Mixins on Grails Domains Classes broken in upgrade to 2.2 - grails

Question

We have a multiple Grails 2.0.3 domain classes that use the #Mixin annotation
like so:
#Mixin(PremisesMixin)
class Clinic {
Premises premises
String name
....
It works really well!
In trying to update to 2.2.2 the mixins don't seem to work. We use the fixtures plugin to bootstrap some data, and in the process of starting up we get errors related to the getters and setters that should injected by the mixins not being present.
I did Find there there are some issues with groovy mixins in more recent versions of grails, but there is a Grails specific replacement http://jira.grails.org/browse/GRAILS-9901
but changing to
#grails.util.Mixin(PremisesMixin)
class Clinic { ...
gives other errors.
Getter for property 'fax' threw exception; nested exception is java.lang.reflect.InvocationTargetException
So is there a way to utilize mixins on Grails domain classes in the latest version of grails or do I need to refactor my code to avoid them?
update:
the premises mixin which is in src/groovy looks like this:
class PremisesMixin implements Serializable {
private static final long serialVersionUID = 1L
static fields = ['addressLine1', 'addressLine2', 'city', 'county', 'state', 'postalCode', 'plus4', 'phone', 'latitude', 'longitude']
String getAddressLine1() { premises?.addressLine1 }
void setAddressLine1(String addressLine1) { premises?.addressLine1 = addressLine1 }
String getAddressLine2() { premises?.addressLine2 }
void setAddressLine2(String addressLine2) { premises?.addressLine2 = addressLine2 }
String getCity() { premises?.city }
void setCity(String city) { premises?.city = city }
...
String getPhone() { premises?.phone }
void setPhone(String phone) { premises?.phone = phone }
String getFax() { premises?.fax }
void setFax(String fax) { premises?.fax = fax }
...
// Workaround for open Groovy bug with Mixins https://issues.apache.org/jira/browse/GROOVY-3612
String toString() {
this as String
}
}
and Premises looks like this:
class Premises {
String addressLine1
String addressLine2
String city
String state
...
String county
String phone
String fax
Double latitude
Double longitude
}

Answer 1

It works for me in Grails 2.2.2 with the below setup:
#grails.util.Mixin(PremisesMixin)
class Clinic {
String name
static constraints = {
}
}
class Premises {
String fax
static constraints = {
fax nullable: true
}
}
class PremisesMixin {
//Without this a runtime error is thrown,
//like property 'premises' not found in Clinic.
Premises premises
void setFax(String fax) {
premises?.fax = fax
}
String getFax() {
premises?.fax
}
}
//Test Case
def clinic = new Clinic(name: "TestClinic")
clinic.premises = new Premises().save(flush: true, failOnError: true)
clinic.fax = "123456"
clinic.save(flush: true, failOnError: true)
Clinic.list().each{assert it.fax == '123456'}
Premises.list().each{assert it.fax == '123456'}
The logic for Mixin transformation has not been modified for 2.2.x version although I see modifications done on it in master branch, but the change is minute(generic class literals used).
Few Questions:
1. How was premises accessible in the mixin class? I do not see where it is defined in the Mixin class.
2. Actually when were you facing the error, run-app or during creation of Clinic(similar to what is done in test above)?