Add has_named_route? to the mapper API

2 files changed, 18 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index c3fd0c18ec..3c58a2cfc3 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -515,6 +515,11 @@ module ActionDispatch
           end
         end
 
+        # Query if the following named route was already defined.
+        def has_named_route?(name)
+          @set.named_routes.routes[name.to_sym]
+        end
+
         private
           def app_name(app)
             return unless app.respond_to?(:routes)
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index 5b42ca0f21..16ba746b9c 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -2662,6 +2662,19 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
     assert_raises(ArgumentError) { routes.redirect Object.new }
   end
 
+  def test_named_route_check
+    before, after = nil
+
+    draw do
+      before = has_named_route?(:hello)
+      get "/hello", as: :hello, to: "hello#world"
+      after = has_named_route?(:hello)
+    end
+
+    assert !before, "expected to not have named route :hello before route definition"
+    assert after, "expected to have named route :hello after route definition"
+  end
+
   def test_explicitly_avoiding_the_named_route
     draw do
       scope :as => "routes" do