default accept nil VE

abci/strategies/codec/codec_test.go

@@ -151,4 +151,10 @@ func TestCompressionExtendedCommitCodec(t *testing.T) {
 		// make sure it's the same
 		require.Equal(t, eci, decodedEci)
 	})
+
+	t.Run("test decoding empty byte array", func(t *testing.T) {
+		codec := compression.NewCompressionExtendedCommitCodec(compression.NewDefaultExtendedCommitCodec(), compression.NewZStdCompressor())
+		_, err := codec.Decode([]byte{})
+		require.NoError(t, err)
+	})
 }

abci/ve/vote_extension.go

@@ -232,6 +232,17 @@ func (h *VoteExtensionHandler) VerifyVoteExtensionHandler() sdk.VerifyVoteExtens
 			h.logger.Error("VerifyVoteExtensionHandler received a nil request")
 			return nil, err
 		}
+
+		// By default, we accept empty vote extensions.
+		if len(req.VoteExtension) == 0 {
+			h.logger.Info(
+				"empty vote extension",
+				"height", req.Height,
+			)
+
+			return &cometabci.ResponseVerifyVoteExtension{Status: cometabci.ResponseVerifyVoteExtension_ACCEPT}, nil
+		}
+
 		// decode the vote-extension bytes
 		voteExtension, err := h.voteExtensionCodec.Decode(req.VoteExtension)
 		if err != nil {