Breaking: drop Node.js 8 support (refs eslint/rfcs#44)

.github/workflows/ci.yml

@@ -26,20 +26,16 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        node: [13.x, 12.x, 10.x, 8.x, "8.10.0"]
+        node: [13.x, 12.x, 10.x, "10.12.0"]
         exclude:
         - os: windows-latest
-          node: "8.10.0"
-        - os: windows-latest
-          node: 8.x
+          node: "10.12.0"
         - os: windows-latest
           node: 10.x
         - os: windows-latest
           node: 13.x
         - os: macOS-latest
-          node: "8.10.0"
-        - os: macOS-latest
-          node: 8.x
+          node: "10.12.0"
         - os: macOS-latest
           node: 10.x
         - os: macOS-latest

README.md

@@ -39,7 +39,7 @@ ESLint is a tool for identifying and reporting on patterns found in ECMAScript/J
 
 ## <a name="installation-and-usage"></a>Installation and Usage
 
-Prerequisites: [Node.js](https://nodejs.org/) (`^8.10.0`, `^10.13.0`, or `>=11.10.1`) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)
+Prerequisites: [Node.js](https://nodejs.org/) (`^10.12.0`, or `>=12.0.0`) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)
 
 You can install ESLint using npm:
 

docs/user-guide/getting-started.md

@@ -8,7 +8,7 @@ ESLint is a tool for identifying and reporting on patterns found in ECMAScript/J
 
 ## Installation and Usage
 
-Prerequisites: [Node.js](https://nodejs.org/en/) (`^8.10.0`, `^10.13.0`, or `>=11.10.1`) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)
+Prerequisites: [Node.js](https://nodejs.org/en/) (`^10.12.0`, or `>=12.0.0`) built with SSL support. (If you are using an official Node.js distribution, SSL is always built in.)
 
 You can install ESLint using npm or yarn:
 

lib/cli-engine/file-enumerator.js

@@ -127,12 +127,12 @@ function statSafeSync(filePath) {
 /**
  * Get filenames in a given path to a directory.
  * @param {string} directoryPath The path to target directory.
- * @returns {string[]} The filenames.
+ * @returns {import("fs").Dirent[]} The filenames.
  * @private
  */
 function readdirSafeSync(directoryPath) {
     try {
-        return fs.readdirSync(directoryPath);
+        return fs.readdirSync(directoryPath, { withFileTypes: true });
     } catch (error) {
         /* istanbul ignore next */
         if (error.code !== "ENOENT") {
@@ -386,12 +386,11 @@ class FileEnumerator {
         let config = null;
 
         // Enumerate the files of this directory.
-        for (const filename of readdirSafeSync(directoryPath)) {
-            const filePath = path.join(directoryPath, filename);
-            const stat = statSafeSync(filePath); // TODO: Use `withFileTypes` in the future.
+        for (const entry of readdirSafeSync(directoryPath)) {
+            const filePath = path.join(directoryPath, entry.name);
 
             // Check if the file is matched.
-            if (stat && stat.isFile()) {
+            if (entry.isFile()) {
                 if (!config) {
                     config = configArrayFactory.getConfigArrayForFile(
                         filePath,
@@ -415,18 +414,18 @@ class FileEnumerator {
                     : extensionRegExp.test(filePath);
 
                 if (matched) {
-                    debug(`Yield: ${filename}${ignored ? " but ignored" : ""}`);
+                    debug(`Yield: ${entry.name}${ignored ? " but ignored" : ""}`);
                     yield {
                         config: configArrayFactory.getConfigArrayForFile(filePath),
                         filePath,
                         flag
                     };
                 } else {
-                    debug(`Didn't match: ${filename}`);
+                    debug(`Didn't match: ${entry.name}`);
                 }
 
             // Dive into the sub directory.
-            } else if (options.recursive && stat && stat.isDirectory()) {
+            } else if (options.recursive && entry.isDirectory()) {
                 if (!config) {
                     config = configArrayFactory.getConfigArrayForFile(
                         filePath,

lib/shared/relative-module-resolver.js

@@ -6,35 +6,18 @@
 "use strict";
 
 const Module = require("module");
-const path = require("path");
 
