Fix generated demo path hints for custom Shakapacker roots

CHANGELOG.md

@@ -28,6 +28,8 @@ After a release, run `/update-changelog` in Claude Code to analyze commits, writ
 
 - **Explicit Webpack installs now pass the resolved bundler to Shakapacker.** `rails generate react_on_rails:install --no-rspack` and `--webpack` now set `SHAKAPACKER_ASSETS_BUNDLER=webpack` before running `shakapacker:install`, so Shakapacker installs Webpack dependencies instead of falling back to its default bundler. Fixes [Issue 4108](https://github.com/shakacode/react_on_rails/issues/4108). [PR 4109](https://github.com/shakacode/react_on_rails/pull/4109) by [ihabadham](https://github.com/ihabadham).
 
+- **Generated demo paths now honor custom Shakapacker source roots.** The install generator resolves demo components, entrypoints, stylesheets, TypeScript includes, Tailwind imports, and RSC hints from the app's Shakapacker `source_path` / `source_entry_path` settings, including slash entry roots, while wrapping long source hints in the generated demo views. Fixes [Issue 4062](https://github.com/shakacode/react_on_rails/issues/4062). [PR 4130](https://github.com/shakacode/react_on_rails/pull/4130) by [justin808](https://github.com/justin808).
+
 - **Abort the in-flight SSR render when the client disconnects (Pro streaming)**: Previously, when an HTTP client disconnected (or a request timed out) mid-stream, the Node renderer kept driving the React render to completion against a consumer that was already gone — wasting CPU and, for RSC/`cache()`-wrapped data fetches, continuing to hit the app's database/APIs. The Pro streaming layer now propagates the consumer-side teardown upstream into ReactDOM's `PipeableStream.abort()`: when the renderer worker detects the client disconnect it destroys the render's output stream, which aborts the in-flight render and releases the request's RSC payload streams. Normal completion is unaffected (the abort only fires when the output is destroyed before it ends, and never when a render error closes the stream). This also establishes the precondition for React 19.2's [`cacheSignal`](https://react.dev/reference/react/cacheSignal), which React settles automatically once a render is aborted (the `cacheSignal`-specific test and docs remain a follow-up). Part of [Issue 3885](https://github.com/shakacode/react_on_rails/issues/3885). [PR 4093](https://github.com/shakacode/react_on_rails/pull/4093) by [justin808](https://github.com/justin808).
 
 #### Added

react_on_rails/lib/generators/react_on_rails/base_generator.rb

@@ -188,11 +188,46 @@ def add_hello_world_route
         route "get 'hello_world', to: 'hello_world#index'"
       end
 
+      def copy_packer_config
+        # Rails generator actions run in method definition order.
+        # Keep this before actions that call shakapacker_source_path or
+        # shakapacker_source_entry_path; those helpers memoize on first read.
+        if instance_variable_defined?(:@shakapacker_source_path) ||
+           instance_variable_defined?(:@shakapacker_source_entry_path)
+          raise Thor::Error, "copy_packer_config must run before path-dependent generator actions"
+        end
+
+        base_path = "base/base/"
+        config = "config/shakapacker.yml"
+        use_rspack = using_rspack?
+
+        if options.shakapacker_just_installed?
+          say "Replacing Shakapacker default config with React on Rails version"
+          # Shakapacker's installer just created this file from scratch (no pre-existing config).
+          # Safe to overwrite silently with RoR's version-aware template (e.g., private_output_path).
+          template("#{base_path}#{config}.tt", config, force: true)
+        else
+          say "Adding Shakapacker #{ReactOnRails::PackerUtils.shakapacker_version} config"
+          # Thor handles the conflict: prompts user interactively, or respects --force/--skip flags.
+          template("#{base_path}#{config}.tt", config)
+        end
+
+        # Configure bundler-specific settings
+        configure_rspack_in_shakapacker if use_rspack
+
+        # Always ensure precompile_hook is configured (Shakapacker 9.0+ only)
+        configure_precompile_hook_in_shakapacker
+
+        # For SSR bundles, configure Shakapacker private_output_path (9.0+ only)
+        # This keeps Shakapacker and React on Rails server bundle paths in sync.
+        configure_private_output_path_in_shakapacker
+      end
+
       def create_react_directories
         # Skip HelloWorld directory for Redux (uses HelloWorldApp) or RSC (uses HelloServer)
         return if options.redux? || use_rsc?
 
