Symfony 3 composer update ContextErrorException

Question

I'm trying to implement a Symfony2 project (from Ubuntu 14.04) in Symfony 3 for Ubuntu 16.04, and I've hit a bit of a wall. When I run composer update (verbose) I receive the following exception and trace at the end, and I'm not really sure how to clear it up. I know I'm doing something wrong, but the exception isn't exactly helpful in pinning down where the problem might be. Has anyone run into this problem before and know some likely culprits?

 [Symfony\Component\Debug\Exception\ContextErrorException]  
  Warning: Invalid argument supplied for foreach()           


Script Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::clearCache handling the symfony-scripts event terminated with an exception


  [RuntimeException]                                                         
  An error occurred when executing the "'cache:clear --no-warmup'" command:  





    [Symfony\Component\Debug\Exception\ContextErrorException]                
    Warning: Invalid argument supplied for foreach()                         





Exception trace:
 () at /vendor/sensio/distribution-bundle/Composer/ScriptHandler.php:293
 Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::executeCommand() at /vendor/sensio/distribution-bundle/Composer/ScriptHandler.php:143
 Sensio\Bundle\DistributionBundle\Composer\ScriptHandler::clearCache() at /usr/share/php/Composer/EventDispatcher/EventDispatcher.php:238
 Composer\EventDispatcher\EventDispatcher->executeEventPhpScript() at /usr/share/php/Composer/EventDispatcher/EventDispatcher.php:192
 Composer\EventDispatcher\EventDispatcher->doDispatch() at /usr/share/php/Composer/EventDispatcher/EventDispatcher.php:79
 Composer\EventDispatcher\EventDispatcher->dispatch() at /usr/share/php/Composer/EventDispatcher/EventDispatcher.php:177
 Composer\EventDispatcher\EventDispatcher->doDispatch() at /usr/share/php/Composer/EventDispatcher/EventDispatcher.php:94
 Composer\EventDispatcher\EventDispatcher->dispatchScript() at /usr/share/php/Composer/Installer.php:337
 Composer\Installer->run() at /usr/share/php/Composer/Command/UpdateCommand.php:173
 Composer\Command\UpdateCommand->execute() at /usr/share/php/Symfony/Component/Console/Command/Command.php:256
 Symfony\Component\Console\Command\Command->run() at /usr/share/php/Symfony/Component/Console/Application.php:841
 Symfony\Component\Console\Application->doRunCommand() at /usr/share/php/Symfony/Component/Console/Application.php:189
 Symfony\Component\Console\Application->doRun() at /usr/share/php/Composer/Console/Application.php:166
 Composer\Console\Application->doRun() at /usr/share/php/Symfony/Component/Console/Application.php:120
 Symfony\Component\Console\Application->run() at /usr/share/php/Composer/Console/Application.php:99
 Composer\Console\Application->run() at /usr/bin/composer:44

Answer 1

您是否已删除/添加了一个库，却忘记了从AppKernel中删除/添加了它？