Why does JMS Serializer ignore mappings for nested collections?
Since there were no anwsers, I'll post what I eventually did/found out (for future reference and anyone who encounters the same problem). I'll quote my edit:
After some suggestions I added @ExclusionPolicy("ALL") annotation to the Brick class and @Expose on ID, just to see what happens.. and suddenly it works! Not only ID is exposed, but everything is like in my YML configuration.
So I removed the annotations.. and it still works!
So it seems that adding Annotations somehow forced serializer to recognize my YML config. I don't know why though. That worries me.
Apparently adding use JMS\Serializer\Annotation\ExclusionPolicy; to the entity is enough.
I m guessing it was not working because we did not implement the class to do so.