check that default value isn't an execution error

Author: esjee

lib/graphql/query/literal_input.rb

@@ -77,6 +77,10 @@ def self.from_arguments(ast_arguments, argument_defns, variables)
             # `context` isn't present when pre-calculating defaults
             if context
               value = arg_defn.prepare(value, context)
+              if value.is_a?(GraphQL::ExecutionError)
+                value.ast_node = ast_arg
+                raise value
+              end
             end
             values_hash[arg_name] = value
           end

spec/graphql/query/literal_input_spec.rb

@@ -20,6 +20,19 @@
             end
             resolve ->(t, a, c) { a[:value] }
           end
+
+          field :fieldWithArgumentThatIsBadByDefault do
+            type types.Int
+            argument :value do
+              type types.Int
+              default_value 7
+              prepare ->(arg, ctx) do
+                GraphQL::ExecutionError.new("Always bad")
+              end
+            end
+
+            resolve ->(*args) { 42 }
+          end
         end
 
         GraphQL::Schema.define(query: query)
@@ -35,6 +48,11 @@
         assert_equal(7, result["data"]["addToArgumentValue"])
       end
 
+      it "raises an execution error if the default value is bad" do
+        result = schema.execute("{ fieldWithArgumentThatIsBadByDefault }", context: { })
+        assert_equal(result["errors"], [{"message" => "Always bad"}])
+      end
+
       it "prepares values from variables" do
         result = schema.execute("query ($value: Int!) { addToArgumentValue(value: $value) }", variables: { "value" => 1}, context: { val: 2 } )
         assert_equal(result["data"]["addToArgumentValue"], 3)