When using the association-key attribute on an id element in an XML mapping, a MappingException is thrown:
No identifier/primary key specified for Entity 'Foo\BarBundle\Entity\Baz'. Every Entity must have an identifier/primary key.
This is because in the XMLDriver.php file (version 2.1.2)
Line 213 reads: $associationIds[(string)$idElement['fieldName']] = true;
When it should read: $associationIds[(string)$idElement['name']] = true;
This was fixed on master here, but has not be back ported – as I understand it master is 2.x. This is a fairly significant issues for users of the XMLDriver, currently a show stopper on our work, especially as we're using Symfony Standard distribution 2.0.6 – 2.0.7 references a version of Doctrine with another bug.
I've confirmed that this bug exists in 2.1.2, and 2.1.4, but it probably effects more versions.