core/types: support yParity field in JSON transactions (#27744)

This adds support for the "yParity" field in transaction objects returned by RPC
APIs. We somehow forgot to add this field even though it has been in the spec for
a long time.

internal/ethapi/api.go

@@ -1375,6 +1375,7 @@ type RPCTransaction struct {
 	V                *hexutil.Big      `json:"v"`
 	R                *hexutil.Big      `json:"r"`
 	S                *hexutil.Big      `json:"s"`
+	YParity          *hexutil.Uint64   `json:"yParity,omitempty"`
 }
 
 // newRPCTransaction returns a transaction that will serialize to the RPC
@@ -1402,20 +1403,27 @@ func newRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber
 		result.BlockNumber = (*hexutil.Big)(new(big.Int).SetUint64(blockNumber))
 		result.TransactionIndex = (*hexutil.Uint64)(&index)
 	}
+
 	switch tx.Type() {
 	case types.LegacyTxType:
 		// if a legacy transaction has an EIP-155 chain id, include it explicitly
 		if id := tx.ChainId(); id.Sign() != 0 {
 			result.ChainID = (*hexutil.Big)(id)
 		}
+
 	case types.AccessListTxType:
 		al := tx.AccessList()
+		yparity := hexutil.Uint64(v.Sign())
 		result.Accesses = &al
 		result.ChainID = (*hexutil.Big)(tx.ChainId())
+		result.YParity = &yparity
+
 	case types.DynamicFeeTxType:
 		al := tx.AccessList()
+		yparity := hexutil.Uint64(v.Sign())
 		result.Accesses = &al
 		result.ChainID = (*hexutil.Big)(tx.ChainId())
+		result.YParity = &yparity
 		result.GasFeeCap = (*hexutil.Big)(tx.GasFeeCap())
 		result.GasTipCap = (*hexutil.Big)(tx.GasTipCap())
 		// if the transaction has been mined, compute the effective gas price