[FIX] mail: fix back button issue to close channel

Before this commit:

When switching to mobile view and refreshing the channel in discuss than back
arrow button is not working

After this commit:

Back arrow button will close the channel

Task-2685187

closes odoo/odoo#85034

X-original-commit: ebe56aac6d11e967d3b2fc8b57031e1b0e8ea726
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/components/discuss/discuss.js

@@ -25,8 +25,6 @@ export class Discuss extends Component {
         }
         if (this.discussView.discuss.thread) {
             this.trigger('o-push-state-action-manager');
-        } else if (!this._activeThreadCache) {
-            this.discussView.discuss.openInitThread();
         }
         if (
             this.discussView.discuss.thread &&
@@ -37,7 +35,6 @@ export class Discuss extends Component {
         ) {
             this.trigger('o-show-rainbow-man');
         }
-        this._activeThreadCache = this.discussView.discuss.threadView && this.discussView.discuss.threadView.threadCache;
         this._updateLocalStoreProps();
     }
 

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

@@ -161,9 +161,7 @@ registerModel({
             this.update({ discussView: insertAndReplace() });
         },
         /**
-         * Open thread from init active id. `initActiveId` is used to refer to
-         * a thread that we may not have full data yet, such as when messaging
-         * is not yet initialized.
+         * Opens thread from init active id if the thread exists.
          */
         openInitThread() {
             const [model, id] = typeof this.initActiveId === 'number'
@@ -396,6 +394,14 @@ registerModel({
             compute: '_computeIsAddingChat',
             default: false,
         }),
+        /**
+         * Determines if the logic for opening a thread via the `initActiveId`
+         * has been processed. This is necessary to ensure that this only
+         * happens once.
+         */
+        isInitThreadHandled: attr({
+            default: false,
+        }),
         /**
          * The menu_id of discuss app, received on mail/init_messaging and
          * used to open discuss from elsewhere.

addons/mail/static/src/widgets/discuss/discuss.js

@@ -1,6 +1,7 @@
 /** @odoo-module **/
 
 import { DiscussContainer } from "@mail/components/discuss_container/discuss_container";
+import { insertAndReplace } from '@mail/model/model_field_command';
 
 import AbstractAction from 'web.AbstractAction';
 
@@ -31,14 +32,23 @@ export const DiscussWidget = AbstractAction.extend({
 
         this._lastPushStateActiveThread = null;
         this.env = Component.env;
-        Component.env.services.messaging.modelManager.messagingCreatedPromise.then(() => {
+        Component.env.services.messaging.modelManager.messagingCreatedPromise.then(async () => {
             const messaging = Component.env.services.messaging.modelManager.messaging;
             const initActiveId = this.options.active_id ||
                 (this.action.context && this.action.context.active_id) ||
                 (this.action.params && this.action.params.default_active_id) ||
                 'mail.box_inbox';
             this.discuss = messaging.discuss;
-            this.discuss.update({ initActiveId });
+            this.discuss.update({ discussView: insertAndReplace(), initActiveId });
+            // Wait for messaging to be initialized to make sure the system
+            // knows of the "init thread" if it exists.
+            await messaging.initializedPromise;
+            if (!this.discuss.isInitThreadHandled) {
+                this.discuss.update({ isInitThreadHandled: true });
+                if (!this.discuss.thread) {
+                    this.discuss.openInitThread();
+                }
+            }
         });
     },
     /**