[ARIES-1989] Blueprint not able to assign complex generics

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.0
• Component/s: Blueprint
• Assignee: Unassigned
• Reporter: Andrew MacGaffey
• Created: 10/Jul/20 17:30
• Updated: 10/Jul/20 17:31

Description

Initializing a property with a "ref" element fails with complex generics

public interface EndpointHandler {} 

public interface EndpointServer <H extends EndpointHandler>{}

public interface HandlerFactory <S> {}

public abstract class AbstractFactory <H extends EndpointHandler, S extends EndpointServer<H>>{
 HandlerFactory<S> handlerFactory = null;
 public HandlerFactory<S> getHandlerFactory() {
  return handlerFactory;
 }
 public void setHandlerFactory(HandlerFactory<S> handlerFactory) {
  this.handlerFactory = handlerFactory;
 }
}

public class ConcreteFactory extends AbstractFactory<MyHandler, MyServer<MyHandler>> { }

public class ConcreteHandlerFactory implements HandlerFactory<MyServer<MyHandler>> {}

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
 xmlns:ext="http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.2.0">
 
 <bean id="concreteHandlerFactory" class="bugtest.ConcreteHandlerFactory" />
 <bean id="concreteFactory" class="bugtest.ConcreteFactory">
 <property name="handlerFactory" ref="concreteHandlerFactory" />
 </bean>
 
</blueprint>

The problem manifests in

if (from.equals(to)) {
 return true;
 }
 if (from.getRawClass() == to.getRawClass()) {
 if (to.size() == 0) {
 return true;
 }
 if (from.size() == to.size()) {
 boolean ok = true;
 for (int i = 0; i < from.size(); i++) {
 ReifiedType tf = from.getActualTypeArgument(i);
 ReifiedType tt = to.getActualTypeArgument(i);
 if (!isWildcardCompatible(tf, tt)) {         <<================= HERE
 ok = false;
 break;
 }
 }
 if (ok) {
 return true;
 }
 }
 } else {
 ReifiedType t = getExactSuperType(from, to.getRawClass());
 if (t != null) {
 return isTypeAssignable(t, to);
 }
 }
 return false;
 }

ReifiedType tt has the correct generic class EndpointServer but has 0 parameters. So the assignment fails.

Hacking this with a property of type"Object" and a cast works. The type structure and assignment also work in rather ancient spring-dm