From 4f6ffd0a481a428958c403f83858d9326ed6c3ce Mon Sep 17 00:00:00 2001
From: Piers Powlesland <pierspowlesland@gmail.com>
Date: Fri, 30 Aug 2024 11:49:45 +0100
Subject: [PATCH] core/types: more extensible tx signing

Having just a single return point in methods that build signers makes it
easier for forks of go ethereum to add their own signers that delegate
to the underlying signer chain, since they can intercept the signer
chain at a single point.
---
 core/types/transaction_signing.go | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/core/types/transaction_signing.go b/core/types/transaction_signing.go
index dd25f081f7..7eb5938bb7 100644
--- a/core/types/transaction_signing.go
+++ b/core/types/transaction_signing.go
@@ -64,21 +64,20 @@ func MakeSigner(config *params.ChainConfig, blockNumber *big.Int, blockTime uint
 // Use this in transaction-handling code where the current block number is unknown. If you
 // have the current block number available, use MakeSigner instead.
 func LatestSigner(config *params.ChainConfig) Signer {
+	var signer Signer = HomesteadSigner{}
 	if config.ChainID != nil {
-		if config.CancunTime != nil {
-			return NewCancunSigner(config.ChainID)
-		}
-		if config.LondonBlock != nil {
-			return NewLondonSigner(config.ChainID)
-		}
-		if config.BerlinBlock != nil {
-			return NewEIP2930Signer(config.ChainID)
-		}
-		if config.EIP155Block != nil {
-			return NewEIP155Signer(config.ChainID)
+		switch {
+		case config.CancunTime != nil:
+			signer = NewCancunSigner(config.ChainID)
+		case config.LondonBlock != nil:
+			signer = NewLondonSigner(config.ChainID)
+		case config.BerlinBlock != nil:
+			signer = NewEIP2930Signer(config.ChainID)
+		case config.EIP155Block != nil:
+			signer = NewEIP155Signer(config.ChainID)
 		}
 	}
-	return HomesteadSigner{}
+	return signer
 }
 
 // LatestSignerForChainID returns the 'most permissive' Signer available. Specifically,
@@ -89,10 +88,11 @@ func LatestSigner(config *params.ChainConfig) Signer {
 // configuration are unknown. If you have a ChainConfig, use LatestSigner instead.
 // If you have a ChainConfig and know the current block number, use MakeSigner instead.
 func LatestSignerForChainID(chainID *big.Int) Signer {
-	if chainID == nil {
-		return HomesteadSigner{}
+	var signer Signer = HomesteadSigner{}
+	if chainID != nil {
+		signer = NewCancunSigner(chainID)
 	}
-	return NewCancunSigner(chainID)
+	return signer
 }
 
 // SignTx signs the transaction using the given signer and private key.