client: Replace panics with errors in sign logic

Signed-off-by: Evgenii Baidakov <evgenii@nspcc.io>

client/errors.go

@@ -23,6 +23,8 @@ var (
 
 	ErrUnexpectedReadCall = errors.New("unexpected call to `Read`")
 
+	ErrSign SignError
+
 	errMissingResponseField missingResponseFieldErr
 )
 
@@ -53,3 +55,28 @@ func newErrMissingResponseField(name string) error {
 func newErrInvalidResponseField(name string, err error) error {
 	return fmt.Errorf("invalid %s field in the response: %w", name, err)
 }
+
+type SignError struct {
+	err error
+}
+
+func NewSignError(err error) SignError {
+	return SignError{err: err}
+}
+
+func (e SignError) Error() string {
+	return fmt.Sprintf("sign: %v", e.err)
+}
+
+func (e SignError) Unwrap() error {
+	return e.err
+}
+
+func (e SignError) Is(target error) bool {
+	switch target.(type) {
+	default:
+		return false
+	case SignError, *SignError:
+		return true
+	}
+}

client/errors_test.go

@@ -0,0 +1,17 @@
+package client_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/nspcc-dev/neofs-sdk-go/client"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_SignError(t *testing.T) {
+	someErr := errors.New("some error")
+	signErr := client.NewSignError(someErr)
+
+	require.ErrorIs(t, signErr, someErr)
+	require.ErrorIs(t, signErr, client.ErrSign)
+}

client/object_search_test.go

@@ -2,7 +2,6 @@ package client
 
 import (
 	"errors"
-	"fmt"
 	"io"
 	"testing"
 
@@ -152,7 +151,7 @@ func (s *singleStreamResponder) Read(resp *v2object.SearchResponse) error {
 
 	err := signServiceMessage(s.signer, resp)
 	if err != nil {
-		panic(fmt.Errorf("error: %w", err))
+		return err
 	}
 
 	s.n++

client/sign.go

@@ -132,6 +132,8 @@ func (s stableMarshalerWrapper) SignedDataSize() int {
 }
 
 // signServiceMessage signing request or response messages which can be sent or received from neofs endpoint.
+// Return errors:
+//   - [ErrSign]
 func signServiceMessage(signer neofscrypto.Signer, msg interface{}) error {
 	var (
 		body, meta, verifyOrigin stableMarshaler
@@ -165,24 +167,24 @@ func signServiceMessage(signer neofscrypto.Signer, msg interface{}) error {
 			verifyOrigin = h
 		}
 	default:
-		panic(fmt.Sprintf("unsupported session message %T", v))
+		return NewSignError(fmt.Errorf("unsupported session message %T", v))
 	}
 
 	if verifyOrigin == nil {
 		// sign session message body
 		if err := signServiceMessagePart(signer, body, verifyHdr.SetBodySignature); err != nil {
-			return fmt.Errorf("could not sign body: %w", err)
+			return NewSignError(fmt.Errorf("body: %w", err))
 		}
 	}
 
 	// sign meta header
 	if err := signServiceMessagePart(signer, meta, verifyHdr.SetMetaSignature); err != nil {
-		return fmt.Errorf("could not sign meta header: %w", err)
+		return NewSignError(fmt.Errorf("meta header: %w", err))
 	}
 
 	// sign verification header origin
 	if err := signServiceMessagePart(signer, verifyOrigin, verifyHdr.SetOriginSignature); err != nil {
-		return fmt.Errorf("could not sign origin of verification header: %w", err)
+		return NewSignError(fmt.Errorf("origin of verification header: %w", err))
 	}
 
 	// wrap origin verification header
@@ -240,7 +242,7 @@ func verifyServiceMessage(msg interface{}) error {
 			ResponseVerificationHeader: v.GetVerificationHeader(),
 		}
 	default:
-		panic(fmt.Sprintf("unsupported session message %T", v))
+		return fmt.Errorf("unsupported session message %T", v)
 	}
 
 	body := serviceMessageBody(msg)