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Issue Link:

None

Changelog Description:

Calling FileSystemEntity.watch(...) will throw on Mac OS and Windows.

Impact Description:

Calling FileSystemEntity.watch(...) will throw on Mac OS and Windows, instead of correctly watching the path.

Workaround:

No user level work-around. dart:io is broken.

Risk:

What is the risk level of this cherry-pick?

• Low
• Medium
• High

Test Coverage:

Are you confident that your fix is well-tested by automated tests?

• Yes
• No

It's tested by tests in Dart SDK

Validation Steps:

Run a Mac OS or Windows app with the following main. It should do nothing - rather than throw an exception.

import 'dart:async';
import 'dart:io';

void main() async {
  final sub = Directory.systemTemp.watch(recursive: true).listen((_) {});
  await Future.delayed(Duration(seconds: 1));
  sub.cancel();
}