[JCR-3105] NPE when versioning operations are concurrent

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.2.10, 2.3.1
• Component/s: jackrabbit-core, versioning
• Assignee: Julian Reschke
• Reporter: Julian Reschke
• Created: 10/Oct/11 17:39
• Updated: 08/Nov/11 15:44
• Resolved: 11/Oct/11 11:11

Description

InternalVersionManagerBase.getParentNode occasionally throws an NPE:

protected static NodeStateEx getParentNode(NodeStateEx parent, String uuid, Name interNT)
throws RepositoryException {
NodeStateEx n = parent;
for (int i = 0; i < 3; i++) {
Name name = getName(uuid.substring(i * 2, i * 2 + 2));
if (n.hasNode(name))

{ n = n.getNode(name, 1); assert n != null; }

else if (interNT != null)

{ n.addNode(name, interNT, null, false); n.store(); n = n.getNode(name, 1); assert n != null; }

else

{ return null; }
}
return n;
}

Apparently getNode occasionally returns null due to race conditions.

Changing the code to what's below appears to fix it:



protected static NodeStateEx getParentNode(NodeStateEx parent, String uuid, Name interNT)
throws RepositoryException {
NodeStateEx n = parent;
for (int i = 0; i < 3; i++) {
Name name = getName(uuid.substring(i * 2, i * 2 + 2));
NodeStateEx n2 = n.getNode(name, 1);
if (n2 != null) { n = n2; } else if (interNT != null) { n2 = n.addNode(name, interNT, null, false); n.store(); n = n2; } else { return null; }

}
return n;
}

(but likely moves the race condition somewhere else)