core/types: make receipt PostState optional

core/state_processor.go

@@ -105,15 +105,15 @@ func ApplyTransaction(config *params.ChainConfig, bc *BlockChain, author *common
 
 	// Update the state with pending changes
 	usedGas.Add(usedGas, gas)
-	var root common.Hash
+	var root []byte
 	if config.IsMetropolis(header.Number) {
 		statedb.Finalise()
 	} else {
-		root = statedb.IntermediateRoot(config.IsEIP158(header.Number))
+		root = statedb.IntermediateRoot(config.IsEIP158(header.Number)).Bytes()
 	}
 	// Create a new receipt for the transaction, storing the intermediate root and gas used by the tx
 	// based on the eip phase, we're passing wether the root touch-delete accounts.
-	receipt := types.NewReceipt(root.Bytes(), usedGas)
+	receipt := types.NewReceipt(root, usedGas)
 	receipt.TxHash = tx.Hash()
 	receipt.GasUsed = new(big.Int).Set(gas)
 	// if the transaction created a contract, store the creation address in the receipt.

core/types/gen_receipt_json.go

@@ -13,7 +13,7 @@ import (
 
 func (r Receipt) MarshalJSON() ([]byte, error) {
 	type Receipt struct {
-		PostState         hexutil.Bytes  `json:"root"              gencodec:"required"`
+		PostState         hexutil.Bytes  `json:"root"`
 		CumulativeGasUsed *hexutil.Big   `json:"cumulativeGasUsed" gencodec:"required"`
 		Bloom             Bloom          `json:"logsBloom"         gencodec:"required"`
 		Logs              []*Log         `json:"logs"              gencodec:"required"`
@@ -34,7 +34,7 @@ func (r Receipt) MarshalJSON() ([]byte, error) {
 
 func (r *Receipt) UnmarshalJSON(input []byte) error {
 	type Receipt struct {
-		PostState         hexutil.Bytes   `json:"root"              gencodec:"required"`
+		PostState         hexutil.Bytes   `json:"root"`
 		CumulativeGasUsed *hexutil.Big    `json:"cumulativeGasUsed" gencodec:"required"`
 		Bloom             *Bloom          `json:"logsBloom"         gencodec:"required"`
 		Logs              []*Log          `json:"logs"              gencodec:"required"`
@@ -46,10 +46,9 @@ func (r *Receipt) UnmarshalJSON(input []byte) error {
 	if err := json.Unmarshal(input, &dec); err != nil {
 		return err
 	}
-	if dec.PostState == nil {
+	if dec.PostState != nil {
-		return errors.New("missing required field 'root' for Receipt")
+		r.PostState = dec.PostState
 	}
-	r.PostState = dec.PostState
 	if dec.CumulativeGasUsed == nil {
 		return errors.New("missing required field 'cumulativeGasUsed' for Receipt")
 	}

core/types/receipt.go

@@ -31,7 +31,7 @@ import (
 // Receipt represents the results of a transaction.
 type Receipt struct {
 	// Consensus fields
-	PostState         []byte   `json:"root"              gencodec:"required"`
+	PostState         []byte   `json:"root"`
 	CumulativeGasUsed *big.Int `json:"cumulativeGasUsed" gencodec:"required"`
 	Bloom             Bloom    `json:"logsBloom"         gencodec:"required"`
 	Logs              []*Log   `json:"logs"              gencodec:"required"`
@@ -48,6 +48,19 @@ type receiptMarshaling struct {
 	GasUsed           *hexutil.Big
 }
 
+type homesteadReceiptRLP struct {
+	PostState         []byte
+	CumulativeGasUsed *big.Int
+	Bloom             Bloom
+	Logs              []*Log
+}
+
+type metropolisReceiptRLP struct {
+	CumulativeGasUsed *big.Int
+	Bloom             Bloom
+	Logs              []*Log
+}
+
 // NewReceipt creates a barebone transaction receipt, copying the init fields.
 func NewReceipt(root []byte, cumulativeGasUsed *big.Int) *Receipt {
 	return &Receipt{PostState: common.CopyBytes(root), CumulativeGasUsed: new(big.Int).Set(cumulativeGasUsed)}
@@ -56,23 +69,28 @@ func NewReceipt(root []byte, cumulativeGasUsed *big.Int) *Receipt {
 // EncodeRLP implements rlp.Encoder, and flattens the consensus fields of a receipt
 // into an RLP stream.
 func (r *Receipt) EncodeRLP(w io.Writer) error {
-	return rlp.Encode(w, []interface{}{r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs})
+	if r.PostState == nil {
+		return rlp.Encode(w, &metropolisReceiptRLP{r.CumulativeGasUsed, r.Bloom, r.Logs})
+	} else {
+		return rlp.Encode(w, &homesteadReceiptRLP{r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs})
+	}
 }
 
 // DecodeRLP implements rlp.Decoder, and loads the consensus fields of a receipt
 // from an RLP stream.
 func (r *Receipt) DecodeRLP(s *rlp.Stream) error {
-	var receipt struct {
+	raw, err := s.Raw()
-		PostState         []byte
+	if err != nil {
-		CumulativeGasUsed *big.Int
-		Bloom             Bloom
-		Logs              []*Log
-	}
-	if err := s.Decode(&receipt); err != nil {
 		return err
 	}
-	r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs = receipt.PostState, receipt.CumulativeGasUsed, receipt.Bloom, receipt.Logs
+	var hr homesteadReceiptRLP
-	return nil
+	var mr metropolisReceiptRLP
+	if err = rlp.DecodeBytes(raw, &mr); err == nil {
+		r.CumulativeGasUsed, r.Bloom, r.Logs = mr.CumulativeGasUsed, mr.Bloom, mr.Logs
+	} else if err = rlp.DecodeBytes(raw, &hr); err == nil {
+		r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs = hr.PostState[:], hr.CumulativeGasUsed, hr.Bloom, hr.Logs
+	}
+	return err
 }
 
 // String implements the Stringer interface.

ethclient/ethclient.go

@@ -203,8 +203,6 @@ func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*
 	if err == nil {
 		if r == nil {
 			return nil, ethereum.NotFound
-		} else if len(r.PostState) == 0 {
-			return nil, fmt.Errorf("server returned receipt without post state")
 		}
 	}
 	return r, err