Bug 1790354 - warn about using browser/ code from toolkit, r=Standard8

Differential Revision: https://phabricator.services.mozilla.com/D191976

.eslintrc.js

@@ -1987,5 +1987,12 @@ module.exports = {
         "mozilla/reject-chromeutils-import": "error",
       },
     },
+    {
+      files: ["toolkit/**"],
+      excludedFiles: ["toolkit/**/test/**", "toolkit/**/tests/**"],
+      rules: {
+        "mozilla/no-browser-refs-in-toolkit": "warn",
+      },
+    },
   ],
 };

docs/code-quality/lint/linters/eslint-plugin-mozilla/no-browser-refs-in-toolkit.rst

@@ -0,0 +1,24 @@
+no-browser-refs-in-toolkit
+==========================
+
+Rejects for using any code from ``browser/`` (Desktop Firefox) inside
+``toolkit``, as ``toolkit`` is for code shared with other Gecko consumers
+like Firefox on Android, Thunderbird, etc.
+
+Examples of incorrect code for this rule:
+-----------------------------------------
+
+.. code-block:: js
+
+    "chrome://browser/content/browser.xhtml"
+    "resource:///modules/BrowserWindowTracker.sys.mjs"
+    "browser/browser.ftl"
+
+Examples of correct code for this rule:
+---------------------------------------
+
+.. code-block:: js
+
+    "chrome://global/content/aboutAbout.html"
+    "resource://gre/modules/AppConstants.sys.mjs"
+    "toolkit/global/aboutFoo.ftl"

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

@@ -53,6 +53,7 @@ module.exports = {
     "no-aArgs": require("../lib/rules/no-aArgs"),
     "no-addtask-setup": require("../lib/rules/no-addtask-setup"),
     "no-arbitrary-setTimeout": require("../lib/rules/no-arbitrary-setTimeout"),
+    "no-browser-refs-in-toolkit": require("../lib/rules/no-browser-refs-in-toolkit"),
     "no-compare-against-boolean-literals": require("../lib/rules/no-compare-against-boolean-literals"),
     "no-cu-reportError": require("../lib/rules/no-cu-reportError"),
     "no-define-cc-etc": require("../lib/rules/no-define-cc-etc"),

tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-browser-refs-in-toolkit.js

@@ -0,0 +1,48 @@
+/**
+ * @fileoverview Reject use of browser/-based references from code in
+ *               directories like toolkit/ that ought not to depend on
+ *               running inside desktop Firefox.
+ *
+ * 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/no-browser-refs-in-toolkit.html",
+    },
+    messages: {
+      noBrowserChrome:
+        "> {{url}} is part of Desktop Firefox and cannot be unconditionally " +
+        "used by this code (which has to also work elsewhere).",
+    },
+    schema: [],
+    type: "suggestion",
+  },
+
+  create(context) {
+    return {
+      Literal(node) {
+        if (typeof node.value != "string") {
+          return;
+        }
+        if (
+          node.value.startsWith("chrome://browser") ||
+          node.value.startsWith("resource:///") ||
+          node.value.startsWith("resource://app/") ||
+          (node.value.startsWith("browser/") && node.value.endsWith(".ftl"))
+        ) {
+          context.report({
+            node,
+            messageId: "noBrowserChrome",
+            data: { url: node.value },
+          });
+        }
+      },
+    };
+  },
+};