Merge pull request #18939 from georgeclaghorn/variant-inquiry

Provide friendlier access to request variants

1 files changed, 9 insertions, 7 deletions

diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
index 53a98c5d0a..ff336b7354 100644
--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -10,8 +10,6 @@ module ActionDispatch
         self.ignore_accept_header = false
       end
 
-      attr_reader :variant
-
       # The MIME type of the HTTP request, such as Mime::XML.
       #
       # For backward compatibility, the post \format is extracted from the
@@ -75,18 +73,22 @@ module ActionDispatch
 
       # Sets the \variant for template.
       def variant=(variant)
-        if variant.is_a?(Symbol)
-          @variant = [variant]
-        elsif variant.nil? || variant.is_a?(Array) && variant.any? && variant.all?{ |v| v.is_a?(Symbol) }
-          @variant = variant
+        variant = Array(variant)
+
+        if variant.all? { |v| v.is_a?(Symbol) }
+          @variant = ActiveSupport::ArrayInquirer.new(variant)
         else
-          raise ArgumentError, "request.variant must be set to a Symbol or an Array of Symbols, not a #{variant.class}. " \
+          raise ArgumentError, "request.variant must be set to a Symbol or an Array of Symbols. " \
             "For security reasons, never directly set the variant to a user-provided value, " \
             "like params[:variant].to_sym. Check user-provided value against a whitelist first, " \
             "then set the variant: request.variant = :tablet if params[:variant] == 'tablet'"
         end
       end
 
+      def variant
+        @variant ||= ActiveSupport::ArrayInquirer.new
+      end
+
       # Sets the \format by string extension, which can be used to force custom formats
       # that are not controlled by the extension.
       #