core/types: encode receipt status in PostState field

This fixes a regression where the new Failed field in ReceiptForStorage
rejected previously stored receipts. Fix it by removing the new field
and store status in the PostState field. This also removes massive RLP
hackery around the status field.

core/database_util_test.go

@@ -340,7 +340,7 @@ func TestBlockReceiptStorage(t *testing.T) {
 	db, _ := ethdb.NewMemDatabase()
 
 	receipt1 := &types.Receipt{
-		PostState:         []byte{0x01},
+		Failed:            true,
 		CumulativeGasUsed: big.NewInt(1),
 		Logs: []*types.Log{
 			{Address: common.BytesToAddress([]byte{0x11})},
@@ -351,7 +351,7 @@ func TestBlockReceiptStorage(t *testing.T) {
 		GasUsed:         big.NewInt(111111),
 	}
 	receipt2 := &types.Receipt{
-		PostState:         []byte{0x02},
+		PostState:         common.Hash{2}.Bytes(),
 		CumulativeGasUsed: big.NewInt(2),
 		Logs: []*types.Log{
 			{Address: common.BytesToAddress([]byte{0x22})},

core/types/receipt.go

@@ -17,6 +17,7 @@
 package types
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"math/big"
@@ -28,9 +29,9 @@ import (
 
 //go:generate gencodec -type Receipt -field-override receiptMarshaling -out gen_receipt_json.go
 
-const (
-	receiptStatusSuccessful = byte(0x01)
-	receiptStatusFailed     = byte(0x00)
+var (
+	receiptStatusFailed     = []byte{}
+	receiptStatusSuccessful = []byte{0x01}
 )
 
 // Receipt represents the results of a transaction.
@@ -54,22 +55,22 @@ type receiptMarshaling struct {
 	GasUsed           *hexutil.Big
 }
 
-// homesteadReceiptRLP contains the receipt's Homestead consensus fields, used
-// during RLP serialization.
-type homesteadReceiptRLP struct {
-	PostState         []byte
+// receiptRLP is the consensus encoding of a receipt.
+type receiptRLP struct {
+	PostStateOrStatus []byte
 	CumulativeGasUsed *big.Int
 	Bloom             Bloom
 	Logs              []*Log
 }
 
-// metropolisReceiptRLP contains the receipt's Metropolis consensus fields, used
-// during RLP serialization.
-type metropolisReceiptRLP struct {
-	Status            byte
+type receiptStorageRLP struct {
+	PostStateOrStatus []byte
 	CumulativeGasUsed *big.Int
 	Bloom             Bloom
-	Logs              []*Log
+	TxHash            common.Hash
+	ContractAddress   common.Address
+	Logs              []*LogForStorage
+	GasUsed           *big.Int
 }
 
 // NewReceipt creates a barebone transaction receipt, copying the init fields.
@@ -80,69 +81,46 @@ func NewReceipt(root []byte, failed bool, cumulativeGasUsed *big.Int) *Receipt {
 // EncodeRLP implements rlp.Encoder, and flattens the consensus fields of a receipt
 // into an RLP stream. If no post state is present, metropolis fork is assumed.
 func (r *Receipt) EncodeRLP(w io.Writer) error {
-	if r.PostState == nil {
-		status := receiptStatusSuccessful
-		if r.Failed {
-			status = receiptStatusFailed
-		}
-		return rlp.Encode(w, &metropolisReceiptRLP{status, r.CumulativeGasUsed, r.Bloom, r.Logs})
-	}
-	return rlp.Encode(w, &homesteadReceiptRLP{r.PostState, r.CumulativeGasUsed, r.Bloom, r.Logs})
+	return rlp.Encode(w, &receiptRLP{r.statusEncoding(), 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 {
-	// Load the raw bytes since we have multiple possible formats
-	raw, err := s.Raw()
-	if err != nil {
+	var dec receiptRLP
+	if err := s.Decode(&dec); err != nil {
 		return err
 	}
-	content, _, err := rlp.SplitList(raw)
-	if err != nil {
+	if err := r.setStatus(dec.PostStateOrStatus); err != nil {
 		return err
 	}
-	kind, cnt, _, err := rlp.Split(content)
-	if err != nil {
-		return err
-	}
-	// Deserialize based on the first component type.
+	r.CumulativeGasUsed, r.Bloom, r.Logs = dec.CumulativeGasUsed, dec.Bloom, dec.Logs
+	return nil
+}
+
+func (r *Receipt) setStatus(postStateOrStatus []byte) error {
 	switch {
-	case kind == rlp.Byte || (kind == rlp.String && len(cnt) == 0):
-		// The first component of metropolis receipts is Byte (0x01), or the empty
-		// string (0x80, decoded as a byte with 0x00 value).
-		var metro metropolisReceiptRLP
-		if err := rlp.DecodeBytes(raw, &metro); err != nil {
-			return err
-		}
-		switch metro.Status {
-		case receiptStatusSuccessful:
-			r.Failed = false
-		case receiptStatusFailed:
-			r.Failed = true
-		default:
-			return fmt.Errorf("invalid status byte: 0x%x", metro.Status)
-		}
-		r.CumulativeGasUsed = metro.CumulativeGasUsed
-		r.Bloom = metro.Bloom
-		r.Logs = metro.Logs
-		return nil
-
-	case kind == rlp.String:
-		// The first component of homestead receipts is non-empty String.
-		var home homesteadReceiptRLP
-		if err := rlp.DecodeBytes(raw, &home); err != nil {
-			return err
-		}
-		r.PostState = home.PostState[:]
-		r.CumulativeGasUsed = home.CumulativeGasUsed
-		r.Bloom = home.Bloom
-		r.Logs = home.Logs
-		return nil
-
+	case bytes.Equal(postStateOrStatus, receiptStatusSuccessful):
+		r.Failed = false
+	case bytes.Equal(postStateOrStatus, receiptStatusFailed):
+		r.Failed = true
+	case len(postStateOrStatus) == len(common.Hash{}):
+		r.PostState = postStateOrStatus
 	default:
-		return fmt.Errorf("invalid first receipt component: %v", kind)
+		return fmt.Errorf("invalid receipt status %x", postStateOrStatus)
 	}
+	return nil
+}
+
+func (r *Receipt) statusEncoding() []byte {
+	if len(r.PostState) == 0 {
+		if r.Failed {
+			return receiptStatusFailed
+		} else {
+			return receiptStatusSuccessful
+		}
+	}
+	return r.PostState
 }
 
