Doctrine ORM Error - symfony

Question

ContextErrorException:
Catchable Fatal Error: Argument 1 passed to Sonata\EasyExtendsBundle\Mapper\DoctrineORMMapper::loadClassMetadata() must be an instance of Doctrine\Common\Persistence\Event\LoadClassMetadataEventArgs, instance of Doctrine\ORM\Event\LoadClassMetadataEventArgs given
{
"name": "symfony/framework-standard-edition",
"license": "MIT",
"type": "project",
"description": "The \"Symfony Standard Edition\" distribution",
"autoload": {
"psr-0": { "": "src/" }
},
"require": {
"php": ">=5.3.3",
"symfony/symfony": "2.3.*",
"doctrine/orm": "2.3.*",
"doctrine/doctrine-bundle": "1.2.*",
"twig/extensions": "1.0.*",
"symfony/assetic-bundle": "2.3.*",
"symfony/swiftmailer-bundle": "2.3.*",
"symfony/monolog-bundle": "2.3.*",
"sensio/distribution-bundle": "2.3.*",
"sensio/framework-extra-bundle": "2.3.*",
"sensio/generator-bundle": "2.3.*",
"incenteev/composer-parameter-handler": "~2.0",
"sonata-project/admin-bundle": "2.3.*",
"friendsofsymfony/user-bundle": "1.3.2",
"sonata-project/user-bundle": "dev-master",
"sonata-project/datagrid-bundle": "~2.2#dev",
"sonata-project/doctrine-orm-admin-bundle": "2.3.*"
},
"scripts": {
"post-install-cmd": [
"Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile"
],
"post-update-cmd": [
"Incenteev\\ParameterHandler\\ScriptHandler::buildParameters",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
"Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile"
]
},
"config": {
"bin-dir": "bin"
},
"minimum-stability": "stable",
"extra": {
"symfony-app-dir": "app",
"symfony-web-dir": "web",
"incenteev-parameters": {
"file": "app/config/parameters.yml"
},
"branch-alias": {
"dev-master": "2.3-dev"
}
}
}

Answer 1

Edit:
This is now fixed in the 2.1.9 version (source).
There was a commit in the EasyExtends bundle (source) that seems to have caused this.
My suggestion is to add an explicit version in your composer.json file for the time being. The version I got this error in is 2.1.8, so I used the version before that commit:
"sonata-project/easy-extends-bundle": "2.1.7"

Answer 2

Check your use statements in the class where you're getting the exception, try replacing use Doctrine\ORM\Event\LoadClassMetadataEventArgs; with use Doctrine\Common\Persistence\Event\LoadClassMetadataEventArgs;, or try digging around with a debugger.