[linter] throw synchronously when you return a Future 👿

[stephane-archer]

Future<int> foo() {
     throw "my caller will try catch where the future is await 👿";
}

[bwilkerson]

My understanding is that the example is valid code, but it does require the caller to use onError to catch the exception. Given that, I'm concerned about false positives. If I think of this as a lint focused on 'style' rather than 'correctness' then I suppose it's ok, though I don't know how likely we are to add it.

[stephane-archer]

#59639 (comment) by @lrhn

I'll re-open as a reminder to change it to an asynchronrous error.

you have that kind of error in your codebase so I think you should consider seriously this lint

[stephane-archer]

@bwilkerson From my understanding if you throw synchronously you can only try catch on the function call. I don't think onError is of any use here.

[stephane-archer]

error should be thrown asynchronrously if you return a future. while it is technically valid to do it synchronously the caller will never expect that and if you throw synchronously in the middle of some async code the behavior of the code become extremely hard to understand.

I think this is 80% of the time a mistake