✨ add yarn workspaces support in no-extraneous-import

docs/rules/no-extraneous-import.md

@@ -17,7 +17,8 @@ This rule warns `import` declarations of extraneous modules.
         "node/no-extraneous-import": ["error", {
             "allowModules": [],
             "resolvePaths": [],
-            "tryExtensions": []
+            "tryExtensions": [],
+            "yarnWorkspaces": false
         }]
     }
 }
@@ -55,6 +56,13 @@ When an import path does not exist, this rule checks whether or not any of `path
 
 Default is `[".js", ".json", ".node"]`.
 
+#### yarnWorkspaces
+
+When using [yarn workspaces](https://classic.yarnpkg.com/en/docs/workspaces), the dependencies are
+defined in the top level folder.
+
+Default is `false`
+
 ### Shared Settings
 
 The following options can be set by [shared settings](http://eslint.org/docs/user-guide/configuring.html#adding-shared-settings).
@@ -63,6 +71,7 @@ Several rules have the same option, but we can set this option at once.
 - `allowModules`
 - `resolvePaths`
 - `tryExtensions`
+- `yarnWorkspaces`
 
 ```js
 // .eslintrc.js
@@ -71,7 +80,8 @@ module.exports = {
         "node": {
             "allowModules": ["electron"],
             "resolvePaths": [__dirname],
-            "tryExtensions": [".js", ".json", ".node"]
+            "tryExtensions": [".js", ".json", ".node"],
+            "yarnWorkspaces": true
         }
     },
     "rules": {

lib/rules/no-extraneous-import.js

@@ -9,6 +9,7 @@ const getAllowModules = require("../util/get-allow-modules")
 const getConvertPath = require("../util/get-convert-path")
 const getResolvePaths = require("../util/get-resolve-paths")
 const getTryExtensions = require("../util/get-try-extensions")
+const getYarnWorkspaces = require("../util/get-yarn-workspaces")
 const visitImport = require("../util/visit-import")
 
 module.exports = {
@@ -31,6 +32,7 @@ module.exports = {
                     convertPath: getConvertPath.schema,
                     resolvePaths: getResolvePaths.schema,
                     tryExtensions: getTryExtensions.schema,
+                    yarnWorkspaces: getYarnWorkspaces.schema,
                 },
                 additionalProperties: false,
             },

lib/util/check-extraneous.js

@@ -4,6 +4,7 @@
  */
 "use strict"
 
+const path = require("path")
 const getAllowModules = require("./get-allow-modules")
 const getPackageJson = require("./get-package-json")
 
@@ -18,7 +19,15 @@ const getPackageJson = require("./get-package-json")
  * @returns {void}
  */
 module.exports = function checkForExtraneous(context, filePath, targets) {
-    const packageInfo = getPackageJson(filePath)
+    const options = context.options[0] || {}
+
+    let packageInfo = getPackageJson(filePath)
+
+    // When using yarn workspaces, we should look in the parent folder
+    if (options.yarnWorkspaces && packageInfo && !packageInfo.workspaces) {
+        packageInfo = getPackageJson(path.dirname(packageInfo.filePath))
+    }
+
     if (!packageInfo) {
         return
     }

lib/util/get-yarn-workspaces.js

@@ -0,0 +1,42 @@
+/**
+ * @author Toru Nagashima
+ * See LICENSE file in root directory for full license.
+ */
+"use strict"
+
+const DEFAULT_VALUE = false
+
+/**
+ * Gets `yarnWorkspaces` property from a given option object.
+ *
+ * @param {object|undefined} option - An option object to get.
+ * @returns {boolean|null} The `yarnWorkspaces` value, or `null`.
+ */
+function get(option) {
+    if (option && "yarnWorkspaces" in option) {
+        return option.yarnWorkspaces
+    }
+    return null
+}
+
+/**
+ * Gets "yarnWorkspaces" setting.
+ *
+ * 1. This checks `options` property, then returns it if exists.
+ * 2. This checks `settings.node` property, then returns it if exists.
+ * 3. This returns `false`.
+ *
+ * @param {RuleContext} context - The rule context.
