Bug 94438 [Undo] - javadoc - clarify operation remaining in history for undo/redo with INFO/WARNING
The javadoc for the IOperationHistory#undo(...) redo(...) methods is very explicit about the operation remaining in the history on CANCEL and ERROR status, and that it is moved between undo/redo histories when ok. Some minor clarifications: The lack of an explicit statement about INFO and WARNING makes one wonder what happens to the operation. It remains in the history in this case also... Technically, on OK status the operation is not guaranteed to move between the stacks. If it cannot redo after undoing, or cannot undo after redoing, it won't be transferred to the other stack, but in effect will be removed from the history.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/IOperationHistory.java
* </p>
	 * <p>
	 * <code>CANCEL</code> severity indicates that the user cancelled the
	 * operation and that the operation was not added to the history.
	 * <code>ERROR</code> severity indicates that the operation did not
	 * successfully execute and that it was not added to the history. Any other
	 * severity code is not specifically interpreted by the history, and the
	 * operation will not be added to the history. For all severities other than
	 * <code>OK</code>, listeners will receive the
	 * <code>OPERATION_NOT_OK</code> notification instead of the
	 * <code>DONE</code> notification.
	 * </p>
	 * 
	 * @throws ExecutionException
	 *             if an exception occurred during execution.
	 * 
	 */
	IStatus execute(IUndoableOperation operation, IProgressMonitor monitor,
			IAdaptable info) throws ExecutionException;
	/**
	 * <p>
	 * Return the limit on the undo and redo history for a particular context.
	 * </p>
	 * 
	 * @param context
	 *            the context whose limit is requested
	 * 
	 * @return limit the undo and redo history limit for the specified context.
	 */
	int getLimit(IUndoContext context);