[JCR-3887] Cannot combine move and unlock in a transaction

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.10
• Component/s: locks, transactions
• Assignee: Unassigned
• Reporter: Thomas Thonhofer
• Created: 09/Jun/15 14:39
• Updated: 09/Jun/15 14:40

Description

Without transactions, when you create a Node, lock it and then move it, the (now nonexistent) source Node will no longer be locked, but the target Node will be. If the target node should not be locked, we can either unlock the source Node before move, or unlock the target Node after move. However, this stops working as soon as we start using transactions.

In our example code (see below), the following problems occur:
a) If we call unlock on the source Node before the move, committing the transaction fails and complains that the target node is not locked
b) If we call unlock on the target node after the move instead (see commented out line), committing the transaction fails and complains that the target node is not locked
c) If we don't call unlock at all, the assertion that tests the lock after the move fails because the target node is locked

As far as I have investigated, this is the problem:
Because we are in a transaction, the real changes of the move are not done immediately but upon commit (as it should be). This also includes updating the node path in the global LockManager. The unlocking however doesn't happen during the actual commit, but during the prepare, so it will always happen before the move. Because the move didn't happen yet, the global LockManager doesn't have an entry for the new path of the node yet, so if org.apache.jackrabbit.core.lock.LockManagerImpl tries to do the unlock in the method internalUnlock(NodeImpl node), it will throw "LockException: Node not locked", because it can't find the correct path for the lock.

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Test code:
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package com.infinica.tests.jackrabbit;

import java.io.File;
import java.io.IOException;
import javax.jcr.LoginException;
import javax.jcr.Node;
import javax.jcr.Repository;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.SimpleCredentials;
import javax.jcr.lock.LockException;
import javax.jcr.lock.LockManager;
import javax.transaction.HeuristicMixedException;
import javax.transaction.HeuristicRollbackException;
import javax.transaction.NotSupportedException;
import javax.transaction.RollbackException;
import javax.transaction.SystemException;
import javax.transaction.xa.XAException;
import javax.transaction.xa.XAResource;
import org.apache.geronimo.transaction.manager.GeronimoTransactionManager;
import org.apache.jackrabbit.core.TransientRepository;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

public class JackrabbitTransactionTest
{
                public static final String NODE_CONTENT = "content";
                public static final String PROPERTY_DATA = "data";
                private File tempDir;

                @Before
                public void before() throws IOException
                {
                               tempDir = File.createTempFile("jackrabbit_test", "");
                               tempDir.delete();
                }

                @After
                public void after()
                {
                               if(tempDir != null)
                               {
                                               delete(tempDir);
                               }
                }

                private static void delete(File file)
                {
                               File[] children = file.listFiles();

                               if(children != null)
                               {
                                               for(File child: children)
                                               {
                                                               delete(child);
                                               }
                               }

                               if(!file.delete())
                               {
                                               System.err.println("Could not delete: " + file);
                               }
                }

                @Test
                public void testMoveAndLock() throws LoginException, RepositoryException,
XAException, NotSupportedException, SystemException, IllegalStateException, RollbackException,
SecurityException, HeuristicMixedException, HeuristicRollbackException
                {
                               GeronimoTransactionManager tm = new GeronimoTransactionManager();

                               tm.begin();

                               Repository repository = new TransientRepository(tempDir);
                               String token;
                               Session session = repository.login(new SimpleCredentials("admin",
"admin".toCharArray()));
                               tm.getTransaction().enlistResource((XAResource) session);
                               LockManager lockMan = session.getWorkspace().getLockManager();

                               try
                               {
                                               String user = session.getUserID();
                                               String name = repository.getDescriptor(Repository.REP_NAME_DESC);
                                               System.out.println("Logged in as " + user +
" to a " + name + " repository.");

                                               Node root = session.getRootNode();

                                               Node folderSrc = createNode(root, "src");
                                               Node fileSrc = createFile(folderSrc, "test.txt",
"Test");
                                               System.out.println("Created source file: "
+ fileSrc.getPath());
                                               session.save();

                                               token = lockMan.lock("/src/test.txt", false,
false, Long.MAX_VALUE, "admin").getLockToken();
                               }
                               finally
                               {
                                               removeLockTokens(lockMan);
                                               tm.commit();
                                               session.logout();
                               }

                               tm.begin();
                               session = repository.login(new SimpleCredentials("admin", "admin".toCharArray()));
                               tm.getTransaction().enlistResource((XAResource) session);
                               lockMan = session.getWorkspace().getLockManager();

                               try
                               {
                                               Node root = session.getRootNode();

                                               lockMan.addLockToken(token);
                                               lockMan.unlock("/src/test.txt");

                                               Node folderDest = createNode(root, "dest");
                                               session.move("/src/test.txt", "/dest/test.txt");
                                               session.save();
//                                           lockMan.unlock("/dest/test.txt");

                                               Assert.assertTrue(root.hasNode("src"));
                                               Assert.assertFalse(root.hasNode("src/test.txt"));

                                               folderDest = root.getNode(folderDest.getName());
                                               Node fileDest = folderDest.getNode("test.txt");
                                               Assert.assertEquals("Test", getFileStringProperty(fileDest,
PROPERTY_DATA));
                                               Assert.assertFalse(lockMan.isLocked(fileDest.getPath()));
                               }
                               finally
                               {
                                               removeLockTokens(lockMan);
                                               tm.commit();
                                               session.logout();
                               }
                }

                /**
                * Necessary because of JCR-3438.
                */
                private static void removeLockTokens(LockManager man) throws LockException,
RepositoryException
                {
                               if(man == null)
                               {
                                               return;
                               }

                               for(String token: man.getLockTokens())
                               {
                                               man.removeLockToken(token);
                               }
                }

                private String getFileStringProperty(Node file, String property) throws RepositoryException
                {
                               Node contentNode = file.getNode(NODE_CONTENT);
                               return contentNode.getProperty(property).getString();
                }

                private Node createFile(Node parent, String path, String content) throws RepositoryException
                {
                               Node node = parent.addNode(path);
                               node.addMixin("mix:lockable");
                               Node contentNode = node.addNode(NODE_CONTENT);
                               contentNode.setProperty(PROPERTY_DATA, content);
                               return node;
                }

                private static Node createNode(Node parent, String path) throws RepositoryException
                {
                               return parent.addNode(path);
                }
}