[codex] Fix ESM-safe config helper binstubs

CHANGELOG.md

@@ -48,6 +48,7 @@
 - **Detected single-dot (`./...`) local-path declarations in `NodePackageVersion#find_version`**. [PR #1106](https://github.com/shakacode/shakapacker/pull/1106) by [justin808](https://github.com/justin808). Extended `LOCAL_PATH_REGEX` to treat `./vendor/shakapacker`-style declarations as local-path installs (alongside the `../` and `file:` patterns added in [#1086](https://github.com/shakacode/shakapacker/pull/1086)), so version checks short-circuit before consulting potentially stale lockfile semvers. Fixes [#1103](https://github.com/shakacode/shakapacker/issues/1103).
 - **Fix rspack setup not reusing certain shared webpack-rspack config settings**. [PR #1085](https://github.com/shakacode/shakapacker/pull/1085) by [brunodccarvalho](https://github.com/brunodccarvalho). Default config changes include `optimization.splitChunks.chunks="all"`, `optimization.runtimeChunk="single"`, the webpack compression plugin in production, and the removal of minimization plugins in development. Fixes [#984](https://github.com/shakacode/shakapacker/issues/984).
 - **Fixed Rspack Sass rule blocking `sass-embedded` users by requiring the `sass` package**. [PR #1105](https://github.com/shakacode/shakapacker/pull/1105) by [justin808](https://github.com/justin808). Rspack Sass detection now only checks for `sass-loader`; the implementation (`sass`, `sass-embedded`, etc.) is resolved by the loader at build time, matching the webpack code path.
+- **Fixed `bin/shakapacker-config` and `bin/diff-bundler-config` in ESM apps**. [PR #1104](https://github.com/shakacode/shakapacker/pull/1104) by [justin808](https://github.com/justin808). Apps with `"type": "module"` in `package.json` failed to run the JavaScript binstubs because Node parsed them as ESM. The binstubs are now Ruby wrappers that locate Node and invoke `.cjs` package scripts shipped inside `node_modules/shakapacker/package/bin/`. Existing apps with the old JavaScript binstubs should re-run `bundle exec rake shakapacker:binstubs` to install the new Ruby wrappers.
 
 ## [v10.0.0] - April 8, 2026
 

lib/install/bin/diff-bundler-config

@@ -1,64 +1,45 @@
-#!/usr/bin/env node
-
-const { createRequire } = require("module")
-
-const PACK_CONFIG_DIFF_PACKAGE = "pack-config-diff"
-
-function formatError(error) {
-  return error instanceof Error ? error.message : String(error)
-}
-
-function exitWithCode(exitCode) {
-  if (!Number.isInteger(exitCode)) {
-    console.error(
-      `[Shakapacker] ${PACK_CONFIG_DIFF_PACKAGE} returned a non-integer exit code: ${String(exitCode)}`
-    )
-    process.exit(2)
-  }
-
-  // Forward only pack-config-diff's documented exit codes (0 = no diffs, 1 = diffs found).
-  // Any other code is a tool failure — normalize to 2.
-  process.exit(exitCode <= 1 ? exitCode : 2)
-}
-
-let run
-
-try {
-  // Resolve pack-config-diff via shakapacker's dependency tree so strict package
-  // managers (pnpm, Yarn PnP) can find the transitive dependency.
-  const shakapackerRequire = createRequire(
-    require.resolve("shakapacker/package.json")
-  )
-  const loadedModule = shakapackerRequire("pack-config-diff")
-  run = loadedModule.run
-} catch (error) {
-  console.error(
-    `[Shakapacker] Failed to load ${PACK_CONFIG_DIFF_PACKAGE}: ${formatError(error)}`
-  )
-  process.exit(2)
-}
-
-if (typeof run !== "function") {
-  console.error(
-    `[Shakapacker] ${PACK_CONFIG_DIFF_PACKAGE} did not export a run() function`
-  )
-  process.exit(2)
-}
-
-try {
-  const runResult = run(process.argv.slice(2))
-
-  if (runResult && typeof runResult.then === "function") {
-    runResult
-      .then((exitCode) => exitWithCode(exitCode))
-      .catch((error) => {
-        console.error(formatError(error))
-        process.exit(2)
-      })
-  } else {
-    exitWithCode(runResult)
-  }
-} catch (error) {
-  console.error(formatError(error))
-  process.exit(2)
-}
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# Keep in sync with lib/install/bin/shakapacker-config and the template in
+# package/configExporter/cli.ts (createBinStub).
+def shakapacker_app_root
+  candidate = File.expand_path("..", __dir__)
+  return candidate if File.exist?(File.join(candidate, "Gemfile"))
+
+  warn "[Shakapacker] No Gemfile found at #{candidate.inspect}; " \
+       "falling back to the current directory (#{Dir.pwd.inspect})."
+  Dir.pwd
+end
+
+def shakapacker_node_binary
+  node_bin = "node"
+  return node_bin if system(node_bin, "--version", out: File::NULL, err: File::NULL)
+
+  warn "[Shakapacker] Could not find Node.js executable #{node_bin.inspect}. " \
+       "Install Node.js and try again."
+  exit 1
+end
+
+ENV["RAILS_ENV"] ||= ENV["RACK_ENV"] || "development"
+ENV["NODE_ENV"] ||= "development"
+
+app_root = shakapacker_app_root
+node_bin = shakapacker_node_binary
+script_path = File.join(
+  app_root,
+  "node_modules",
+  "shakapacker",
+  "package",
+  "bin",
+  "diff-bundler-config.cjs"
+)
+
+unless File.file?(script_path)
+  warn "[Shakapacker] Could not find #{script_path}. Run your package manager install command and try again."
+  exit 1
+end
+
+Dir.chdir(app_root) do
+  exec node_bin, script_path, *ARGV
+end

