Bug 89020 [Undo] Operation throws assertion failure if undo limit is set to 0
I20050324-0800 Unfortunately existing clients of text's undo manager were allowed to set any number without failing. This is no longer possible: an assertion failure occurrs if the limit is smaller than 1. I will add code on my side that will handle the negative numbers but the operation history must allow 0.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IOperationHistory#operationChanged(org.eclipse.core.commands.operations.IUndoableOperation)
	 */
	public void operationChanged(IUndoableOperation operation) {
		if (undoList.contains(operation) || redoList.contains(operation)) {
			notifyChanged(operation);
		}
	}
	
	/*
	 * Handle an exception that occurred while sending a notification about
	 * something happening in the operation history.  When notifications fail,
	 * execution should continue, but the exception should be logged.
	 */
	private void handleNotificationException(Throwable e) {
		if (e instanceof OperationCanceledException)
			return;
		
		
		if (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
			System.out.print("OPERATIONHISTORY >>> Exception during notification callback ");  
			System.out.print(e);
			System.out.println();
		}
		e.printStackTrace();
	}
}