Bean definition override leads to NPE due to inconsistent equality check

[andrey-vasilyev]

Hi, I've recently tried to switch to spring 5.1.9. And my old code (based on spring 4.3.4) stopped working because of NPE during context refresh. I've created a minimal reproducible example https://gist.github.com/andrey-vasilyev/ad42b33c13ce850bfd7065ef35f95017

The issues (difference in behaviour) seems to be in AbstractBeanDefinition.equals method. Could you please take a look?

[jhoeller]

This turns out to be caused by an inconsistent equality check in ConstructorArgumentValues (for indexed argument mismatches) as well as GenericBeanDefinition (which misses a check for parent name equality). While the reported NPE effect may only manifest in recent versions, the underlying bugs are present in 4.3.x too and should get backported there as well.