tools: update to ESLint 4.3.0

PR-URL: #14417
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Refael Ackermann <refack@gmail.com>

Author: Trott

Diff for: tools/eslint/bin/eslint.js

@@ -44,11 +44,12 @@ process.once("uncaughtException", err => {
     if (typeof err.messageTemplate === "string" && err.messageTemplate.length > 0) {
         const template = lodash.template(fs.readFileSync(path.resolve(__dirname, `../messages/${err.messageTemplate}.txt`), "utf-8"));
 
-        console.log("\nOops! Something went wrong! :(");
-        console.log(`\n${template(err.messageData || {})}`);
+        console.error("\nOops! Something went wrong! :(");
+        console.error(`\n${template(err.messageData || {})}`);
     } else {
-        console.log(err.message);
-        console.log(err.stack);
+
+        console.error(err.message);
+        console.error(err.stack);
     }
 
     process.exitCode = 1;

Diff for: tools/eslint/conf/category-list.json

@@ -10,12 +10,12 @@
     ],
     "deprecated": {
         "name": "Deprecated",
-        "description": "These rules have been deprecated and replaced by newer rules:",
+        "description": "These rules have been deprecated in accordance with the [deprecation policy](/docs/user-guide/rule-deprecation), and replaced by newer rules:",
         "rules": []
     },
     "removed": {
         "name": "Removed",
-        "description": "These rules from older versions of ESLint have been replaced by newer rules:",
+        "description": "These rules from older versions of ESLint (before the [deprecation policy](/docs/user-guide/rule-deprecation) existed) have been replaced by newer rules:",
         "rules": [
             { "removed": "generator-star", "replacedBy": ["generator-star-spacing"] },
             { "removed": "global-strict", "replacedBy": ["strict"] },

Diff for: tools/eslint/conf/config-schema.js

@@ -12,7 +12,9 @@ const baseConfigProperties = {
     parserOptions: { type: "object" },
     plugins: { type: "array" },
     rules: { type: "object" },
-    settings: { type: "object" }
+    settings: { type: "object" },
+
+    ecmaFeatures: { type: "object" } // deprecated; logs a warning when used
 };
 
 const overrideProperties = Object.assign(

Diff for: tools/eslint/conf/eslint-recommended.js

@@ -6,13 +6,10 @@
 
 "use strict";
 
-/* eslint sort-keys: ["error", "asc"], quote-props: ["error", "consistent"] */
-/* eslint-disable sort-keys */
+/* eslint sort-keys: ["error", "asc"] */
 
 module.exports = {
     rules: {
-
-        /* eslint-enable sort-keys */
         "accessor-pairs": "off",
         "array-bracket-newline": "off",
         "array-bracket-spacing": "off",
@@ -25,23 +22,23 @@ module.exports = {
         "block-spacing": "off",
         "brace-style": "off",
         "callback-return": "off",
-        "camelcase": "off",
+        camelcase: "off",
         "capitalized-comments": "off",
         "class-methods-use-this": "off",
         "comma-dangle": "off",
         "comma-spacing": "off",
         "comma-style": "off",
-        "complexity": "off",
+        complexity: "off",
         "computed-property-spacing": "off",
         "consistent-return": "off",
         "consistent-this": "off",
         "constructor-super": "error",
-        "curly": "off",
+        curly: "off",
         "default-case": "off",
         "dot-location": "off",
         "dot-notation": "off",
         "eol-last": "off",
-        "eqeqeq": "off",
+        eqeqeq: "off",
         "for-direction": "off",
         "func-call-spacing": "off",
         "func-name-matching": "off",
@@ -55,7 +52,7 @@ module.exports = {
         "id-blacklist": "off",
         "id-length": "off",
         "id-match": "off",
-        "indent": "off",
+        indent: "off",
         "indent-legacy": "off",
         "init-declarations": "off",
         "jsx-quotes": "off",
@@ -234,13 +231,13 @@ module.exports = {
         "prefer-spread": "off",
         "prefer-template": "off",
         "quote-props": "off",
-        "quotes": "off",
-        "radix": "off",
+        quotes: "off",
+        radix: "off",
         "require-await": "off",
         "require-jsdoc": "off",
         "require-yield": "error",
         "rest-spread-spacing": "off",
-        "semi": "off",
+        semi: "off",
         "semi-spacing": "off",
         "semi-style": "off",
         "sort-imports": "off",
@@ -252,7 +249,7 @@ module.exports = {
         "space-infix-ops": "off",
         "space-unary-ops": "off",
         "spaced-comment": "off",
-        "strict": "off",
+        strict: "off",
         "switch-colon-spacing": "off",
         "symbol-description": "off",
         "template-curly-spacing": "off",
@@ -265,6 +262,6 @@ module.exports = {
         "wrap-iife": "off",
         "wrap-regex": "off",
         "yield-star-spacing": "off",
-        "yoda": "off"
+        yoda: "off"
     }
 };