 // String implements the Stringer interface.
@@ -160,38 +138,39 @@ type ReceiptForStorage Receipt
 // EncodeRLP implements rlp.Encoder, and flattens all content fields of a receipt
 // into an RLP stream.
 func (r *ReceiptForStorage) EncodeRLP(w io.Writer) error {
-	logs := make([]*LogForStorage, len(r.Logs))
-	for i, log := range r.Logs {
-		logs[i] = (*LogForStorage)(log)
+	enc := &receiptStorageRLP{
+		PostStateOrStatus: (*Receipt)(r).statusEncoding(),
+		CumulativeGasUsed: r.CumulativeGasUsed,
+		Bloom:             r.Bloom,
+		TxHash:            r.TxHash,
+		ContractAddress:   r.ContractAddress,
+		Logs:              make([]*LogForStorage, len(r.Logs)),
+		GasUsed:           r.GasUsed,
 	}
-	return rlp.Encode(w, []interface{}{r.PostState, r.Failed, r.CumulativeGasUsed, r.Bloom, r.TxHash, r.ContractAddress, logs, r.GasUsed})
+	for i, log := range r.Logs {
+		enc.Logs[i] = (*LogForStorage)(log)
+	}
+	return rlp.Encode(w, enc)
 }
 
 // DecodeRLP implements rlp.Decoder, and loads both consensus and implementation
 // fields of a receipt from an RLP stream.
 func (r *ReceiptForStorage) DecodeRLP(s *rlp.Stream) error {
-	var receipt struct {
-		PostState         []byte
-		Failed            bool
-		CumulativeGasUsed *big.Int
-		Bloom             Bloom
-		TxHash            common.Hash
-		ContractAddress   common.Address
-		Logs              []*LogForStorage
-		GasUsed           *big.Int
+	var dec receiptStorageRLP
+	if err := s.Decode(&dec); err != nil {
+		return err
 	}
-	if err := s.Decode(&receipt); err != nil {
+	if err := (*Receipt)(r).setStatus(dec.PostStateOrStatus); err != nil {
 		return err
 	}
 	// Assign the consensus fields
-	r.PostState, r.Failed, r.CumulativeGasUsed, r.Bloom = receipt.PostState, receipt.Failed, receipt.CumulativeGasUsed, receipt.Bloom
-	r.Logs = make([]*Log, len(receipt.Logs))
-	for i, log := range receipt.Logs {
+	r.CumulativeGasUsed, r.Bloom = dec.CumulativeGasUsed, dec.Bloom
+	r.Logs = make([]*Log, len(dec.Logs))
+	for i, log := range dec.Logs {
 		r.Logs[i] = (*Log)(log)
 	}
 	// Assign the implementation fields
-	r.TxHash, r.ContractAddress, r.GasUsed = receipt.TxHash, receipt.ContractAddress, receipt.GasUsed
-
+	r.TxHash, r.ContractAddress, r.GasUsed = dec.TxHash, dec.ContractAddress, dec.GasUsed
 	return nil
 }