[jboss-jira] [JBoss JIRA] (WFLY-5537) Singleton EJBs with multiple views does not honor Lock semantics

[Nicky Mølholm (JIRA)]

Nicky Mølholm created WFLY-5537:
-----------------------------------

             Summary: Singleton EJBs with multiple views does not honor Lock semantics
                 Key: WFLY-5537
                 URL: https://issues.jboss.org/browse/WFLY-5537
             Project: WildFly
          Issue Type: Bug
          Components: EJB
    Affects Versions: 10.0.0.CR2
         Environment: 10.0.0.CR2
            Reporter: Nicky Mølholm


Upon method invocations to Singleton EJBs with multiple views... the *ContainerManagedConcurrencyInterceptor* randomly selects a wrong Lock (READ / WRITE).

Here is an example:

{code:java}
@Singleton
@Lock(LockType.READ)
@Local({ GreeterSayMyName.class, GreeterSayHello.class })
public class GreeterBean implements GreeterSayMyName, GreeterSayHello {

    @EJB
    GreeterSayMyName myself;

    @Override
    public String sayHello() {
        return "hello from " + myself.sayMyName();
    }

    @Override
    public String sayMyName() {
        return "The Greeter";
    }
}

public interface GreeterSayHello {
    
    String sayHello();
    
}

public interface GreeterSayMyName {

    String sayMyName();

}
{code}

Sometimes (randomly) invoking the 'sayHello' method on this example EJB causes lock upgrade exceptions. They look like this:

{noformat}
13:14:10,436 ERROR [f2PtkwmdRgaoHCdnZ7Vurg] [anonymous] [org.jboss.as.ejb3.invocation] (default task-5 f2PtkwmdRgaoHCdnZ7Vurg) WFLYEJB0034: EJB Invocation failed on component GreeterBean for method public abstract java.lang.String hello.world.GreeterSayHello.sayHello(): javax.ejb.IllegalLoopbackException: WFLYEJB0238: EJB 3.1 PFD2 4.8.5.1.1 upgrading from read to write lock is not allowed
	at org.jboss.as.ejb3.concurrency.EJBReadWriteLock.checkLoopback(EJBReadWriteLock.java:232)
	at org.jboss.as.ejb3.concurrency.EJBReadWriteLock.access$300(EJBReadWriteLock.java:40)

{noformat}

This happens completely randomly. 

The problem is that the interceptor only knows about one of the views' methods. At deployment time the ViewService will start the views concurrently - and the interceptorfactory only adds an interceptor instance to the interceptor context if one does not already exist. 

When the exception does NOT occur -then there is still a problem (although not visible from the code): A WRITE lock is selected - even though , given the above code, it should never ever be possible.  So in fact - the issue , in that case, does not cause an exception because .... it already has the WRITE lock. 

( When the exception occurs ...then it is because the sayHello() invocation resulted in a READ lock ... and the reentrant invocation caused a WRITE lock to be selected by the interceptor ... but as this is not allowed, it results in a horrible exception )



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