use the payload type's non-null error

Author: rmosolgo

lib/graphql/execution/interpreter/runtime.rb

@@ -254,7 +254,8 @@ def evaluate_selections(path, scoped_context, owner_object, owner_type, selectio
         def continue_value(path, value, field, is_non_null, ast_node)
           if value.nil?
             if is_non_null
-              err = field.owner::InvalidNullError.new(field.owner, field, value)
+              parent_type = field.owner_type
+              err = parent_type::InvalidNullError.new(parent_type, field, value)
               write_invalid_null_in_response(path, err)
             else
               write_in_response(path, nil)
@@ -311,7 +312,7 @@ def continue_field(path, value, field, type, ast_node, next_selections, is_non_n
               possible_types = query.possible_types(type)
 
               if !possible_types.include?(resolved_type)
-                parent_type = field.owner
+                parent_type = field.owner_type
                 err_class = type::UnresolvedTypeError
                 type_error = err_class.new(resolved_value, field, parent_type, resolved_type, possible_types)
                 schema.type_error(type_error, context)

lib/graphql/schema/field.rb

@@ -36,9 +36,18 @@ class Field
       # @return [Symbol] The method on the type to look up
       attr_reader :resolver_method
 
-      # @return [Class] The type that this field belongs to
+      # @return [Class] The thing this field was defined on (type, mutation, resolver)
       attr_accessor :owner
 
+      # @return [Class] The GraphQL type this field belongs to. (For fields defined on mutations, it's the payload type)
+      def owner_type
+        @owner_type ||= if owner < GraphQL::Schema::Mutation
+          owner.payload_type
+        else
+          owner
+        end
+      end
+
       # @return [Symbol] the original name of the field, passed in by the user
       attr_reader :original_name
 

lib/graphql/schema/member.rb

@@ -4,7 +4,6 @@
 require 'graphql/schema/member/cached_graphql_definition'
 require 'graphql/schema/member/graphql_type_names'
 require 'graphql/schema/member/has_ast_node'
-require 'graphql/schema/member/has_invalid_null_error'
 require 'graphql/schema/member/has_path'
 require 'graphql/schema/member/has_unresolved_type_error'
 require 'graphql/schema/member/relay_shortcuts'

lib/graphql/schema/member/has_invalid_null_error.rb

@@ -60,7 +60,6 @@ class Schema
     #
     class Mutation < GraphQL::Schema::Resolver
       extend GraphQL::Schema::Member::HasFields
-      extend GraphQL::Schema::Member::HasInvalidNullError
       extend GraphQL::Schema::Resolver::HasPayloadType
 
       class << self

lib/graphql/schema/mutation.rb

@@ -7,7 +7,6 @@ class Schema
     class Object < GraphQL::Schema::Member
       extend GraphQL::Schema::Member::AcceptsDefinition
       extend GraphQL::Schema::Member::HasFields
-      extend GraphQL::Schema::Member::HasInvalidNullError
 
       # @return [Object] the application object this type is wrapping
       attr_reader :object
@@ -72,6 +71,13 @@ def initialize(object, context)
       end
 
       class << self
+        # Set up a type-specific invalid null error to use when this object's non-null fields wrongly return `nil`.
+        # It should help with debugging and bug tracker integrations.
+        def inherited(child_class)
+          child_class.const_set(:InvalidNullError, Class.new(GraphQL::InvalidNullError))
+          super
+        end
+
         def implements(*new_interfaces, **options)
           new_memberships = []
           new_interfaces.each do |int|

lib/graphql/schema/object.rb

@@ -117,8 +117,8 @@
     it "raises a mutation-specific invalid null error" do
       query_str = "mutation { returnInvalidNull { int } }"
       response = Jazz::Schema.execute(query_str)
-      assert_equal ["Cannot return null for non-nullable field ReturnInvalidNull.int"], response["errors"].map { |e| e["message"] }
-      assert_instance_of Jazz::ReturnInvalidNull::InvalidNullError, response.query.context.errors.first
+      assert_equal ["Cannot return null for non-nullable field ReturnInvalidNullPayload.int"], response["errors"].map { |e| e["message"] }
+      assert_instance_of Jazz::ReturnInvalidNull.payload_type::InvalidNullError, response.query.context.errors.first
     end
   end