Don't ignore constraints in redirect routes

https://github.com/rails/rails/commit/402c2af55053c2f29319091ad21fd6fa6b90ee89
introduced a regression that caused any constraints added to redirect routes
to be ignored.

Fixes #16605

3 files changed, 31 insertions, 2 deletions

diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 050ec5e649..dbb80bb901 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Fix bug where the router would ignore any constraints added to redirect
+    routes.
+
+    Fixes #16605.
+
+    *Agis Anastasopoulos*
+
 *   Allow `config.action_dispatch.trusted_proxies` to accept an IPAddr object.
 
     Example:
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index e92baa5aa7..fc28740828 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -241,8 +241,6 @@ module ActionDispatch
           end
 
           def app(blocks)
-            return to if Redirect === to
-
             if to.respond_to?(:call)
               Constraints.new(to, blocks, false)
             else
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index b8e20c52a0..d141210ad9 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -14,6 +14,12 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
     end
   end
 
+  class GrumpyRestrictor
+    def self.matches?(request)
+      false
+    end
+  end
+
   class YoutubeFavoritesRedirector
     def self.call(params, request)
       "http://www.youtube.com/watch?v=#{params[:youtube_id]}"
@@ -89,6 +95,24 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
     verify_redirect 'http://www.example.com/private/index'
   end
 
+  def test_redirect_with_failing_constraint
+    draw do
+      get 'hi', to: redirect("/foo"), constraints: ::TestRoutingMapper::GrumpyRestrictor
+    end
+
+    get '/hi'
+    assert_equal 404, status
+  end
+
+  def test_redirect_with_passing_constraint
+    draw do
+      get 'hi', to: redirect("/foo"), constraints: ->(req) { true }
+    end
+
+    get '/hi'
+    assert_equal 301, status
+  end
+
   def test_namespace_with_controller_segment
     assert_raise(ArgumentError) do
       draw do