James Daugherty created GROOVY-11508:
----------------------------------------

             Summary: Revert Groovy-5106 or allow it to be a warning only
                 Key: GROOVY-11508
                 URL: https://issues.apache.org/jira/browse/GROOVY-11508
             Project: Groovy
          Issue Type: Bug
          Components: Compiler
    Affects Versions: 4.0.0
            Reporter: James Daugherty


When updating Grails from Groovy 3.x to 4.x we discovered that Groovy-5106 
prevents us from updating to Groovy 4 for the grails-data-mapping (GORM) 
project.  Groovy-5106 does not take into relationships between generic types 
and groovy does not support inheritance in generic types on traits so we have 
no workable solution for using Groovy 4. 

 

For example, the following is not possible in Groovy 4:
{code:java}
class Parent extends GormEntity<Parent> {

}

class Child extends GormEntity<Child> {

} 

class GormEntity<? extends GormEntity> { // ? extends GormEntity is not allowed

}{code}
 

We have documented this issue on the grails-data-mapping project here:  
[https://github.com/grails/grails-data-mapping/issues/1811]   We have 
discovered that the original change could be reverted and continue to work with 
the latest Java & Groovy. 

 

For Grails Data Mapping (GORM), there is support for inheritance between a 
Parent & Child domain object.  This is often implemented like this:
{code:java}
class Parent extends GormEntity<Parent> {

}

class Child extends GormEntity<Child> {

}

trait GormEntity<D> {
    static D get(Serializable id)

    // Simplified for this ticket
    static List<D> getAll()
}
 {code}
This allows someone to do the following in code:
{code:java}
Parent.get(1L) // Will find either a Child or Parent
Child.get(1L) // Will find only child types{code}
 

Since Groovy-5106 does not take into account inheritance, can this change be 
reverted or changed to a warning until inheritance is taken into account?



--
This message was sent by Atlassian Jira
(v8.20.10#820010)

Reply via email to