lib/install/bin/shakapacker-config

@@ -1,11 +1,45 @@
-#!/usr/bin/env node
+#!/usr/bin/env ruby
+# frozen_string_literal: true
 
-// Minimal shim - all logic is in the TypeScript module
-const { run } = require("shakapacker/configExporter")
+# Keep in sync with lib/install/bin/diff-bundler-config and the template in
+# package/configExporter/cli.ts (createBinStub).
+def shakapacker_app_root
+  candidate = File.expand_path("..", __dir__)
+  return candidate if File.exist?(File.join(candidate, "Gemfile"))
 
-run(process.argv.slice(2))
-  .then((exitCode) => process.exit(exitCode))
-  .catch((error) => {
-    console.error(error.message)
-    process.exit(1)
-  })
+  warn "[Shakapacker] No Gemfile found at #{candidate.inspect}; " \
+       "falling back to the current directory (#{Dir.pwd.inspect})."
+  Dir.pwd
+end
+
+def shakapacker_node_binary
+  node_bin = "node"
+  return node_bin if system(node_bin, "--version", out: File::NULL, err: File::NULL)
+
+  warn "[Shakapacker] Could not find Node.js executable #{node_bin.inspect}. " \
+       "Install Node.js and try again."
+  exit 1
+end
+
+ENV["RAILS_ENV"] ||= ENV["RACK_ENV"] || "development"
+ENV["NODE_ENV"] ||= "development"
+
+app_root = shakapacker_app_root
+node_bin = shakapacker_node_binary
+script_path = File.join(
+  app_root,
+  "node_modules",
+  "shakapacker",
+  "package",
+  "bin",
+  "shakapacker-config.cjs"
+)
+
+unless File.file?(script_path)
+  warn "[Shakapacker] Could not find #{script_path}. Run your package manager install command and try again."
+  exit 1
+end
+
+Dir.chdir(app_root) do
+  exec node_bin, script_path, *ARGV
+end

lib/tasks/shakapacker/export_bundler_config.rake

@@ -54,14 +54,14 @@ namespace :shakapacker do
       $stderr.puts ""
 
       Dir.chdir(Rails.root) do
-        exec("node", gem_bin_path, *ARGV[1..])
+        exec(RbConfig.ruby, gem_bin_path, *ARGV[1..])
       end
     else
-      # Pass through command-line arguments after the task name
-      # Use exec to replace the rake process with the export script
-      # This ensures proper exit codes and signal handling
+      # Pass through command-line arguments after the task name.
+      # Invoke with RbConfig.ruby so the binstub runs under the same Ruby as Rake
+      # (avoids version-manager/shebang mismatches and works on Windows).
       Dir.chdir(Rails.root) do
-        exec(bin_path.to_s, *ARGV[1..])
+        exec(RbConfig.ruby, bin_path.to_s, *ARGV[1..])
       end
     end
   end

package.json

@@ -27,6 +27,10 @@
     "./package/config": "./package/config.js",
     "./package/*": "./package/*"
   },
+  "bin": {
+    "shakapacker-config": "package/bin/shakapacker-config.cjs",
+    "diff-bundler-config": "package/bin/diff-bundler-config.cjs"
+  },
   "files": [
     "package",
     "lib/install/config/shakapacker.yml"

