Version 12
I have defined an object called order. In my application, the user "order_entry" is supposed to have read and write rights for orders, for which he has been assigned (user_id = user.id) and which are in the state "draft". 
If he has not been assigned, he has read rights but no write rights for all orders in state "draft".

I defined an access_right for user "order_entry" in ir.model.access.csv (perm_read=1,perm_write=0) and then defined two records in security.xml, one for  <field name="domain_force">["&amp;",('state','=','draft'),('user_id','=', 'user.id')]</field> with <field name="perm_write" eval="1"/> and one record for domain_force (user_id != user.id) . 

When I run the code, the user has no write rights, even on orders, for which he is assigned. So  <field name="perm_write" eval="1"/> doesnt seem to work here.