[GROOVY-10757] Regression from 2.5.16+: ClassCastException at runtime

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.16, 2.5.17, 2.5.18
• Fix Version/s: 2.5.19, 4.0.6, 3.0.14
• Component/s: Compiler
• Assignee: Eric Milles
• Reporter: Mauro Molinari
• Created: 14/Sep/22 12:44
• Updated: 10/Feb/23 21:40
• Resolved: 26/Sep/22 13:19

Description

I've found a very nasty bug in Groovy 2.5.16+.

It's really hard to extract a simple test case, so I'll try to explain what is going on as much as possible.

I have a @CompileStatic Groovy class hierarchy. Compilation succeeds, but a ClassCastException happens at runtime. The hierarchy is like this:

@Named
@CompileStatic
@Scope('session')
abstract class GenericServicePurchaseBean<T extends GenericServicePurchaseDao> implements Serializable {
    T dao

    void setDao(final T dao) {
        this.dao = dao
    }

    protected abstract List<? extends ProductIdto> retrieveAvailableProducts()

	@CompileDynamic // see note below
	void resetState() {
		// ...
                retrieveAvailableProducts()
                // ...
        }
}

 

@Named
@CompileStatic
@Scope('session')
class FooPurchaseBean extends GenericServicePurchaseBean<FooPurchaseDao> {
	@Inject
	@Named('fooPurchaseDao')
	@Override
	void setDao(final FooPurchaseDao dao) {
		super.setDao(dao)
	}

	@Override
	protected List<? extends ProductIdto> retrieveAvailableProducts() {
		dao.loadAllAvailableProductsForNewPurchase(customer)
	}

	@Override
	void resetState() {
		super.resetState();
                // ...
        }
}

The error I get at runtime is this:

Caused by: java.lang.ClassCastException: class it.dcssrl.shop.web.purchase.view.dao.FooPurchaseDao$$EnhancerBySpringCGLIB$$271ceca2 cannot be cast to class it.dcssrl.shop.web.purchase.view.dao.BarPurchaseDao (it.dcssrl.shop.web.purchase.view.dao.FooPurchaseDao$$EnhancerBySpringCGLIB$$271ceca2 and it.dcssrl.shop.web.purchase.view.dao.BarPurchaseDao are in unnamed module of loader org.apache.catalina.loader.ParallelWebappClassLoader @5a075a)
        at it.dcssrl.shop.web.purchase.view.FooPurchaseBean.retrieveAvailableProducts(FooPurchaseBean.groovy:217)
        at org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:234)
        at it.dcssrl.shop.web.purchase.view.GenericServicePurchaseBean.resetState(GenericServicePurchaseBean.groovy:682)
        at it.dcssrl.shop.web.purchase.view.FooPurchaseBean.resetState(FooPurchaseBean.groovy:148)
 [...]

If I remove the Groovy compiler optimization to enable Indy compilation, the error happens all the same, but the stack trace does not have the line about org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:234).

Please note that:

• this problem does not happen with Groovy 2.5.15
• it happens with Groovy 2.5.16, 2.5.17 and 2.5.18
• it DOES NOT happen if compiling/running the application within Eclipse/WTP and Groovy Eclipse plugin
• the resetState() method above in the base class is marked with @CompileDynamic because of another nasty problem I was not able to isolate, which otherwise produces another ClassCastException at runtime, although completely different from this one; this has been happening from 2.5.13 at least (it was not occurring with 2.5.9)

Any idea of what is going on? And of a possible not-too-dirty workaround (apart from downgrading to Groovy 2.5.15)?