build: ESM へ移行し @actions/tool-cache を 4.x へ更新

@actions/tool-cache 4.0.0 および @actions/core/io/exec 3.x は pure ESM
(package.json "type":"module"、exports に require エントリなし) のため、
バージョンを上げるにはプロジェクト全体を CommonJS から ESM へ移行する
必要がある。一連の移行をまとめて行う。

- package.json: "type":"module" 化、toolkit 依存を 4.x/3.x へ更新、
  src/テストで未使用の @actions/github を削除、test を
  experimental-vm-modules で起動
- tsconfig: module/moduleResolution を NodeNext、isolatedModules を有効化
- src: 相対 import に .js 拡張子を付与。NodeNext は CJS パッケージの
  サブパスにも拡張子を要求するため typed-rest-client/HttpClient を
  明示拡張子付きで import
- jest: ESM 化 (jest.config.mjs + ts-jest useESM)。ESM では jest.mock の
  巻き上げが効かないため、テストの jest.mock を jest.unstable_mockModule
  + 動的 import へ書き換え。equivalence は __dirname を import.meta.url 由来へ
- lib/ dist/ を ESM で再生成。ncc 0.38.4 も type:module を見て ESM 出力し、
  sourcemap-register を .cjs 化、dist/package.json を生成する

download/extract から /usr/local/bin・C:\SeleniumWebDrivers への配置まで
実行パスの parity は不変。lib のレガシー shell/ps1 も従来どおり残置。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: nanasess

__tests__/chromedriver-api.test.ts

@@ -5,12 +5,13 @@
  * Run with: RUN_CHROMEDRIVER_API_TESTS=1 pnpm test __tests__/chromedriver-api.test.ts
  */
 
+import { jest } from "@jest/globals";
 import {
   buildLegacyLatestReleaseUrl,
   extractDriverUrlFromJson,
   ChromeKnownGoodVersions,
   ChromeVersion,
-} from "../src/chromedriver-helper";
+} from "../src/chromedriver-helper.js";
 
 const JSON_URL =
   "https://googlechromelabs.github.io/chrome-for-testing/known-good-versions-with-downloads.json";

__tests__/chromedriver-helper.test.ts

@@ -11,7 +11,7 @@ import {
   findFallbackVersion,
   getDefaultChromePath,
   getInstallPath,
-} from "../src/chromedriver-helper";
+} from "../src/chromedriver-helper.js";
 
 // ---------------------------------------------------------------------------
 // Mock API response fixture

__tests__/equivalence.test.ts

@@ -7,6 +7,7 @@
 
 import { execSync } from "child_process";
 import * as path from "path";
+import { fileURLToPath } from "url";
 import {
   parseMajorVersion,
   parseVersion3,
@@ -19,7 +20,10 @@ import {
   getInstallPath,
   extractDriverUrlFromJson,
   findFallbackVersion,
-} from "../src/chromedriver-helper";
+} from "../src/chromedriver-helper.js";
+
+// ESM has no __dirname; derive this file's directory from import.meta.url.
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 // ---------------------------------------------------------------------------
 // Run shell script and parse output

__tests__/installer-download.test.ts

@@ -2,14 +2,23 @@
  * Unit tests for src/installer/download.ts.
  *
  * @actions/tool-cache is mocked so no real network or filesystem I/O occurs.
+ *
+ * The project is ESM, so the mock is registered with
+ * `jest.unstable_mockModule` and both the mocked module and the module under
+ * test are pulled in with dynamic `import()` *after* the mock is in place.
  */
 
-import * as tc from "@actions/tool-cache";
-import { downloadAndExtractZip } from "../src/installer/download";
+import { jest } from "@jest/globals";
+
+jest.unstable_mockModule("@actions/tool-cache", () => ({
+  downloadTool: jest.fn(),
+  extractZip: jest.fn(),
+}));
 
-jest.mock("@actions/tool-cache");
+const tc = await import("@actions/tool-cache");
+const { downloadAndExtractZip } = await import("../src/installer/download.js");
 
-const mockedTc = tc as jest.Mocked<typeof tc>;
+const mockedTc = jest.mocked(tc);
 
 describe("downloadAndExtractZip", () => {
   beforeEach(() => {

__tests__/installer-http.test.ts

@@ -13,18 +13,21 @@
  * typed-rest-client is mocked so no real network I/O occurs.
  */
 
+import { jest } from "@jest/globals";
+
 // Shared mock for the HttpClient instance method `get`. The module under test
 // constructs a single client at load time, so the constructor mock must return
-// an object backed by this shared mock.
-const mockGet = jest.fn();
+// an object backed by this shared mock. Declared before the mock factory so it
+// is captured by the closure when `await import()` evaluates http.ts.
+const mockGet = jest.fn() as jest.Mock<(url: string) => Promise<unknown>>;
 
-jest.mock("typed-rest-client/HttpClient", () => ({
+jest.unstable_mockModule("typed-rest-client/HttpClient.js", () => ({
   HttpClient: jest.fn().mockImplementation(() => ({
     get: mockGet,
   })),
 }));
 
