PHP Fatal error: Method GuzzleHttp\Psr7\Uri::__toString() must not throw an exception

[curtis1000]

Hello, I'm running into this fatal error with one of my tests:

PHP Fatal error:  Method GuzzleHttp\Psr7\Uri::__toString() must not throw an exception in /path-to/test/TestCase.php on line 0

It appears to stem from a call to GuzzleHttp\Client::getAsync(), though wrapping that call in a try/catch doesn't seem to catch an exception.

Thanks

[mtdowling]

The toString method of the Uri class doesn't throw exceptions. It just calls this method: https://github.com/guzzle/psr7/blob/master/src/Uri.php#L480. I don't see how it would have directly called anything from the Guzzle client because this project doesn't know about Guzzle. Can you show what your test does?

[elazar]

For posterity:

The issue ended up not being with Guzzle at all, but was due to how our test suite was set up.

In our subclass of PHPUnit_Framework_TestCase, we were overriding tearDown() and from there calling GuzzleHttp\Promise\unwrap() with an array of GuzzleHttp\Promise\PromiseInterface instances obtained from calling GuzzleHttp\Client->*Async() methods.

When Guzzle encounters an error condition (e.g. a response with a 401 status code), it throws an instance of GuzzleHttp\Exception\ClientException. We had a try / catch block in tearDown() to handle this condition by obtaining relevant debugging information and throwing a new RuntimeException instance.

The actual problem was that this catch block was causing a PHP notice to be emitted. If we excluded E_NOTICE from the error_reporting setting, the tests ran without encountering the condition originally reported in this issue, which appeared to happen partly due to a behavior of PHPUnit.

By default, PHPUnit converts PHP errors, warnings, and notices that are triggered during the execution of a test to an exception.

https://phpunit.de/manual/current/en/writing-tests-for-phpunit.html#writing-tests-for-phpunit.errors

By calling restore_error_handler() in setUp() in our test case class, we were able to deactivate PHPUnit's custom error handler, revealing the PHP notice being emitted, which as it turns out was completely unrelated to Uri::__toString().

I'm not altogether certain why the error originally reported here was the result of all of this. All attempts to debug an issue in Uri::__toString() -- adding a try / catch block there, outputting backtraces, etc. failed because the issue simply wasn't with that area of code.