-        empty_directory("app/javascript/src/HelloWorld/ror_components")
+        empty_directory(File.join(example_component_source_directory("HelloWorld"), "ror_components"))
       end
 
       def copy_base_files
@@ -235,14 +270,15 @@ def copy_base_files
 
       def copy_js_bundle_files
         base_path = "base/base/"
-        base_files = %w[app/javascript/packs/server-bundle.js]
+        copy_file("#{base_path}app/javascript/packs/server-bundle.js",
+                  shakapacker_entrypoint_path("server-bundle.js"))
 
         # Skip HelloWorld CSS for Redux (uses HelloWorldApp) or RSC (uses HelloServer)
-        unless options.redux? || use_rsc? || use_tailwind?
-          base_files << "app/javascript/src/HelloWorld/ror_components/HelloWorld.module.css"
-        end
+        return if options.redux? || use_rsc? || use_tailwind?
 
-        base_files.each { |file| copy_file("#{base_path}#{file}", file) }
+        copy_file("#{base_path}app/javascript/src/HelloWorld/ror_components/HelloWorld.module.css",
+                  File.join(example_component_source_directory("HelloWorld"),
+                            "ror_components/HelloWorld.module.css"))
       end
 
       def copy_webpack_config
@@ -274,33 +310,7 @@ def copy_tailwind_files
 
         base_path = "base/tailwind/"
         copy_file("#{base_path}app/javascript/stylesheets/application.css",
-                  "app/javascript/stylesheets/application.css")
-      end
-
-      def copy_packer_config
-        base_path = "base/base/"
-        config = "config/shakapacker.yml"
-
-        if options.shakapacker_just_installed?
-          say "Replacing Shakapacker default config with React on Rails version"
-          # Shakapacker's installer just created this file from scratch (no pre-existing config).
-          # Safe to overwrite silently with RoR's version-aware template (e.g., private_output_path).
-          template("#{base_path}#{config}.tt", config, force: true)
-        else
-          say "Adding Shakapacker #{ReactOnRails::PackerUtils.shakapacker_version} config"
-          # Thor handles the conflict: prompts user interactively, or respects --force/--skip flags.
-          template("#{base_path}#{config}.tt", config)
-        end
-
-        # Configure bundler-specific settings
-        configure_rspack_in_shakapacker if using_rspack?
-
-        # Always ensure precompile_hook is configured (Shakapacker 9.0+ only)
-        configure_precompile_hook_in_shakapacker
-
-        # For SSR bundles, configure Shakapacker private_output_path (9.0+ only)
-        # This keeps Shakapacker and React on Rails server bundle paths in sync.
-        configure_private_output_path_in_shakapacker
+                  shakapacker_stylesheet_path("application.css"))
       end
 
       def add_base_gems_to_gemfile
@@ -686,10 +696,10 @@ def home_page_stack_badges
       end
 
       def example_source_path
-        return "app/javascript/src/HelloServer/" if use_rsc? && !options.redux?
-        return "app/javascript/src/HelloWorldApp/" if options.redux?
+        return example_component_source_path("HelloServer") if use_rsc? && !options.redux?
+        return example_component_source_path("HelloWorldApp") if options.redux?
 
-        "app/javascript/src/HelloWorld/"
+        example_component_source_path("HelloWorld")
       end
 
       def example_view_path

react_on_rails/lib/generators/react_on_rails/demo_page_config.rb

@@ -15,13 +15,13 @@ def build_hello_world_view_config(component_name:, source_path:, landing_page:,
         }
       end
 
-      def build_hello_server_view_config(landing_page:, redux_demo:)
+      def build_hello_server_view_config(landing_page:, redux_demo:, source_path:)
         {
           title: "React Server Components Demo",
           intro: "This route shows the Pro React Server Components flow: Rails streams an async server " \
                  "component response while only client islands ship JavaScript to the browser.",
           highlights: hello_server_highlights,
-          file_hints: hello_server_file_hints,
+          file_hints: hello_server_file_hints(source_path:),
           quick_links: hello_server_quick_links(landing_page:, redux_demo:),
           learning_links: hello_server_learning_links
         }
@@ -167,10 +167,10 @@ def hello_server_highlights
         ]
       end
 
-      def hello_server_file_hints
+      def hello_server_file_hints(source_path:)
         [
           {
-            path: "app/javascript/src/HelloServer/",
+            path: source_path,
             description: "Source for the generated server component example and client island."
           },
           {

react_on_rails/lib/generators/react_on_rails/generator_helper.rb

@@ -1,12 +1,17 @@
 # frozen_string_literal: true
 
 require "json"
+require "pathname"
 require_relative "shakapacker_precompile_hook_helper"
 
 # rubocop:disable Metrics/ModuleLength
 module GeneratorHelper
   include ReactOnRails::Generators::ShakapackerPrecompileHookHelper
 