Diff for: tools/eslint/lib/config/config-file.js

@@ -3,8 +3,6 @@
  * @author Nicholas C. Zakas
  */
 
-/* eslint no-use-before-define: 0 */
-
 "use strict";
 
 //------------------------------------------------------------------------------
@@ -418,6 +416,8 @@ function applyExtends(config, configContext, filePath, relativeTo) {
                 );
             }
             debug(`Loading ${parentPath}`);
+
+            // eslint-disable-next-line no-use-before-define
             return ConfigOps.merge(load(parentPath, configContext, relativeTo), previousValue);
         } catch (e) {
 
@@ -502,8 +502,8 @@ function resolve(filePath, relativeTo) {
 
     if (filePath.startsWith("plugin:")) {
         const configFullName = filePath;
-        const pluginName = filePath.substr(7, filePath.lastIndexOf("/") - 7);
-        const configName = filePath.substr(filePath.lastIndexOf("/") + 1, filePath.length - filePath.lastIndexOf("/") - 1);
+        const pluginName = filePath.slice(7, filePath.lastIndexOf("/"));
+        const configName = filePath.slice(filePath.lastIndexOf("/") + 1);
 
         normalizedPackageName = normalizePackageName(pluginName, "eslint-plugin");
         debug(`Attempting to resolve ${normalizedPackageName}`);
@@ -546,7 +546,7 @@ function loadFromDisk(resolvedPath, configContext) {
         }
 
         // validate the configuration before continuing
-        validator.validate(config, resolvedPath, configContext.linterContext.rules, configContext.linterContext.environments);
+        validator.validate(config, resolvedPath.configFullName, configContext.linterContext.rules, configContext.linterContext.environments);
 
         /*
          * If an `extends` property is defined, it represents a configuration file to use as

Diff for: tools/eslint/lib/config/config-initializer.js

@@ -12,10 +12,12 @@
 const util = require("util"),
     inquirer = require("inquirer"),
     ProgressBar = require("progress"),
+    semver = require("semver"),
     autoconfig = require("./autoconfig.js"),
     ConfigFile = require("./config-file"),
     ConfigOps = require("./config-ops"),
     getSourceCodeOfFiles = require("../util/source-code-util").getSourceCodeOfFiles,
+    ModuleResolver = require("../util/module-resolver"),
     npmUtil = require("../util/npm-util"),
     recConfig = require("../../conf/eslint-recommended"),
     log = require("../logging");
@@ -56,12 +58,35 @@ function writeFile(config, format) {
     }
 }
 
+/**
+ * Get the peer dependencies of the given module.
+ * This adds the gotten value to cache at the first time, then reuses it.
+ * In a process, this function is called twice, but `npmUtil.fetchPeerDependencies` needs to access network which is relatively slow.
+ * @param {string} moduleName The module name to get.
+ * @returns {Object} The peer dependencies of the given module.
+ * This object is the object of `peerDependencies` field of `package.json`.
+ */
+function getPeerDependencies(moduleName) {
+    let result = getPeerDependencies.cache.get(moduleName);
+
+    if (!result) {
+        log.info(`Checking peerDependencies of ${moduleName}`);
+
+        result = npmUtil.fetchPeerDependencies(moduleName);
+        getPeerDependencies.cache.set(moduleName, result);
+    }
+
+    return result;
+}
+getPeerDependencies.cache = new Map();
+
 /**
  * Synchronously install necessary plugins, configs, parsers, etc. based on the config
  * @param   {Object} config  config object
+ * @param   {boolean} [installESLint=true]  If `false` is given, it does not install eslint.
  * @returns {void}
  */
-function installModules(config) {
+function installModules(config, installESLint) {
     const modules = {};
 
     // Create a list of modules which should be installed based on config
@@ -73,11 +98,10 @@ function installModules(config) {
     if (config.extends && config.extends.indexOf("eslint:") === -1) {
         const moduleName = `eslint-config-${config.extends}`;
 
-        log.info(`Checking peerDependencies of ${moduleName}`);
         modules[moduleName] = "latest";
         Object.assign(
             modules,
-            npmUtil.fetchPeerDependencies(`${moduleName}@latest`)
+            getPeerDependencies(`${moduleName}@latest`)
         );
     }
 
@@ -86,15 +110,17 @@ function installModules(config) {
         return;
     }
 
-    // Add eslint to list in case user does not have it installed locally
-    modules.eslint = modules.eslint || "latest";
-
-    // Mark to show messages if it's new installation of eslint.
-    const installStatus = npmUtil.checkDevDeps(["eslint"]);
+    if (installESLint === false) {
+        delete modules.eslint;
+    } else {
+        const installStatus = npmUtil.checkDevDeps(["eslint"]);
 
-    if (installStatus.eslint === false) {
-        log.info("Local ESLint installation not found.");
-        config.installedESLint = true;
+        // Mark to show messages if it's new installation of eslint.
+        if (installStatus.eslint === false) {
+            log.info("Local ESLint installation not found.");
+            modules.eslint = modules.eslint || "latest";
+            config.installedESLint = true;
+        }
     }
 
