From f6064f32c4abeffa99c4c29674fe9ba756e90e08 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Tue, 14 Oct 2025 14:40:54 +0200
Subject: [PATCH] internal/ethapi: convert legacy blobtx proofs in
 sendRawTransaction (#32849)

This adds a temporary conversion path for blob transactions with legacy
proof sidecar. This feature will activate after Fusaka. We will phase
this out when the fork has sufficiently settled and client side
libraries have been upgraded to send the new proofs.
---
 internal/ethapi/api.go | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index a2cb28d3b2..c10a4754af 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -1619,16 +1619,9 @@ func (api *TransactionAPI) SendTransaction(ctx context.Context, args Transaction
 // processing (signing + broadcast).
 func (api *TransactionAPI) FillTransaction(ctx context.Context, args TransactionArgs) (*SignTransactionResult, error) {
 	// Set some sanity defaults and terminate on failure
-	sidecarVersion := types.BlobSidecarVersion0
-	if len(args.Blobs) > 0 {
-		h := api.b.CurrentHeader()
-		if api.b.ChainConfig().IsOsaka(h.Number, h.Time) {
-			sidecarVersion = types.BlobSidecarVersion1
-		}
-	}
 	config := sidecarConfig{
 		blobSidecarAllowed: true,
-		blobSidecarVersion: sidecarVersion,
+		blobSidecarVersion: api.currentBlobSidecarVersion(),
 	}
 	if err := args.setDefaults(ctx, api.b, config); err != nil {
 		return nil, err
@@ -1642,6 +1635,14 @@ func (api *TransactionAPI) FillTransaction(ctx context.Context, args Transaction
 	return &SignTransactionResult{data, tx}, nil
 }
 
+func (api *TransactionAPI) currentBlobSidecarVersion() byte {
+	h := api.b.CurrentHeader()
+	if api.b.ChainConfig().IsOsaka(h.Number, h.Time) {
+		return types.BlobSidecarVersion1
+	}
+	return types.BlobSidecarVersion0
+}
+
 // SendRawTransaction will add the signed transaction to the transaction pool.
 // The sender is responsible for signing the transaction and using the correct nonce.
 func (api *TransactionAPI) SendRawTransaction(ctx context.Context, input hexutil.Bytes) (common.Hash, error) {
@@ -1649,6 +1650,19 @@ func (api *TransactionAPI) SendRawTransaction(ctx context.Context, input hexutil
 	if err := tx.UnmarshalBinary(input); err != nil {
 		return common.Hash{}, err
 	}
+
+	// Convert legacy blob transaction proofs.
+	// TODO: remove in go-ethereum v1.17.x
+	if sc := tx.BlobTxSidecar(); sc != nil {
+		exp := api.currentBlobSidecarVersion()
+		if sc.Version == types.BlobSidecarVersion0 && exp == types.BlobSidecarVersion1 {
+			if err := sc.ToV1(); err != nil {
+				return common.Hash{}, fmt.Errorf("blob sidecar conversion failed: %v", err)
+			}
+			tx = tx.WithBlobTxSidecar(sc)
+		}
+	}
+
 	return SubmitTransaction(ctx, api.b, tx)
 }