After updating ruby-3.2.2 and using pundit-2.1 version, Getting error: Invalid constructor<> is called

[pragya-sriharsh]

Recently i tried with ruby 3.0.0 & ruby-3.2.2 and using pundit-2.1 version. It gives me an error on this line

authorize :home

After refreshing two times, it is working fine and didn't get error again. After clearing browser cache then error comes again. It's weird.

Any comment on this?

I have tried with the new version of pundit - 2.3.0 and got same error. You have changed the authorize , policy & policy_scope! method in the 2.3.0 version. Can you guide me what will be write in place of authorize :home ? because i am getting the same error: Invalid constructor.

[Burgestrand]

I tried, but I can't find a way to reproduce your error. You need to provide some more information. A detailed backtrace would provide more clues, since the InvalidConstructorError is raised from an underlying ArgumentError. The backtrace of the cause might show us what's actually happening.

Absolute best would be if you could provide a small example we can run ourselves that shows your error.

From the context you've provided, I'm thinking:

• The code called by authorize that raises this error is here. From this code I would expect the policy class name to be present in the error.

  pundit/lib/pundit.rb

  Lines 152 to 157 in 16554a5

  	def policy!(user, record)
  	policy = PolicyFinder.new(record).policy!
  	policy.new(user, pundit_model(record))
  	rescue ArgumentError
  	raise InvalidConstructorError, "Invalid #<#{policy}> constructor is called"
  	end

• I would expect the error to at the very least be Invalid #<HomePolicy> constructor is called, but your policy class doesn't render its' name as a string so we can't tell which policy is actually being used.
• nil.to_s does render an empty string, but considering PolicyFinder#policy! didn't raise an error it's unlikely that policy is nil here.
• it's also unlikely that policy is nil because nil.new(user, pundit_model(record)) doesn't raise an ArgumentError, it raises a NoMethodError

[pragya-sriharsh]

Previously i was using ruby version 2.7.6, So everything was working fine. After updating the ruby version 3.0.0, i am facing this issue. I am trying to find out what is the root cause.

In terminal, i can see only few lines of backtrace(see screenshot)

May be you can get the following error by configuring these settings:

ruby3.0.0 version
rails 6.1.7.3 version
pundit 2.1 version

Create HomeController and Create HomePolicy

class HomeController < ApplicationController
  def index
    authorize :home
  end
end

class HomePolicy < ApplicationPolicy
  def index?
    true
  end
end

If we can modify in other way to make it work then i am open. Let me know if you want anything or we can connect.

[Burgestrand]

I'm sorry, I don't think I can help you with that information.

I would advise you to figure out why the Invalid #<> constructor is called has an empty class name in it. Something is amiss there.

The Pundit source code is relatively small. There's not a lot to dig through.

I tried to replicate the code you sent in a full example, but it runs just fine with no errors. It took too long trying to figure out how to bootstrap Rails in this tiny example.

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  ruby "3.2.2"

  gem "pundit", "2.1.0"
end

class ApplicationController
  include Pundit

  def current_user = "Not actual User"
end

class HomeController < ApplicationController
  def index
    authorize :home

    "Works fine!"
  end

  private

  # Rails sets this. Pundit uses it to find the query method.
  def action_name = :index
end

class ApplicationPolicy
  def initialize(user, record)
    @user = user
    @record = record
  end
end

class HomePolicy < ApplicationPolicy
  def index? = true
end

controller = HomeController.new
puts controller.index # => "Works fine!"

[pragya-sriharsh]

Its a misleading error. Problem was in delegation method in ruby 3.0. Thanks for your support. Appreciate for that!