     // Install packages
@@ -265,9 +291,10 @@ function processAnswers(answers) {
 /**
  * process user's style guide of choice and return an appropriate config object.
  * @param {string} guide name of the chosen style guide
+ * @param {boolean} [installESLint=true]  If `false` is given, it does not install eslint.
  * @returns {Object} config object
  */
-function getConfigForStyleGuide(guide) {
+function getConfigForStyleGuide(guide, installESLint) {
     const guides = {
         google: { extends: "google" },
         airbnb: { extends: "airbnb" },
@@ -279,11 +306,74 @@ function getConfigForStyleGuide(guide) {
         throw new Error("You referenced an unsupported guide.");
     }
 
-    installModules(guides[guide]);
+    installModules(guides[guide], installESLint);
 
     return guides[guide];
 }
 
+/**
+ * Get the version of the local ESLint.
+ * @returns {string|null} The version. If the local ESLint was not found, returns null.
+ */
+function getLocalESLintVersion() {
+    try {
+        const resolver = new ModuleResolver();
+        const eslintPath = resolver.resolve("eslint", process.cwd());
+        const eslint = require(eslintPath);
+
+        return eslint.linter.version || null;
+    } catch (_err) {
+        return null;
+    }
+}
+
+/**
+ * Get the shareable config name of the chosen style guide.
+ * @param {Object} answers The answers object.
+ * @returns {string} The shareable config name.
+ */
+function getStyleGuideName(answers) {
+    if (answers.styleguide === "airbnb" && !answers.airbnbReact) {
+        return "airbnb-base";
+    }
+    return answers.styleguide;
+}
+
+/**
+ * Check whether the local ESLint version conflicts with the required version of the chosen shareable config.
+ * @param {Object} answers The answers object.
+ * @returns {boolean} `true` if the local ESLint is found then it conflicts with the required version of the chosen shareable config.
+ */
+function hasESLintVersionConflict(answers) {
+
+    // Get the local ESLint version.
+    const localESLintVersion = getLocalESLintVersion();
+
+    if (!localESLintVersion) {
+        return false;
+    }
+
+    // Get the required range of ESLint version.
+    const configName = getStyleGuideName(answers);
+    const moduleName = `eslint-config-${configName}@latest`;
+    const requiredESLintVersionRange = getPeerDependencies(moduleName).eslint;
+
+    if (!requiredESLintVersionRange) {
+        return false;
+    }
+
+    answers.localESLintVersion = localESLintVersion;
+    answers.requiredESLintVersionRange = requiredESLintVersionRange;
+
+    // Check the version.
+    if (semver.satisfies(localESLintVersion, requiredESLintVersionRange)) {
+        answers.installESLint = false;
+        return false;
+    }
+
+    return true;
+}
+
 /* istanbul ignore next: no need to test inquirer*/
 /**
  * Ask use a few questions on command prompt
@@ -346,6 +436,21 @@ function promptUser() {
             when(answers) {
                 return ((answers.source === "guide" && answers.packageJsonExists) || answers.source === "auto");
             }
+        },
+        {
+            type: "confirm",
+            name: "installESLint",
+            message(answers) {
+                const verb = semver.ltr(answers.localESLintVersion, answers.requiredESLintVersionRange)
+                    ? "upgrade"
+                    : "downgrade";
+
+                return `The style guide "${answers.styleguide}" requires eslint@${answers.requiredESLintVersionRange}. You are currently using eslint@${answers.localESLintVersion}.\n  Do you want to ${verb}?`;
+            },
+            default: true,
+            when(answers) {
+                return answers.source === "guide" && answers.packageJsonExists && hasESLintVersionConflict(answers);
+            }
         }
     ]).then(earlyAnswers => {
 
@@ -355,11 +460,14 @@ function promptUser() {
                 log.info("A package.json is necessary to install plugins such as style guides. Run `npm init` to create a package.json file and try again.");
                 return void 0;
             }
+            if (earlyAnswers.installESLint === false && !semver.satisfies(earlyAnswers.localESLintVersion, earlyAnswers.requiredESLintVersionRange)) {
+                log.info(`Note: it might not work since ESLint's version is mismatched with the ${earlyAnswers.styleguide} config.`);
+            }
             if (earlyAnswers.styleguide === "airbnb" && !earlyAnswers.airbnbReact) {
                 earlyAnswers.styleguide = "airbnb-base";
             }
 
-            config = getConfigForStyleGuide(earlyAnswers.styleguide);
+            config = getConfigForStyleGuide(earlyAnswers.styleguide, earlyAnswers.installESLint);
             writeFile(config, earlyAnswers.format);
 
             return void 0;
@@ -479,6 +587,7 @@ function promptUser() {
 
 const init = {
     getConfigForStyleGuide,
+    hasESLintVersionConflict,
     processAnswers,
     /* istanbul ignore next */initializeConfig() {
         return promptUser();