Variant negotiation

Allow setting `request.variant` as an array - an order in which they will be
rendered.

For example:

  request.variant = [:tablet, :phone]

  respond_to do |format|
    format.html.none
    format.html.phone # this gets rendered
  end

1 files changed, 4 insertions, 2 deletions

diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
index c33ba201e1..b75d7ffe9d 100644
--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -68,10 +68,12 @@ module ActionDispatch
 
       # Sets the \variant for template.
       def variant=(variant)
-        if variant.is_a? Symbol
+        if variant.is_a?(Symbol)
+          @variant = [variant]
+        elsif variant.is_a?(Array)
           @variant = variant
         else
-          raise ArgumentError, "request.variant must be set to a Symbol, not a #{variant.class}. " \
+          raise ArgumentError, "request.variant must be set to a Symbol or Array, not a #{variant.class}. " \
             "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'"