Nextras\Orm\Entity\Reflection\MetadataValidator::validate PHP Method

    public function validate(array $metadata, IRepositoryLoader $repositoryLoader)
    {
        $pairs = [PropertyRelationshipMetadata::MANY_HAS_MANY => PropertyRelationshipMetadata::MANY_HAS_MANY, PropertyRelationshipMetadata::MANY_HAS_ONE => PropertyRelationshipMetadata::ONE_HAS_MANY, PropertyRelationshipMetadata::ONE_HAS_MANY => PropertyRelationshipMetadata::MANY_HAS_ONE, PropertyRelationshipMetadata::ONE_HAS_ONE => PropertyRelationshipMetadata::ONE_HAS_ONE];
        foreach ($metadata as $entityMeta) {
            foreach ($entityMeta->getProperties() as $propertyMeta) {
                if (!$propertyMeta->relationship) {
                    continue;
                }
                $repositoryName = $propertyMeta->relationship->repository;
                if (!$repositoryLoader->hasRepository($repositoryName)) {
                    throw new InvalidStateException("{$entityMeta->className}::\${$propertyMeta->name} points to unknown '{$propertyMeta->relationship->repository}' repository.");
                }
                if ($propertyMeta->relationship->property === null) {
                    $relType = $propertyMeta->relationship->type;
                    $isAllowedOneSided = $relType === PropertyRelationshipMetadata::ONE_HAS_ONE && $propertyMeta->relationship->isMain || $relType === PropertyRelationshipMetadata::MANY_HAS_ONE || $relType === PropertyRelationshipMetadata::MANY_HAS_MANY && $propertyMeta->relationship->isMain;
                    if (!$isAllowedOneSided) {
                        throw new InvalidStateException("{$entityMeta->className}::\${$propertyMeta->name} must have defined a symetric relationship.");
                    } else {
                        continue;
                    }
                }
                $symetricEntityMeta = $metadata[$propertyMeta->relationship->entity];
                if (!$symetricEntityMeta->hasProperty($propertyMeta->relationship->property)) {
                    throw new InvalidStateException("{$entityMeta->className}::\${$propertyMeta->name} has not defined a symetric relationship in {$symetricEntityMeta->className}::\${$propertyMeta->relationship->property}.");
                }
                /** @var PropertyMetadata $symetricPropertyMeta */
                $symetricPropertyMeta = $symetricEntityMeta->getProperty($propertyMeta->relationship->property);
                if ($symetricPropertyMeta->relationship === null) {
                    throw new InvalidStateException("{$entityMeta->className}::\${$propertyMeta->name} has not defined a symetric relationship in {$symetricEntityMeta->className}::\${$propertyMeta->relationship->property}.");
                }
                if ($propertyMeta->name !== $symetricPropertyMeta->relationship->property) {
                    throw new InvalidStateException("{$entityMeta->className}::\${$propertyMeta->name} relationship with {$symetricEntityMeta->className}::\${$propertyMeta->relationship->property} is not symetric.");
                }
                if ($symetricPropertyMeta->relationship->type !== $pairs[$propertyMeta->relationship->type]) {
                    throw new InvalidStateException("{$entityMeta->className}::\${$propertyMeta->name} has not defined a proper reverse relationship type in {$symetricEntityMeta->className}::\${$propertyMeta->relationship->property}.");
                }
                if ($propertyMeta->relationship->type === PropertyRelationshipMetadata::MANY_HAS_MANY || $propertyMeta->relationship->type === PropertyRelationshipMetadata::ONE_HAS_ONE) {
                    if ($propertyMeta->relationship->isMain && $symetricPropertyMeta->relationship->isMain) {
                        throw new InvalidStateException("Only one side of relationship {$entityMeta->className}::\${$propertyMeta->name} × {$symetricEntityMeta->className}::\${$propertyMeta->relationship->property} could be defined as a primary.");
                    } elseif (!$propertyMeta->relationship->isMain && !$symetricPropertyMeta->relationship->isMain) {
                        throw new InvalidStateException("At least one side of relationship {$entityMeta->className}::\${$propertyMeta->name} × {$symetricEntityMeta->className}::\${$propertyMeta->relationship->property} has to be defined as a primary.");
                    }
                }
            }
        }
    }

 public function __construct(IStorage $cacheStorage, array $entityClasses, IModel $model)
 {
     $cache = new Cache($cacheStorage, 'Nextras.Orm.metadata');
     static::$metadata = $cache->load($entityClasses, function (&$dp) use($entityClasses, $model) {
         $metadata = $this->parseMetadata($entityClasses, $dp[Cache::FILES]);
         $validator = new MetadataValidator();
         $validator->validate($metadata, $model);
         return $metadata;
     });
 }