I am facing a small issue on Doctrine 2 that causes OneToOne relation needed to be part of the parent class. The error occurs when doing $content->getVersions() but not when doing $em->find("Model\Lantern\Content\Version", $id). The error message is:
Simply by having a look at the model we can see what's causing the Bug, will avoid class annotations to make it simpler:
As you can see, Article::$summary targets Summary::$version, but Summary::$version targets Version::$summary. This in OOP is valid as Version is contained inside Article, so doing a downcasting will get Article::summary.
The reason I believe why using $em->find works is that $em->find already knows which child class is before doing map, and relations works fine.
On the other hand, when doing $content->getVersions(), Content::$versions targets Version, and looks like Doctrine does not resolve which child class it before mapping OneToOne relationshipg.
This bug doesn't occur with OneToMany or ManyToMany relationships.