[IMP] mail,*: support tracking x2many fields

X2many fields tracking was not supported in the implementation of
`mail` module:
* not needed in the past
* the logic was not hooked in the same place before.  Now that it is
managed pre-commit, x2many values don't have to be handled as commands,
but can be compared as records.
* ...

The support was added for two specific models in specific modules, but
it's a good opportunity to clean that and to support it directly in `mail`.

Task-3316528

Part-of: odoo/odoo#121244

addons/account/models/account_move_line.py

@@ -1572,27 +1572,6 @@ class AccountMoveLine(models.Model):
             for root in self.env['account.root'].browse(id for [id] in self.env.cr.fetchall())
         }
 
-    # -------------------------------------------------------------------------
-    # TRACKING METHODS
-    # -------------------------------------------------------------------------
-
-    def _mail_track(self, tracked_fields, initial):
-        changes, tracking_value_ids = super()._mail_track(tracked_fields, initial)
-        if len(changes) > len(tracking_value_ids):
-            for i, changed_field in enumerate(changes):
-                if tracked_fields[changed_field]['type'] in ['one2many', 'many2many']:
-                    field = self.env['ir.model.fields']._get(self._name, changed_field)
-                    vals = {
-                        'field': field.id,
-                        'field_desc': field.field_description,
-                        'field_type': field.ttype,
-                        'tracking_sequence': field.tracking,
-                        'old_value_char': ', '.join(initial[changed_field].mapped('name')),
-                        'new_value_char': ', '.join(self[changed_field].mapped('name')),
-                    }
-                    tracking_value_ids.insert(i, Command.create(vals))
-        return changes, tracking_value_ids
-
     # -------------------------------------------------------------------------
     # RECONCILIATION
     # -------------------------------------------------------------------------

addons/mail/models/mail_tracking_value.py

@@ -81,6 +81,11 @@ class MailTracking(models.Model):
                 'old_value_char': initial_value and initial_value.sudo().name_get()[0][1] or '',
                 'new_value_char': new_value and new_value.sudo().name_get()[0][1] or ''
             })
+        elif col_info['type'] in ['many2many', 'one2many']:
+            values.update({
+                'old_value_char': initial_value and ', '.join(initial_value.mapped('display_name')) or '',
+                'new_value_char': new_value and ', '.join(new_value.mapped('display_name')) or ''
+            })
         else:
             tracked = False
 

addons/project/models/project_task.py

@@ -1157,24 +1157,6 @@ class Task(models.Model):
                 pass
         return new_followers
 
-    def _mail_track(self, tracked_fields, initial_values):
-        changes, tracking_value_ids = super()._mail_track(tracked_fields, initial_values)
-        # Many2many tracking
-        if len(changes) > len(tracking_value_ids):
-            for changed_field in changes:
-                if tracked_fields[changed_field]['type'] in ['one2many', 'many2many']:
-                    field = self.env['ir.model.fields']._get(self._name, changed_field)
-                    vals = {
-                        'field': field.id,
-                        'field_desc': field.field_description,
-                        'field_type': field.ttype,
-                        'tracking_sequence': field.tracking,
-                        'old_value_char': ', '.join(initial_values[changed_field].mapped('name')),
-                        'new_value_char': ', '.join(self[changed_field].mapped('name')),
-                    }
-                    tracking_value_ids.append(Command.create(vals))
-        return changes, tracking_value_ids
-
     def _track_template(self, changes):
         res = super(Task, self)._track_template(changes)
         test_task = self[0]