package/bin/diff-bundler-config.cjs

@@ -0,0 +1,67 @@
+#!/usr/bin/env node
+
+const { createRequire } = require("module")
+
+const PACK_CONFIG_DIFF_PACKAGE = "pack-config-diff"
+
+function formatError(error) {
+  return error instanceof Error ? error.message : String(error)
+}
+
+function exitWithCode(exitCode) {
+  if (!Number.isInteger(exitCode)) {
+    console.error(
+      `[Shakapacker] ${PACK_CONFIG_DIFF_PACKAGE} returned a non-integer exit code: ${String(exitCode)}`
+    )
+    process.exit(2)
+  }
+
+  // Forward only pack-config-diff's documented exit codes (0 = no diffs, 1 = diffs found).
+  // Any other code is a tool failure; normalize to 2.
+  process.exit(exitCode <= 1 ? exitCode : 2)
+}
+
+let run
+
+try {
+  // Anchor createRequire at __filename: this file lives inside
+  // node_modules/shakapacker/package/bin/, so resolution starts from
+  // Shakapacker's own dependency subtree. That is what strict package
+  // managers (pnpm, Yarn PnP) require to find pack-config-diff as
+  // Shakapacker's transitive dependency. Do not "simplify" this to
+  // createRequire(__dirname) or to a path computed by hand — __filename
+  // is the canonical anchor that keeps virtual-store layouts working.
+  const shakapackerRequire = createRequire(__filename)
+  const loadedModule = shakapackerRequire(PACK_CONFIG_DIFF_PACKAGE)
+  run = loadedModule.run
+} catch (error) {
+  console.error(
+    `[Shakapacker] Failed to load ${PACK_CONFIG_DIFF_PACKAGE}: ${formatError(error)}`
+  )
+  process.exit(2)
+}
+
+if (typeof run !== "function") {
+  console.error(
+    `[Shakapacker] ${PACK_CONFIG_DIFF_PACKAGE} did not export a run() function`
+  )
+  process.exit(2)
+}
+
+try {
+  const runResult = run(process.argv.slice(2))
+
+  if (runResult && typeof runResult.then === "function") {
+    runResult
+      .then((exitCode) => exitWithCode(exitCode))
+      .catch((error) => {
+        console.error(formatError(error))
+        process.exit(2)
+      })
+  } else {
+    exitWithCode(runResult)
+  }
+} catch (error) {
+  console.error(formatError(error))
+  process.exit(2)
+}

package/bin/shakapacker-config.cjs

@@ -0,0 +1,10 @@
+#!/usr/bin/env node
+
+const { run } = require("../configExporter")
+
+run(process.argv.slice(2))
+  .then((exitCode) => process.exit(exitCode))
+  .catch((error) => {
+    console.error(error.message)
+    process.exit(1)
+  })

package/configExporter/cli.ts

@@ -512,6 +512,7 @@ function runInitCommand(options: ExportOptions): number {
 
 function createBinStub(binStubPath: string): void {
   const binDir = dirname(binStubPath)
+  const packageScript = `${basename(binStubPath)}.cjs`
   const { mkdirSync, chmodSync } = require("fs")
 
   // Ensure bin directory exists
@@ -522,28 +523,60 @@ function createBinStub(binStubPath: string): void {
   const stubContent = `#!/usr/bin/env ruby
 # frozen_string_literal: true
 
+# Keep in sync with lib/install/bin/shakapacker-config and
+# lib/install/bin/diff-bundler-config; update all three when changing helpers.
+def shakapacker_app_root
+  candidate = File.expand_path("..", __dir__)
+  return candidate if File.exist?(File.join(candidate, "Gemfile"))
+
+  warn "[Shakapacker] No Gemfile found at #{candidate.inspect}; " \\
+       "falling back to the current directory (#{Dir.pwd.inspect})."
+  Dir.pwd
+end
+
+def shakapacker_node_binary
+  node_bin = "node"
+  return node_bin if system(node_bin, "--version", out: File::NULL, err: File::NULL)
+
+  warn "[Shakapacker] Could not find Node.js executable #{node_bin.inspect}. " \\
+       "Install Node.js and try again."
+  exit 1
+end
+
 ENV["RAILS_ENV"] ||= ENV["RACK_ENV"] || "development"
 ENV["NODE_ENV"] ||= "development"
 
-require "pathname"
-ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
-  Pathname.new(__FILE__).realpath)
-
-require "bundler/setup"
+app_root = shakapacker_app_root
+node_bin = shakapacker_node_binary
+script_path = File.join(
+  app_root,
+  "node_modules",
+  "shakapacker",
+  "package",
+  "bin",
+  "${packageScript}"
+)
+
+unless File.file?(script_path)
+  warn "[Shakapacker] Could not find #{script_path}. Run your package manager install command and try again."
+  exit 1
+end
 
-APP_ROOT = File.expand_path("..", __dir__)
-Dir.chdir(APP_ROOT) do
-  exec "node", "./node_modules/.bin/shakapacker-config", *ARGV
+Dir.chdir(app_root) do
+  exec node_bin, script_path, *ARGV
 end
 `
 
   writeFileSync(binStubPath, stubContent, { mode: 0o755 })
 
-  // Make executable
+  // writeFileSync's mode is filtered by the process umask (e.g. umask 077
+  // strips the execute bit). chmodSync ensures the file is actually 0o755
+  // regardless of umask. It can throw on filesystems that don't support
+  // permission bits (Windows/FAT), so the try/catch is intentional.
   try {
     chmodSync(binStubPath, 0o755)
   } catch (_e) {
-    // chmod might fail on some systems, but mode in writeFileSync should handle it
+    // ignore - file was created with executable mode on supporting filesystems
   }
 }