Bug 220697 [Undo] Exceptions when validating a delete operation
Build ID: M20071023-1652 Steps To Reproduce: It is hard to reproduce. But it happens from time to time. From our editor, when user saves the file, we write to an IFile. We get the exception shown below. We are using File.setContents(stream, true, true, progressmonitor); So we are setting keep history to true and we are using force flag. More information: Problems occurred when invoking code from plug-in: "org.eclipse.core.resources". java.lang.NullPointerException at org.eclipse.ui.ide.undo.AbstractResourcesOperation.computeCreateStatus(AbstractResourcesOperation.java:164) at org.eclipse.ui.ide.undo.DeleteResourcesOperation.computeUndoableStatus(DeleteResourcesOperation.java:156) at org.eclipse.ui.internal.ide.undo.WorkspaceUndoMonitor.checkOperationHistory(WorkspaceUndoMonitor.java:235) at org.eclipse.ui.internal.ide.undo.WorkspaceUndoMonitor.access$4(WorkspaceUndoMonitor.java:209) at org.eclipse.ui.internal.ide.undo.WorkspaceUndoMonitor$1.resourceChanged(WorkspaceUndoMonitor.java:132) at org.eclipse.core.internal.events.NotificationManager$2.run(NotificationManager.java:282) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37) at org.eclipse.core.internal.events.NotificationManager.notify(NotificationManager.java:276) at org.eclipse.core.internal.events.NotificationManager.broadcastChanges(NotificationManager.java:148) at org.eclipse.core.internal.resources.Workspace.broadcastPostChange(Workspace.java:311) at org.eclipse.core.internal.resources.Workspace.endOperation(Workspace.java:1018) at org.eclipse.core.internal.resources.File.setContents(File.java:363) at org.eclipse.core.internal.resources.File.setContents(File.java:458) at com.fnfr.documents.helpers.DocumentHelper.writeToDocument(DocumentHelper.java:216) at com.fnfr.documents.helpers.DocumentHelper.writeToDocument(DocumentHelper.java:223) at com.fnfr.svt.ui.common.editors.FanfareFormEditor.saveDocumentToFile(FanfareFormEditor.java:979) at com.fnfr.svt.ui.common.editors.FanfareFormEditor$5.doPersistence(FanfareFormEditor.java:810) at com.fnfr.svt.ui.common.interfaces.AbstractPersistenceDelegate.persist(AbstractPersistenceDelegate.java:34) at com.fnfr.svt.ui.common.editors.FanfareFormEditor.managePersistence(FanfareFormEditor.java:935) at com.fnfr.svt.ui.common.editors.FanfareFormEditor.doSave(FanfareFormEditor.java:830) at org.eclipse.ui.internal.SaveableHelper$1.run(SaveableHelper.java:143) at org.eclipse.ui.internal.SaveableHelper$4.run(SaveableHelper.java:266) at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:369) at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:313) at org.eclipse.jface.window.ApplicationWindow$1.run(ApplicationWindow.java:758) at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:67) at org.eclipse.jface.window.ApplicationWindow.run(ApplicationWindow.java:755) at org.eclipse.ui.internal.WorkbenchWindow.run(WorkbenchWindow.java:2451) at org.eclipse.ui.internal.SaveableHelper.runProgressMonitorOperation(SaveableHelper.java:274) at org.eclipse.ui.internal.SaveableHelper.runProgressMonitorOperation(SaveableHelper.java:253) at org.eclipse.ui.internal.SaveableHelper.savePart(SaveableHelper.java:148) at org.eclipse.ui.internal.EditorManager.savePart(EditorManager.java:1345) at org.eclipse.ui.internal.WorkbenchPage.savePart(WorkbenchPage.java:3184) at org.eclipse.ui.internal.WorkbenchPage.saveEditor(WorkbenchPage.java:3197) at org.eclipse.ui.internal.SaveAction.run(SaveAction.java:73) at org.eclipse.jface.action.Action.runWithEvent(Action.java:498) at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:545) at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:490) at org.eclipse.jface.action.ActionContributionItem$6.handleEvent(ActionContributionItem.java:443) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:938) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3682) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3293) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2389) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2353) at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2219) at org.eclipse.ui.internal.Workbench$4.run(Workbench.java:466) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:289) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:461) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at com.fnfr.svt.rcp.Application.runWorkbench(Application.java:144) at com.fnfr.svt.rcp.Application.start(Application.java:132) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:153) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:106) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:76) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:363) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:176) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:504) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:443) at org.eclipse.equinox.launcher.Main.run(Main.java:1169)
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/undo/AbstractWorkspaceOperation.java
* Return whether the resources known by this operation currently exist.
	 * 
	 * @return <code>true</code> if there are existing resources and
	 *         <code>false</code> if there are no known resources or any one
	 *         of them does not exist
	 */
	protected boolean resourcesExist() {
		if (resources == null || resources.length == 0) {
			return false;
		}
		for (int i = 0; i < resources.length; i++) {
			if (!resources[i].exists()) {
				return false;
			}
		}
		return true;
	}
	/**
	 * Return whether the resources known by this operation contain any
	 * projects.
	 * 
	 * @return <code>true</code> if there is one or more projects known by
	 *         this operation and false if there are no projects.
	 */
	protected boolean resourcesIncludesProjects() {
		if (resources == null || resources.length == 0) {
			return false;
		}
		for (int i = 0; i < resources.length; i++) {
			if (resources[i].getType() == IResource.PROJECT) {