Avoid triggering Symfony HTTPlug Client exception

[matt-allan]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	resolves #171
Documentation	N/A
License	MIT

What's in this PR?

This PR prevents the following LogicException from being triggered if you attempt to use Psr18ClientDiscovery::find() when the "php-http/httplug" package is not installed.

PHP Fatal error:  Uncaught LogicException: You cannot use "Symfony\Component\HttpClient\HttplugClient" as the "php-http/httplug" package is not installed. Try running "composer require php-http/httplug". in /Users/matt/code/discovery-repro/vendor/symfony/http-client/HttplugClient.php:44
Stack trace:
#0 /Users/matt/code/discovery-repro/vendor/composer/ClassLoader.php(444): include()
#1 /Users/matt/code/discovery-repro/vendor/composer/ClassLoader.php(322): Composer\Autoload\includeFile('/Users/matt/cod...')
#2 [internal function]: Composer\Autoload\ClassLoader->loadClass('Symfony\\Compone...')
#3 [internal function]: spl_autoload_call('Symfony\\Compone...')
#4 /Users/matt/code/discovery-repro/vendor/php-http/discovery/src/Strategy/CommonClassesStrategy.php(115): is_subclass_of('Symfony\\Compone...', 'Psr\\Http\\Client...')
#5 [internal function]: Http\Discovery\Strategy\CommonClassesStrategy::getCandidates('Psr\\Http\\Client...')
#6 /Users/matt/code/discovery-repro/vendor/php-http/discovery/src/ClassDiscovery.php(56): call_user_ in /Users/matt/code/discovery-repro/vendor/symfony/http-client/HttplugClient.php on line 44

Why?

When the Symfony\Component\HttpClient\HttplugClient class is loaded Symfony checks if the Http\Client\HttpClient interface exists. If it doesn't exist an exception is thrown.

When discovering a PSR-18 client the CommonClassesStrategy calls is_subclass_of on the Symfony\Component\HttpClient\HttplugClient, which triggers the exception.

We don't need to call is_subclass_of on the Symfony Httplug client because we know it doesn't implement the PSR-18 interface, so we can just avoid calling it, thus avoiding the exception.

There might be a more elegant way to solve this. Let me know if you would prefer an alternative solution.

Checklist

• Updated CHANGELOG.md to describe BC breaks / deprecations | new feature | bugfix
• Documentation pull request created (if not simply a bugfix)

[matt-allan]

I tried following the contributor guide but I couldn't run the tests locally because composer install is failing with this message:

Warning: Plugin initialization failed: The "puli"/"puli.phar" command could not be found.
PHP Fatal error:  Uncaught Error: Call to a member function run() on null in /Users/matt/code/discovery/vendor/puli/composer-plugin/src/PuliPluginImpl.php:671
Stack trace:
#0 /Users/matt/code/discovery/vendor/puli/composer-plugin/src/PuliPluginImpl.php(220): Puli\ComposerPlugin\PuliPluginImpl->verifyPuliVersion()
#1 /Users/matt/code/discovery/vendor/puli/composer-plugin/src/PuliPluginImpl.php(114): Puli\ComposerPlugin\PuliPluginImpl->initialize()
#2 /Users/matt/code/discovery/vendor/puli/composer-plugin/src/PuliPlugin.php(82): Puli\ComposerPlugin\PuliPluginImpl->postAutoloadDump()
#3 [internal function]: Puli\ComposerPlugin\PuliPlugin->listen(Object(Composer\Script\Event))
#4 phar:///usr/local/Cellar/composer/1.9.1/bin/composer/src/Composer/EventDispatcher/EventDispatcher.php(176): call_user_func(Array, Object(Composer\Script\Event))
#5 phar:///usr/local/Cellar/composer/1.9.1/bin/composer/src/Composer/EventDispatcher/EventDispatcher.php(96): Composer\EventDispatcher\EventDispatcher->doDispatch(Object(Composer\Script\Event))
#6 in /Users/matt/code/discovery/vendor/puli/composer-plugin/src/PuliPluginImpl.php on line 671

I tried to check the Puli docs but I'm getting a Server not found error. Let me know if you know how to fix the error.

[dbu]

the alternative would be to wrap the is_subclass in a try-catch that catches everything. that would be the more generic solution, in case others decide to do similar things. wdyt, would that make sense to you?

[matt-allan]

Thanks @dbu, that makes sense to me. I added a call to trigger_error like the isPsr17FactoryInstalled method so we don't completely swallow the exception.

[dbu]

i like the user warning level error log