[FIX] mail: handle server error in the front-end part

Issue

    - Install Time Off
    - Marc Demo > Create leave request
    - Admin > Validate the leave request
    - Marc Demo > Add an attachment

    Nothing happens

Cause

    There is a access right issue that is not handled in the
    JS.

Solution

    Handle it by doing a do_warn.

OPW-2171791

closes odoo/odoo#43484

X-original-commit: 6a98c75ebfca694e1e68fa09eca95e47472bed92
Signed-off-by: Jason Van Malder <jvm-odoo@users.noreply.github.com>

addons/mail/i18n/mail.pot

@@ -6113,6 +6113,13 @@ msgstr ""
 msgid "You are in channel <b>#%s</b>."
 msgstr ""
 
+#. module: mail
+#. openerp-web
+#: code:addons/mail/static/src/js/attachment_box.js:0
+#, python-format
+msgid "You are not allowed to upload an attachment here."
+msgstr ""
+
 #. module: mail
 #. openerp-web
 #: code:addons/mail/static/src/js/discuss.js:0

addons/mail/static/src/js/attachment_box.js

@@ -127,8 +127,12 @@ var AttachmentBox = Widget.extend({
     /**
      * @private
      */
-    _onUploaded: function() {
-        this.trigger_up('reload_attachment_box');
+    _onUploaded: function(ev, response) {
+        if (response.error) {
+            this.do_warn(_t("Error"), _t("You are not allowed to upload an attachment here."));
+        } else {
+            this.trigger_up('reload_attachment_box');
+        }
     },
 });