From 7e831741f9507e11a2272c982c9ea1d791d459ae Mon Sep 17 00:00:00 2001
From: Aliaksandr Valialkin <valyala@gmail.com>
Date: Thu, 14 May 2020 15:32:07 +0300
Subject: [PATCH] lib/{storage,mergeset}: return dst on error from
 unmarshalBlockHeaders, so it could be reused

---
 lib/mergeset/block_header.go | 6 +++---
 lib/storage/block_header.go  | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/mergeset/block_header.go b/lib/mergeset/block_header.go
index 6067a9e0e0..67007796b2 100644
--- a/lib/mergeset/block_header.go
+++ b/lib/mergeset/block_header.go
@@ -148,18 +148,18 @@ func unmarshalBlockHeaders(dst []blockHeader, src []byte, blockHeadersCount int)
 	for i := 0; i < blockHeadersCount; i++ {
 		tail, err := dst[dstLen+i].Unmarshal(src)
 		if err != nil {
-			return nil, fmt.Errorf("cannot unmarshal block header: %s", err)
+			return dst, fmt.Errorf("cannot unmarshal block header: %s", err)
 		}
 		src = tail
 	}
 	if len(src) > 0 {
-		return nil, fmt.Errorf("unexpected non-zero tail left after unmarshaling %d block headers; len(tail)=%d", blockHeadersCount, len(src))
+		return dst, fmt.Errorf("unexpected non-zero tail left after unmarshaling %d block headers; len(tail)=%d", blockHeadersCount, len(src))
 	}
 	newBHS := dst[dstLen:]
 
 	// Verify that block headers are sorted by firstItem.
 	if !sort.SliceIsSorted(newBHS, func(i, j int) bool { return string(newBHS[i].firstItem) < string(newBHS[j].firstItem) }) {
-		return nil, fmt.Errorf("block headers must be sorted by firstItem; unmarshaled unsorted block headers: %#v", newBHS)
+		return dst, fmt.Errorf("block headers must be sorted by firstItem; unmarshaled unsorted block headers: %#v", newBHS)
 	}
 
 	return dst, nil
diff --git a/lib/storage/block_header.go b/lib/storage/block_header.go
index 304eb54a37..d41c41167d 100644
--- a/lib/storage/block_header.go
+++ b/lib/storage/block_header.go
@@ -189,7 +189,7 @@ func unmarshalBlockHeaders(dst []blockHeader, src []byte, blockHeadersCount int)
 	for len(src) > 0 {
 		tmp, err := bh.Unmarshal(src)
 		if err != nil {
-			return nil, fmt.Errorf("cannot unmarshal block header: %s", err)
+			return dst, fmt.Errorf("cannot unmarshal block header: %s", err)
 		}
 		src = tmp
 		dst = append(dst, bh)
@@ -199,12 +199,12 @@ func unmarshalBlockHeaders(dst []blockHeader, src []byte, blockHeadersCount int)
 
 	// Verify the number of read block headers.
 	if len(newBHS) != blockHeadersCount {
-		return nil, fmt.Errorf("invalid number of block headers found: %d; want %d block headers", len(newBHS), blockHeadersCount)
+		return dst, fmt.Errorf("invalid number of block headers found: %d; want %d block headers", len(newBHS), blockHeadersCount)
 	}
 
 	// Verify that block headers are sorted by tsid.
 	if !sort.SliceIsSorted(newBHS, func(i, j int) bool { return newBHS[i].TSID.Less(&newBHS[j].TSID) }) {
-		return nil, fmt.Errorf("block headers must be sorted by tsid; unmarshaled unsorted block headers: %+v", newBHS)
+		return dst, fmt.Errorf("block headers must be sorted by tsid; unmarshaled unsorted block headers: %+v", newBHS)
 	}
 
 	return dst, nil