Merge branch 'master' of github.com:rails/rails

1 files changed, 15 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch/journey/formatter.rb b/actionpack/lib/action_dispatch/journey/formatter.rb
index 992c1a9efe..177f586c0e 100644
--- a/actionpack/lib/action_dispatch/journey/formatter.rb
+++ b/actionpack/lib/action_dispatch/journey/formatter.rb
@@ -1,4 +1,5 @@
 require 'action_controller/metal/exceptions'
+require 'active_support/deprecation'
 
 module ActionDispatch
   module Journey
@@ -80,6 +81,9 @@ module ActionDispatch
           if named_routes.key?(name)
             yield named_routes[name]
           else
+            # Make sure we don't show the deprecation warning more than once
+            warned = false
+
             routes = non_recursive(cache, options)
 
             hash = routes.group_by { |_, r| r.score(options) }
@@ -88,6 +92,17 @@ module ActionDispatch
               break if score < 0
 
               hash[score].sort_by { |i, _| i }.each do |_, route|
+                if name && !warned
+                  ActiveSupport::Deprecation.warn <<-MSG.squish
+                    You are trying to generate the URL for a named route called
+                    #{name.inspect} but no such route was found. In the future,
+                    this will result in an `ActionController::UrlGenerationError`
+                    exception.
+                  MSG
+
+                  warned = true
+                end
+
                 yield route
               end
             end