conundrum

conundrum.rb

# How can this line throw an error?
@folder = object.respond_to?(:project_element) ? object.project_element : nil

# The error is this:
# undefined method `project_element' for #<Report::Event:0x007fbb6eb8ca78>

# Surely This should be protected, right?

# -----------------------------

# Here's the answer. `object` is an instance of Report::Template, which contains this line.

module Report
  class Template < ActiveRecord::Base
    
    belongs_to :event, foreign_key: 'report_event_id'
    delegate :project_element, :class_name, to: :event, allow_nil: true
    
    #...
    
  end
end 

# but Report::Event doesn't implement `project_element`

# Report::Template responds to `project_element` by delegating it to the related Report::Event
# Report::Event does not respond to `project_element` so it throws an error.