7.2.x (grails-scaffolding) - Parameterize the @Scaffold controller superclass so scaffolded controller members aren't type-erased

[codeconsole]

Summary

Controller-side counterpart of #15717. ScaffoldingControllerInjector set the injected superclass via GrailsASTUtils.nonGeneric(superClassNode, domainClass), so a scaffolded controller's superclass was written raw and every inherited generic member erased to its GormEntity upper bound under static compilation:

@Scaffold(RestfulController<Widget>)
@GrailsCompileStatic
class WidgetController {
    @Override
    protected Widget queryForResource(Serializable id) {
        def widget = super.queryForResource(id)   // before: typed GormEntity, not Widget
        (widget?.owner == currentOwner) ? widget : null
    }
}

fails with:

[Static type checking] - No such property: owner for class: org.grails.datastore.gorm.GormEntity
[Static type checking] - Cannot return value of type org.grails.datastore.gorm.GormEntity for method returning com.example.Widget

The common workaround in real apps is sprinkling @CompileDynamic over every queryForResource/createResource/listAllResources override, giving up static compilation exactly where project-scoping security checks live.

Design

Same pattern #15717 applied to ScaffoldingServiceInjector: take a getPlainNodeReference() copy of the resolved superclass, set its generics to the domain type, mark the class node with setUsingGenerics(true) — injection runs at CANONICALIZATION (after generics resolution), so the generic superclass signature is only emitted when the class node itself reports usesGenerics; otherwise it is written raw — then setSuperClass(parameterizedSuper). Applies to all three forms: @Scaffold(Widget), @Scaffold(RestfulController<Widget>), and custom bases @Scaffold(ApiController<Widget>) (the declared base is preserved, not collapsed to RestfulController).

Tests

New ScaffoldingControllerInjectorSpec mirroring ScaffoldingServiceInjectorSpec:

• simple form @Scaffold(Widget) → genericSuperclass is RestfulController<Widget>, not raw
• generic form @Scaffold(RestfulController<Widget>) → parameterized
• custom scaffold base preserved and parameterized as CustomBase<Widget>
• a @CompileStatic scaffolded controller overriding queryForResource / createResource / listAllResources and narrowing the super.* results to the domain type compiles without casts

All four tests fail against the previous injector and pass with the fix; :grails-scaffolding:test passes in full.

[codeconsole]

Added a small robustness guard (both injectors, since the merged #15717 service-injector code shares the shape): the superclass is only parameterized when the base declares exactly one type parameter. A base with zero or multiple type parameters — e.g. @Scaffold(MultiParamBase<Widget, String>) — previously would have received a malformed single-argument generic signature; it now keeps the prior raw form. Covered by a new spec case in each injector spec (both fail without the guard).

[testlens-app]

✅ All tests passed ✅

🏷️ Commit: a32edba
▶️ Tests: 28363 executed
⚪️ Checks: 37/37 completed

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[jdaugherty]

In 8.x, I 100% agree with this change. In 7.2.x, I'm not sure. @matrei would you consider this a breaking change?

[codeconsole]

@jdaugherty it matches #15717 which is already in 7.2.x

[jdaugherty]

I'm good to merge then.

[codeconsole]

@jdaugherty thanks