+ * @returns {boolean}
+ */
+module.exports = function getTryExtensions(context, optionIndex = 0) {
+    return (
+        get(context.options && context.options[optionIndex]) ||
+        get(context.settings && context.settings.node) ||
+        DEFAULT_VALUE
+    )
+}
+
+module.exports.schema = {
+    type: "boolean",
+}

tests/fixtures/no-extraneous/yarnWorkspaces/aaa/package.json

@@ -0,0 +1,4 @@
+{
+    "name": "aaa",
+    "version": "0.0.0"
+}

tests/fixtures/no-extraneous/yarnWorkspaces/bbb/package.json

@@ -0,0 +1,4 @@
+{
+    "name": "bbb",
+    "version": "0.0.0"
+}

tests/fixtures/no-extraneous/yarnWorkspaces/package.json

@@ -0,0 +1,12 @@
+{
+    "private": true,
+    "name": "test",
+    "version": "0.0.0",
+    "dependencies": {
+      "ccc": "*"
+    },
+    "workspaces": [
+      "aaa",
+      "bbb"
+    ]
+}

tests/lib/rules/no-extraneous-import.js

@@ -4,6 +4,7 @@
  */
 "use strict"
 
+const fs = require("fs")
 const path = require("path")
 const { Linter, RuleTester } = require("eslint")
 const rule = require("../../../lib/rules/no-extraneous-import")
@@ -31,6 +32,16 @@ function fixture(name) {
     return path.resolve(__dirname, "../../fixtures/no-extraneous", name)
 }
 
+// We need to simulate `yarn workspaces` by creating symlinks inside `node_modules`
+fs.symlinkSync(
+    fixture("yarnWorkspaces/aaa"),
+    fixture("yarnWorkspaces/node_modules/aaa")
+)
+fs.symlinkSync(
+    fixture("yarnWorkspaces/bbb"),
+    fixture("yarnWorkspaces/node_modules/bbb")
+)
+
 const ruleTester = new RuleTester({
     parserOptions: {
         ecmaVersion: 2015,
@@ -71,12 +82,51 @@ ruleTester.run("no-extraneous-import", rule, {
             filename: fixture("optionalDependencies/a.js"),
             code: "import aaa from 'aaa'",
         },
+        {
+            filename: fixture("yarnWorkspaces/a.js"),
+            code: "import aaa from 'aaa'",
+        },
+        {
+            filename: fixture("yarnWorkspaces/b.js"),
+            code: "import bbb from 'bbb'",
+        },
+        {
+            filename: fixture("yarnWorkspaces/c.js"),
+            code: "import ccc from 'ccc'",
+        },
 
         // missing packages are warned by no-missing-import
         {
             filename: fixture("dependencies/a.js"),
             code: "import ccc from 'ccc'",
         },
+
+        // yarnWorkspaces
+        {
+            filename: fixture("yarnWorkspaces/a.js"),
+            code: "import aaa from 'aaa'",
+            options: [{ yarnWorkspaces: true }],
+        },
+        {
+            filename: fixture("yarnWorkspaces/b.js"),
+            code: "import bbb from 'bbb'",
+            options: [{ yarnWorkspaces: true }],
+        },
+        {
+            filename: fixture("yarnWorkspaces/c.js"),
+            code: "import ccc from 'ccc'",
+            options: [{ yarnWorkspaces: true }],
+        },
+        {
+            filename: fixture("yarnWorkspaces/aaa/c.js"),
+            code: "import ccc from 'ccc'",
+            options: [{ yarnWorkspaces: true }],
+        },
+        {
+            filename: fixture("yarnWorkspaces/bbb/c.js"),
+            code: "import ccc from 'ccc'",
+            options: [{ yarnWorkspaces: true }],
+        },
     ],
     invalid: [
         {
@@ -100,6 +150,17 @@ ruleTester.run("no-extraneous-import", rule, {
             errors: ['"bbb" is extraneous.'],
         },
 
+        {
+            filename: fixture("yarnWorkspaces/aaa/c.js"),
+            code: "import ccc from 'ccc'",
+            errors: ['"ccc" is extraneous.'],
+        },
+        {
+            filename: fixture("yarnWorkspaces/bbb/c.js"),
+            code: "import ccc from 'ccc'",
+            errors: ['"ccc" is extraneous.'],
+        },
+
         // import()
         ...(DynamicImportSupported
             ? [