+  DEFAULT_SHAKAPACKER_SOURCE_PATH = "app/javascript"
+  DEFAULT_SHAKAPACKER_SOURCE_ENTRY_PATH = "packs"
+  private_constant :DEFAULT_SHAKAPACKER_SOURCE_PATH, :DEFAULT_SHAKAPACKER_SOURCE_ENTRY_PATH
+
   def package_json
     # Lazy load package_json gem only when actually needed for dependency management
 
@@ -75,6 +80,108 @@ def component_extension(options)
     options.typescript? ? "tsx" : "jsx"
   end
 
+  def shakapacker_source_path
+    # These helpers memoize config-backed paths. Install generators must copy or
+    # overwrite config/shakapacker.yml before any path-dependent copy action runs.
+    @shakapacker_source_path ||= configured_shakapacker_relative_path("source_path", DEFAULT_SHAKAPACKER_SOURCE_PATH)
+  end
+
+  def shakapacker_source_entry_path
+    @shakapacker_source_entry_path ||= configured_shakapacker_relative_path(
+      "source_entry_path",
+      DEFAULT_SHAKAPACKER_SOURCE_ENTRY_PATH,
+      allow_root: true
+    )
+  end
+
+  def shakapacker_entrypoint_path(filename)
+    filename = filename.to_s
+    raise ArgumentError, "filename must be present" if filename.empty?
+
+    entry_dir = shakapacker_source_entry_path # "" means entrypoints live directly under source_path.
+    File.join(*[shakapacker_source_path, entry_dir, filename].reject(&:empty?))
+  end
+
+  def shakapacker_stylesheet_path(filename)
+    # "stylesheets" is a generated demo convention, not a Shakapacker config key.
+    File.join(shakapacker_source_path, "stylesheets", filename)
+  end
+
+  def relative_stylesheet_import_path(entry_path, filename: "application.css")
+    # InstallGenerator copies the final Shakapacker config before path-dependent demo files are generated.
+    safe_entry_path = safe_generator_destination_path(entry_path, default: nil)
+    raise ArgumentError, "entry_path must stay inside the generator destination" if safe_entry_path.nil?
+
+    entry_dir = Pathname.new(File.join(destination_root, safe_entry_path)).dirname
+    stylesheet = Pathname.new(File.join(destination_root, shakapacker_stylesheet_path(filename)))
+
+    stylesheet.relative_path_from(entry_dir).to_s
+  end
+
+  def example_component_source_directory(component_name)
+    File.join(shakapacker_source_path, "src", component_name)
+  end
+
+  def example_component_source_path(component_name)
+    # Trailing slash is intentional: this value is only for generated demo file hints.
+    "#{example_component_source_directory(component_name)}/"
+  end
+
+  def configured_shakapacker_relative_path(config_key, default, allow_root: false)
+    config_path = File.join(destination_root, "config/shakapacker.yml")
+    return default unless File.exist?(config_path)
+
+    config = parse_shakapacker_yml(config_path)
+    configured_path = shakapacker_path_config_value(config, config_key)
+
+    safe_generator_destination_path(configured_path, default:, allow_root:)
+  rescue Psych::SyntaxError
+    default
+  end
+
+  def shakapacker_path_config_value(config, config_key)
+    # Generators run in the development context, so prefer that section before falling back to shared defaults.
+    %w[development default].each do |section_name|
+      section = shakapacker_config_section(config, section_name)
+      value = shakapacker_config_value(section, config_key)
+      return value unless value.to_s.strip.empty?
+    end
+
+    nil
+  end
+
+  def safe_generator_destination_path(path, default:, allow_root: false)
+    candidate = path.to_s.strip
+    return default if candidate.empty?
+
+    pathname = Pathname.new(candidate).cleanpath
+    # Shakapacker uses "/" to mean entrypoints live directly under source_path.
+    return "" if allow_root && pathname.to_s == "/"
+
+    relative_path = if pathname.absolute?
+                      absolute_path_relative_to_destination(pathname)
+                    else
+                      pathname.to_s
+                    end
+
+    return default if unsafe_generator_destination_path?(relative_path)
+
+    relative_path
+  rescue ArgumentError # Pathname.new raises on null bytes in path strings.
+    default
+  end
+
+  def absolute_path_relative_to_destination(pathname)
+    destination = Pathname.new(destination_root).cleanpath
+    pathname.relative_path_from(destination).to_s
+  rescue ArgumentError
+    nil # Signals the caller to fall back to the default path.
+  end
+
+  def unsafe_generator_destination_path?(path)
+    path.nil? || path == "." || path == ".." || path.start_with?("../")
+  end
+
   # Check if a gem is present in Gemfile.lock
   # Always checks the target app's Gemfile.lock, not inherited BUNDLE_GEMFILE
   # See: https://github.com/shakacode/react_on_rails/issues/2287

