NoMethodError: undefined method `expire_action' for #<FormulasSweeper:0x00000004e935f0 @controller=nil>

[zedtux]

I have the same issue but in my running application (not RSpec) with rails 5.1.4.

In my controller:

class FormulasController < ApplicationController
  ...
  caches_action :index
  cache_sweeper :formulas_sweeper, only: :index

  def index
    ...
  end
end

And my Sweeper class:

class FormulasSweeper < ActionController::Caching::Sweeper
  observe Import

  def after_update(import)
    expire_action controller: 'formulas', action: 'index'
  end
end

The Sweeper is running and failing with the following error when I'm updating an Import from the Rails console, or from a Sidekiq job:

NoMethodError: undefined method `expire_action' for #<FormulasSweeper:0x00000004e935f0 @controller=nil>
	from app/sweepers/formulas_sweeper.rb:6:in `after_update'
	from (irb):2

@nnattawat's fix from rails/rails-observers#31

Updating my Sweeper as following:

class FormulasSweeper < ActionController::Caching::Sweeper
  observe Import

  def after_update(import)
    @controller ||= ActionController::Base.new
    expire_action controller: 'formulas', action: 'index'
  end
end

Makes the code fail with:

NoMethodError: undefined method `host' for nil:NilClass
	from app/sweepers/formulas_sweeper.rb:7:in `after_update'
	from (irb):2

This is due to the fact that ActionController::UrlFor.url_options is expecting a request object which is nil in my case.

[zedtux]

I finally found a way to make it working ... not perfect but working.

In my controller I set the :cache_path:

class FormulasController < ApplicationController
  ...
  caches_action :index, cache_path: 'formulas'
  cache_sweeper :formulas_sweeper, only: :index

  def index
    ...
  end
end

And then I expire the fragment myself in my Sweeper:

class FormulasSweeper < ActionController::Caching::Sweeper
  observe Import

  def after_update(import)
    ActionController::Base.new.expire_fragment('formulas')
  end
end

[zedtux]

Thank you @dgmstuart for your contributions and @Angelmmiguel for merging the PR. Does this mean this issue can be closed ?

[Angelmmiguel]

@zedtux yes, I think you can close it. The only difference with the code above is to use self.controller= instead of @controller:

self.controller ||= ActionController::Base.new

Btw, the PR was merged but the new version is not released yet.