Merge pull request rails#45719 from bensheldon/subpath_engine_route_helpers

Allow Mounted Engine url_helpers to use config.relative_url_root

Author: jonathanhefner

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -652,7 +652,7 @@ def define_generate_prefix(app, name)
 
             script_namer = ->(options) do
               prefix_options = options.slice(*_route.segment_keys)
-              prefix_options[:relative_url_root] = ""
+              prefix_options[:script_name] = "" if options[:original_script_name]
 
               if options[:_recall]
                 prefix_options.reverse_merge!(options[:_recall].slice(*_route.segment_keys))

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -779,18 +779,14 @@ def generate(route_name, options, recall = {}, method_name = nil)
 
       RESERVED_OPTIONS = [:host, :protocol, :port, :subdomain, :domain, :tld_length,
                           :trailing_slash, :anchor, :params, :only_path, :script_name,
-                          :original_script_name, :relative_url_root]
+                          :original_script_name]
 
       def optimize_routes_generation?
         default_url_options.empty?
       end
 
       def find_script_name(options)
-        options.delete(:script_name) || find_relative_url_root(options) || ""
-      end
-
-      def find_relative_url_root(options)
-        options.delete(:relative_url_root) || relative_url_root
+        options.delete(:script_name) || relative_url_root || ""
       end
 
       def path_for(options, route_name = nil, reserved = RESERVED_OPTIONS)

railties/test/railties/engine_test.rb

@@ -1511,7 +1511,11 @@ class Engine < ::Rails::Engine
       app_file "app/controllers/bar_controller.rb", <<-RUBY
         class BarController < ApplicationController
           def index
-            render plain: bukkits.bukkit_path
+            text = <<~TEXT
+              bukkits.bukkit_path: \#{bukkits.bukkit_path}
+              Bukkits::Engine.routes.url_helpers.bukkit_path: \#{Bukkits::Engine.routes.url_helpers.bukkit_path}
+            TEXT
+            render plain: text
           end
         end
       RUBY
@@ -1532,18 +1536,32 @@ def index
       @plugin.write "app/controllers/bukkits/bukkit_controller.rb", <<-RUBY
         class Bukkits::BukkitController < ActionController::Base
           def index
-            render plain: main_app.bar_path
+            text = <<~TEXT
+              main_app.bar_path: \#{main_app.bar_path}
+              Rails.application.routes.url_helpers.bar_path: \#{Rails.application.routes.url_helpers.bar_path}
+            TEXT
+            render plain: text
           end
         end
       RUBY
 
       boot_rails
 
+      expected = <<~TEXT
+        main_app.bar_path: /foo/bar
+        Rails.application.routes.url_helpers.bar_path: /foo/bar
+      TEXT
       get("/bukkits/bukkit", {}, { "SCRIPT_NAME" => "/foo" })
-      assert_equal "/foo/bar", last_response.body
+      assert_equal expected,
+                   last_response.body
 
+      expected = <<~TEXT
+        bukkits.bukkit_path: /foo/bukkits/bukkit
+        Bukkits::Engine.routes.url_helpers.bukkit_path: /foo/bukkits/bukkit
+      TEXT
       get("/bar", {}, { "SCRIPT_NAME" => "/foo" })
-      assert_equal "/foo/bukkits/bukkit", last_response.body
+      assert_equal expected,
+                   last_response.body
     end
 
     test "isolated engine can be mounted under multiple static locations" do