In socialist countries there were many unwritten regulations/instructions - what is allowed/verboten in politics? The law would not state that explicitly becaus

In socialist countries there were many unwritten regulations/instructions - what is allowed/verboten in politics? The law would not state that explicitly because the policy of the party could change suddenly (like with the Molotov - Ribbentrop packt) and the law is not that easily adjusted. Therefore behavior was regulated by taboos - don't say anything that is not stated by the state media, better don't say anything because politics keep changing. I wonder if secret laws are a move in the same direction.