1 files changed, 70 insertions, 0 deletions
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-globalThis-modification.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-globalThis-modification.js
new file mode 100644
index 0000000000..4bcf7e3822
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/reject-globalThis-modification.js
@@ -0,0 +1,70 @@
+/**
+ * @fileoverview Enforce the standard object name for
+ * ChromeUtils.defineESMGetters
+ *
+ * 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";
+
+function isIdentifier(node, id) {
+  return node.type === "Identifier" && node.name === id;
+}
+
+function calleeToString(node) {
+  if (node.type === "Identifier") {
+    return node.name;
+  }
+
+  if (node.type === "MemberExpression" && !node.computed) {
+    return calleeToString(node.object) + "." + node.property.name;
+  }
+
+  return "???";
+}
+
+module.exports = {
+  meta: {
+    docs: {
+      url: "https://firefox-source-docs.mozilla.org/code-quality/lint/linters/eslint-plugin-mozilla/reject-globalThis-modification.html",
+    },
+    schema: [],
+    type: "problem",
+  },
+
+  create(context) {
+    return {
+      AssignmentExpression(node, parents) {
+        let target = node.left;
+        while (target.type === "MemberExpression") {
+          target = target.object;
+        }
+        if (isIdentifier(target, "globalThis")) {
+          context.report({
+            node,
+            message:
+              "`globalThis` shouldn't be modified. `globalThis` is the shared global inside the system module, and properties defined on it is visible from all modules.",
+          });
+        }
+      },
+      CallExpression(node) {
+        const calleeStr = calleeToString(node.callee);
+        if (calleeStr.endsWith(".deserialize")) {
+          return;
+        }
+
+        for (const arg of node.arguments) {
+          if (isIdentifier(arg, "globalThis")) {
+            context.report({
+              node,
+              message:
+                "`globalThis` shouldn't be passed to function that can modify it. `globalThis` is the shared global inside the system module, and properties defined on it is visible from all modules.",
+            });
+          }
+        }
+      },
+    };
+  },
+};