avoid_void_async

Avoid async functions that return void.

DO mark async functions as returning Future<void>.

When declaring an async method or function which does not return a value, declare that it returns Future<void> and not just void.

BAD:

void f() async {}
void f2() async => null;

GOOD:

Future<void> f() async {}
Future<void> f2() async => null;

EXCEPTION:

An exception is made for top-level main functions, where the Future annotation can (and generally should) be dropped in favor of void.

GOOD:

Future<void> f() async {}

void main() async {
  await f();
}

To enable the avoid_void_async rule, add avoid_void_async under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - avoid_void_async

If you're instead using the YAML map syntax to configure linter rules, add avoid_void_async: true under linter > rules:

linter:
  rules:
    avoid_void_async: true

Unless stated otherwise, the documentation on this site reflects Dart 3.6.2. Page last updated on 2025-01-27. View source or report an issue.