Drop support for Doctrine cache adapter for metadata

[GromNaN]

Remove BC layer introduced in #690 to keep support for Doctrine cache adapters. PSR-6 is now required.

[GromNaN]

@Ahummeling, you introduced this compatibility layer, I'd be glad to have your review if you can find the time.

[franmomu]

There are also these class definitions involved:

DoctrineMongoDBBundle/Resources/config/mongodb.xml

Lines 22 to 30 in ddf39bb

	<!-- cache -->
	<parameter key="doctrine_mongodb.odm.cache.array.class">Doctrine\Common\Cache\ArrayCache</parameter>
	<parameter key="doctrine_mongodb.odm.cache.apc.class">Doctrine\Common\Cache\ApcCache</parameter>
	<parameter key="doctrine_mongodb.odm.cache.apcu.class">Doctrine\Common\Cache\ApcuCache</parameter>
	<parameter key="doctrine_mongodb.odm.cache.memcache.class">Doctrine\Common\Cache\MemcacheCache</parameter>
	<parameter key="doctrine_mongodb.odm.cache.memcache_host">localhost</parameter>
	<parameter key="doctrine_mongodb.odm.cache.memcache_port">11211</parameter>
	<parameter key="doctrine_mongodb.odm.cache.memcache_instance.class">Memcache</parameter>
	<parameter key="doctrine_mongodb.odm.cache.xcache.class">Doctrine\Common\Cache\XcacheCache</parameter>

I don't know (I haven't properly checked) if changing them would also allow us to remove:

DoctrineMongoDBBundle/DependencyInjection/DoctrineMongoDBExtension.php

Lines 580 to 650 in ddf39bb

	protected function loadCacheDriver(string $cacheName, string $objectManagerName, array $cacheDriver, ContainerBuilder $container): string
	{
	if (isset($cacheDriver['namespace'])) {
	return parent::loadCacheDriver($cacheName, $objectManagerName, $cacheDriver, $container);
	}
	$cacheDriverServiceId = $this->getObjectManagerElementName($objectManagerName . '_' . $cacheName);
	switch ($cacheDriver['type']) {
	case 'service':
	$container->setAlias($cacheDriverServiceId, new Alias($cacheDriver['id'], false));
	return $cacheDriverServiceId;
	case 'memcached':
	if (! empty($cacheDriver['class']) && $cacheDriver['class'] !== MemcacheCache::class) {
	return parent::loadCacheDriver($cacheName, $objectManagerName, $cacheDriver, $container);
	}
	$memcachedInstanceClass = ! empty($cacheDriver['instance_class']) ? $cacheDriver['instance_class'] : '%' . $this->getObjectManagerElementName('cache.memcached_instance.class') . '%';
	$memcachedHost = ! empty($cacheDriver['host']) ? $cacheDriver['host'] : '%' . $this->getObjectManagerElementName('cache.memcached_host') . '%';
	$memcachedPort = ! empty($cacheDriver['port']) ? $cacheDriver['port'] : '%' . $this->getObjectManagerElementName('cache.memcached_port') . '%';
	$memcachedInstance = new Definition($memcachedInstanceClass);
	$memcachedInstance->addMethodCall('addServer', [
	$memcachedHost,
	$memcachedPort,
	]);
	$container->setDefinition($this->getObjectManagerElementName(sprintf('%s_memcached_instance', $objectManagerName)), $memcachedInstance);
	$cacheDef = new Definition(MemcachedAdapter::class, [new Reference($this->getObjectManagerElementName(sprintf('%s_memcached_instance', $objectManagerName)))]);
	break;
	case 'redis':
	if (! empty($cacheDriver['class']) && $cacheDriver['class'] !== RedisCache::class) {
	return parent::loadCacheDriver($cacheName, $objectManagerName, $cacheDriver, $container);
	}
	$redisInstanceClass = ! empty($cacheDriver['instance_class']) ? $cacheDriver['instance_class'] : '%' . $this->getObjectManagerElementName('cache.redis_instance.class') . '%';
	$redisHost = ! empty($cacheDriver['host']) ? $cacheDriver['host'] : '%' . $this->getObjectManagerElementName('cache.redis_host') . '%';
	$redisPort = ! empty($cacheDriver['port']) ? $cacheDriver['port'] : '%' . $this->getObjectManagerElementName('cache.redis_port') . '%';
	$redisInstance = new Definition($redisInstanceClass);
	$redisInstance->addMethodCall('connect', [
	$redisHost,
	$redisPort,
	]);
	$container->setDefinition($this->getObjectManagerElementName(sprintf('%s_redis_instance', $objectManagerName)), $redisInstance);
	$cacheDef = new Definition(RedisAdapter::class, [new Reference($this->getObjectManagerElementName(sprintf('%s_redis_instance', $objectManagerName)))]);
	break;
	case 'apcu':
	$cacheDef = new Definition(ApcuAdapter::class);
	break;
	case 'array':
	$cacheDef = new Definition(ArrayAdapter::class);
	break;
	default:
	return parent::loadCacheDriver($cacheName, $objectManagerName, $cacheDriver, $container);
	}
	$cacheDef->setPublic(false);
	$container->setDefinition($cacheDriverServiceId, $cacheDef);
	return $cacheDriverServiceId;
	}

since apparently these classes are used by AbstractDoctrineExtension.

[Ahummeling]

@Ahummeling, you introduced this compatibility layer, I'd be glad to have your review if you can find the time.

It's been a while since I've touched this code, I might be able to find some time over the weekend. It was quite a complex task, so would like to take the time for it to properly review this.

[alcaeus]

LGTM. Do we have any other remnants of doctrine/cache to clean up?

[GromNaN]

Should be deprecated in 4.7. This is not used.

[GromNaN]

@alcaeus @franmomu I updated the extension and service definitions to not rely on the abstract extension from doctrine-bridge.