Default and custom error handler about c-sharp-promise HOT 1 CLOSED

Having the default rejection handler is necessary even if you specify a custom rejection handler to handle the case where your custom rejection handler threw an exception itself. In the code you mention, if your custom rejection handler handled the exception then the default handler should not be called

    Then(onResolved, onRejected) // onRejected handles rejection
        .Catch(ex =>   // <- this callback should never be executed if the rejection was already handled.
            Promise.PropagateUnhandledException(this, ex)
        );

If that's not happening and Promise.PropagateUnhandeldException is still being called in addition to or instead of your custom onRejected callback, then that is a bug.

from c-sharp-promise.