TaskSet::joinAny

(PHP 8.6+, True Async 1.0)

public TaskSet::joinAny(): Async\Future

Returns a Future that resolves with the result of the first successfully completed task. Tasks that finished with an error are skipped.

After delivering the result, the entry is automatically removed from the set.

Remaining tasks continue running.

If all tasks finished with errors, the Future rejects with CompositeException.

The returned Future supports a cancellation token via await(?Completable $cancellation).

Return Value

Async\Future — a future result of the first successful task. Call ->await() to get the value.

Errors

Throws Async\AsyncException if the set is empty.
The Future rejects with Async\CompositeException if all tasks finished with errors.

Examples

Example #1 First successful result

<?php

use Async\TaskSet;

spawn(function() {
    $set = new TaskSet();

    $set->spawn(fn() => throw new \RuntimeException("fail 1"));
    $set->spawn(fn() => throw new \RuntimeException("fail 2"));
    $set->spawn(fn() => "success!");

    $result = $set->joinAny()->await();
    echo $result . "\n"; // "success!"
    echo $set->count() . "\n"; // 2 (failed tasks remain)
});

Example #2 All tasks failed

<?php

use Async\TaskSet;

spawn(function() {
    $set = new TaskSet();

    $set->spawn(fn() => throw new \RuntimeException("err 1"));
    $set->spawn(fn() => throw new \RuntimeException("err 2"));

    $set->seal();

    try {
        $set->joinAny()->await();
    } catch (\Async\CompositeException $e) {
        echo count($e->getExceptions()) . " errors\n"; // "2 errors"
    }
});

Example #3 Resilient search

<?php

use Async\TaskSet;

spawn(function() {
    $set = new TaskSet();

    $set->spawn(fn() => searchGoogle($query));
    $set->spawn(fn() => searchBing($query));
    $set->spawn(fn() => searchDuckDuckGo($query));

    $result = $set->joinAny()->await(Async\timeout(3.0));
    echo "Found, active: {$set->count()}\n";
});

Documentation