Map constructor does not assign String to Object in Grails - grails

Question

Given the following domain class:
class Dog {
Object name // changing the type to String fixes it
}
And this unit test:
import grails.test.mixin.Mock
import grails.test.mixin.TestMixin
import grails.test.mixin.support.GrailsUnitTestMixin
import spock.lang.*
/**
* See the API for {#link grails.test.mixin.support.GrailsUnitTestMixin} for usage instructions
*/
#TestMixin(GrailsUnitTestMixin)
#Mock([Dog])
class DogSpec extends Specification {
def setup() {
}
def cleanup() {
}
void "test something"() {
Dog dog = new Dog(name:"sparky")
// dog.name = "sparky" // adding this line also fixes it
expect:"fix me"
dog.name == "sparky"
}
}
Running grails test-app fails, but if you change the type of Dog.name to String, it works fine. Debugging brings me to realize that Dog.name never gets assigned and is null. If I were to set dog.name via regular assignment after constructing it as above, the test passes.
This issue does not occur in Groovy Script using the same map constructor assignment.
I want my type to be Object as it varies depending on the use case.
Any idea why this is happening? Is it a bug in Grails?

Answer 1

I did some debugging and I found out that when a field accepts an Object, grails framework doesn't do databinding on this property.
More specifically, the Dog#name field doesn't belongs to the whitelist of properties when It is declared as Object.
That's why this doesn't work.
If you want to debug, see the
grails.web.databinding.DataBindingUtils#getBindingIncludeList(final Object object)
If you put a breakpoint there, you will see how grails generates the whitelist of properties.
I think this makes a lot of sense since It's related to security!
See more about it here
If you wanna bind on an Object field nevertheless, this code may help you:
class Dog {
Object name
static constraints = {
name(bindable: true)
}
}