Bug 162655 [Undo] [IDE] - Undoing a delete should check for existence of resources to be restored
N20061027. - I deleted two projects (along with their content). I read the warning that undo delete cannot restore the content and said "OK." - Then I checked out those same projects from HEAD. - Then I selected "Undo Delete Resources." This overwrote my code with empty projects. I think that "Undo Delete Resources" should become invalid if the resources exist again, because you'll end up replacing content without keeping a backup.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/undo/AbstractCreateResourcesOperation.java
*            the resourceDescriptions describing resources to be created
	 * @param label
	 *            the label of the operation
	 */
	AbstractCreateResourcesOperation(
			ResourceDescription[] resourceDescriptions, String label) {
		super(resourceDescriptions, label);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * This implementation creates resources from the known resource
	 * descriptions.
	 * 
	 * @see org.eclipse.ui.ide.undo.AbstractWorkspaceOperation#doExecute(org.eclipse.core.runtime.IProgressMonitor,
	 *      org.eclipse.core.runtime.IAdaptable)
	 */
	protected void doExecute(IProgressMonitor monitor, IAdaptable uiInfo)
			throws CoreException {
		recreate(monitor, uiInfo);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * This implementation deletes resources.
	 * 
	 * @see org.eclipse.ui.ide.undo.AbstractWorkspaceOperation#doUndo(org.eclipse.core.runtime.IProgressMonitor,
	 *      org.eclipse.core.runtime.IAdaptable)
	 */
	protected void doUndo(IProgressMonitor monitor, IAdaptable uiInfo)