push is_a?(Dispatcher) check in to one place

actionpack/lib/action_dispatch/journey/route.rb

@@ -16,14 +16,6 @@ def initialize(name, app, path, constraints, defaults = {})
         @app         = app
         @path        = path
 
-        # Unwrap any constraints so we can see what's inside for route generation.
-        # This allows the formatter to skip over any mounted applications or redirects
-        # that shouldn't be matched when using a url_for without a route name.
-        if app.is_a?(Routing::Mapper::Constraints)
-          app = app.app
-        end
-        @dispatcher  = app.is_a?(Routing::RouteSet::Dispatcher)
-
         @constraints = constraints
         @defaults    = defaults
         @required_defaults = nil
@@ -99,7 +91,7 @@ def glob?
       end
 
       def dispatcher?
-        @dispatcher
+        @app.dispatcher?
       end
 
       def matches?(request)

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -28,9 +28,16 @@ def initialize(app, constraints, request)
             app = app.app
           end
 
+          # Unwrap any constraints so we can see what's inside for route generation.
+          # This allows the formatter to skip over any mounted applications or redirects
+          # that shouldn't be matched when using a url_for without a route name.
+          @dispatcher  = app.is_a?(Routing::RouteSet::Dispatcher)
+
           @app, @constraints, @request = app, constraints, request
         end
 
+        def dispatcher?; @dispatcher; end
+
         def matches?(env)
           req = @request.new(env)
 

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -703,12 +703,10 @@ def recognize_path(path, environment = {})
           end
           old_params = req.path_parameters
           req.path_parameters = old_params.merge params
-          dispatcher = route.app
-          if dispatcher.matches?(env)
-            dispatcher = dispatcher.app
-          end
+          app = route.app
+          if app.matches?(env) && app.dispatcher?
+            dispatcher = app.app
 
-          if dispatcher.is_a?(Dispatcher)
             if dispatcher.controller(params, false)
               dispatcher.prepare_params!(params)
               return params

actionpack/test/journey/router_test.rb

@@ -9,6 +9,7 @@ class StubDispatcher < Routing::RouteSet::Dispatcher
         def initialize
           super({})
         end
+        def dispatcher?; true; end
       end
 
       attr_reader :routes