Bug 1771097 - Add ESLint rule for ChromeUtils.defineESModuleGetters l…

…azy object name. r=Standard8

Differential Revision: https://phabricator.services.mozilla.com/D147400

docs/code-quality/lint/linters/eslint-plugin-mozilla.rst

@@ -33,6 +33,7 @@ The plugin implements the following rules:
    eslint-plugin-mozilla/import-globals
    eslint-plugin-mozilla/import-globals-from
    eslint-plugin-mozilla/import-headjs-globals
+   eslint-plugin-mozilla/lazy-getter-object-name
    eslint-plugin-mozilla/mark-exported-symbols-as-used
    eslint-plugin-mozilla/mark-test-function-used
    eslint-plugin-mozilla/no-aArgs

docs/code-quality/lint/linters/eslint-plugin-mozilla/lazy-getter-object-name.rst

@@ -0,0 +1,25 @@
+lazy-getter-object-name
+=============================
+
+Enforce the standard object variable name ``lazy`` for
+``ChromeUtils.defineESModuleGetters``
+
+Examples of incorrect code for this rule:
+-----------------------------------------
+
+.. code-block:: js
+
+    const obj = {};
+    ChromeUtils.defineESModuleGetters(obj, {
+      Services: “resource://gre/modules/Services.sys.mjs”,
+    });
+
+Examples of correct code for this rule:
+---------------------------------------
+
+.. code-block:: js
+
+    const lazy = {};
+    ChromeUtils.defineESModuleGetters(lazy, {
+      Services: “resource://gre/modules/Services.sys.mjs”,
+    });

tools/lint/eslint/eslint-plugin-mozilla/lib/configs/recommended.js

@@ -50,6 +50,7 @@ module.exports = {
       },
       files: ["**/*.sys.mjs", "**/*.jsm", "**/*.jsm.js"],
       rules: {
+        "mozilla/lazy-getter-object-name": "error",
         "mozilla/reject-global-this": "error",
         "mozilla/reject-globalThis-modification": "error",
         "mozilla/reject-top-level-await": "error",

tools/lint/eslint/eslint-plugin-mozilla/lib/index.js

@@ -39,6 +39,7 @@ module.exports = {
     "import-content-task-globals": require("../lib/rules/import-content-task-globals"),
     "import-globals": require("../lib/rules/import-globals"),
     "import-headjs-globals": require("../lib/rules/import-headjs-globals"),
+    "lazy-getter-object-name": require("../lib/rules/lazy-getter-object-name"),
     "mark-exported-symbols-as-used": require("../lib/rules/mark-exported-symbols-as-used"),
     "mark-test-function-used": require("../lib/rules/mark-test-function-used"),
     "no-aArgs": require("../lib/rules/no-aArgs"),

tools/lint/eslint/eslint-plugin-mozilla/lib/rules/lazy-getter-object-name.js

@@ -0,0 +1,45 @@
+/**
+ * @fileoverview Enforce the standard object name for
+ * ChromeUtils.defineESModuleGetters
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+function isIdentifier(node, id) {
+  return node.type === "Identifier" && node.name === id;
+}
+
+module.exports = {
+  meta: {
+    docs: {
+      url:
+        "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/lazy-getter-object-name.html",
+    },
+    type: "problem",
+  },
+
+  create(context) {
+    return {
+      CallExpression(node) {
+        let { callee } = node;
+        if (
+          callee.type === "MemberExpression" &&
+          isIdentifier(callee.object, "ChromeUtils") &&
+          isIdentifier(callee.property, "defineESModuleGetters") &&
+          node.arguments.length >= 1 &&
+          !isIdentifier(node.arguments[0], "lazy")
+        ) {
+          context.report({
+            node,
+            message:
+              "The variable name of the object passed to ChromeUtils.defineESModuleGetters must be `lazy`",
+          });
+        }
+      },
+    };
+  },
+};

tools/lint/eslint/eslint-plugin-mozilla/tests/lazy-getter-object-name.js

@@ -0,0 +1,50 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require("../lib/rules/lazy-getter-object-name");
+var RuleTester = require("eslint").RuleTester;
+
+const ruleTester = new RuleTester();
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+function invalidCode(code) {
+  let message =
+    "The variable name of the object passed to ChromeUtils.defineESModuleGetters must be `lazy`";
+  return { code, errors: [{ message, type: "CallExpression" }] };
+}
+
+ruleTester.run("lazy-getter-object-name", rule, {
+  valid: [
+    `
+    ChromeUtils.defineESModuleGetters(lazy, {
+      Services: "resource://gre/modules/Services.sys.mjs",
+    });
+`,
+  ],
+  invalid: [
+    invalidCode(`
+    ChromeUtils.defineESModuleGetters(obj, {
+      Services: "resource://gre/modules/Services.sys.mjs",
+    });
+`),
+    invalidCode(`
+    ChromeUtils.defineESModuleGetters(this, {
+      Services: "resource://gre/modules/Services.sys.mjs",
+    });
+`),
+    invalidCode(`
+    ChromeUtils.defineESModuleGetters(window, {
+      Services: "resource://gre/modules/Services.sys.mjs",
+    });
+`),
+  ],
+});