From 76f6e5a3a3abdbd6b32c95b662e439db9029174e Mon Sep 17 00:00:00 2001
From: Valentin Chaboche <valentin.chaboche@nomadic-labs.com>
Date: Mon, 23 Feb 2026 11:39:15 +0100
Subject: [PATCH] Decode round from fitness and use it in getround for
 proposals

---
 protocol/core/shell.go                      | 22 +++++++++++++++++++++
 protocol/proto_022_PsRiotum/sign_request.go |  8 +++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/protocol/core/shell.go b/protocol/core/shell.go
index bf9ed4f..4ab9687 100644
--- a/protocol/core/shell.go
+++ b/protocol/core/shell.go
@@ -1,6 +1,8 @@
 package core
 
 import (
+	"encoding/binary"
+	"errors"
 	tz "github.com/ecadlabs/gotez/v2"
 	"github.com/ecadlabs/gotez/v2/encoding"
 )
@@ -16,6 +18,26 @@ type ShellHeader struct {
 	Context        *tz.ContextHash    `json:"context"`
 }
 
+// GetRoundFromTenderbakeBlock extracts the round from a Tenderbake block fitness
+func GetRoundFromTenderbakeBlock(data tz.Bytes) (uint32, error) {
+	/* FITNESS=
+	   (<fitness_length(4)> not in gotez)
+	   <version_len(4)><version(1)>
+	   <level_len(4)><level(4)>
+	   <locked_round_len(4)><locked_round(0 OR 4)>
+	   <predecessor_round_len(4)><predecessor_round(4)>
+	   <round_len(4)><round(4)> */
+
+	if len(data) < 4 {
+		return 0, errors.New("data too short to extract round")
+	}
+	// The fitness data has been stripped from its prefixed length
+	// The round value is always the 4 last bytes
+	round := binary.BigEndian.Uint32(data[len(data)-4:])
+
+	return round, nil
+}
+
 type BlockMetadataHeader struct {
 	TestChainStatus        TestChainStatus           `json:"test_chain_status"`
 	MaxOperationsTTL       int32                     `json:"max_operations_ttl"`
diff --git a/protocol/proto_022_PsRiotum/sign_request.go b/protocol/proto_022_PsRiotum/sign_request.go
index deeaf3b..6cb1312 100644
--- a/protocol/proto_022_PsRiotum/sign_request.go
+++ b/protocol/proto_022_PsRiotum/sign_request.go
@@ -56,7 +56,13 @@ type BlockSignRequest struct {
 
 func (r *BlockSignRequest) GetChainID() *tz.ChainID { return r.Chain }
 func (r *BlockSignRequest) GetLevel() int32         { return r.BlockHeader.Level }
-func (r *BlockSignRequest) GetRound() int32         { return r.BlockHeader.PayloadRound }
+func (r *BlockSignRequest) GetRound() int32 {
+	round, err := core.GetRoundFromTenderbakeBlock(r.BlockHeader.Fitness)
+	if err != nil {
+		fmt.Println("Error: ", err)
+	}
+	return int32(round)
+}
 func (*BlockSignRequest) SignRequestKind() string   { return "block" }
 
 type ConsensusSignRequest[T core.OperationContents] struct {