[IMP] mail: email channels duplicated notifications

This commit prevents sending a notification within Odoo when a
message is posted from a mailing channel to a user whose notification
management preference is set to "Handle by Emails".

Task-ID 2033302

closes odoo/odoo#36000

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/addons/mail/static/src/js/services/mail_notification_manager.js b/addons/mail/static/src/js/services/mail_notification_manager.js
index 9cef9742747..ba9230eb32b 100644
--- a/addons/mail/static/src/js/services/mail_notification_manager.js
+++ b/addons/mail/static/src/js/services/mail_notification_manager.js
@@ -97,9 +97,14 @@ MailManager.include({
     _handleChannelMessageNotification: function (messageData) {
         var self = this;
         var def;
-        var channelAlreadyInCache = true;
+        let notify = true;
         if (messageData.channel_ids.length === 1) {
-            channelAlreadyInCache = !!this.getChannel(messageData.channel_ids[0]);
+            const channel = this.getChannel(messageData.channel_ids[0]);
+            // Message from mailing channel should not make a notification in Odoo for users
+            // with notification "Handled by Email", but web client should receive the message.
+            // Channel has been marked as read server-side in this case, so it should not display
+            // a notification by incrementing the unread counter.
+            notify = channel && (!channel.isMassMailing() || session.notification_type !== 'email');
             def = this.joinChannel(messageData.channel_ids[0], { autoswitch: false });
         } else {
             def = Promise.resolve();
@@ -109,7 +114,7 @@ MailManager.include({
             // its unread counter has just been fetched
             return self.addMessage(messageData, {
                 showNotification: true,
-                incrementUnread: channelAlreadyInCache
+                incrementUnread: notify,
             });
         });
     },