From 72e2bc8fb6c6c0c67fd8ebf0786ade6b1970985f Mon Sep 17 00:00:00 2001
From: Leonard Lyubich <leonard@nspcc.ru>
Date: Tue, 18 May 2021 15:13:40 +0300
Subject: [PATCH] [#532] object/hash: Fix NPE during request forwarding

In current implementation `Object.GetRangeHash` RPC handler forwards range
requests for payload data. Missing request forwarder of the original request
caused NPE during execution.

Do not call request forwarder if payload range hash is requested.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
---
 pkg/services/object/get/exec.go | 12 +++++++++++-
 pkg/services/object/get/get.go  |  8 ++++++--
 pkg/services/object/get/util.go |  2 +-
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/pkg/services/object/get/exec.go b/pkg/services/object/get/exec.go
index 4752e60b..140ece9f 100644
--- a/pkg/services/object/get/exec.go
+++ b/pkg/services/object/get/exec.go
@@ -38,7 +38,7 @@ type execCtx struct {
 
 	curOff uint64
 
-	head bool
+	head, hash bool
 
 	curProcEpoch uint64
 
@@ -71,6 +71,12 @@ func withPayloadRange(r *objectSDK.Range) execOption {
 	}
 }
 
+func hashOnly() execOption {
+	return func(c *execCtx) {
+		c.hash = true
+	}
+}
+
 func (exec *execCtx) setLogger(l *logger.Logger) {
 	req := "GET"
 	if exec.headOnly() {
@@ -146,6 +152,10 @@ func (exec *execCtx) headOnly() bool {
 	return exec.head
 }
 
+func (exec *execCtx) hashOnly() bool {
+	return exec.hash
+}
+
 func (exec *execCtx) netmapEpoch() uint64 {
 	return exec.prm.common.NetmapEpoch()
 }
diff --git a/pkg/services/object/get/get.go b/pkg/services/object/get/get.go
index 43e7d50b..d7f23011 100644
--- a/pkg/services/object/get/get.go
+++ b/pkg/services/object/get/get.go
@@ -15,7 +15,11 @@ func (s *Service) Get(ctx context.Context, prm Prm) error {
 
 // GetRange serves a request to get an object by address, and returns Streamer instance.
 func (s *Service) GetRange(ctx context.Context, prm RangePrm) error {
-	return s.get(ctx, prm.commonPrm, withPayloadRange(prm.rng)).err
+	return s.getRange(ctx, prm)
+}
+
+func (s *Service) getRange(ctx context.Context, prm RangePrm, opts ...execOption) error {
+	return s.get(ctx, prm.commonPrm, append(opts, withPayloadRange(prm.rng))...).err
 }
 
 func (s *Service) GetRangeHash(ctx context.Context, prm RangeHashPrm) (*RangeHashRes, error) {
@@ -37,7 +41,7 @@ func (s *Service) GetRangeHash(ctx context.Context, prm RangeHashPrm) (*RangeHas
 			hash: util.NewSaltingWriter(h, prm.salt),
 		})
 
-		if err := s.GetRange(ctx, rngPrm); err != nil {
+		if err := s.getRange(ctx, rngPrm, hashOnly()); err != nil {
 			return nil, err
 		}
 
diff --git a/pkg/services/object/get/util.go b/pkg/services/object/get/util.go
index 3c992bd9..eb3316de 100644
--- a/pkg/services/object/get/util.go
+++ b/pkg/services/object/get/util.go
@@ -80,7 +80,7 @@ func (c *clientCacheWrapper) get(addr string) (getClient, error) {
 }
 
 func (c *clientWrapper) getObject(exec *execCtx) (*objectSDK.Object, error) {
-	if !exec.assembling {
+	if !exec.assembling && !exec.hashOnly() {
 		return exec.prm.forwarder(c.client)
 	}