[WIP] AC::Parameters is no longer inherited from Hash in Rails 5

Rails commit rails/rails@14a3bd5 began a
series of changes that might affect many apps/gems and cause subtle
bugs.

This commit is a start to Ransack adapting to these changes.

lib/ransack/helpers/form_helper.rb

@@ -79,7 +79,7 @@ def url(routing_proxy, options_for_url)
       class SortLink
         def initialize(search, attribute, args, params)
           @search         = search
-          @params         = params
+          @params         = parameters_hash(params)
           @field          = attribute.to_s
           @sort_fields    = extract_sort_fields_and_mutate_args!(args).compact
           @current_dir    = existing_sort_direction
@@ -113,6 +113,11 @@ def html_options(args)
 
         private
 
+          def parameters_hash(params)
+            return params unless params.instance_variable_defined?(:@parameters)
+            params.instance_variable_get(:@parameters)
+          end
+
           def extract_sort_fields_and_mutate_args!(args)
             return args.shift if args[0].is_a?(Array)
             [@field]
@@ -133,7 +138,7 @@ def search_and_sort_params
           end
 
           def search_params
-            @params[@search.context.search_key].presence || {}
+            parameters_hash(@params[@search.context.search_key]).presence || {}
           end
 
           def sort_params

lib/ransack/search.rb

@@ -15,6 +15,9 @@ class Search
              :translate, :to => :base
 
     def initialize(object, params = {}, options = {})
+      if params.instance_variable_defined?(:@parameters)
+        params = params.instance_variable_get :@parameters
+      end
       if params.is_a? Hash
         params = params.dup
         params.delete_if { |k, v| [*v].all?{ |i| i.blank? && i != false } }