stack level too deep : rails 2.3.8

Question

Getting error when trying to pass an optional argument to a rails model method. My model is like below

Class Antigen 
has_and_belongs_to_many :projects

I want to do

antigen = Antigen.first
antigen.projects(injection) 

or even

antigen.projects

Model Method to pass arguement

def projects(injection=nil)
    if injection == nil 
       return projects
    else 
       ..do something with injection and then pass projects
    end
end

Why is this not working

Answer 1

Instead of calling projects (which you have just overriden) use super:

def projects(injection=nil)
  if injection == nil 
    return super()
  else 
   ..do something with injection and then pass projects
  end
end

I would refactor it slightly to get rid of one level of abstraction:

def projects(injection=nil)
  return super() unless injection
  #..do something with injection and then pass projects
end

UPDATE:

Since you're using rails 2.3.8 super cannot be used to access association metho. Instead try:

class Model < AR::Base
  has_and_belongs_to_many :proxy_projects, class_name: 'Projects'
  private :proxy_projects

  def projects(injection=nil)
    return proxy_projects unless injection
    #..do something with injection and then pass projects
  end
end