Developer ZmnSCPxj brought to mind that in the Elements Project implementation of lightning network, receiving via an unpublished channel doesn’t work as it should, as he was implementating support for r field in invoices he stumbled upon some issues regarding creating invoices with r fields.

The issue was that if we wanted to receive via an unpublished channel, we should know what lightning fees the other side of the channel charges, but in an unpublished channel, neither channel_announcement nor channel_updates are sent, so the other side of the channel never informs us of the fees needed to receive through their channel.

A suggested fix here would be to send the channel_update as soon as the channel locks in, this is supposedly used in other Lightning implementations, but not in the Elements Project one.

Discussion