Bug 1754477 - [devtools] Clear Workers console message cache in WebConsoleActor#clearMessagesCache. r=ochameau.

With Bug 1674336 fixed, we can properly clear worker messages.
A test is added to check this works as expected.

Differential Revision: https://phabricator.services.mozilla.com/D138315

devtools/client/webconsole/test/browser/browser_webconsole_console_logging_workers_api.js

@@ -83,4 +83,37 @@ async function testWorkerMessage(directConnectionToWorkerThread = false) {
   const onMessagesCleared = hud.ui.once("messages-cleared");
   await clearOutput(hud);
   await onMessagesCleared;
+
+  is(
+    findMessage(hud, "initial-message-from-worker"),
+    undefined,
+    "cached message was removed"
+  );
+  is(findMessage(hud, "log-from-worker"), undefined, "as well as live message");
+
+  info("Close and reopen the console to check messages were cleared properly");
+  await closeConsole();
+  const toolbox = await openToolboxForTab(gBrowser.selectedTab, "webconsole");
+  const newHud = toolbox.getCurrentPanel().hud;
+
+  info(
+    "Log a message and wait for it to appear so older messages would have been displayed"
+  );
+  const onSmokeMessage = waitForMessage(newHud, "smoke");
+  SpecialPowers.spawn(gBrowser.selectedBrowser, [], () => {
+    content.wrappedJSObject.console.log("smoke");
+  });
+  await onSmokeMessage;
+
+  is(
+    findMessage(newHud, "initial-message-from-worker"),
+    undefined,
+    "Message cache was cleared"
+  );
+  is(
+    findMessage(newHud, "log-from-worker"),
+    undefined,
+    "Live message were cleared as well"
+  );
+  await closeTabAndToolbox();
 }

devtools/server/actors/webconsole.js

@@ -2,6 +2,8 @@
  * 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/. */
 
+/* global clearConsoleEvents */
+
 "use strict";
 
 const { ActorClassWithSpec, Actor } = require("devtools/shared/protocol");
@@ -1462,11 +1464,8 @@ const WebConsoleActor = ActorClassWithSpec(webconsoleSpec, {
    */
   clearMessagesCache: function() {
     if (isWorker) {
-      // At the moment there is no mechanism available to clear the Console API cache for
-      // a given worker target (See https://bugzilla.mozilla.org/show_bug.cgi?id=1674336).
-      // Worker messages from the console service (e.g. error) are emitted from the main
-      // thread, so this cache will be cleared when the associated document target cache
-      // is cleared.
+      // Defined on WorkerScope
+      clearConsoleEvents();
       return;
     }
 

devtools/shared/loader/worker-loader.js

@@ -516,6 +516,7 @@ this.worker = new WorkerDebuggerLoader({
     setImmediate: setImmediate,
     retrieveConsoleEvents: this.retrieveConsoleEvents,
     setConsoleEventHandler: this.setConsoleEventHandler,
+    clearConsoleEvents: this.clearConsoleEvents,
     console: console,
     btoa: this.btoa,
     atob: this.atob,