Promises do not throw unhandled exceptions

[SerafimArts]

It seems to me that all unhandled exceptions (for example, without ->otherwise) should be thrown out but this does not happen. Those. In fact, any exceptions impossible to intercept.

I will cite as an example another language where such a class is already implemented and where behaviour is different.

Code sample

ReactPHP (~2.7)

use React\Promise\Deferred;

$deferred = new Deferred();

$deferred->promise()->then(function(): void {
    throw new \Exception('Example');
});

$deferred->resolve();

A similar JS example:

let p = new Promise((c) => {
  setTimeout(() => c(), 1000);
});

p.then(() => { throw new Error(); });

Expected

Uncaught Exception: Example in ...

Actual

ReactPHP: Nothing

JS: Uncaught (in promise) Error ...

[sz-po]

Why this ticket was closed? This behavior is intentional?

[WyriHaximus]

@szymon-podeszwa done rethrows unhandled promises:

use React\Promise\Deferred;

$deferred = new Deferred();

$deferred->promise()->then(function(): void {
    throw new \Exception('Example');
})->done();

$deferred->resolve();

[clue]

Duplicate of #87