[FIX] mail: fix permission issue when starring/marking messages

If a user does not have write permissions on a model, he should still be
able to remove himself from the many2many relation.

This caused a problem: some messages could not be modified by a user
(star/unstar or mark as read)

addons/mail/models/mail_message.py

@@ -150,12 +150,18 @@ class Message(models.Model):
     def set_message_needaction(self, partner_ids=None):
         if not partner_ids:
             partner_ids = [self.env.user.partner_id.id]
+        if set(partner_ids) == set([self.env.user.partner_id.id]):
+            # a user should be able to mark a message as needaction for him
+            self = self.sudo()
         return self.write({'needaction_partner_ids': [(4, pid) for pid in partner_ids]})
 
     @api.multi
     def set_message_done(self, partner_ids=None):
         if not partner_ids:
             partner_ids = [self.env.user.partner_id.id]
+        if set(partner_ids) == set([self.env.user.partner_id.id]):
+            # a user should be able to mark a message as done for him
+            self = self.sudo()
         return self.write({'needaction_partner_ids': [(3, pid) for pid in partner_ids]})
 
     @api.multi
@@ -167,10 +173,12 @@ class Message(models.Model):
             :param bool create_missing: create notifications for missing entries
                 (i.e. when acting on displayed messages not notified)
         """
+        # a user should always be able to star a message he can read
+        self.check_access_rule('read')
         if starred:
-            self.write({'starred_partner_ids': [(4, self.env.user.partner_id.id)]})
+            self.sudo().write({'starred_partner_ids': [(4, self.env.user.partner_id.id)]})
         else:
-            self.write({'starred_partner_ids': [(3, self.env.user.partner_id.id)]})
+            self.sudo().write({'starred_partner_ids': [(3, self.env.user.partner_id.id)]})
         return starred
 
     #------------------------------------------------------