fix: nil pointers identified by nilaway (part 2)

cbor/value.go

@@ -63,7 +63,7 @@ func (v *Value) UnmarshalCBOR(data []byte) error {
 		case CborTagCbor:
 			v.value = tmpTag.Content
 		case CborTagRational:
-			var tmpRat []int64
+			tmpRat := []int64{}
 			if _, err := Decode(tmpTag.Content, &tmpRat); err != nil {
 				return err
 			}

ledger/block.go

@@ -105,9 +105,12 @@ func DetermineBlockType(data []byte) (uint, error) {
 }
 
 func generateBlockHeaderHash(data []byte, prefix []byte) string {
-	// We can ignore the error return here because our fixed size/key arguments will
-	// never trigger an error
-	tmpHash, _ := blake2b.New256(nil)
+	tmpHash, err := blake2b.New256(nil)
+	if err != nil {
+		panic(
+			fmt.Sprintf("unexpected error generating empty blake2b hash: %s", err),
+		)
+	}
 	if prefix != nil {
 		tmpHash.Write(prefix)
 	}

ledger/common.go

@@ -161,9 +161,12 @@ func NewAssetFingerprint(policyId []byte, assetName []byte) AssetFingerprint {
 }
 
 func (a AssetFingerprint) Hash() Blake2b160 {
-	// We can ignore the error return here because our fixed size/key arguments will
-	// never trigger an error
-	tmpHash, _ := blake2b.New(20, nil)
+	tmpHash, err := blake2b.New(20, nil)
+	if err != nil {
+		panic(
+			fmt.Sprintf("unexpected error creating empty blake2b hash: %s", err),
+		)
+	}
 	tmpHash.Write(a.policyId)
 	tmpHash.Write(a.assetName)
 	return NewBlake2b160(tmpHash.Sum(nil))
@@ -375,9 +378,12 @@ func (a Address) MarshalJSON() ([]byte, error) {
 type IssuerVkey [32]byte
 
 func (i IssuerVkey) Hash() Blake2b224 {
-	// We can ignore the error return here because our fixed size/key arguments will
-	// never trigger an error
-	hash, _ := blake2b.New(28, nil)
+	hash, err := blake2b.New(28, nil)
+	if err != nil {
+		panic(
+			fmt.Sprintf("unexpected error creating empty blake2b hash: %s", err),
+		)
+	}
 	hash.Write(i[:])
 	return Blake2b224(hash.Sum(nil))
 }

ledger/era.go

@@ -50,12 +50,17 @@ var eras = map[uint8]Era{
 	},
 }
 
-func GetEraById(eraId uint8) *Era {
+var EraInvalid = Era{
+	Id:   0,
+	Name: "invalid",
+}
+
+func GetEraById(eraId uint8) Era {
 	era, ok := eras[eraId]
 	if !ok {
-		return nil
+		return EraInvalid
 	}
-	return &era
+	return era
 }
 
 // BlockHeaderToBlockTypeMap is a mapping of NtN chainsync block header types

ledger/era_test.go

@@ -20,9 +20,8 @@ import (
 )
 
 type getEraByIdTestDefinition struct {
-	Id        uint8
-	Name      string
-	ExpectNil bool
+	Id   uint8
+	Name string
 }
 
 var getEraByIdTests = []getEraByIdTestDefinition{
@@ -51,17 +50,17 @@ var getEraByIdTests = []getEraByIdTestDefinition{
 		Name: "Babbage",
 	},
 	{
-		Id:        99,
-		ExpectNil: true,
+		Id:   99,
+		Name: "invalid",
 	},
 }
 
 func TestGetEraById(t *testing.T) {
 	for _, test := range getEraByIdTests {
 		era := ledger.GetEraById(test.Id)
-		if era == nil {
-			if !test.ExpectNil {
-				t.Fatalf("got unexpected nil, wanted %s", test.Name)
+		if era == ledger.EraInvalid {
+			if test.Name != "invalid" {
+				t.Fatalf("got unexpected EraInvalid, wanted %s", test.Name)
 			}
 		} else {
 			if era.Name != test.Name {

