Throwing Exception from within promises handler doesn't stop script execution about promises

[jsor]

Exceptions thrown in fulfillment callbacks reject the promise returned from then(). You must call wait() on the returned promise.

$newPromise = $promise->then(
    function ($response) {
        throw new Exception('Invalid hit sent. got response: ' . $response->getBody());
    }
);

$newPromise->wait();

[PauloPhagula]

Ohhhh sorry ... Didn't notice I have to wait on the new promise returned by then on the first promise.

Doing as suggested does work.

Thanks

[alexeyshockov]

If this is the complete code, then the behaviour is valid. You have to call ->wait() on a promise to process the callback (task) queue. Or use some aggregation functions like all().

[PauloPhagula]

I do call ->wait() after this bit to ensure the promise is processed. And it does get processed as later on I'm able to see the log message. My problem is that the exception does not bubble up, and thus I cannot know if there was an exception thrown or not.

Is it like within the task queue there's some sort of global error trapper?

[PauloPhagula]

Probably I could clarify my issue with the sample bellow.

I have phpunit installed globally and guzzle installed as a library

require 'vendor/autoload.php';

use GuzzleHttp\Client;

class GuzzlePromisesTest extends \PHPUnit_Framework_TestCase
{
    /**
     * The http client
     * @var GuzzleHttp\ClientInterface
     */
    protected $httpClient;

    public function setUp() {
        $this->httpClient = new Client();
    }

    /**
     * @test
     * @expectedException Exception
     */
    public function should_trap_thrown_exception() {
        $promise = $this->httpClient->requestAsync('GET', 'https://www.google-analytics.com/debug/collect?v=1&aip=1&tid=UA-0000-00');

        $promise->then(
            function ($response){
                throw new Exception('Invalid hit sent. got response: ' . $response->getBody());
            }
        );

        $promise->wait();
    }
}

➜  tracking git:(use-guzzle-for-async-http-reqs) ✗ phpunit ~/Desktop/files/file.php
PHPUnit 5.1.3 by Sebastian Bergmann and contributors.

F                                                                   1 / 1 (100%)

Time: 1.69 seconds, Memory: 10.00Mb

There was 1 failure:

1) GuzzlePromisesTest::should_trap_thrown_exception
Failed asserting that exception of type "Exception" is thrown.

FAILURES!
Tests: 1, Assertions: 1, Failures: 1.

Note that if you navigate to the URL used in the test, you'll get a JSON response stating there are errors in the request data, but please mind the status code is 200. Meaning no "error" should be thrown by guzzle regarding the request.

However an error should be thrown from the promise handling. And that is what I expect to trap of the test

Thanks

[jsor]

That's exactly covered by my comment #78 (comment) above.

You need to wait() on the returned promise.

    public function should_trap_thrown_exception() {
        $promise = $this->httpClient->requestAsync('GET', 'https://www.google-analytics.com/debug/collect?v=1&aip=1&tid=UA-0000-00');

        $newPromise = $promise->then(
            function ($response){
                throw new Exception('Invalid hit sent. got response: ' . $response->getBody());
            }
        );

        $newPromise->wait();
    }