Raise

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Raise an exception to the async generator

public function raise(
  Exception $exception,
): Awaitable<?(Tk, Tv)>;

You should always await the returned Awaitable to get the actual key/value tuple.

If null is returned, that means you have reached the end of iteration.

You cannot call raise() without having the value returned from a previous call to raise(), next(), send(), having first awaited.

Parameters

• Exception $exception

Returns

• Awaitable<?(Tk,Tv)> - The Awaitable that produced the yielded key/value tuple after the exception is processed. What is returned is a tuple or null.