-import { fetchText, fetchJson } from "../src/installer/http";
+const { fetchText, fetchJson } = await import("../src/installer/http.js");
 
 /**
  * Build a fake typed-rest-client response with the given status code and body.
@@ -33,7 +36,7 @@ import { fetchText, fetchJson } from "../src/installer/http";
 function makeResponse(statusCode: number, body: string) {
   return {
     message: { statusCode },
-    readBody: jest.fn().mockResolvedValue(body),
+    readBody: jest.fn(() => Promise.resolve(body)),
   };
 }
 

__tests__/installer-unix.test.ts

@@ -12,39 +12,47 @@
  *   - sudo present vs absent in the `mv` command
  */
 
-import * as exec from "@actions/exec";
-import * as io from "@actions/io";
+import { jest } from "@jest/globals";
 import * as path from "path";
-
-import { installOnUnix } from "../src/installer/unix";
-import { downloadAndExtractZip as _downloadAndExtractZip } from "../src/installer/download";
-import {
-  detectFullChromeVersion as _detectFullChromeVersion,
-  resolveLegacyVersion as _resolveLegacyVersion,
-  resolveModernDownload as _resolveModernDownload,
-} from "../src/installer/version";
-import { getInstallPath } from "../src/chromedriver-helper";
-
-jest.mock("@actions/exec");
-jest.mock("@actions/io");
-jest.mock("@actions/core");
-jest.mock("../src/installer/download");
-jest.mock("../src/installer/version");
-
-const execMock = exec.exec as jest.MockedFunction<typeof exec.exec>;
-const whichMock = io.which as jest.MockedFunction<typeof io.which>;
-const downloadAndExtractZip = _downloadAndExtractZip as jest.MockedFunction<
-  typeof _downloadAndExtractZip
->;
-const detectFullChromeVersion = _detectFullChromeVersion as jest.MockedFunction<
-  typeof _detectFullChromeVersion
->;
-const resolveLegacyVersion = _resolveLegacyVersion as jest.MockedFunction<
-  typeof _resolveLegacyVersion
->;
-const resolveModernDownload = _resolveModernDownload as jest.MockedFunction<
-  typeof _resolveModernDownload
->;
+import type { ExecOptions } from "@actions/exec";
+import { getInstallPath } from "../src/chromedriver-helper.js";
+
+jest.unstable_mockModule("@actions/exec", () => ({
+  exec: jest.fn(),
+}));
+jest.unstable_mockModule("@actions/io", () => ({
+  which: jest.fn(),
+  cp: jest.fn(),
+  mkdirP: jest.fn(),
+  mv: jest.fn(),
+}));
+jest.unstable_mockModule("@actions/core", () => ({
+  addPath: jest.fn(),
+  getInput: jest.fn(),
+  info: jest.fn(),
+  setFailed: jest.fn(),
+}));
+jest.unstable_mockModule("../src/installer/download.js", () => ({
+  downloadAndExtractZip: jest.fn(),
+}));
+jest.unstable_mockModule("../src/installer/version.js", () => ({
+  detectFullChromeVersion: jest.fn(),
+  resolveLegacyVersion: jest.fn(),
+  resolveModernDownload: jest.fn(),
+}));
+
+const exec = await import("@actions/exec");
+const io = await import("@actions/io");
+const { installOnUnix } = await import("../src/installer/unix.js");
+const downloadMod = await import("../src/installer/download.js");
+const versionMod = await import("../src/installer/version.js");
+
+const execMock = jest.mocked(exec.exec);
+const whichMock = jest.mocked(io.which);
+const downloadAndExtractZip = jest.mocked(downloadMod.downloadAndExtractZip);
+const detectFullChromeVersion = jest.mocked(versionMod.detectFullChromeVersion);
+const resolveLegacyVersion = jest.mocked(versionMod.resolveLegacyVersion);
+const resolveModernDownload = jest.mocked(versionMod.resolveModernDownload);
 
 // The install path is derived from process.platform at runtime. Compute the
 // expected value the same way the implementation does so the test is valid
@@ -70,12 +78,12 @@ function setPresentCommands(present: string[]): void {
 function execCalls(): Array<{
   command: string;
   args: string[];
-  options?: exec.ExecOptions;
+  options?: ExecOptions;
 }> {
   return execMock.mock.calls.map((call) => ({
     command: call[0],
     args: (call[1] as string[]) ?? [],
-    options: call[2] as exec.ExecOptions | undefined,
+    options: call[2] as ExecOptions | undefined,
   }));
 }
 

