[REF] mail: get rid of thread_model context key

message_post and various mail.thread related code still support a thread_model
context key allowing to redirect message post on another model. Purpose of
this commit is to get rid of that context key and support model / res_id
fields coming from either the record on which we run, either parameters of
message_post. Indeed those parameter match the one used as fields on mail
message. It makes sense to support them for customization if necessary
instead of using a context key.

This context key exists since a lot of time. It is difficult to find the
source as history is quite complex when the mail was refactored in 2012.
See notably 6aa4f80b2d9696a8dcbcc970bbd656b5842b02d4 and 2c4ed841b915cef42fe1f65d27427b7d86d659cd for example.

3 files changed, 18 insertions, 24 deletions

diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index 2ce459cce4e..1fdf8cb656b 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -1274,8 +1274,6 @@ class MailThread(models.AbstractModel):
                 if thread_id:
                     raise ValueError("Posting a message without model should be with a null res_id, to create a private message.")
                 thread = self.env['mail.thread']
-            if not hasattr(thread, 'message_post'):
-                thread = self.env['mail.thread'].with_context(thread_model=model)
 
             # replies to internal message are considered as notes, but parent message
             # author is added in recipients to ensure he is notified of a private answer
@@ -1287,7 +1285,11 @@ class MailThread(models.AbstractModel):
                     partner_ids = [(4, parent_message.author_id.id)]
             else:
                 subtype = 'mail.mt_comment'
-            new_msg = thread.message_post(subtype=subtype, partner_ids=partner_ids, **message_dict)
+
+            post_params = dict(subtype=subtype, partner_ids=partner_ids, **message_dict)
+            if not hasattr(thread, 'message_post'):
+                post_params['model'] = model
+            new_msg = thread.message_post(**post_params)
 
             if original_partner_ids:
                 # postponed after message_post, because this is an external message and we don't want to create
@@ -1379,23 +1381,17 @@ class MailThread(models.AbstractModel):
                                       when creating the new thread record.
                                       Be careful, these values may override
                                       any other values coming from the message.
-           :param dict context: if a ``thread_model`` value is present
-                                in the context, its value will be used
-                                to determine the model of the record
-                                to create (instead of the current model).
            :rtype: int
            :return: the id of the newly created thread object
         """
         data = {}
         if isinstance(custom_values, dict):
             data = custom_values.copy()
-        model = self._context.get('thread_model') or self._name
-        RecordModel = self.env[model]
-        fields = RecordModel.fields_get()
-        name_field = RecordModel._rec_name or 'name'
+        fields = self.fields_get()
+        name_field = self._rec_name or 'name'
         if name_field in fields and not data.get('name'):
             data[name_field] = msg_dict.get('subject', '')
-        return RecordModel.create(data)
+        return self.create(data)
 
     @api.multi
     def message_update(self, msg_dict, update_vals=None):
@@ -1887,10 +1883,9 @@ class MailThread(models.AbstractModel):
         model = False
         if self.ids:
             self.ensure_one()
-            model = self._context.get('thread_model', False) if self._name == 'mail.thread' else self._name
+            model = kwargs.get('model', False) if self._name == 'mail.thread' else self._name
             if model and model != self._name and hasattr(self.env[model], 'message_post'):
-                RecordModel = self.env[model].with_context(thread_model=None)  # TDE: was removing the key ?
-                return RecordModel.browse(self.ids).message_post(
+                return self.env[model].browse(self.ids).message_post(
                     body=body, subject=subject, message_type=message_type,
                     subtype=subtype, parent_id=parent_id, attachments=attachments,
                     notif_layout=notif_layout, notif_values=notif_values, **kwargs)
diff --git a/addons/mail/wizard/mail_compose_message.py b/addons/mail/wizard/mail_compose_message.py
index 91718f21f8a..e16cd71815b 100644
--- a/addons/mail/wizard/mail_compose_message.py
+++ b/addons/mail/wizard/mail_compose_message.py
@@ -216,9 +216,7 @@ class MailComposer(models.TransientModel):
             mass_mode = wizard.composition_mode in ('mass_mail', 'mass_post')
 
             Mail = self.env['mail.mail']
-            ActiveModel = self.env[wizard.model if wizard.model else 'mail.thread']
-            if not hasattr(ActiveModel, 'message_post'):
-                ActiveModel = self.env['mail.thread'].with_context(thread_model=wizard.model)
+            ActiveModel = self.env[wizard.model] if wizard.model and hasattr(self.env[wizard.model], 'message_post') else self.env['mail.thread']
             if wizard.composition_mode == 'mass_post':
                 # do not send emails directly but use the queue instead
                 # add context key to avoid subscribing the author
@@ -248,7 +246,7 @@ class MailComposer(models.TransientModel):
                     if wizard.composition_mode == 'mass_mail':
                         batch_mails |= Mail.create(mail_values)
                     else:
-                        ActiveModel.browse(res_id).message_post(
+                        post_params = dict(
                             message_type=wizard.message_type,
                             subtype_id=subtype_id,
                             notif_layout=notif_layout,
@@ -257,6 +255,9 @@ class MailComposer(models.TransientModel):
                                 'mail_auto_delete': wizard.template_id.auto_delete if wizard.template_id else False,
                             },
                             **mail_values)
+                        if ActiveModel._name == 'mail.thread' and wizard.model:
+                            post_params['model'] = wizard.model
+                        ActiveModel.browse(res_id).message_post(**post_params)
 
                 if wizard.composition_mode == 'mass_mail':
                     batch_mails.send(auto_commit=auto_commit)
diff --git a/addons/test_mail/tests/test_mail_gateway.py b/addons/test_mail/tests/test_mail_gateway.py
index ccf5fb64423..a9286797384 100644
--- a/addons/test_mail/tests/test_mail_gateway.py
+++ b/addons/test_mail/tests/test_mail_gateway.py
@@ -475,17 +475,15 @@ class TestMailgateway(BaseFunctionalTest, MockEmails):
         """ Testing private discussion between partners. """
         msg1_pids = [self.env.user.partner_id.id, self.partner_1.id]
 
-        # Do: Raoul writes to Bert and Administrator, with a thread_model in context that should not be taken into account
-        msg1 = self.env['mail.thread'].with_context({
-            'thread_model': 'mail.test'
-        }).sudo(self.user_employee).message_post(partner_ids=msg1_pids, subtype='mail.mt_comment')
+        # Do: Raoul writes to Bert and Administrator, with a model specific by parameter that should not be taken into account
+        msg1 = self.env['mail.thread'].sudo(self.user_employee).message_post(partner_ids=msg1_pids, subtype='mail.mt_comment', model='mail.test')
 
         # Test: message recipients
         msg = self.env['mail.message'].browse(msg1.id)
         self.assertEqual(msg.partner_ids, self.env.user.partner_id | self.partner_1,
                          'message_post: private discussion: incorrect recipients')
         self.assertEqual(msg.model, False,
-                         'message_post: private discussion: context key "thread_model" not correctly ignored when having no res_id')
+                         'message_post: private discussion: parameter model not correctly ignored when having no res_id')
         # Test: message-id
         self.assertIn('openerp-private', msg.message_id, 'message_post: private discussion: message-id should contain the private keyword')