Future.wait() not catching exceptions (Dart) - exception

Question

In my Flutter app I'd like to make multiple network calls simultaneously and then do something when they all have finished. For this I use Future.wait(), which does what I want. However when a call fails it throws an exception, which is somehow not caught in the exception handler (i.e. uncaught exception).
When I do await _fetchSomeData() separately (outside Future.wait()) the exception does get called by the exception handler as expected.
Future<bool> someMethod() async {
try {
var results = await Future.wait([
_fetchSomeData(),
_fetchSomeOtherData()
]);
//do some stuf when both have finished...
return true;
}
on Exception catch(e) {
//does not get triggered somehow...
_handleError(e);
return false;
}
}
What do I need to do to catch the exceptions while using Future.wait()?
Update:
I have narrowed down the issue. Turns out if you use another await statement in the method that is called by the Future.wait() it causes the issue. Here an example:
void _futureWaitTest() async {
try {
//await _someMethod(); //using this does not cause an uncaught exception, but the line below does
await Future.wait([ _someMethod(), ]);
}
on Exception catch(e) {
print(e);
}
}
Future<bool> _someMethod() async {
await Future.delayed(Duration(seconds: 0), () => print('wait')); //removing this prevents the uncaught exception
throw Exception('some exception');
}
So if you either remove the await line from _someMethod() or if you just call _someMethod() outside of Future.wait() will prevent the uncaught exception. This is most unfortunate of course, I need await for an http call... some bug in Dart?
I have the Uncaught Exceptions breakpoints enabled. If I turn this off the issue seems to be gone. Perhaps it's an issue with the debugger. I am using Visual Studio Code and the latest flutter.

Answer 1

What do I need to do to catch the exceptions while using Future.wait()?
What I found out when I used the same code as you the code inside of each procedure which is used in Future.wait() must be wrapped with try/catch and on catch must return Future.error(). Also eagerError must be set to true.
try {
await Future.wait([proc1, ...], eagerError: true);
} on catch(e) {
print('error: $e')
}
/// Proc 1
Future<void> proc1() async {
try {
final result = await func();
} on SomeException catch(e) {
return Future.error('proc 1 error: $');
}
}

Answer 2

I think you are a bit mislead by the Future.wait() naming. Future.wait() returns another future that will have a List of elements returned by each future when it completes with success.
Now since the Future.wait() is still a future. You can handle it in two ways:
Using await with try catch.
Using onError callback.
Tis will be something like
Future.wait([futureOne, futureTwo])
.then((listOfValues) {
print("ALL GOOD")
},
onError: (error) { print("Something is not ok") }