Undefined method `reason' for #<Pundit::NotAuthorizedError> in Pundit 2.1.0

[Ashutoshkushwaha]

An object of Pundit::NotAuthorizedError class raises an undefined method reason error when the method .reason is called. This expectation was raised when I was accessing exception.reason after rescuing NotAuthorizedError.

In the console, I reproduced it by running

a = Pundit::NotAuthorizedError.new
a.reason

Pundit Version: 2.1.0
Rails Version: 6.0.2.2

[libin0120]

I believe this feature is not released yet, it is only in the master branch.

[Ashutoshkushwaha]

When this feature is expected to release?

[rlue]

I am actually hoping that this feature is not released, as I have prepared an alternative approach in PR #655.

In fact, if you could have a look and let me know what you think of it, I'd really appreciate it. (If you like it, it might help persuade the maintainers to merge it.) 😉

[brightchimp]

I agree with @rlue. I don't think raising exceptions in policies is a good pattern and #655 looks better. With that said, this workaround might be useful if:

• You want the behaviour that :reason supports (multiple error messages from the same policy method).
• You want to use a tagged release of Pundit, not master.
• You're OK with raising errors in policies until a solution is finalised.

I think this workaround is unsatisfactory for a couple of reasons:

• It still raises exceptions in policies, but this is the pattern that :reason would require anyway.
• It uses error_message to place an I18n key, which is not expected.

With those caveats, you can achieve the desired behaviour with something like this...

# ApplicationController
rescue_from Pundit::NotAuthorizedError do |exception|
  # Attempt to get custom message from Pundit error locale files.
  message = t(exception.message, scope: ["pundit","errors"], default: :default)
  if message == t("default", scope: ["pundit","errors"])
    # We have not specified a defined key in the I18n error scope.
    # Either set your own default or use the custom errors from locales
    # https://github.com/varvet/pundit#creating-custom-error-messages
    message = "You're not allowed to do this."
  end

  flash[:error] = message
  redirect_to(request.referrer || root_path)
end

# config/locales/pundit/errors.en.yml (better organisation)
# or
# config/locales/pundit.en.yml (if you just want it to try it out)
en:
  pundit:
    errors:
      # default is not used other that to check if a specific error was found.
      default: "magic_undefined_string"
      account:
        reached_max: "You've reached the maximum."
        is_locked: "This account is locked."

# AccountPolicy
def update?
  if maximum_reached?
    raise Pundit::NotAuthorizedError, message: "account.reached_max"
  elsif is_locked?
    raise Pundit::NotAuthorizedError, message: "account.is_locked"
  end
  return false if any_other_reason?
end

[Burgestrand]

The feature this issue is referring to has been reverted, see #684 for more information.