Details
Description
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 account 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:
class Parent extends GormEntity<Parent> { } class Child extends GormEntity<Child> { } class GormEntity<? extends GormEntity> { // ? extends GormEntity is not allowed }
We have documented the impacts of 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:
class Parent extends GormEntity<Parent> { } class Child extends GormEntity<Child> { } trait GormEntity<D> { // Simplified for this ticket static D get(Serializable id) static List<D> getAll() }
This allows someone to do the following in code:
Parent.get(1L) // Will find either a Child or Parent Child.get(1L) // Will find only child types
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?
Attachments
Attachments
Issue Links
- is caused by
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GROOVY-5106 Same interface can be implemented with two different generic types
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- Closed
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- is related to
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GROOVY-8864 Backwards compatibility of traits
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- Closed
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- links to