From: Matt Corallo <git@bluematt.me>
Date: Fri, 16 Feb 2024 19:26:22 +0000 (+0000)
Subject: Fix `Route` serialization round-trip
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=795000ce546107cfa67638ed3100ff79120ddb3c;p=rust-lightning

Fix `Route` serialization round-trip

When the `max_total_routing_fee_msat` parameter was added to
`RouteParameters`, the serialization used `map` to get the max fee,
accidentally writing an `Option<Option<u64>>`, but then read it as
an `Option<u64>`. Thus, any `Route`s with a `route_params` written
will fail to be read back.

Luckily, this is an incredibly rarely-used bit of code, so only one
user managed to hit it.
---

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index dcd7b2e5b..d52917f3e 100644
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -411,7 +411,7 @@ impl Writeable for Route {
 			(1, self.route_params.as_ref().map(|p| &p.payment_params), option),
 			(2, blinded_tails, optional_vec),
 			(3, self.route_params.as_ref().map(|p| p.final_value_msat), option),
-			(5, self.route_params.as_ref().map(|p| p.max_total_routing_fee_msat), option),
+			(5, self.route_params.as_ref().and_then(|p| p.max_total_routing_fee_msat), option),
 		});
 		Ok(())
 	}