Communists are socialist who mean it.
Another article that I believe is worthwhile reading:
An article on Democratic Socialism
At the bottom of the article, there is a section on differences between communism and democrat socialism.
By definition, Putin could be considered a democrat socialist.
Also, without a doubt, Hugo Chavez was, and Nicolás Maduro is, a democrat socialist.
By definition, a communist will overthrow the government by revolution to implement socialism...an act of treason. This is why Bernie, and closet communists, will not label themselves as "communists".