__tests__/installer-version.test.ts

@@ -1,19 +1,23 @@
-import * as exec from "@actions/exec";
-
-import {
-  detectFullChromeVersion,
-  resolveLegacyVersion,
-  resolveModernDownload,
-} from "../src/installer/version";
-import { fetchJson, fetchText } from "../src/installer/http";
-import { ChromeKnownGoodVersions } from "../src/chromedriver-helper";
-
-jest.mock("@actions/exec");
-jest.mock("../src/installer/http");
-
-const mockedExec = exec.exec as jest.MockedFunction<typeof exec.exec>;
-const mockedFetchJson = fetchJson as jest.MockedFunction<typeof fetchJson>;
-const mockedFetchText = fetchText as jest.MockedFunction<typeof fetchText>;
+import { jest } from "@jest/globals";
+import type { ExecOptions } from "@actions/exec";
+import type { ChromeKnownGoodVersions } from "../src/chromedriver-helper.js";
+
+jest.unstable_mockModule("@actions/exec", () => ({
+  exec: jest.fn(),
+}));
+jest.unstable_mockModule("../src/installer/http.js", () => ({
+  fetchJson: jest.fn(),
+  fetchText: jest.fn(),
+}));
+
+const exec = await import("@actions/exec");
+const { detectFullChromeVersion, resolveLegacyVersion, resolveModernDownload } =
+  await import("../src/installer/version.js");
+const { fetchJson, fetchText } = await import("../src/installer/http.js");
+
+const mockedExec = jest.mocked(exec.exec);
+const mockedFetchJson = jest.mocked(fetchJson);
+const mockedFetchText = jest.mocked(fetchText);
 
 // ---------------------------------------------------------------------------
 // Mock Chrome-for-Testing JSON fixture
@@ -59,7 +63,7 @@ const JSON_URL =
  */
 function execWithStdout(output: string): typeof mockedExec {
   return mockedExec.mockImplementation(
-    async (_cmd: string, _args?: string[], options?: exec.ExecOptions) => {
+    async (_cmd: string, _args?: string[], options?: ExecOptions) => {
       options?.listeners?.stdout?.(Buffer.from(output));
       return 0;
     },
@@ -149,7 +153,7 @@ describe("detectFullChromeVersion", () => {
 
   it("accumulates stdout emitted across multiple chunks", async () => {
     mockedExec.mockImplementation(
-      async (_cmd: string, _args?: string[], options?: exec.ExecOptions) => {
+      async (_cmd: string, _args?: string[], options?: ExecOptions) => {
         options?.listeners?.stdout?.(Buffer.from("Google Chrome "));
         options?.listeners?.stdout?.(Buffer.from("131.0.6778.204\n"));
         return 0;

__tests__/installer-windows.test.ts

@@ -13,33 +13,40 @@
  *   - the binary is installed to `C:\SeleniumWebDrivers\ChromeDriver`.
  */
 
+import { jest } from "@jest/globals";
 import * as path from "path";
 
-import * as io from "@actions/io";
-import { installOnWindows } from "../src/installer/windows";
-import { downloadAndExtractZip } from "../src/installer/download";
-import {
-  detectFullChromeVersion,
-  resolveLegacyVersion,
-  resolveModernDownload,
-} from "../src/installer/version";
-
-jest.mock("@actions/io");
-jest.mock("../src/installer/download");
-jest.mock("../src/installer/version");
-
-const mockedIo = io as jest.Mocked<typeof io>;
-const mockedDownloadAndExtractZip =
-  downloadAndExtractZip as jest.MockedFunction<typeof downloadAndExtractZip>;
-const mockedDetectFullChromeVersion =
-  detectFullChromeVersion as jest.MockedFunction<
-    typeof detectFullChromeVersion
-  >;
-const mockedResolveLegacyVersion = resolveLegacyVersion as jest.MockedFunction<
-  typeof resolveLegacyVersion
->;
-const mockedResolveModernDownload =
-  resolveModernDownload as jest.MockedFunction<typeof resolveModernDownload>;
+jest.unstable_mockModule("@actions/io", () => ({
+  which: jest.fn(),
+  cp: jest.fn(),
+  mkdirP: jest.fn(),
+  mv: jest.fn(),
+}));
+jest.unstable_mockModule("../src/installer/download.js", () => ({
+  downloadAndExtractZip: jest.fn(),
+}));
+jest.unstable_mockModule("../src/installer/version.js", () => ({
+  detectFullChromeVersion: jest.fn(),
+  resolveLegacyVersion: jest.fn(),
+  resolveModernDownload: jest.fn(),
+}));
+
+const io = await import("@actions/io");
+const { installOnWindows } = await import("../src/installer/windows.js");
+const downloadMod = await import("../src/installer/download.js");
+const versionMod = await import("../src/installer/version.js");
+
+const mockedIo = jest.mocked(io);
+const mockedDownloadAndExtractZip = jest.mocked(
+  downloadMod.downloadAndExtractZip,
+);
+const mockedDetectFullChromeVersion = jest.mocked(
+  versionMod.detectFullChromeVersion,
+);
+const mockedResolveLegacyVersion = jest.mocked(versionMod.resolveLegacyVersion);
+const mockedResolveModernDownload = jest.mocked(
+  versionMod.resolveModernDownload,
+);
 
 const INSTALL_PATH = "C:\\SeleniumWebDrivers\\ChromeDriver";
 const DEFAULT_CHROME_PATH =