In particular, if the total amount we're sending is less than the minimum amount
the channel insists on, we can eliminate it.
This fixes the problem that we're really trying to send a de-minumus
amount (rather than the more obscure case where we divide the amount
and then it is below the minimum).
After trying several other approaches, this was by far the cleanest!
Reported-by: https://github.com/JssDWt
Fixes: https://github.com/ElementsProject/lightning/issues/8045
Changelog-Fixed: xpay: don't simply give up if our total amount is less than htlc_minimum_msat on some channel.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
And unify logging for better debugging.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-EXPERIMENTAL: `askrene` now has better logging, gives notifications of progress.
1. describe_disabled should point out if node itself is disabled.
2. Hoist constraint check for neater if branching.
3. Use amount_msat_max/min for greater clarity.
4. Simply disable channels, don't zero htlc_min/max when node disabled.
I also fixed the diagnostic of htlc_max correctly, which removes a FIXME.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This turns out to be critical for users: also stops them from
bothering us when their node is offline or has insufficient capacity!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
