Properly handle the bot's host change

src/hooks.py

@@ -159,6 +159,25 @@ def end_who(cli, bot_server, bot_nick, target, rest):
 
     Event("who_end", {}).dispatch(var, target)
 
+### Host changing handling
+
+@hook("event_hosthidden")
+def host_hidden(cli, server, nick, host, message):
+    """Properly update the bot's knowledge of itself.
+
+    Ordering and meaning of arguments for a host hidden event:
+
+    0 - The IRCClient instance (like everywhere else)
+    1 - The server the bot is on
+    2 - The user's nick (i.e. the bot's nick)
+    3 - The new host we are now using
+    4 - A human-friendly message (e.g. "is now your hidden host")
+
+    """
+
+    assert nick == users.Bot.nick
+    users.Bot = users.Bot.with_host(host)
+
 ### Server PING handling
 
 @hook("ping")

src/users.py

@@ -594,6 +594,14 @@ class BotUser(User): # TODO: change all the 'if x is Bot' for 'if isinstance(x,
         self.modes = set()
         return self
 
+    def with_host(self, host):
+        """Create a new bot instance with a new host."""
+        new = super().__new__(type(self), self.client, self.nick, self.ident, host, self.realname, self.account)
+        if new is not self:
+            new.modes = set(self.modes)
+            new.channels = {chan: set(modes) for chan, modes in self.channels.items()}
+        return new
+
     def lower(self):
         temp = type(self)(self.client, lower(self.nick))
         if temp is not self: