From c5b4580e37b44a57605a07a9acdd5057c1b06010 Mon Sep 17 00:00:00 2001
From: Pawan Dhananjay <pawandhananjay@gmail.com>
Date: Wed, 18 Feb 2026 09:47:07 +0530
Subject: [PATCH] Return correct variant for snappy errors (#8841)

N/A


  Handle snappy crate errors as InvalidData instead of IoError.


Co-Authored-By: Pawan Dhananjay <pawandhananjay@gmail.com>
---
 .../lighthouse_network/src/rpc/codec.rs       | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/beacon_node/lighthouse_network/src/rpc/codec.rs b/beacon_node/lighthouse_network/src/rpc/codec.rs
index 36d9726dd9..d1a3182fad 100644
--- a/beacon_node/lighthouse_network/src/rpc/codec.rs
+++ b/beacon_node/lighthouse_network/src/rpc/codec.rs
@@ -457,6 +457,9 @@ fn handle_error<T>(
                 Ok(None)
             }
         }
+        // All snappy errors from the snap crate bubble up as `Other` kind errors
+        // that imply invalid response
+        ErrorKind::Other => Err(RPCError::InvalidData(err.to_string())),
         _ => Err(RPCError::from(err)),
     }
 }
@@ -2317,4 +2320,43 @@ mod tests {
             RPCError::InvalidData(_)
         ));
     }
+
+    /// Test invalid snappy response.
+    #[test]
+    fn test_invalid_snappy_response() {
+        let spec = spec_with_all_forks_enabled();
+        let fork_ctx = Arc::new(fork_context(ForkName::latest(), &spec));
+        let max_packet_size = spec.max_payload_size as usize; // 10 MiB.
+
+        let protocol = ProtocolId::new(SupportedProtocol::BlocksByRangeV2, Encoding::SSZSnappy);
+
+        let mut codec = SSZSnappyOutboundCodec::<Spec>::new(
+            protocol.clone(),
+            max_packet_size,
+            fork_ctx.clone(),
+        );
+
+        let mut payload = BytesMut::new();
+        payload.extend_from_slice(&[0u8]);
+        let deneb_epoch = spec.deneb_fork_epoch.unwrap();
+        payload.extend_from_slice(&fork_ctx.context_bytes(deneb_epoch));
+
+        // Claim the MAXIMUM allowed size (10 MiB)
+        let claimed_size = max_packet_size;
+        let mut uvi_codec: Uvi<usize> = Uvi::default();
+        uvi_codec.encode(claimed_size, &mut payload).unwrap();
+        payload.extend_from_slice(&[0xBB; 16]); // Junk snappy.
+
+        let result = codec.decode(&mut payload);
+
+        assert!(result.is_err(), "Expected decode to fail");
+
+        // IoError = reached snappy decode (allocation happened).
+        let err = result.unwrap_err();
+        assert!(
+            matches!(err, RPCError::InvalidData(_)),
+            "Should return invalid data variant {}",
+            err
+        );
+    }
 }