From d12fe799eb2660ab925c5baffd53bccbdff9899b Mon Sep 17 00:00:00 2001
From: teebaumcrypto <72811287+teebaumcrypto@users.noreply.github.com>
Date: Sat, 29 Jun 2024 20:08:16 +0200
Subject: [PATCH] fix(network): handle end of list in tx monitor response
 (#305)

---
 .../src/miniprotocols/txmonitor/codec.rs      | 32 ++++++++++++++-----
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/pallas-network/src/miniprotocols/txmonitor/codec.rs b/pallas-network/src/miniprotocols/txmonitor/codec.rs
index 15da33c..0bbc5b8 100644
--- a/pallas-network/src/miniprotocols/txmonitor/codec.rs
+++ b/pallas-network/src/miniprotocols/txmonitor/codec.rs
@@ -80,14 +80,19 @@ impl<'b> Decode<'b, ()> for Message {
             // find the specs
             4 => Ok(Message::AwaitAcquire),
             5 => Ok(Message::RequestNextTx),
-            6 => match d.datatype()? {
-                pallas_codec::minicbor::data::Type::Array
-                | pallas_codec::minicbor::data::Type::ArrayIndef => {
-                    let tx = d.decode()?;
-                    Ok(Message::ResponseNextTx(Some(tx)))
-                }
-                _ => Ok(Message::ResponseNextTx(None)),
-            },
+            6 => match d.datatype() {
+                Ok(datatype) => {
+                    match datatype {
+                        pallas_codec::minicbor::data::Type::Array
+                        | pallas_codec::minicbor::data::Type::ArrayIndef => {
+                            let tx = d.decode()?;
+                            Ok(Message::ResponseNextTx(Some(tx)))
+                        }
+                        _ => Ok(Message::ResponseNextTx(None))
+                    }
+                },
+                Err(_) => Ok(Message::ResponseNextTx(None))
+            }
             7 => {
                 let id = d.decode()?;
                 Ok(Message::RequestHasTx(id))
@@ -130,4 +135,15 @@ pub mod tests {
             unreachable!();
         }
     }
+    #[test]
+    fn test_empty_next_tx_response() {
+        let bytes = vec![129, 6];
+        let msg: super::Message = pallas_codec::minicbor::decode(&bytes).unwrap();
+
+        if let super::Message::ResponseNextTx(None) = msg {
+            assert_eq!(0u64, 0u64);
+        } else {
+            unreachable!();
+        }
+    }
 }