I can't imagine that they changed the method from public to protected, but perhaps they did. Try using the recommended build 1230 (it's what I used for my test example). If that works, then the problem is Forge changed the method visibility, and you'll have to put it inside your block class.

public class YourBlock extends Block {
public YourBlock() {
super(Material.rock);
setBlockTextureName("stone");
}
}

 

If it still doesn't work using the recommended build, then the problem is somehow with your workspace, in which case you should re-run 'gradlew --refresh-dependencies setupDecompWorkspace'.

 

 

How would one change the SRC that they are using?

So I switched versions and it seems that I am now able to define the .setBlockTextureName method now, thank you for your sage advice, or methods of change, rather.