Remove railties runtime dependency

Gemfile.lock

@@ -5,7 +5,6 @@ PATH
       actionpack (>= 7.0.0)
       activesupport (>= 7.0.0)
       rack
-      railties (>= 7.0.0)
 
 GEM
   remote: https://rubygems.org/

lib/propshaft.rb

@@ -10,4 +10,4 @@ module Propshaft
 require "propshaft/assembly"
 require "propshaft/errors"
 require "propshaft/helper"
-require "propshaft/railtie"
+require "propshaft/railtie" if defined?(Rails::Railtie)

lib/propshaft/assembly.rb

@@ -16,7 +16,7 @@ def initialize(config)
   end
 
   def load_path
-    @load_path ||= Propshaft::LoadPath.new(config.paths, compilers: compilers, version: config.version)
+    @load_path ||= Propshaft::LoadPath.new(config.paths, compilers: compilers, version: config.version, file_watcher: config.file_watcher)
   end
 
   def resolver
@@ -47,7 +47,7 @@ def compilers
 
   def reveal(path_type = :logical_path)
     path_type = path_type.presence_in(%i[ logical_path path ]) || raise(ArgumentError, "Unknown path_type: #{path_type}")
-    
+
     load_path.assets.collect do |asset|
       asset.send(path_type)
     end

lib/propshaft/load_path.rb

@@ -1,10 +1,21 @@
 require "propshaft/asset"
 
 class Propshaft::LoadPath
+  class NullFileWatcher # :nodoc:
+    def initialize(paths, files_to_watch, &block)
+      @block = block
+    end
+
+    def execute_if_updated
+      @block.call
+    end
+  end
+
   attr_reader :paths, :compilers, :version
 
-  def initialize(paths = [], compilers:, version: nil)
+  def initialize(paths = [], compilers:, version: nil, file_watcher: nil)
     @paths, @compilers, @version = dedup(paths), compilers, version
+    @file_watcher = file_watcher || NullFileWatcher
   end
 
   def find(asset_name)
@@ -46,7 +57,7 @@ def cache_sweeper
       files_to_watch = Array(paths).collect { |dir| [ dir.to_s, exts_to_watch ] }.to_h
       mutex = Mutex.new
 
-      Rails.application.config.file_watcher.new([], files_to_watch) do
+      @file_watcher.new([], files_to_watch) do
         mutex.synchronize do
           clear_cache
           seed_cache

lib/propshaft/railtie.rb

@@ -35,6 +35,8 @@ class Railtie < ::Rails::Railtie
       # Prioritize assets from within the application over assets of the same path from engines/gems.
       config.assets.paths.sort_by!.with_index { |path, i| [path.to_s.start_with?(Rails.root.to_s) ? 0 : 1, i] }
 
+      config.assets.file_watcher ||= app.config.file_watcher
+
       config.assets.relative_url_root ||= app.config.relative_url_root
       config.assets.output_path ||=
         Pathname.new(File.join(app.config.paths["public"].first, app.config.assets.prefix))

lib/propshaft/server.rb

@@ -47,6 +47,6 @@ def extract_path_and_digest(env)
     end
 
     def execute_cache_sweeper_if_updated
-      Rails.application.assets.load_path.cache_sweeper.execute_if_updated
+      @assembly.load_path.cache_sweeper.execute_if_updated
     end
 end

propshaft.gemspec

@@ -16,7 +16,6 @@ Gem::Specification.new do |s|
   s.required_ruby_version = ">= 2.7.0"
   s.add_dependency "actionpack", ">= 7.0.0"
   s.add_dependency "activesupport", ">= 7.0.0"
-  s.add_dependency "railties", ">= 7.0.0"
   s.add_dependency "rack"
 
   s.files = Dir["lib/**/*", "MIT-LICENSE", "Rakefile", "README.md"]