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Bug 354019

Summary:	NPE when launching diff
Product:	[Modeling] EMFCompare	Reporter:	William Piers <william.piers>
Component:	Core	Assignee:	EMF Compare <emf.compare-inbox>
Status:	CLOSED FIXED	QA Contact:
Severity:	normal
Priority:	P3	CC:	laurent.goubet
Version:	1.2
Target Milestone:	---
Hardware:	PC
OS:	Windows 7
Whiteboard:

Description William Piers

2011-08-05 11:27:23 EDT

Bug detected on build I201108051005 (2011/08/05) 

When launching a diff I get the following NPE:
java.lang.NullPointerException
	at org.eclipse.emf.compare.diff.engine.check.ReferencesCheck.checkContainmentReferenceOrderChange(ReferencesCheck.java:151)
	at org.eclipse.emf.compare.diff.engine.check.ReferencesCheck.checkReferencesUpdates(ReferencesCheck.java:80)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.checkForDiffs(GenericDiffEngine.java:336)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiffDelegate(GenericDiffEngine.java:890)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiffDelegate(GenericDiffEngine.java:913)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiffDelegate(GenericDiffEngine.java:913)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiffDelegate(GenericDiffEngine.java:913)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiffDelegate(GenericDiffEngine.java:913)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiffTwoWay(GenericDiffEngine.java:572)
	at org.eclipse.emf.compare.diff.engine.GenericDiffEngine.doDiff(GenericDiffEngine.java:110)
	at org.eclipse.emf.compare.diff.service.DiffService.doDiff(DiffService.java:102)

It appears that in org.eclipse.emf.compare.diff.engine.check.AbstractCheck.getMatchedEObject(EObject), the crossReferencer.get(from) returns null.

Comment 1 Laurent Goubet

2011-08-08 04:35:50 EDT

The cross referencer is returning null here because the object is out of the scope. Scope should be taken into account when checking for containment reference ordering.

Comment 2 Laurent Goubet

2011-08-09 04:36:00 EDT

The match, diff and merge process have seen a great deal of improvement in the past week, with the addition of unit tests for most of the different use cases (one use case = one possible "diff" between models) we could think of.

The particular issue with scope-external EObjects is one of the things that has been tested and fixed.

These changes have been pushed on both master and the 1.2 maintenance stream. They are available in the builds
 - 1.2 integration : I201108090404
 - 1.3 integration : I201108090415