A simple principle to understand Ruby inheritance is LIFO (Last In First Out).
- Ruby will search the object you’re calling it from
- It will search it in any included modules, starting with the last loaded module
- It will go in the superclass (technically, modules get in the inheritance hierarchy as well, but whatever)
When the method is found, the search stops.
A Note About Calling super.
The same rule applies if you use super. If you have the same method defined in both module and a parent class, the module method will be called.
Here’s a simple example:
module Test def abc puts 'abc from Module' end end class TestClassParent def abc puts 'abc from parent' end end class TestClassChild &lt; TestClassParent include Test def abc super end end TestClassChild.new.abc
Running this will result in:
abc from Module