ledger/error.go

@@ -167,7 +167,7 @@ func (e *ApplyTxError) UnmarshalCBOR(data []byte) error {
 		return err
 	}
 	for _, failure := range tmpData {
-		var tmpFailure []cbor.RawMessage
+		tmpFailure := []cbor.RawMessage{}
 		if _, err := cbor.Decode(failure, &tmpFailure); err != nil {
 			return err
 		}
@@ -212,7 +212,7 @@ type UtxowFailure struct {
 }
 
 func (e *UtxowFailure) UnmarshalCBOR(data []byte) error {
-	var tmpFailure []cbor.RawMessage
+	tmpFailure := []cbor.RawMessage{}
 	if _, err := cbor.Decode(data, &tmpFailure); err != nil {
 		return err
 	}

ledger/shelley.go

@@ -233,7 +233,7 @@ func (b *ShelleyTransactionBody) Utxorpc() *utxorpc.Tx {
 	if err != nil {
 		return &utxorpc.Tx{}
 	}
-	tx := &utxorpc.Tx {
+	tx := &utxorpc.Tx{
 		Inputs:  txi,
 		Outputs: txo,
 		Fee:     b.Fee(),

ledger/tx.go

@@ -147,9 +147,12 @@ func DetermineTransactionType(data []byte) (uint, error) {
 }
 
 func generateTransactionHash(data []byte, prefix []byte) string {
-	// We can ignore the error return here because our fixed size/key arguments will
-	// never trigger an error
-	tmpHash, _ := blake2b.New256(nil)
+	tmpHash, err := blake2b.New256(nil)
+	if err != nil {
+		panic(
+			fmt.Sprintf("unexpected error generating empty blake2b hash: %s", err),
+		)
+	}
 	if prefix != nil {
 		tmpHash.Write(prefix)
 	}

protocol/localstatequery/client.go

@@ -248,7 +248,7 @@ func (c *Client) GetChainBlockNo() (int64, error) {
 	query := buildQuery(
 		QueryTypeChainBlockNo,
 	)
-	var result []int64
+	result := []int64{}
 	if err := c.runQuery(query, &result); err != nil {
 		return 0, err
 	}
@@ -293,7 +293,7 @@ func (c *Client) GetEpochNo() (int, error) {
 		currentEra,
 		QueryTypeShelleyEpochNo,
 	)
-	var result []int
+	result := []int{}
 	if err := c.runQuery(query, &result); err != nil {
 		return 0, err
 	}
@@ -331,7 +331,7 @@ func (c *Client) GetCurrentProtocolParams() (*CurrentProtocolParamsResult, error
 		currentEra,
 		QueryTypeShelleyCurrentProtocolParams,
 	)
-	var result []CurrentProtocolParamsResult
+	result := []CurrentProtocolParamsResult{}
 	if err := c.runQuery(query, &result); err != nil {
 		return nil, err
 	}
@@ -470,7 +470,7 @@ func (c *Client) GetGenesisConfig() (*GenesisConfigResult, error) {
 		currentEra,
 		QueryTypeShelleyGenesisConfig,
 	)
-	var result []GenesisConfigResult
+	result := []GenesisConfigResult{}
 	if err := c.runQuery(query, &result); err != nil {
 		return nil, err
 	}

protocol/protocol.go

@@ -322,7 +322,7 @@ func (p *Protocol) recvLoop() {
 		// Decode message into generic list until we can determine what type of message it is.
 		// This also lets us determine how many bytes the message is. We use RawMessage here to
 		// avoid parsing things that we may not be able to parse
-		var tmpMsg []cbor.RawMessage
+		tmpMsg := []cbor.RawMessage{}
 		numBytesRead, err := cbor.Decode(recvBuffer.Bytes(), &tmpMsg)
 		if err != nil {
 			if err == io.ErrUnexpectedEOF && recvBuffer.Len() > 0 {