Fix blinded path serialization in `Route`

`Route`'s blinded_path serialization logic writes a blinded path
`Option` per path hop, however on read we (correctly) only read one
blinded path `Option` per path. This causes serialization of
`Route`s with blinded paths to fail to round-trip.

Here we fix this by writing blinded paths per path.

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index 436a37144b459a4e73d03bace511b875b47e4386..42556ff3400fe8215064822cd954003f058b9e71 100644 (file)
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -508,20 +508,20 @@ impl Writeable for Route {
                write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
                (self.paths.len() as u64).write(writer)?;
                let mut blinded_tails = Vec::new();
-               for path in self.paths.iter() {
+               for (idx, path) in self.paths.iter().enumerate() {
                        (path.hops.len() as u8).write(writer)?;
-                       for (idx, hop) in path.hops.iter().enumerate() {
+                       for hop in path.hops.iter() {
                                hop.write(writer)?;
-                               if let Some(blinded_tail) = &path.blinded_tail {
-                                       if blinded_tails.is_empty() {
-                                               blinded_tails = Vec::with_capacity(path.hops.len());
-                                               for _ in 0..idx {
-                                                       blinded_tails.push(None);
-                                               }
-                                       }
-                                       blinded_tails.push(Some(blinded_tail));
-                               } else if !blinded_tails.is_empty() { blinded_tails.push(None); }
                        }
+                       if let Some(blinded_tail) = &path.blinded_tail {
+                               if blinded_tails.is_empty() {
+                                       blinded_tails = Vec::with_capacity(path.hops.len());
+                                       for _ in 0..idx {
+                                               blinded_tails.push(None);
+                                       }
+                               }
+                               blinded_tails.push(Some(blinded_tail));
+                       } else if !blinded_tails.is_empty() { blinded_tails.push(None); }
                }
                write_tlv_fields!(writer, {
                        // For compatibility with LDK versions prior to 0.0.117, we take the individual