From 36ff424c3b122efee47fe11b084d0bee3d974b3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89tienne=20Barri=C3=A9?= <etienne.barrie@gmail.com>
Date: Tue, 9 Apr 2024 13:47:43 +0200
Subject: [PATCH] Restore to: option with an implicit controller

The `:to` option for routes can once again be a String without a
controller if the controller is implicitly provided by a nesting
`controller` or `resources` call.
---
 actionpack/CHANGELOG.md                          | 12 ++++++++++++
 actionpack/lib/action_dispatch/routing/mapper.rb | 15 ++++++++++-----
 actionpack/test/dispatch/routing_test.rb         | 14 ++++++++++++--
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index f86b51e6393e5..98e8abb1c8177 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,3 +1,15 @@
+*   Fix a regression in 7.1.3 passing a `to:` option without a controller when the controller is already defined by a scope.
+
+    ```ruby
+    Rails.application.routes.draw do
+      controller :home do
+        get "recent", to: "recent_posts"
+      end
+    end
+    ```
+
+    *Étienne Barrié*
+
 *   Request Forgery takes relative paths into account.
 
     *Stefan Wienert*
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 724bf72e5c508..317e8886f6258 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -231,12 +231,17 @@ def normalize_options!(options, path_params, modyoule)
               if to.nil?
                 controller = default_controller
                 action = default_action
-              elsif to.is_a?(String) && to.include?("#")
-                to_endpoint = to.split("#").map!(&:-@)
-                controller  = to_endpoint[0]
-                action      = to_endpoint[1]
+              elsif to.is_a?(String)
+                if to.include?("#")
+                  to_endpoint = to.split("#").map!(&:-@)
+                  controller  = to_endpoint[0]
+                  action      = to_endpoint[1]
+                else
+                  controller = default_controller
+                  action = to
+                end
               else
-                raise ArgumentError, ":to must respond to `action` or `call`, or it must be a String that includes '#'"
+                raise ArgumentError, ":to must respond to `action` or `call`, or it must be a String that includes '#', or the controller should be implicit"
               end
 
               controller = add_controller_module(controller, modyoule)
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index 460cd1aa10c5d..7d396f0c05d15 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -4037,6 +4037,7 @@ def draw(&block)
     routes = ActionDispatch::Routing::RouteSet.new
     routes.draw(&block)
     @app = self.class.build_app routes
+    @routes = routes
   end
 
   def test_missing_controller
@@ -4054,7 +4055,16 @@ def test_missing_controller_with_to
         get "/foo/bar", to: "foo"
       end
     }
-    assert_match(/:to must respond to/, ex.message)
+    assert_match(/Missing :controller/, ex.message)
+  end
+
+  def test_implicit_controller_with_to
+    draw do
+      controller :foo do
+        get "/foo/bar", to: "bar"
+      end
+    end
+    assert_routing "/foo/bar", controller: "foo", action: "bar"
   end
 
   def test_to_is_a_symbol
@@ -4066,7 +4076,7 @@ def test_to_is_a_symbol
     assert_match(/:to must respond to/, ex.message)
   end
 
-  def test_missing_action_on_hash
+  def test_missing_action_with_to
     ex = assert_raises(ArgumentError) {
       draw do
         get "/foo/bar", to: "foo#"