[JCR-1650] XPathQueryBuilder may not handle multiple jcr:deref correctly

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.4, core 1.4.5
• Fix Version/s: core 1.4.6
• Component/s: jackrabbit-spi-commons, xpath
• Assignee: Unassigned
• Reporter: Sébastien Launay
• Created: 16/Jun/08 08:34
• Updated: 06/Jan/09 15:57
• Resolved: 16/Jun/08 09:25

Description

If you have the following tree (inspired from DerefTest) :
+ people
+ carl (worksfor -> company/microsoft)
+ frank (worksfor -> company/microsoft)
+ company
+ microsoft (eotm -> carl)

The following queries will be translated to :

testroot/people/frank/jcr:deref(@worksfor, '')/jcr:deref(@eotm, '')
+ Root node
+ Select properties: *
+ PathQueryNode
+ LocationStepQueryNode: NodeTest={}testroot Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}people Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}frank Descendants=false Index=NONE
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
=> Matching carl node

testroot/people/frank/jcr:deref(@worksfor, '')/jcr:deref(@eotm, '')[@jcr:uuid]
+ Root node
+ Select properties: *
+ PathQueryNode
+ LocationStepQueryNode: NodeTest={}testroot Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}people Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}frank Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest=* Descendants=false Index=NONE
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
+ RelationQueryNode: Op: NOT NULL Prop=@

{http://www.jcp.org/jcr/1.0}

uuid
=> Not matching carl node

testroot/people/frank/jcr:deref(@worksfor, '')[@jcr:uuid]/jcr:deref(@eotm, '')[@jcr:uuid]
+ Root node
+ Select properties: *
+ PathQueryNode
+ LocationStepQueryNode: NodeTest={}testroot Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}people Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}frank Descendants=false Index=NONE
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
+ RelationQueryNode: Op: NOT NULL Prop=@

{http://www.jcp.org/jcr/1.0}

uuid
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
+ RelationQueryNode: Op: NOT NULL Prop=@

{http://www.jcp.org/jcr/1.0}

uuid
=> Matching carl node

testroot/people/frank/jcr:deref(@worksfor, '')[@jcr:uuid]/jcr:deref(@eotm, '')
+ Root node
+ Select properties: *
+ PathQueryNode
+ LocationStepQueryNode: NodeTest={}testroot Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}people Descendants=false Index=NONE
+ LocationStepQueryNode: NodeTest={}frank Descendants=false Index=NONE
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
+ RelationQueryNode: Op: NOT NULL Prop=@

{http://www.jcp.org/jcr/1.0}

uuid
+ DerefQueryNode: NodeTest=* Descendants=false Index=NONE
=> Matching carl node

This is because XPathQueryBuilder calls NAryQueryNode#removeOperand(QueryNode)
in order to replace current LocationStepQueryNode with a DerefQueryNode.

NAryQueryNode#removeOperand(QueryNode) uses internally a List and thus
relies on Object#equals(Object) for retrieving the object to remove.

But the equals method is redefined for every QueryNode with a different semantic.

Then, the call to NAryQueryNode#removeOperand(QueryNode) will not remove the
wanted operand but the first operand returning true after calling equals in
ArrayList#remove(Object).

Issue Links

• duplicates: JCR-1075 Error with predicate in query with multiple jcr:deref()