Allow displayname updates if ghost user has no name

mautrix_telegram/portal/telegram.py

@@ -589,6 +589,9 @@ class PortalTelegram(BasePortal, ABC):
                            "displayname, updating info...")
             entity = await source.client.get_entity(PeerUser(sender.tgid))
             await sender.update_info(source, entity)
+            if not sender.displayname:
+                self.log.debug(f"Telegram user {sender.tgid} doesn't have a displayname even after"
+                               f" updating with data {entity!s}")
 
         allowed_media = (MessageMediaPhoto, MessageMediaDocument, MessageMediaGeo,
                          MessageMediaGame, MessageMediaDice, MessageMediaPoll,

mautrix_telegram/puppet.py

@@ -270,8 +270,10 @@ class Puppet(BasePuppet):
             allow_because = "user is the primary source"
         elif not isinstance(info, UpdateUserName) and not info.contact:
             allow_because = "user is not a contact"
-        elif self.displayname_source is None:
+        elif not self.displayname_source:
             allow_because = "no primary source set"
+        elif not self.displayname:
+            allow_because = "user has no name"
         else:
             return False