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Bug 344605 - NPE in MergeService.merge
Summary: NPE in MergeService.merge
Status: CLOSED WORKSFORME
Alias: None
Product: EMFCompare
Classification: Modeling
Component: Core (show other bugs)
Version: unspecified   Edit
Hardware: PC Windows XP
: P3 major (vote)
Target Milestone: ---   Edit
Assignee: EMF Compare CLA
QA Contact:
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Keywords:
Depends on:
Blocks:
 
Reported: 2011-05-03 12:19 EDT by Martin Domig CLA
Modified: 2011-06-15 10:17 EDT (History)
1 user (show)

See Also:

Attachments
ecore file causing the NPE (3.14 KB, application/octet-stream)
2011-05-03 12:23 EDT, Martin Domig CLA 		no flags Details
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Description Martin Domig CLA 2011-05-03 12:19:17 EDT 
Build Identifier: 20110218-0911

After adding an EInt attribute to a model, the following code fails with a NullPointerException:

MatchModel match = MatchService.doContentMatch(newSection, section, null);
DiffModel diff = DiffService.doDiff(match, false);
MergeService.merge(diff.getOwnedElements(), true);


Stacktrace:

java.lang.NullPointerException
	at org.eclipse.emf.compare.util.EFactory.eStructuralFeature(EFactory.java:287)
	at org.eclipse.emf.compare.util.EFactory.eGet(EFactory.java:156)
	at org.eclipse.emf.compare.diff.internal.merge.impl.UpdateAttributeMerger.undoInTarget(UpdateAttributeMerger.java:58)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.doMerge(MergeService.java:166)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.merge(MergeService.java:130)
	at org.eclipse.emf.compare.diff.internal.merge.impl.DiffGroupMerger.undoInTarget(DiffGroupMerger.java:48)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.doMerge(MergeService.java:166)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.merge(MergeService.java:130)
	at org.eclipse.emf.compare.diff.internal.merge.impl.DiffGroupMerger.undoInTarget(DiffGroupMerger.java:48)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.doMerge(MergeService.java:166)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.merge(MergeService.java:130)
	at org.eclipse.emf.compare.diff.internal.merge.impl.DiffGroupMerger.undoInTarget(DiffGroupMerger.java:48)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.doMerge(MergeService.java:166)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.merge(MergeService.java:130)
	at org.eclipse.emf.compare.diff.internal.merge.impl.DiffGroupMerger.undoInTarget(DiffGroupMerger.java:48)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.doMerge(MergeService.java:166)
	at org.eclipse.emf.compare.diff.merge.service.MergeService.merge(MergeService.java:130)


Problem seems to be in UpdateAttributeMerger.undoInTarget:

final UpdateAttribute theDiff = (UpdateAttribute)this.diff;
...
final EObject origin = theDiff.getLeftElement();

origin is null here for some reason, and later dereferenced in EFactory.eGet().

Reproducible: Always

Steps to Reproduce:
Use the attached ecore model.
Create two identical section objects with a few groups and parameters.
Change one parameter in one of them.
Do the merge as described.
Comment 1 Martin Domig CLA 2011-05-03 12:23:45 EDT 
Created attachment 194607 [details]
ecore file causing the NPE

ecore file describing the model. After adding the ParameterGroup/order attribute, things went south.
Comment 2 Martin Domig CLA 2011-05-03 12:25:28 EDT 
Eclipse Version: Helios Service Release 2
EMF Compare SDK version: 1.1.2.v20110202-0936
Comment 3 Laurent Goubet CLA 2011-05-04 05:03:05 EDT 
Martin,

This cannot be reproduced from the GUI, or at least not with the example models I've created using the provided metamodel.

Do you still have this issue when you use "MatchService.doResourceSetMatch(newSection.eResource().getResourceSet(), section.eResource().getResourceSet())" instead of "doContentMatch" ?

Could you create a small unit test that would allow us to reproduce the failure?
Comment 4 Laurent Goubet CLA 2011-06-15 10:17:20 EDT 
Closing this bug as for now, will reopen if it can be reproduced.