From bc3702ec428bf4a170b9a00da20d24c58405b2b0 Mon Sep 17 00:00:00 2001
From: Dan Cline <6798349+Rjected@users.noreply.github.com>
Date: Thu, 1 Dec 2022 21:27:33 -0500
Subject: [PATCH] chore(rlp): add comment on `0x80` decoding (#312)

* add comment on 0x80 decoding

 * decode 0x80 into zero explicitly

* add explicit 0x80 decoding for ethereum types
---
 crates/common/rlp/src/decode.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/crates/common/rlp/src/decode.rs b/crates/common/rlp/src/decode.rs
index 68e030228f..ca96be2f02 100644
--- a/crates/common/rlp/src/decode.rs
+++ b/crates/common/rlp/src/decode.rs
@@ -185,6 +185,12 @@ macro_rules! decode_integer {
                 if buf.remaining() < h.payload_length {
                     return Err(DecodeError::InputTooShort)
                 }
+                // In the case of 0x80, the Header will be decoded, leaving h.payload_length to be
+                // zero.
+                // 0x80 is the canonical encoding of 0, so we return 0 here.
+                if h.payload_length == 0 {
+                    return Ok(<$t>::from(0u8))
+                }
                 let v = <$t>::from_be_bytes(
                     static_left_pad(&buf[..h.payload_length]).ok_or(DecodeError::LeadingZero)?,
                 );
@@ -252,6 +258,12 @@ mod ethereum_types_support {
                     if buf.remaining() < h.payload_length {
                         return Err(DecodeError::InputTooShort)
                     }
+                    // In the case of 0x80, the Header will be decoded, leaving h.payload_length to
+                    // be zero.
+                    // 0x80 is the canonical encoding of 0, so we return 0 here.
+                    if h.payload_length == 0 {
+                        return Ok(<$t>::from(0u8))
+                    }
                     let n = <$t>::from_big_endian(
                         &static_left_pad::<$n_bytes>(&buf[..h.payload_length])
                             .ok_or(DecodeError::LeadingZero)?,