Explain skip_before_filter workaround.

app/controllers/projects/uploads_controller.rb

 class Projects::UploadsController < Projects::ApplicationController
   layout 'project'
 
-  skip_before_filter :authenticate_user!, :reject_blocked!, :project, :repository, only: [:show]
-  before_filter :authenticate_user!, :reject_blocked!, :project, :repository, only: [:show], unless: :image?
+  # We want to skip these filters for only the `show` action if `image?` is true, 
+  # but `skip_before_filter` doesn't work with both `only` and `if`, so we accomplish the same like this.
+  skipped_filters = [:authenticate_user!, :reject_blocked!, :project, :repository]
+  skip_before_filter  *skipped_filters, only: [:show]
+  before_filter       *skipped_filters, only: [:show], unless: :image?
 
   def create
     link_to_file = ::Projects::UploadService.new(project, params[:file]).