You seem to forget that "update_add_htlc", which forces commitment update, always includes "onion_routing_packet" which contains routing instructions. That's how both peers know how to update the channel.
and multiple times i have been saying you cant update a HTLC until you know the amounts, and details to put into a HTLC
alice is not psychic.
i know you want to play the whole 'everyone is seen online, there is no privacy, all the data is found when people start their node/app..
but this is not the case.
you say that the transparent network map is on by default and requires an opt out to become private. but its actually the opposite. its an opt-in process of being private first and deciding to go public
https://github.com/lightning/bolts/blob/master/07-routing-gossip.md#the-announcement_signatures-messageThe announcement_signatures Message
This is a direct message between the two endpoints of a channel and serves as an opt-in mechanism to allow the announcement of the channel to the rest of the network.
in short, nodes dont announce, and can reject requests and not announce, unless they choose to go public.
nodes are not forced to announce and then choose to go private
even while private they can still be routes to only the channels they want to accept
EG if i was C in ABCDE
i can keep my BC side private. thus A wont know about me through network map. but set my CD as public and so E can see me on the network map.
E could use network gossip to build a route to A
but if A wanted to build a route to E. A would need to do channel requests to B to see that B is actually connected to C.. (and then to D and then to E )SEPARATE from the network map
this if you learned it could actually become a positive privacy feature.. allowing payments to be made without having to be public.
but as always you want to deny it happens because it doesnt fit your narrative.
.. which is starting to seem like your not actually interested in promoting LN for its positive features for the niche service it offers. but just want to cause debate and misinformation to fit a narrative where you thought that everything was done via commitment changes and only done by commitment changes(facepalm)
so please. try to learn about the messages. the HUNDREDS of different messages that happen before a HTLC is even changed.
because you cant change a HTLC unless you first know the data to put into the change