Bug 1460100 - Added ESLint rule to prevent use of nsIScriptableUnicodeConverter r=Standard8

Differential Revision: https://phabricator.services.mozilla.com/D129668

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

@@ -44,6 +44,7 @@ The plugin implements the following rules:
    eslint-plugin-mozilla/reject-chromeutils-import-params
    eslint-plugin-mozilla/reject-importGlobalProperties
    eslint-plugin-mozilla/reject-osfile
+   eslint-plugin-mozilla/reject-scriptableunicodeconverter
    eslint-plugin-mozilla/reject-some-requires
    eslint-plugin-mozilla/use-cc-etc
    eslint-plugin-mozilla/use-chromeutils-import

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

@@ -0,0 +1,13 @@
+reject-scriptableunicodeconverter
+================================================
+
+Rejects calls into ``Ci.nsIScriptableUnicodeConverter``. This is configured as a warning.
+You should use |TextEncoder|_ or |TextDecoder|_  for new code.
+If modifying old code, please consider swapping it in if possible; if this is tricky please ensure
+a bug is on file.
+
+.. |TextEncoder| replace:: ``TextEncoder``
+.. _TextEncoder: https://searchfox.org/mozilla-central/source/dom/webidl/TextEncoder.webidl
+
+.. |TextDecoder| replace:: ``TextDecoder``
+.. _TextDecoder: https://searchfox.org/mozilla-central/source/dom/webidl/TextDecoder.webidl

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

@@ -133,6 +133,7 @@ module.exports = {
     "mozilla/reject-chromeutils-import-params": "error",
     "mozilla/reject-importGlobalProperties": ["error", "allownonwebidl"],
     "mozilla/reject-osfile": "warn",
+    "mozilla/reject-scriptableunicodeconverter": "warn",
     "mozilla/rejects-requires-await": "error",
     "mozilla/use-cc-etc": "error",
     "mozilla/use-chromeutils-generateqi": "error",

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

@@ -57,6 +57,7 @@ module.exports = {
     "reject-chromeutils-import-params": require("../lib/rules/reject-chromeutils-import-params"),
     "reject-importGlobalProperties": require("../lib/rules/reject-importGlobalProperties"),
     "reject-osfile": require("../lib/rules/reject-osfile"),
+    "reject-scriptableunicodeconverter": require("../lib/rules/reject-scriptableunicodeconverter"),
     "reject-relative-requires": require("../lib/rules/reject-relative-requires"),
     "reject-some-requires": require("../lib/rules/reject-some-requires"),
     "rejects-requires-await": require("../lib/rules/rejects-requires-await"),

tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-scriptableunicodeconverter.js

@@ -0,0 +1,38 @@
+/**
+ * @fileoverview Reject calls into Ci.nsIScriptableUnicodeConverter. We're phasing this out in
+ * favour of TextEncoder or TextDecoder.
+ *
+ * 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";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+function isIdentifier(node, id) {
+  return node && node.type === "Identifier" && node.name === id;
+}
+
+module.exports = function(context) {
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  return {
+    MemberExpression(node) {
+      if (
+        isIdentifier(node.object, "Ci") &&
+        isIdentifier(node.property, "nsIScriptableUnicodeConverter")
+      ) {
+        context.report(
+          node,
+          "Ci.nsIScriptableUnicodeConverter is deprecated. You should use TextEncoder or TextDecoder instead."
+        );
+      }
+    },
+  };
+};

tools/lint/eslint/eslint-plugin-mozilla/tests/reject-scriptableunicodeconverter.js

@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require("../lib/rules/reject-scriptableunicodeconverter");
+var RuleTester = require("eslint").RuleTester;
+
+const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 8 } });
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+function invalidError() {
+  let message =
+    "Ci.nsIScriptableUnicodeConverter is deprecated. You should use TextEncoder or TextDecoder instead.";
+  return [{ message, type: "MemberExpression" }];
+}
+
+ruleTester.run("reject-scriptableunicodeconverter", rule, {
+  valid: ["TextEncoder", "TextDecoder"],
+  invalid: [
+    {
+      code: "Ci.nsIScriptableUnicodeConverter",
+      errors: invalidError(),
+    },
+  ],
+});