From 3dbbbb3d2ff65cc89bf0ba040a2c4a198104c15b Mon Sep 17 00:00:00 2001
From: Andrew Novoselac <andrew.novoselac@shopify.com>
Date: Thu, 25 Jul 2024 12:55:39 -0400
Subject: [PATCH] Add embedded engine initializers to spring watcher

This will allow embedded engine initializers to reload the application
when changed. Previously, the server would have to be reloaded manually.

Co-Authored-By: Gannon McGibbon <gannon.mcgibbon@shopify.com>
---
 lib/spring/application.rb       |  6 +++++-
 test/support/acceptance_test.rb | 18 ++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lib/spring/application.rb b/lib/spring/application.rb
index 6fdbbb3a..92477903 100644
--- a/lib/spring/application.rb
+++ b/lib/spring/application.rb
@@ -123,7 +123,11 @@ def preload
       watcher.add Spring.gemfile, Spring.gemfile_lock
 
       if defined?(Rails) && Rails.application
-        watcher.add Rails.application.paths["config/initializers"]
+        Rails::Engine.descendants.each do |engine|
+          if engine.root.to_s.start_with?(Rails.root.to_s)
+            watcher.add engine.paths["config/initializers"]
+          end
+        end
         watcher.add Rails.application.paths["config/database"]
         if secrets_path = Rails.application.paths["config/secrets"]
           watcher.add secrets_path
diff --git a/test/support/acceptance_test.rb b/test/support/acceptance_test.rb
index af2acc31..693cfc3b 100644
--- a/test/support/acceptance_test.rb
+++ b/test/support/acceptance_test.rb
@@ -715,6 +715,24 @@ def exec_name
       test "rails db:system:change" do
         assert_success "bin/rails db:system:change --to=sqlite3"
       end
+
+      test "watches embedded engine initializers" do
+        File.write(app.path("engine/lib/my_engine.rb"), <<~RUBY)
+          require "rails/engine"
+
+          class MyEngine < Rails::Engine
+          end
+        RUBY
+        File.write(app.path("engine/config/initializers/first.rb"), "")
+
+        assert_success app.spring_test_command
+
+        File.write(app.path("engine/config/initializers/second.rb"), "")
+
+        app.await_reload
+
+        assert_success app.spring_test_command
+      end
     end
   end
 end