Fix coercing default values on schema generation

Author: no1seman

graphql/types.lua

@@ -224,6 +224,7 @@ function types.inputObject(config)
       name = fieldName,
       kind = field.kind,
       description = field.description,
+      defaultValue = field.defaultValue,
     }
   end
 

test/integration/graphql_test.lua

@@ -1639,3 +1639,53 @@ function g.test_schema_input_arg_described_with_kind_variable_pass()
     local _, errors = check_request(query, query_schema, nil, nil, { variables = variables })
     t.assert_equals(errors, nil)
 end
+
+function g.test_arguments_default_values()
+    local function callback(_, _)
+        return nil
+    end
+
+    local mutation_schema = {
+        ['test_mutation'] = {
+            kind = types.string.nonNull,
+            arguments = {
+                mutation_arg = types.string,
+                mutation_arg_defaults = {
+                    kind = types.inputObject({
+                        name = 'test_input_object',
+                        fields = {
+                            input_object_arg_defaults = {
+                                kind = types.string,
+                                defaultValue = 'input object argument default value'
+                            },
+                            input_object_arg = types.string,
+                            nested_enum_arg_defaults = {
+                                kind = types.enum({
+                                    schema = schema,
+                                    name = 'mode',
+                                    values = {
+                                        read = 'read',
+                                        write = 'write',
+                                    },
+                                }),
+                                defaultValue = 'write',
+                            }
+                        },
+                        kind = types.string,
+                    }),
+                },
+            },
+            resolve = callback,
+        }
+    }
+
+    local data, errors = check_request(introspection.query, nil, mutation_schema)
+    t.assert_equals(errors, nil)
+
+    local test_input_object = util.find_by_name(data.__schema.types, 'test_input_object')
+    local input_object_arg_defaults = util.find_by_name(test_input_object.inputFields, 'input_object_arg_defaults')
+    t.assert_equals(input_object_arg_defaults.defaultValue, 'input object argument default value')
+
+    local nested_enum_arg_defaults = util.find_by_name(test_input_object.inputFields, 'nested_enum_arg_defaults')
+    t.assert_equals(nested_enum_arg_defaults.defaultValue, 'write')
+end