refactor: replace []byte(fmt.Sprintf) with fmt.Appendf

pkg/bigint/bigint.go

@@ -19,7 +19,7 @@ func (i *BigInt) MarshalJSON() ([]byte, error) {
 		return []byte("null"), nil
 	}
 
-	return []byte(fmt.Sprintf(`"%s"`, i.String())), nil
+	return fmt.Appendf(nil, `"%s"`, i.String()), nil
 }
 
 func (i *BigInt) UnmarshalJSON(b []byte) error {

pkg/crypto/eip712/typeddata.go

@@ -29,7 +29,7 @@ func EncodeForSigning(typedData *TypedData) ([]byte, error) {
 		return nil, err
 	}
 
-	rawData := []byte(fmt.Sprintf("\x19\x01%s%s", string(domainSeparator), string(typedDataHash)))
+	rawData := fmt.Appendf(nil, "\x19\x01%s%s", string(domainSeparator), string(typedDataHash))
 	return rawData, nil
 }
 

pkg/crypto/signer.go

@@ -36,7 +36,7 @@ type Signer interface {
 
 // addEthereumPrefix adds the ethereum prefix to the data.
 func addEthereumPrefix(data []byte) []byte {
-	return []byte(fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data))
+	return fmt.Appendf(nil, "\x19Ethereum Signed Message:\n%d%s", len(data), data)
 }
 
 // hashWithEthereumPrefix returns the hash that should be signed for the given data.

pkg/log/formatter_test.go

@@ -22,7 +22,7 @@ type substr string
 type point struct{ x, y int }
 
 func (p point) MarshalText() ([]byte, error) {
-	return []byte(fmt.Sprintf("(%d, %d)", p.x, p.y)), nil
+	return fmt.Appendf(nil, "(%d, %d)", p.x, p.y), nil
 }
 
 // pointErr implements encoding.TextMarshaler but returns an error.

pkg/storageincentives/proof_test.go

@@ -69,13 +69,13 @@ func TestMakeInclusionProofsRegression(t *testing.T) {
 	// generate chunks that will be used as sample
 	sampleChunks := make([]swarm.Chunk, 0, sampleSize)
 	for i := 0; i < sampleSize; i++ {
-		ch, err := cac.New([]byte(fmt.Sprintf("Unstoppable data! Chunk #%d", i+1)))
+		ch, err := cac.New(fmt.Appendf(nil, "Unstoppable data! Chunk #%d", i+1))
 		if err != nil {
 			t.Fatal(err)
 		}
 
 		if i%2 == 0 {
-			id, err := crypto.LegacyKeccak256([]byte(fmt.Sprintf("ID #%d", i+1)))
+			id, err := crypto.LegacyKeccak256(fmt.Appendf(nil, "ID #%d", i+1))
 			if err != nil {
 				t.Fatal(err)
 			}