Backed out changeset 50f86f169ee8 (bug 1889087) for causing talos performance test failures CLOSED TREE

.eslintrc.js

@@ -2206,7 +2206,10 @@ module.exports = {
       },
     },
     {
-      files: [
+      files: ["**"],
+      excludedFiles: [
+        // Devtools code, see bug 1525652.
+        "devtools/**",
         // Tests specific to JSM
         "dom/encoding/test/test_stringencoding.xhtml",
         "dom/url/tests/test_bug883784.xhtml",
@@ -2221,7 +2224,7 @@ module.exports = {
         "js/xpconnect/loader/XPCOMUtils.sys.mjs",
       ],
       rules: {
-        "mozilla/reject-chromeutils-import": "off",
+        "mozilla/reject-chromeutils-import": "error",
       },
     },
     {

devtools/client/performance-new/shared/#typescript-lazy-load.jsm.js#

@@ -0,0 +1,55 @@
+/* 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/. */
+// @ts-check
+"use strict";
+
+/**
+ * TypeScript can't understand the lazyRequireGetter mechanism, due to how it defines
+ * properties as a getter. This function, instead provides lazy loading in a
+ * TypeScript-friendly manner. It applies the lazy load memoization to each property
+ * of the provided object.
+ *
+ * Example usage:
+ *
+ * const lazy = createLazyLoaders({
+ *   moduleA: () => require("module/a"),
+ *   moduleB: () => require("module/b"),
+ * });
+ *
+ * Later:
+ *
+ * const moduleA = lazy.moduleA();
+ * const { objectInModuleB } = lazy.moduleB();
+ *
+ * @template {{ [key: string]: () => any }} T
+ * @param {T} definition - An object where each property has a function that loads a module.
+ * @returns {T} - The load memoized version of T.
+ */
+function createLazyLoaders(definition) {
+  /** @type {any} */
+  const result = {};
+  for (const [key, callback] of Object.entries(definition)) {
+    /** @type {any} */
+    let cache;
+    result[key] = () => {
+      if (cache === undefined) {
+        cache = callback();
+      }
+      return cache;
+    };
+  }
+  return result;
+}
+
+// Provide an exports object for the JSM to be properly read by TypeScript.
+/** @type {any} */
+var module = {};
+
+module.exports = {
+  createLazyLoaders,
+};
+
+// Object.keys() confuses the linting which expects a static array expression.
+// eslint-disable-next-line
+var EXPORTED_SYMBOLS = Object.keys(module.exports);

devtools/shared/loader/base-loader.sys.mjs

@@ -37,6 +37,9 @@ function* getOwnIdentifiers(x) {
 function isJSONURI(uri) {
   return uri.endsWith(".json");
 }
+function isJSMURI(uri) {
+  return uri.endsWith(".jsm");
+}
 function isSYSMJSURI(uri) {
   return uri.endsWith(".sys.mjs");
 }
@@ -215,7 +218,7 @@ function load(loader, module) {
 
 // Utility function to normalize module `uri`s so they have `.js` extension.
 function normalizeExt(uri) {
-  if (isJSURI(uri) || isJSONURI(uri) || isSYSMJSURI(uri)) {
+  if (isJSURI(uri) || isJSONURI(uri) || isJSMURI(uri) || isSYSMJSURI(uri)) {
     return uri;
   }
   return uri + ".js";
@@ -333,6 +336,9 @@ export function Require(loader, requirer) {
     // If module is already cached by loader then just use it.
     if (uri in modules) {
       module = modules[uri];
+    } else if (isJSMURI(uri)) {
+      module = modules[uri] = Module(requirement, uri);
+      module.exports = ChromeUtils.import(uri);
     } else if (isSYSMJSURI(uri)) {
       module = modules[uri] = Module(requirement, uri);
       module.exports = ChromeUtils.importESModule(uri, {

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

@@ -55,7 +55,6 @@ module.exports = {
       files: ["**/*.sys.mjs", "**/*.jsm"],
       rules: {
         "mozilla/lazy-getter-object-name": "error",
-        "mozilla/reject-chromeutils-import": "error",
         "mozilla/reject-eager-module-in-lazy-getter": "error",
         "mozilla/reject-global-this": "error",
         "mozilla/reject-globalThis-modification": "error",

tools/lint/eslint/eslint-plugin-mozilla/package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-mozilla",
-  "version": "3.7.2",
+  "version": "3.7.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {

tools/lint/eslint/eslint-plugin-mozilla/package.json

@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-mozilla",
-  "version": "3.7.2",
+  "version": "3.7.1",
   "description": "A collection of rules that help enforce JavaScript coding standard in the Mozilla project.",
   "keywords": [
     "eslint",