-// Polyfill Node's `Module.createRequire` if not present. We only support the case where the argument is a filepath, not a URL.
-const createRequire = (
-
-    // Added in v12.2.0
-    Module.createRequire ||
-
-    // Added in v10.12.0, but deprecated in v12.2.0.
-    Module.createRequireFromPath ||
-
-    // Polyfill - This is not executed on the tests on node@>=10.
-    /* istanbul ignore next */
-    (filename => {
-        const mod = new Module(filename, null);
-
-        mod.filename = filename;
-        mod.paths = Module._nodeModulePaths(path.dirname(filename)); // eslint-disable-line no-underscore-dangle
-        mod._compile("module.exports = require;", filename); // eslint-disable-line no-underscore-dangle
-        return mod.exports;
-    })
-);
+/*
+ * `Module.createRequire` is added in v12.2.0. It supports URL as well.
+ * We only support the case where the argument is a filepath, not a URL.
+ */
+const createRequire = Module.createRequire || Module.createRequireFromPath;
 
 module.exports = {
 
     /**
      * Resolves a Node module relative to another module
      * @param {string} moduleName The name of a Node module, or a path to a Node module.
-     *
      * @param {string} relativeToPath An absolute path indicating the module that `moduleName` should be resolved relative to. This must be
      * a file rather than a directory, but the file need not actually exist.
      * @returns {string} The absolute path that would result from calling `require.resolve(moduleName)` in a file located at `relativeToPath`
@@ -43,6 +26,8 @@ module.exports = {
         try {
             return createRequire(relativeToPath).resolve(moduleName);
         } catch (error) {
+
+            // This `if` block is for older Node.js than 12.0.0. We can remove this block in the future.
             if (
                 typeof error === "object" &&
                 error !== null &&

package.json

@@ -116,7 +116,7 @@
     "load-perf": "^0.2.0",
     "markdownlint": "^0.15.0",
     "markdownlint-cli": "^0.17.0",
-    "metro-memory-fs": "^0.54.1",
+    "memfs": "^3.0.1",
     "mocha": "^6.1.2",
     "mocha-junit-reporter": "^1.23.0",
     "npm-license": "^0.3.3",

tests/lib/_utils.js

@@ -6,7 +6,7 @@
 "use strict";
 
 const path = require("path");
-const MemoryFs = require("metro-memory-fs");
+const { Volume, createFsFromVolume } = require("memfs");
 
 /**
  * Prevents leading spaces in a multiline template literal from appearing in the resulting string
@@ -25,36 +25,6 @@ function unIndent(strings, ...values) {
     return lines.map(line => line.slice(minLineIndent)).join("\n");
 }
 
-/**
- * Add support of `recursive` option.
- * @param {import("fs")} fs The in-memory file system.
- * @param {() => string} cwd The current working directory.
- * @returns {void}
- */
-function supportMkdirRecursiveOption(fs, cwd) {
-    const { mkdirSync } = fs;
-
-    fs.mkdirSync = (filePath, options) => {
-        if (typeof options === "object" && options !== null) {
-            if (options.recursive) {
-                const absolutePath = path.resolve(cwd(), filePath);
-                const parentPath = path.dirname(absolutePath);
-
-                if (
-                    parentPath &&
-                    parentPath !== absolutePath &&
-                    !fs.existsSync(parentPath)
-                ) {
-                    fs.mkdirSync(parentPath, options);
-                }
-            }
-            mkdirSync(filePath, options.mode);
-        } else {
-            mkdirSync(filePath, options);
-        }
-    };
-}
-
 /**
  * Define in-memory file system.
  * @param {Object} options The options.
@@ -71,17 +41,8 @@ function defineInMemoryFs({
      * The in-memory file system for this mock.
      * @type {import("fs")}
      */
-    const fs = new MemoryFs({
-        cwd,
-        platform: process.platform === "win32" ? "win32" : "posix"
-    });
-
-    // Support D: drive.
-    if (process.platform === "win32") {
-        fs._roots.set("D:", fs._makeDir(0o777)); // eslint-disable-line no-underscore-dangle
-    }
+    const fs = createFsFromVolume(new Volume());
 
-    supportMkdirRecursiveOption(fs, cwd);
     fs.mkdirSync(cwd(), { recursive: true });
 
     /*