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Bug 364704

Summary: NPE after opening Compare Editor from Synchronize Perspective: at org.eclipse.team.internal.ui.synchronize.LocalResourceTypedElement.fetchAuthor(LocalResourceTypedElement.java:383)
Product: [Technology] EGit Reporter: Daniel Hiller <dhiller>
Component: CoreAssignee: Robin Stocker <robin>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: P3 CC: blizzy, ecwid.tester, matthias.sohn, remy.suen, robin
Version: 2.1   
Target Milestone: 2.3   
Hardware: Macintosh   
OS: Mac OS X - Carbon (unsup.)   
Whiteboard:

Description Daniel Hiller CLA 2011-11-24 06:20:23 EST 
Build Identifier: M20110909-1335

Error Log:

An internal error occurred during: "Updating Compare Editor".

Stacktrace:

java.lang.NullPointerException
	at org.eclipse.team.internal.ui.synchronize.LocalResourceTypedElement.fetchAuthor(LocalResourceTypedElement.java:383)
	at org.eclipse.team.internal.ui.mapping.ResourceDiffCompareInput.updateAuthorInfo(ResourceDiffCompareInput.java:357)
	at org.eclipse.team.internal.ui.mapping.ResourceCompareInputChangeNotifier.fetchAuthors(ResourceCompareInputChangeNotifier.java:327)
	at org.eclipse.team.internal.ui.mapping.ResourceCompareInputChangeNotifier$3.run(ResourceCompareInputChangeNotifier.java:321)
	at org.eclipse.team.internal.core.BackgroundEventHandler$RunnableEvent.run(BackgroundEventHandler.java:176)
	at org.eclipse.team.internal.ui.mapping.CompareInputChangeNotifier$InputChangeEventHandler.executeRunnableNow(CompareInputChangeNotifier.java:146)
	at org.eclipse.team.internal.ui.mapping.CompareInputChangeNotifier$InputChangeEventHandler.doDispatchEvents(CompareInputChangeNotifier.java:101)
	at org.eclipse.team.internal.core.BackgroundEventHandler.dispatchEvents(BackgroundEventHandler.java:394)
	at org.eclipse.team.internal.core.BackgroundEventHandler.processEvents(BackgroundEventHandler.java:374)
	at org.eclipse.team.internal.core.BackgroundEventHandler$1.run(BackgroundEventHandler.java:203)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

Session data: 


eclipse.buildId=M20110909-1335
java.version=1.6.0_26
java.vendor=Apple Inc.
BootLoader constants: OS=macosx, ARCH=x86_64, WS=cocoa, NL=de_DE


Reproducible: Always

Steps to Reproduce:
1. Make changes to a java file in workspace
2. Project > Synchronize workspace (opening Sync perspective)
3. Douzble click to open compare editor on an edited java file
Comment 1 Carsten Reckord CLA 2012-01-30 11:14:06 EST 
This also happens consistently when doing a 'Compare With->Local History' if 'Team->Show file author' preference is enabled. A simple workaround is to disable that preference.

As for the cause of the problem, the offending code in LocalResourceTypedElement reads:

		IFileRevision revision= fileHistoryProvider.getWorkspaceFileRevision(getResource());
		if (revision == null)
			return;

		// NOTE: Must not check for revision#isPropertyMissing() as this will always return true for the workspace file revision
		revision= revision.withAllProperties(monitor);

		author= revision.getAuthor();

With EGit installed, I originally get an instance of WorkspaceFileRevision from the history provider. Looking at the cause of the problem, there seem to be two issues coming together:

1. I don't know anything about the team API interna and Javadoc isn't clear here, but looking at other implementations of IFileRevision, the EGit implementations probably shouldn't just return null in withAllProperties(...)
2. the above code should probably guard against revision.withAllProperties(monitor) == null by using the original value:

		IFileRevision fullRevision = revision.withAllProperties(monitor);
		if (fullRevision != null)
				revision = fullRevision;

Searching for other occurrences of IFileRevision.withAllProperties(), this probably suffers from the same problem:
      org.eclipse.team.internal.ui.history.FileRevisionTypedElement.fetchAuthor(IProgressMonitor)
Comment 2 Maik Schreiber CLA 2012-06-11 09:16:46 EDT 
Bug #358392 looks like it could be related.

Anyway, I'm still seeing this error in EGit 2.0.0.201206090913 (with Indigo SR 2, build 20120216-1857).
Comment 3 Robin Stocker CLA 2012-10-29 16:54:30 EDT 
Fix pushed to review:

https://git.eclipse.org/r/8405
Comment 4 Matthias Sohn CLA 2012-12-24 09:02:59 EST 
merged as fbc5596c971b1194d67b5a18fd18c2dac50b89cf