Fix #1636: optional nested array validation (#1724)

Author: ericproulx

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 * [#1710](https://github.com/ruby-grape/grape/pull/1710): Fix wrong transformation of empty Array in declared params - [@pablonahuelgomez](https://github.com/pablonahuelgomez).
 * [#1722](https://github.com/ruby-grape/grape/pull/1722): Fix catch-all hiding multiple versions of an endpoint after the first definition - [@zherr](https://github.com/zherr).
+* [#1724](https://github.com/ruby-grape/grape/pull/1724): Optional nested array validation - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 ### 1.0.1 (9/8/2017)

lib/grape/validations/params_scope.rb

@@ -39,8 +39,7 @@ def initialize(opts, &block)
       # @return [Boolean] whether or not this entire scope needs to be
       #   validated
       def should_validate?(parameters)
-        return false if @optional && (params(parameters).blank? ||
-                                       any_element_blank?(parameters))
+        return false if @optional && (params(parameters).blank? || all_element_blank?(parameters))
 
         return true if parent.nil?
         parent.should_validate?(parameters)
@@ -441,8 +440,8 @@ def options_key?(type, key, validations)
         validations[type].respond_to?(:key?) && validations[type].key?(key) && !validations[type][key].nil?
       end
 
-      def any_element_blank?(parameters)
-        params(parameters).respond_to?(:any?) && params(parameters).any?(&:blank?)
+      def all_element_blank?(parameters)
+        params(parameters).respond_to?(:all?) && params(parameters).all?(&:blank?)
       end
     end
   end

lib/grape/validations/validators/base.rb

@@ -38,6 +38,7 @@ def validate!(params)
         attributes = AttributesIterator.new(self, @scope, params)
         array_errors = []
         attributes.each do |resource_params, attr_name|
+          next if !@scope.required? && resource_params.empty?
           next unless @required || (resource_params.respond_to?(:key?) && resource_params.key?(attr_name))
           next unless @scope.meets_dependency?(resource_params, params)
 

spec/grape/validations/validators/default_spec.rb

@@ -75,6 +75,21 @@ class API < Grape::API
         get '/nested_optional_array' do
           { root: params[:root] }
         end
+
+        params do
+          requires :root, type: Hash do
+            optional :some_things, type: Array do
+              requires :foo
+              optional :options, type: Array do
+                optional :name, type: String
+                optional :value, type: String
+              end
+            end
+          end
+        end
+        get '/another_nested_optional_array' do
+          { root: params[:root] }
+        end
       end
     end
   end
@@ -99,6 +114,31 @@ def app
     expect(last_response.body).to eq({ root: params }.to_json)
   end
 
+  it 'does not allows faulty optional arrays' do
+    params = { some_things:
+                 [
+                   { foo: 'one', options: [{ name: 'wat', value: 'nope' }] },
+                   { foo: 'two', options: [{ name: 'wat' }] },
+                   { foo: 'three' }
+                 ] }
+    error = { error: 'root[some_things][1][options][0][value] is missing' }
+    get '/nested_optional_array', root: params
+    expect(last_response.status).to eq(400)
+    expect(last_response.body).to eq(error.to_json)
+  end
+
+  it 'allows optional arrays with optional params' do
+    params = { some_things:
+                 [
+                   { foo: 'one', options: [{ value: 'nope' }] },
+                   { foo: 'two', options: [{ name: 'wat' }] },
+                   { foo: 'three' }
+                 ] }
+    get '/another_nested_optional_array', root: params
+    expect(last_response.status).to eq(200)
+    expect(last_response.body).to eq({ root: params }.to_json)
+  end
+
   it 'set default value for optional param' do
     get('/')
     expect(last_response.status).to eq(200)