Locks not released when committing a transaction which contains explicit locks but no modifications

When run the attached unit test, following exception occurs in the first several loops.

2010-10-19 16:36:19,739 INFO [org.infinispan.factories.ComponentRegistry](main)- Infinispan version: Infinispan 'Pagoa' 4.2.0.ALPHA3

2010-10-19 16:36:35,880 ERROR [org.infinispan.interceptors.InvocationContextInterceptor](Thread-4)- Execution error:

org.infinispan.util.concurrent.TimeoutException: Timed out waiting for valid responses!

at org.infinispan.remoting.transport.jgroups.JGroupsTransport.invokeRemotely(JGroupsTransport.java:421)

at org.infinispan.remoting.rpc.RpcManagerImpl.invokeRemotely(RpcManagerImpl.java:100)

at org.infinispan.remoting.rpc.RpcManagerImpl.invokeRemotely(RpcManagerImpl.java:124)

at org.infinispan.remoting.rpc.RpcManagerImpl.invokeRemotely(RpcManagerImpl.java:229)

at org.infinispan.remoting.rpc.RpcManagerImpl.invokeRemotely(RpcManagerImpl.java:216)

at org.infinispan.interceptors.DistributionInterceptor.visitLockControlCommand(DistributionInterceptor.java:214)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:118)

at org.infinispan.interceptors.LockingInterceptor.visitLockControlCommand(LockingInterceptor.java:158)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:118)

at org.infinispan.interceptors.DeadlockDetectingInterceptor.handleDataCommand(DeadlockDetectingInterceptor.java:89)

at org.infinispan.interceptors.DeadlockDetectingInterceptor.visitLockControlCommand(DeadlockDetectingInterceptor.java:71)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:118)

at org.infinispan.interceptors.base.CommandInterceptor.handleDefault(CommandInterceptor.java:132)

at org.infinispan.commands.AbstractVisitor.visitLockControlCommand(AbstractVisitor.java:147)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:118)

at org.infinispan.interceptors.MarshalledValueInterceptor.visitLockControlCommand(MarshalledValueInterceptor.java:93)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:118)

at org.infinispan.interceptors.TxInterceptor.enlistReadAndInvokeNext(TxInterceptor.java:159)

at org.infinispan.interceptors.TxInterceptor.visitLockControlCommand(TxInterceptor.java:115)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.base.CommandInterceptor.invokeNextInterceptor(CommandInterceptor.java:118)

at org.infinispan.interceptors.InvocationContextInterceptor.handleAll(InvocationContextInterceptor.java:87)

at org.infinispan.interceptors.InvocationContextInterceptor.visitLockControlCommand(InvocationContextInterceptor.java:63)

at org.infinispan.commands.control.LockControlCommand.acceptVisitor(LockControlCommand.java:142)

at org.infinispan.interceptors.InterceptorChain.invoke(InterceptorChain.java:273)

at org.infinispan.CacheDelegate.lock(CacheDelegate.java:297)

at org.infinispan.CacheDelegate.lock(CacheDelegate.java:290)

at test.TestSaveMultipleKeys.lockMultipleKeys(TestSaveMultipleKeys.java:100)

at test.TestSaveMultipleKeys.access$000(TestSaveMultipleKeys.java:13)

at test.TestSaveMultipleKeys$XThread.run(TestSaveMultipleKeys.java:84)

ERROR in loop 1: Timed out waiting for valid responses!