react_on_rails/lib/generators/react_on_rails/install_generator.rb

@@ -234,11 +234,7 @@ def rspack_bundler_default
 
       def invoke_generators
         ensure_shakapacker_installed
-        if options.typescript?
-          install_typescript_dependencies
-          create_css_module_types
-          create_typescript_config
-        end
+        install_typescript_dependencies if options.typescript?
         # `invoke` instantiates child generators with a fresh options hash, so
         # --pretend/--force/--skip must be forwarded explicitly at each boundary.
         invoke "react_on_rails:base", [],
@@ -247,6 +243,11 @@ def invoke_generators
                  shakapacker_just_installed: shakapacker_just_installed?,
                  force: options[:force], skip: options[:skip], pretend: options[:pretend] }
 
+        if options.typescript?
+          create_css_module_types
+          create_typescript_config
+        end
+
         # Component generator logic:
         # - --rsc without --redux: Skip HelloWorld, HelloServer will be generated in setup_rsc
         # - --rsc with --redux: Generate HelloWorldApp (user explicitly wants Redux) + HelloServer
@@ -1169,9 +1170,7 @@ def create_css_module_types
 
         say "📝 Creating CSS module type definitions...", :yellow
 
-        # Ensure the types directory exists
-        FileUtils.mkdir_p("app/javascript/types")
-
+        css_module_types_path = File.join(shakapacker_source_path, "types", "css-modules.d.ts")
         css_module_types_content = <<~TS.strip
           // TypeScript definitions for CSS modules
           declare module "*.module.css" {
@@ -1190,7 +1189,7 @@ def create_css_module_types
           }
         TS
 
-        File.write("app/javascript/types/css-modules.d.ts", css_module_types_content)
+        create_file(css_module_types_path, css_module_types_content)
         say "✅ Created CSS module type definitions", :green
       end
 
@@ -1222,7 +1221,7 @@ def create_typescript_config
             "jsx" => "react-jsx"
           },
           "include" => [
-            "app/javascript/**/*"
+            File.join(shakapacker_source_path, "**/*")
           ]
         }
 

react_on_rails/lib/generators/react_on_rails/react_no_redux_generator.rb

@@ -32,22 +32,27 @@ def copy_base_files
         base_js_path = "base/base"
         tailwind_js_path = "base/tailwind"
         ext = component_extension(options)
+        component_dir = example_component_source_directory("HelloWorld")
 
         # Determine which component files to copy based on TypeScript option
         client_component =
-          "app/javascript/src/HelloWorld/ror_components/HelloWorld.client.#{ext}"
+          "#{component_dir}/ror_components/HelloWorld.client.#{ext}"
         server_component =
-          "app/javascript/src/HelloWorld/ror_components/HelloWorld.server.#{ext}"
+          "#{component_dir}/ror_components/HelloWorld.server.#{ext}"
+        client_component_template = "app/javascript/src/HelloWorld/ror_components/HelloWorld.client.#{ext}"
 
+        # Source paths are relative to this generator's templates; only
+        # destinations vary with the app's Shakapacker config.
         if use_tailwind?
-          copy_file("#{tailwind_js_path}/#{client_component}", client_component)
+          copy_file("#{tailwind_js_path}/#{client_component_template}", client_component)
         else
-          copy_file("#{base_js_path}/#{client_component}", client_component)
+          copy_file("#{base_js_path}/#{client_component_template}", client_component)
           copy_file("#{base_js_path}/app/javascript/src/HelloWorld/ror_components/HelloWorld.module.css",
-                    "app/javascript/src/HelloWorld/ror_components/HelloWorld.module.css")
+                    "#{component_dir}/ror_components/HelloWorld.module.css")
         end
 
-        copy_file("#{base_js_path}/#{server_component}", server_component)
+        copy_file("#{base_js_path}/app/javascript/src/HelloWorld/ror_components/HelloWorld.server.#{ext}",
+                  server_component)
       end
 
       def create_appropriate_templates
@@ -58,7 +63,7 @@ def create_appropriate_templates
                  "app/views/hello_world/index.html.erb",
                  build_hello_world_view_config(
                    component_name: "HelloWorld",
-                   source_path: "app/javascript/src/HelloWorld/",
+                   source_path: example_component_source_path("HelloWorld"),
                    landing_page: new_app_landing_page_available?,
                    redux: false,
                    rsc_demo: false