Bug 1771751 - Reject static import for system module from non-system module. r=Standard8 (9975cd73) · Commits · The Tor Project / Applications / Mullvad Browser

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

+1 −0

Original line number	Diff line number	Diff line
		@@ -56,6 +56,7 @@ The plugin implements the following rules:
		eslint-plugin-mozilla/reject-scriptableunicodeconverter
		eslint-plugin-mozilla/reject-some-requires
		eslint-plugin-mozilla/reject-top-level-await
		eslint-plugin-mozilla/reject-import-system-module-from-non-system
		eslint-plugin-mozilla/use-cc-etc
		eslint-plugin-mozilla/use-chromeutils-generateqi
		eslint-plugin-mozilla/use-chromeutils-import

0 → 100644

+36 −0

Original line number	Diff line number	Diff line
		reject-import-system-module-from-non-system
		===========================================

		Rejects static import declaration for system modules (``.sys.mjs``) from non-system
		modules.

		Using static import for a system module into a non-system module would create a separate instance of the imported object(s) that is not shared with the other system modules and would break the per-process singleton expectation.

		The reason for this is that inside system modules, a static import will load the module into the shared global. Inside non-system modules, the static import will load into a different global (e.g. window). This will cause the module to be loaded into different scopes, and hence create separate instances. The fix is to use ``ChromeUtils.importESM`` which will import the object via the system module shared global scope.


		Examples of incorrect code for this rule:
		-----------------------------------------

		Inside a non-system module:

		.. code-block:: js

		import { Services } from "resource://gre/modules/Services.sys.mjs";

		Examples of correct code for this rule:
		---------------------------------------

		Inside a non-system module:

		.. code-block:: js

		const { Services } = ChromeUtils.importESM(
		"resource://gre/modules/Services.sys.mjs"
		);

		Inside a system module:

		.. code-block:: js

		import { Services } from "resource://gre/modules/Services.sys.mjs";

+7 −0

Original line number	Diff line number	Diff line
		@@ -82,6 +82,13 @@ module.exports = {
		],
		},
		},
		{
		excludedFiles: ["*/.sys.mjs"],
		files: ["*/.mjs"],
		rules: {
		"mozilla/reject-import-system-module-from-non-system": "error",
		},
		},
		{
		files: ["*/.jsm", "*/.jsm.js"],
		rules: {

+1 −0

Original line number	Diff line number	Diff line
		@@ -55,6 +55,7 @@ module.exports = {
		"reject-addtask-only": require("../lib/rules/reject-addtask-only"),
		"reject-chromeutils-import-params": require("../lib/rules/reject-chromeutils-import-params"),
		"reject-global-this": require("../lib/rules/reject-global-this"),
		"reject-import-system-module-from-non-system": require("../lib/rules/reject-import-system-module-from-non-system"),
		"reject-importGlobalProperties": require("../lib/rules/reject-importGlobalProperties"),
		"reject-osfile": require("../lib/rules/reject-osfile"),
		"reject-scriptableunicodeconverter": require("../lib/rules/reject-scriptableunicodeconverter"),

0 → 100644

+36 −0

Original line number	Diff line number	Diff line
		/**
		* 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";

		module.exports = {
		meta: {
		docs: {
		url:
		"https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/reject-import-system-module-from-non-system.html",
		},
		messages: {
		rejectStaticImportSystemModuleFromNonSystem:
		"System modules (*.sys.mjs) can be imported with static import declaration only from system modules.",
		},
		type: "problem",
		},

		create(context) {
		return {
		ImportDeclaration(node) {
		if (!node.source.value.endsWith(".sys.mjs")) {
		return;
		}

		context.report({
		node,
		messageId: "rejectStaticImportSystemModuleFromNonSystem",
		});
		},
		};
		},
		};