From f92ab131e4e40da401faf1523412cbd08af93f4f Mon Sep 17 00:00:00 2001
From: Steve Yen <steve.yen@gmail.com>
Date: Thu, 26 Mar 2015 14:28:49 -0700
Subject: [PATCH] KVStore gtreap implementation copies value bytes

---
 index/store/gtreap/gtreap.go      | 7 +++++--
 index/store/gtreap/gtreap_test.go | 6 +++---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/index/store/gtreap/gtreap.go b/index/store/gtreap/gtreap.go
index 5992ca66..514455b3 100644
--- a/index/store/gtreap/gtreap.go
+++ b/index/store/gtreap/gtreap.go
@@ -125,7 +125,7 @@ func (w *Store) Iterator(k []byte) store.KVIterator {
 
 func (w *Store) Set(k, v []byte) (err error) {
 	w.m.Lock()
-	w.t = w.t.Upsert(&Item{k: k, v: v}, rand.Int())
+	w.t = w.t.Upsert(&Item{k: k, v: append([]byte(nil), v...)}, rand.Int())
 	w.m.Unlock()
 	return nil
 }
@@ -243,7 +243,7 @@ func (w *Iterator) Close() error {
 }
 
 func (w *Batch) Set(k, v []byte) {
-	w.items = append(w.items, &Item{k, v})
+	w.items = append(w.items, &Item{k, append([]byte(nil), v...)})
 }
 
 func (w *Batch) Delete(k []byte) {
@@ -269,11 +269,14 @@ func (w *Batch) Execute() (err error) {
 			if itm != nil {
 				v = itm.(*Item).v
 			}
+			// NOTE: mc.Merge() doesn't modify its k or v params.
 			v, err := mc.Merge(k, v)
 			if err != nil {
 				return err
 			}
 			if v != nil {
+				// NOTE: We don't re-copy the result from mc.Merge(),
+				// as it'll return brand new unshared bytes.
 				t = t.Upsert(&Item{k: k, v: v}, rand.Int())
 			} else {
 				t = t.Delete(&Item{k: k})
diff --git a/index/store/gtreap/gtreap_test.go b/index/store/gtreap/gtreap_test.go
index 9c66e968..19cbf317 100644
--- a/index/store/gtreap/gtreap_test.go
+++ b/index/store/gtreap/gtreap_test.go
@@ -38,7 +38,6 @@ func TestReaderIsolation(t *testing.T) {
 }
 
 func CommonTestKVStore(t *testing.T, s store.KVStore) {
-
 	writer, err := s.Writer()
 	if err != nil {
 		t.Error(err)
@@ -162,11 +161,13 @@ func CommonTestReaderIsolation(t *testing.T, s store.KVStore) {
 	if err != nil {
 		t.Error(err)
 	}
-	err = writer.Set([]byte("b"), []byte("val-b"))
+	valB := []byte("val-b")
+	err = writer.Set([]byte("b"), valB)
 	if err != nil {
 		t.Fatal(err)
 	}
 	writer.Close()
+	valB[0] = 'X' // Modify the bytes so we check that writer got its own copy.
 
 	// ensure that a newer reader sees it
 	newReader, err := s.Reader()
@@ -214,5 +215,4 @@ func CommonTestReaderIsolation(t *testing.T, s store.KVStore) {
 	if count != 1 {
 		t.Errorf("expected iterator to see 1, saw %d", count)
 	}
-
 }