[
https://issues.apache.org/jira/browse/GROOVY-12106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18091640#comment-18091640
]
Eric Milles commented on GROOVY-12106:
--------------------------------------
This may be stated in 11985 or 12093: up to Groovy 3 an implementing class was
able to add a static method that shadows or overrides a static trait method.
In Groovy 4 a private static method was guarded as an implementation detail
that could not be replaced. Then in Groovy 5 (under GROOVY-8859, et al.)
public was guarded as well.
I like the Groovy 5 design. Yes, this is a change in behavior but it was saved
for a new major release. Now 11985 and 12093 are trying to straddle the old
and new designs.
Many of the issues noted in the first comment were about allowing access to the
various combinations of public/private, static/non-static, direct/inherited. I
think the "override" scenarios were not well documented. I forget if there
were any test cases for replacing a static method in an implementing class.
> STC cannot resolve inherited static trait method from sub-trait body
> --------------------------------------------------------------------
>
> Key: GROOVY-12106
> URL: https://issues.apache.org/jira/browse/GROOVY-12106
> Project: Groovy
> Issue Type: Bug
> Components: Static Type Checker
> Affects Versions: 5.0.7
> Reporter: James Fredley
> Priority: Major
> Labels: static-method, sts, traits
>
> h2. Summary
> Groovy 5 static type checking does not resolve a static method declared by a
> parent trait when the method is called from a sub-trait body.
> This is independent of Grails and can be reproduced with plain Groovy traits
> under @CompileStatic.
> This was re-tested on Groovy 5.0.7-SNAPSHOT. Both an unqualified call and a
> qualified call fail static type checking:
> {code:groovy}
> inheritedStaticMethod(value)
> {code}
> {code:groovy}
> ParentTrait.inheritedStaticMethod(value)
> {code}
> The failure is distinct from GROOVY-11985, which fixed
> static-override-via-this. This issue is about resolving a parent trait's
> static method from a sub-trait body.
> h2. Standalone reproducer
> {code:groovy}
> import groovy.transform.CompileStatic
> @CompileStatic
> trait ParentTrait {
> static void configure(Closure closure, Object target) {
> if (closure != null) {
> closure.delegate = target
> closure.resolveStrategy = Closure.DELEGATE_ONLY
> closure.call()
> }
> }
> }
> @CompileStatic
> trait ChildTrait extends ParentTrait {
> void applyConfig(Closure closure, Object target) {
> configure(closure, target)
> }
> }
> @CompileStatic
> class Example implements ChildTrait {
> }
> {code}
> h2. Expected result
> The code should pass static type checking. A sub-trait should be able to
> resolve a static method declared by a parent trait.
> h2. Actual result
> Static type checking fails on the call from the sub-trait body:
> {code}
> Cannot find matching method ChildTrait#configure(groovy.lang.Closure,
> java.lang.Object)
> {code}
> Using a qualified call also fails:
> {code:groovy}
> ParentTrait.configure(closure, target)
> {code}
> h2. Real-world use case
> Apache Grails has the same pattern in the GraphQL DSL helper traits.
> Parent trait method:
> {code}
> grails-data-graphql/core/src/main/groovy/org/grails/gorm/graphql/entity/dsl/helpers/ExecutesClosures.groovy
> line 34
> {code}
> {code:groovy}
> @CompileStatic
> trait ExecutesClosures {
> static void withDelegate(@DelegatesTo(strategy = Closure.DELEGATE_ONLY)
> Closure closure, Object delegate) {
> ...
> }
> }
> {code}
> Sub-traits that should be able to call the inherited helper:
> {code}
> grails-data-graphql/core/src/main/groovy/org/grails/gorm/graphql/entity/dsl/helpers/Arguable.groovy
> grails-data-graphql/core/src/main/groovy/org/grails/gorm/graphql/entity/dsl/helpers/ComplexTyped.groovy
> {code}
> Grails currently works around this by inlining the parent trait helper body
> into each sub-trait. Once this Groovy STC issue is fixed, that inline
> workaround can be removed.
> h2. Workaround
> Inline the static helper body in each sub-trait, or avoid calling the
> inherited static trait method from the sub-trait.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
