency|
+            return false if params(parameters).try(:[], dependency).blank?
+          end
+        end
         return true if parent.nil?
         parent.should_validate?(parameters)
       end

spec/grape/validations/params_scope_spec.rb

@@ -278,8 +278,7 @@ def initialize(value)
   context 'when validations are dependent on a parameter' do
     before do
       subject.params do
-        optional :a
-        optional :b
+        optional :a, :b
         given :a, :b do
           requires :c
         end
@@ -291,7 +290,7 @@ def initialize(value)
       get '/test'
       expect(last_response.status).to eq(200)
 
-      get '/test', a: true
+      get '/test', a: true, b: true
       expect(last_response.status).to eq(400)
       expect(last_response.body).to eq('c is missing')