Don't pass NullValue to literal validation

Author: rmosolgo

lib/graphql/static_validation/literal_validator.rb

@@ -18,6 +18,22 @@ def validate(ast_value, type)
 
       private
 
+      def replace_nulls_in(ast_value)
+        case ast_value
+        when Array
+          ast_value.map { |v| replace_nulls_in(v) }
+        when Hash
+          new_v = {}
+          ast_value.each do |k, v|
+            new_v[k] = replace_nulls_in(v)
+          end
+        when GraphQL::Language::Nodes::NullValue
+          nil
+        else
+          ast_value
+        end
+      end
+
       def recursively_validate(ast_value, type)
         if type.nil?
           # this means we're an undefined argument, see #present_input_field_values_are_valid
@@ -42,7 +58,8 @@ def recursively_validate(ast_value, type)
           @valid_response
         elsif type.kind.scalar? && constant_scalar?(ast_value)
           maybe_raise_if_invalid(ast_value) do
-            type.validate_input(ast_value, @context)
+            ruby_value = replace_nulls_in(ast_value)
+            type.validate_input(ruby_value, @context)
           end
         elsif type.kind.enum?
           maybe_raise_if_invalid(ast_value) do

spec/graphql/schema/build_from_definition_spec.rb

@@ -1654,4 +1654,59 @@ class Link < GraphQL::Schema::Directive
     GRAPHQL
     assert_equal expected_schema, schema.to_definition
   end
+
+  describe "JSON type" do
+    class JsonTypeApplication
+      SCHEMA_STRING = <<~EOS
+        scalar JsonValue
+
+        type Query {
+          echoJsonValue(arg: JsonValue): JsonValue
+        }
+      EOS
+
+      def initialize
+        @schema = GraphQL::Schema.from_definition(SCHEMA_STRING, default_resolve: self)
+      end
+
+      def execute_query(query_string, **vars)
+        @schema.execute(query_string, variables: vars)
+      end
+
+      def call(parent_type, field, object, args, context)
+        args.fetch(:arg)
+      end
+
+      def coerce_input(type, value, ctx)
+        (ctx[:nils] ||= []).push(value[2])
+        ::JSON.generate(value)
+      end
+
+      def coerce_result(type, value, ctx)
+        ::JSON.parse(value)
+      end
+    end
+
+    it "Sends normal ruby values to schema coercion" do
+      app = JsonTypeApplication.new
+
+      res_1 = app.execute_query(<<~EOS, arg: [3, "abc", nil, 7])
+        query WithArg($arg: JsonValue) {
+          echoJsonValue(arg: $arg)
+        }
+      EOS
+
+      assert_equal([3, "abc", nil, 7], res_1["data"]["echoJsonValue"])
+      assert_equal [nil, nil], res_1.context[:nils]
+
+      res_2 = app.execute_query(<<~EOS)
+        query {
+          echoJsonValue(arg: [3, "abc", null, 7])
+        }
+      EOS
+      assert_equal([3, "abc", nil, 7], res_2["data"]["echoJsonValue"])
+      assert_equal [nil, nil], res_2.context[:nils]
+
+    end
+  end
 end