Description Paul Webster 2013-07-23 10:23:23 EDT

backport the fix to 4.2.2+

+++ This bug was initially created as a clone of Bug #404312 +++

The javadoc for HandledContributionItem.getContext() states that it should return "the closest context, or global context if none in the hierarchy", but when it its getContextForParent() method delegates to ModelServiceImpl.getContainingContext(), which delegates to ModelUtils.getContainingContext(), it simply returns null when it can't find one in the hierarchy.  This causes an NPE in HandledContributionItem.canExecuteItem(), which assumes a non-null context.  

See stack trace below:

Thread [main] (Suspended (breakpoint at line 194 in ModelUtils))	
	ModelUtils.getContainingContext(MApplicationElement) line: 194	
	ModelServiceImpl.getContainingContext(MUIElement) line: 276	
	HandledContributionItem.getContextForParent(MUIElement) line: 852	
	HandledContributionItem.getContext(MUIElement) line: 866	
	HandledContributionItem.canExecuteItem(Event) line: 822	
	HandledContributionItem.access$2(HandledContributionItem, Event) line: 817	
	HandledContributionItem$3.run() line: 216	
	SafeRunner.run(ISafeRunnable) line: 42	
	HandledContributionItem.updateItemEnablement() line: 243	
	HandledContributionItem$ToolItemUpdateTimer.run() line: 146	
	Display.runTimer(int) line: 4270	
	Display.messageProc(int, int, int, int) line: 3357	
	OS.DispatchMessageW(MSG) line: not available [native method]	
	OS.DispatchMessage(MSG) line: 2546	
	Display.readAndDispatch() line: 3756	
	PartRenderingEngine$9.run() line: 1029	
	Realm.runWithDefault(Realm, Runnable) line: 332	
	PartRenderingEngine.run(MApplicationElement, IEclipseContext) line: 923	
	E4Workbench.createAndRunUI(MApplicationElement) line: 86	
	Workbench$5.run() line: 588	
	Realm.runWithDefault(Realm, Runnable) line: 332	
	Workbench.createAndRunWorkbench(Display, WorkbenchAdvisor) line: 543	
	PlatformUI.createAndRunWorkbench(Display, WorkbenchAdvisor) line: 149	
	IDEApplication.start(IApplicationContext) line: 124	
	EclipseAppHandle.run(Object) line: 196	
	EclipseAppLauncher.runApplication(Object) line: 110	
	EclipseAppLauncher.start(Object) line: 79	
	EclipseStarter.run(Object) line: 353	
	EclipseStarter.run(String[], Runnable) line: 180	
	NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
	NativeMethodAccessorImpl.invoke(Object, Object[]) line: not available	
	DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: not available	
	Method.invoke(Object, Object...) line: not available	
	Main.invokeFramework(String[], URL[]) line: 629	
	Main.basicRun(String[]) line: 584	
	Main.run(String[]) line: 1438	
	Main.main(String[]) line: 1414