[FIX] mail: improve performance of messaging menu counter

Avoid iterating over all channels every time a new channel is added.

Part of task-2702450

closes odoo/odoo#81157

X-original-commit: 6c64781f60599571ef92b011eca7d299e76bf5eb
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/models/messaging_menu/messaging_menu.js

@@ -1,7 +1,7 @@
 /** @odoo-module **/
 
 import { registerModel } from '@mail/model/model_core';
-import { attr } from '@mail/model/model_field';
+import { attr, one2many } from '@mail/model/model_field';
 
 registerModel({
     name: 'mail.messaging_menu',
@@ -40,11 +40,7 @@ registerModel({
                 return 0;
             }
             const inboxCounter = this.messaging.inbox ? this.messaging.inbox.counter : 0;
-            const unreadChannelsCounter = this.messaging.models['mail.thread'].all(channel => (
-                channel.model === 'mail.channel' &&
-                channel.isPinned &&
-                channel.localMessageUnreadCounter > 0
-            )).length;
+            const unreadChannelsCounter = this.pinnedAndUnreadChannels.length;
             const notificationGroupsCounter = this.messaging.models['mail.notification_group'].all().reduce(
                 (total, group) => total + group.notifications.length,
                 0
@@ -81,5 +77,12 @@ registerModel({
         isOpen: attr({
             default: false,
         }),
+        /**
+         * States all the pinned channels that have unread messages.
+         */
+         pinnedAndUnreadChannels: one2many('mail.thread', {
+            inverse: 'messagingMenuAsPinnedAndUnreadChannel',
+            readonly: true,
+        }),
     },
 });

addons/mail/static/src/models/thread/thread.js

@@ -1546,6 +1546,18 @@ registerModel({
             }
             return clear();
         },
+        /**
+         * @private
+         * @returns {FieldCommand}
+         */
+        _computeMessagingMenuAsPinnedAndUnreadChannel() {
+            if (!this.messaging.messagingMenu) {
+                return clear();
+            }
+            return (this.model === 'mail.channel' && this.isPinned && this.localMessageUnreadCounter > 0)
+                ? replace(this.messaging.messagingMenu)
+                : clear();
+        },
         /**
          * @private
          * @returns {mail.message[]}
@@ -2177,6 +2189,11 @@ registerModel({
             inverse: 'ringingThreads',
             readonly: true,
         }),
+        messagingMenuAsPinnedAndUnreadChannel: many2one('mail.messaging_menu', {
+            compute: '_computeMessagingMenuAsPinnedAndUnreadChannel',
+            inverse: 'pinnedAndUnreadChannels',
+            readonly: true,
+        }),
         model: attr({
             readonly: true,
             required: true,