1 files changed, 69 insertions, 0 deletions
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-more-globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-more-globals.js
new file mode 100644
index 0000000000..921ead67bd
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-more-globals.js
@@ -0,0 +1,69 @@
+/**
+ * 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";
+
+const globals = require("../globals");
+
+const fs = require("fs");
+
+module.exports = {
+  meta: {
+    docs: {
+      url: "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/rules/no-more-globals.html",
+    },
+    messages: {
+      newGlobal:
+        "The global {{ name }} was not previously in this file, where new global variables are not permitted.",
+      removedGlobal:
+        "The global {{ name }} was expected to be defined in this file but isn't. Please remove it from the .globals file.",
+      missingGlobalsFile:
+        "This file has mozilla/no-more-globals enabled but has no .globals sibling file. Please create one.",
+    },
+    schema: [],
+    type: "problem",
+  },
+
+  create(context) {
+    return {
+      Program(node) {
+        let filename = context.filename;
+        let code = context.sourceCode.getText();
+        let currentGlobals = globals.getGlobalsForCode(code, {}, false);
+        let knownGlobals;
+        try {
+          knownGlobals = new Set(
+            JSON.parse(fs.readFileSync(filename + ".globals"))
+          );
+        } catch (ex) {
+          context.report({
+            node,
+            messageId: "missingGlobalsFile",
+          });
+          return;
+        }
+        for (let { name } of currentGlobals) {
+          if (!knownGlobals.has(name)) {
+            context.report({
+              node,
+              messageId: "newGlobal",
+              data: { name },
+            });
+          }
+        }
+        for (let known of knownGlobals) {
+          if (!currentGlobals.some(n => n.name == known)) {
+            context.report({
+              node,
+              messageId: "removedGlobal",
+              data: { name: known },
+            });
+          }
+        }
+      },
+    };
+  },
+};