close_sinks

Unclosed instance of 'Sink'.

The analyzer produces this diagnostic when an instance of Sink is created but the method close isn't invoked.

The following code produces this diagnostic because the sink isn't closed:

import 'dart:io';

void g(File f) {
  var sink = f.openWrite();
  sink.write('x');
}

Close the sink:

import 'dart:io';

void g(File f) {
  var sink = f.openWrite();
  sink.write('x');
  sink.close();
}

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.