[OAK-2411] Upgrade may fail with constraint exception

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.0.9, 1.1.4
• Fix Version/s: 1.0.10, 1.1.5
• Component/s: core
• Assignee: Marcel Reutegger
• Reporter: Marcel Reutegger
• Created: 19/Jan/15 10:19
• Updated: 23/Sep/16 07:48
• Resolved: 19/Jan/15 11:14

Description

A repository upgrade to MongoMK sometimes fails with a constraint exception in PrivilegeValidator.childNodeChanged():

18074 [main] ERROR org.apache.jackrabbit.oak.security.user.UserInitializer - Failed to initialize user content.
org.apache.jackrabbit.oak.api.CommitFailedException: OakConstraint0041: Attempt to modify existing privilege definition jcr:nodeTypeManagement
	at org.apache.jackrabbit.oak.security.privilege.PrivilegeValidator.childNodeChanged(PrivilegeValidator.java:109)
	at org.apache.jackrabbit.oak.security.privilege.PrivilegeValidator.childNodeChanged(PrivilegeValidator.java:47)
	at org.apache.jackrabbit.oak.spi.commit.EditorDiff.childNodeChanged(EditorDiff.java:143)
	at org.apache.jackrabbit.oak.plugins.memory.MemoryNodeState.compareAgainstBaseState(MemoryNodeState.java:155)

The problem is related to the way NodeStateDiff.childNodeChanged() is specified:

Called for all child nodes that may contain changes between the before and after states. The comparison implementation is expected to make an effort to avoid calling this method on child nodes under which nothing has changed.

When the upgrade runs, PriviledgeValidator.childNodeChanged() is called even though there isn't actually a difference between the before and after state.

On merge() the MemoryNodeStore squeezes the current NodeState (in MemoryNodeStoreBranch.setRoot()). This operation turns ModifiedNodeStates into equivalent MemoryNodeStates. When the hooks later process the changes, the node state comparison happens for a state that was squeezed with one that wasn't. This leads to MemoryNodeState.compareAgainstBaseState() calls where after != before and therefore diff.childNodeChanged() is called, even though the actual data of the states are equal.

Issue Links

• is related to: OAK-4847 Support any types of node builders in the initializers