Bug 1749675 - [remote] Don't apply session data for modules that don'…

…t exist for a given destination. r=webdriver-reviewers,jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D134266

remote/shared/messagehandler/ModuleCache.jsm

@@ -168,6 +168,21 @@ class ModuleCache {
     return module;
   }
 
+  /**
+   * Check if the given module exists for the destination.
+   *
+   * @param {String} moduleName
+   *     The name of the module.
+   * @param {Destination} destination
+   *     The destination.
+   * @returns {Boolean}
+   *     True if the module exists.
+   */
+  hasModule(moduleName, destination) {
+    const classes = this.getAllModuleClasses(moduleName, destination);
+    return classes.length != 0;
+  }
+
   toString() {
     return `[object ${this.constructor.name} ${this.messageHandler.name}]`;
   }

remote/shared/messagehandler/RootMessageHandler.jsm

@@ -146,19 +146,27 @@ class RootMessageHandler extends MessageHandler {
       return [];
     }
 
+    const destination = {
+      type: WindowGlobalMessageHandler.type,
+      contextDescriptor: {
+        type: CONTEXT_DESCRIPTOR_TYPES.ALL,
+      },
+    };
+
+    // Don't apply session data if the module is not present
+    // for the destination.
+    if (!this._moduleCache.hasModule(moduleName, destination)) {
+      return Promise.resolve();
+    }
+
     return this.handleCommand({
       moduleName,
       commandName: "_applySessionData",
       params: {
         [isAdding ? "added" : "removed"]: updatedValues,
         category,
       },
-      destination: {
-        type: WindowGlobalMessageHandler.type,
-        contextDescriptor: {
-          type: CONTEXT_DESCRIPTOR_TYPES.ALL,
-        },
-      },
+      destination,
     });
   }
 }

remote/shared/messagehandler/WindowGlobalMessageHandler.jsm

@@ -72,6 +72,10 @@ class WindowGlobalMessageHandler extends MessageHandler {
       return;
     }
 
+    const destination = {
+      type: WindowGlobalMessageHandler.type,
+    };
+
     for (const sessionDataItem of sessionDataItems) {
       const {
         moduleName,
@@ -80,6 +84,12 @@ class WindowGlobalMessageHandler extends MessageHandler {
         value,
       } = sessionDataItem;
       if (this._isRelevantContext(contextDescriptor)) {
+        // Don't apply session data if the module is not present
+        // for the destination.
+        if (!this._moduleCache.hasModule(moduleName, destination)) {
+          continue;
+        }
+
         await this.handleCommand({
           moduleName,
           commandName: "_applySessionData",
@@ -91,9 +101,7 @@ class WindowGlobalMessageHandler extends MessageHandler {
             // though it will make the implementation more complex.
             added: [value],
           },
-          destination: {
-            type: WindowGlobalMessageHandler.type,
-          },
+          destination,
         });
       }
     }

remote/shared/messagehandler/test/browser/browser_session_data.js

@@ -158,6 +158,36 @@ add_task(async function test_sessionData() {
   is(sessionDataSnapshot.size, 0, "session data should be empty again");
 });
 
+add_task(async function test_sessionDataRootOnlyModule() {
+  const sessionId = "sessionData-test-rootOnly";
+
+  const rootMessageHandler = createRootMessageHandler(sessionId);
+  ok(rootMessageHandler, "Valid ROOT MessageHandler created");
+
+  await BrowserTestUtils.loadURI(
+    gBrowser,
+    "https://example.com/document-builder.sjs?html=tab"
+  );
+
+  const windowGlobalCreated = rootMessageHandler.once("message-handler-event");
+
+  // Updating the session data on the root message handler should not cause
+  // failures for other message handlers if the module only exists for root.
+  await rootMessageHandler.addSessionData({
+    moduleName: "rootOnly",
+    category: "session_data_root_only",
+    contextDescriptor: {
+      type: CONTEXT_DESCRIPTOR_TYPES.ALL,
+    },
+    values: [true],
+  });
+
+  await windowGlobalCreated;
+  ok(true, "Window global has been initialized");
+
+  rootMessageHandler.destroy();
+});
+
 function checkSessionDataItem(item, moduleName, category, contextType, value) {
   is(item.moduleName, moduleName, "Data item has the expected module name");
   is(item.category, category, "Data item has the expected category");

remote/shared/messagehandler/test/browser/resources/modules/root/rootOnly.jsm

@@ -0,0 +1,25 @@
+/* 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 EXPORTED_SYMBOLS = ["rootOnly"];
+
+const { Module } = ChromeUtils.import(
+  "chrome://remote/content/shared/messagehandler/Module.jsm"
+);
+
+class RootOnly extends Module {
+  destroy() {}
+
+  /**
+   * Commands
+   */
+
+  testCommand(params = {}) {
+    return params;
+  }
+}
+
+const rootOnly = RootOnly;