lib/compo/parent_tracker.rb in compo-0.2.0 vs lib/compo/parent_tracker.rb in compo-0.3.0

@@ -5,16 +5,18 @@
   # Basic implementation of parent tracking as a mixin
   #
   # This implements #parent, #update_parent and #remove_parent to track the
   # current parent and ID function as instance variables.  It also implements
   # #parent, and #id in terms of the ID function.
-  #
-  # Subclasses should call #remove_parent in their #initialize methods, to
-  # set the parent and ID function to their default, empty values.
   module ParentTracker
     extend Forwardable
 
+    def initialize
+      super()
+      remove_parent
+    end
+
     # Gets this object's current ID
     #
     # @api  public
     # @example  Gets the object's parent while it has none.
     #   parent_tracker.parent
@@ -45,9 +47,12 @@
     # @example  Update this Leaf's parent and ID function.
     #   parent_tracker.update_parent(new_parent, new_id_function)
     #
     # @return [void]
     def update_parent(new_parent, new_id_function)
+      fail 'Parent cannot be nil: use #remove_parent.' if new_parent.nil?
+      fail 'ID function cannot be nil: use -> { nil }.' if new_id_function.nil?
+
       @parent = new_parent
       @id_function = new_id_function
     end
 
     # Blanks out this object's parent and ID function