Missing dependency?
After applying (dnf --enablerepo updates-testing drupal8 drupal8-httpd) the test update Website won't load Error in /var/log/php-fpm/www-error.log [30-Mar-2018 16:59:05 UTC] PHP Fatal error: require_once(): Failed opening required '/usr/share/php/Symfony3/Bridge/PsrHttpMessage/autoload.php' (include_path='.:/usr/share/pear:/usr/share/php') in /usr/share/drupal8/autoload.php on line 31

restarted the php-fpm.service and also tried a reboot....

karma: -1

Thanks whoever you are anonymous! Fix in 8.4.6-2 via https://src.fedoraproject.org/rpms/drupal8/c/2b082882a1b0c5fdce466bd32b7b41bf84235bbc?branch=master

Tried drupal8-8.4.6-2.fc27.noarch. Website still won't load. Errors from /var/log/php/www-error.log

[03-Apr-2018 12:37:35 UTC] PHP Warning: require_once(/usr/share/php/Symfony3/Component/Console/autoload.php): failed to open stream: No such file or directory in /usr/share/drupal8/autoload.php on line 34 [03-Apr-2018 12:37:35 UTC] PHP Fatal error: require_once(): Failed opening required '/usr/share/php/Symfony3/Component/Console/autoload.php' (include_path='.:/usr/share/pear:/usr/share/php') in /usr/share/drupal8/autoload.php on line 34

karma: -1

Confirmed. I just installed that php-symfony3 meta package and that resolved all the issues. I had started chasing the dependencies one-by-one but then checked that the php-symfony3 package installs all the subs.

karma: -1

I'm a little lost as to how Symfony 3 is not getting installed as it is listed as a dependency:

$ rpm -qp --requires /home/siwinski/rpmbuild/RPMS/noarch/drupal8-8.4.6-2.fc27.noarch.rpm | grep -i symfony | sort
php-composer(symfony/class-loader) >= 3.2.8
php-composer(symfony/class-loader) < 4.0.0
php-composer(symfony-cmf/routing) >= 1.4
php-composer(symfony-cmf/routing) < 2.0
php-composer(symfony/console) >= 3.2.8
php-composer(symfony/console) < 4.0.0
php-composer(symfony/dependency-injection) >= 3.2.8
php-composer(symfony/dependency-injection) < 4.0.0
php-composer(symfony/event-dispatcher) >= 3.2.8
php-composer(symfony/event-dispatcher) < 4.0.0
php-composer(symfony/http-foundation) >= 3.2.8
php-composer(symfony/http-foundation) < 4.0.0
php-composer(symfony/http-kernel) >= 3.2.8
php-composer(symfony/http-kernel) < 4.0.0
php-composer(symfony/process) >= 3.2.8
php-composer(symfony/process) < 4.0.0
php-composer(symfony/psr-http-message-bridge) >= 1.0
php-composer(symfony/psr-http-message-bridge) < 2.0
php-composer(symfony/routing) >= 3.2.8
php-composer(symfony/routing) < 4.0.0
php-composer(symfony/serializer) >= 3.2.8
php-composer(symfony/serializer) < 4.0.0
php-composer(symfony/translation) >= 3.2.8
php-composer(symfony/translation) < 4.0.0
php-composer(symfony/validator) >= 3.2.8
php-composer(symfony/validator) < 4.0.0
php-composer(symfony/yaml) >= 3.2.8
php-composer(symfony/yaml) < 4.0.0

I'll try modifying the requires to use range dependencies in case it is DNF not installing the correct versions (i.e. just satisfying the "< 4.0.0")

drupal8-8.4.6-3 now uses range dependencies when possible. Also, I finally found that a Symfony Config dependency was missing so that has been added as well.

See https://src.fedoraproject.org/rpms/drupal8/c/dc10ba3d8b6a4839ca7efaaa511d80465dca9a44 for changes

$ rpm -qp --requires /home/siwinski/rpmbuild/RPMS/noarch/drupal8-8.4.6-3.fc27.noarch.rpm | grep -i symfony | sort
(php-composer(symfony/class-loader) >= 3.2.8 with php-composer(symfony/class-loader) < 4.0.0)
(php-composer(symfony-cmf/routing) >= 1.4 with php-composer(symfony-cmf/routing) < 2.0)
(php-composer(symfony/console) >= 3.2.8 with php-composer(symfony/console) < 4.0.0)
(php-composer(symfony/dependency-injection) >= 3.2.8 with php-composer(symfony/dependency-injection) < 4.0.0)
(php-composer(symfony/event-dispatcher) >= 3.2.8 with php-composer(symfony/event-dispatcher) < 4.0.0)
(php-composer(symfony/http-foundation) >= 3.2.8 with php-composer(symfony/http-foundation) < 4.0.0)
(php-composer(symfony/http-kernel) >= 3.2.8 with php-composer(symfony/http-kernel) < 4.0.0)
(php-composer(symfony/process) >= 3.2.8 with php-composer(symfony/process) < 4.0.0)
(php-composer(symfony/psr-http-message-bridge) >= 1.0 with php-composer(symfony/psr-http-message-bridge) < 2.0)
(php-composer(symfony/routing) >= 3.2.8 with php-composer(symfony/routing) < 4.0.0)
(php-composer(symfony/serializer) >= 3.2.8 with php-composer(symfony/serializer) < 4.0.0)
(php-composer(symfony/translation) >= 3.2.8 with php-composer(symfony/translation) < 4.0.0)
(php-composer(symfony/validator) >= 3.2.8 with php-composer(symfony/validator) < 4.0.0)
(php-composer(symfony/yaml) >= 3.2.8 with php-composer(symfony/yaml) < 4.0.0)

The -3 packages seem to do the trick. They bring in a bunch of symfony3 packages, and no symfony4 packages and my site works, at least on my testing VM.