Fix InputObjectType input_fields options

Both `Mutation` and `InputObjectType` input_fields already use
`Define::AssignArgument`, which should be the only way to create
`Argument`s.

But when a `Mutation` builds its `InputObjectType`, it recreates
`Argument`s (`input_field`s) using properties from the `Mutation`'s own
`Argument`s.
It needs to explicitly copy all the options from one argument to
another, which caused rmosolgo#650.

This PR gets rid of this recreation process and just merges the
`Mutation`'s `input_fields` into the new `InputObjectType`'s
`input_fields`.
This change should prevent any divergence between fields and mutation
arguments/input_fields.

Author: lucaspolonio

lib/graphql/input_object_type.rb

@@ -55,6 +55,10 @@ def kind
       GraphQL::TypeKinds::INPUT_OBJECT
     end
 
+    def merge_input_fields!(input_fields)
+      @arguments.merge!(input_fields)
+    end
+
     def validate_non_null_input(input, warden)
       result = GraphQL::Query::InputValidationResult.new
 

lib/graphql/relay/mutation.rb

@@ -163,18 +163,15 @@ def return_type
       def input_type
         @input_type ||= begin
           relay_mutation = self
-          GraphQL::InputObjectType.define do
+          input_object_type = GraphQL::InputObjectType.define do
             name("#{relay_mutation.name}Input")
             description("Autogenerated input type of #{relay_mutation.name}")
             input_field :clientMutationId, types.String, "A unique identifier for the client performing the mutation."
-            relay_mutation.arguments.each do |input_field_name, field_obj|
-              kwargs = {}
-              kwargs[:default_value] = field_obj.default_value if field_obj.default_value?
-              kwargs[:as] = field_obj.as
-              input_field(input_field_name, field_obj.type, field_obj.description, **kwargs)
-            end
             mutation(relay_mutation)
           end
+          input_object_type.merge_input_fields!(input_fields)
+
+          input_object_type
         end
       end
 

spec/graphql/schema/printer_spec.rb

@@ -403,10 +403,11 @@
 
 # Autogenerated input type of CreatePost
 input CreatePostInput {
-  # A unique identifier for the client performing the mutation.
-  clientMutationId: String
   title: String!
   body: String!
+
+  # A unique identifier for the client performing the mutation.
+  clientMutationId: String
 }
 
 # Autogenerated return type of CreatePost
@@ -537,10 +538,11 @@
 
 # Autogenerated input type of CreatePost
 input CreatePostInput {
-  # A unique identifier for the client performing the mutation.
-  clientMutationId: String
   title: String!
   body: String!
+
+  # A unique identifier for the client performing the mutation.
+  clientMutationId: String
 }
 
 # Autogenerated return type of CreatePost