doctrine/phpcr-odm — comment on commit 79bdb0c4a1312116b6544755d26e0560dfc858a8
File: lib/Doctrine/ODM/PHPCR/UnitOfWork.php line 821
By dbu:

if there is any way the user can provide his own types here, we should use the phpcr method NodeType::isNodeType to decide whether we must set the uuid. if its all hardcoded then yes, we have to do it for all cases where a type extending mix:referenceable is used, if we want the uuid to be set programmatically.
another thing: are we sure all phpcr implementations allow you to manually set a uuid or can an implementation force this to be generated?