From d30e1d83b63a9b4d3765ea5be1287bf6af67108c Mon Sep 17 00:00:00 2001
From: Erik Grinaker <erik@interchain.berlin>
Date: Tue, 25 Aug 2020 11:23:16 +0200
Subject: [PATCH] types: comment on need for length prefixing (#5283)

Fixes #5276.
---
 types/proposal.go | 6 ++++--
 types/vote.go     | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/types/proposal.go b/types/proposal.go
index f714de309..20f9e5fbe 100644
--- a/types/proposal.go
+++ b/types/proposal.go
@@ -100,9 +100,11 @@ func (p *Proposal) String() string {
 }
 
 // ProposalSignBytes returns the proto-encoding of the canonicalized Proposal,
-// for signing.
+// for signing. Panics if the marshaling fails.
 //
-// Panics if the marshaling fails.
+// The encoded Protobuf message is varint length-prefixed (using MarshalDelimited)
+// for backwards-compatibility with the Amino encoding, due to e.g. hardware
+// devices that rely on this encoding.
 //
 // See CanonicalizeProposal
 func ProposalSignBytes(chainID string, p *tmproto.Proposal) []byte {
diff --git a/types/vote.go b/types/vote.go
index aff0b1730..177eb23a7 100644
--- a/types/vote.go
+++ b/types/vote.go
@@ -85,9 +85,11 @@ func (vote *Vote) CommitSig() CommitSig {
 }
 
 // VoteSignBytes returns the proto-encoding of the canonicalized Vote, for
-// signing.
+// signing. Panics is the marshaling fails.
 //
-// Panics if the marshaling fails.
+// The encoded Protobuf message is varint length-prefixed (using MarshalDelimited)
+// for backwards-compatibility with the Amino encoding, due to e.g. hardware
+// devices that rely on this encoding.
 //
 // See CanonicalizeVote
 func VoteSignBytes(chainID string, vote *tmproto.Vote) []byte {