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/AbstractResourcesOperation.java
* @param descriptions
	 *            the array of resource descriptions
	 */
	protected void setResourceDescriptions(ResourceDescription[] descriptions) {
		if (descriptions == null) {
			resourceDescriptions = new ResourceDescription[0];
		} else {
			resourceDescriptions = descriptions;
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.ide.undo.AbstractWorkspaceOperation#appendDescriptiveText(java.lang.StringBuffer)
	 */
	protected void appendDescriptiveText(StringBuffer text) {
		super.appendDescriptiveText(text);
		text.append(" resourceDescriptions: "); 
		text.append(resourceDescriptions);
		text.append('\'');
	}
	/**
	 * Compute a scheduling rule for creating resources.
	 * 
	 * @return a scheduling rule appropriate for creating the resources
	 *         specified in the resource descriptions
	 */
	protected ISchedulingRule computeCreateSchedulingRule() {
		ISchedulingRule[] ruleArray = new ISchedulingRule[resourceDescriptions.length * 3];
		for (int i = 0; i < resourceDescriptions.length; i++) {