Bug 577126 - NPE in LazyResourceManager.shouldBeCached
Summary: NPE in LazyResourceManager.shouldBeCached
Status: RESOLVED FIXED
Alias: None
Product: Platform
Classification: Eclipse Project
Component: UI (show other bugs)
Version: 4.22   Edit
Hardware: PC Linux
: P3 normal (vote)
Target Milestone: 4.22 M3   Edit
Assignee: Andrey Loskutov CLA
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Keywords: regression
Depends on:
Blocks: 576740
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Reported: 2021-11-08 04:32 EST by Andrey Loskutov CLA
Modified: 2021-11-09 09:36 EST (History)
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Description Andrey Loskutov CLA 2021-11-08 04:32:35 EST 
We see few NPE's coming after opening/closing various wizards in our application tests.

All NPE's are looking very similar:

!ENTRY org.eclipse.jface 4 4 2021-11-06 02:36:56.471
!MESSAGE NullPointerException
!STACK 0
java.lang.NullPointerException
	at org.eclipse.jface.resource.LazyResourceManager.shouldBeCached(LazyResourceManager.java:78)
	at org.eclipse.jface.resource.LazyResourceManager.destroy(LazyResourceManager.java:114)
	at org.eclipse.jface.resource.ResourceManager.destroyImage(ResourceManager.java:224)
	at org.eclipse.jface.wizard.Wizard.dispose(Wizard.java:208)
	at org.eclipse.jface.wizard.WizardDialog.hardClose(WizardDialog.java:878)
	at org.eclipse.jface.wizard.WizardDialog.finishPressed(WizardDialog.java:840)
	at org.eclipse.jface.wizard.WizardDialog.buttonPressed(WizardDialog.java:472)
	at org.eclipse.jface.dialogs.Dialog.lambda$0(Dialog.java:619)
	at org.eclipse.swt.events.SelectionListener$1.widgetSelected(SelectionListener.java:84)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:252)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5889)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1515)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1541)

The problem is that some wizards were initialized with null descriptor (which is allowed), but on dispose that fails to release image for null descriptor in the new LazyResourceManager.destroy() code. 

Note: JFaceResources.getResources().createImageWithDefault(defaultImageDescriptor) which is called in org.eclipse.jface.wizard.Wizard.getDefaultPageImage() allows to create an image for null descriptor.

I have a patch.
Comment 1 Eclipse Genie CLA 2021-11-08 04:36:03 EST 
New Gerrit change created: https://git.eclipse.org/r/c/platform/eclipse.platform.ui/+/187498