From f1a7f2fc9d0b7de097a230f89c131685b6a7dc1d Mon Sep 17 00:00:00 2001
From: oysheng <33340252+oysheng@users.noreply.github.com>
Date: Fri, 28 Jun 2019 12:29:05 +0800
Subject: [PATCH] fix array out of index range (#231)

---
 protocol/block.go      |  2 +-
 protocol/block_test.go | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/protocol/block.go b/protocol/block.go
index a1d5830d..0eafe279 100644
--- a/protocol/block.go
+++ b/protocol/block.go
@@ -205,7 +205,7 @@ func (c *Chain) reorganizeChain(blockHeader *types.BlockHeader) error {
 		log.WithFields(log.Fields{"module": logModule, "height": blockHeader.Height, "hash": blockHash.String()}).Debug("attach from mainchain")
 	}
 
-	if detachBlockHeaders[len(detachBlockHeaders)-1].Height <= c.bestIrrBlockHeader.Height && irrBlockHeader.Height <= c.bestIrrBlockHeader.Height {
+	if len(detachBlockHeaders) > 0 && detachBlockHeaders[len(detachBlockHeaders)-1].Height <= c.bestIrrBlockHeader.Height && irrBlockHeader.Height <= c.bestIrrBlockHeader.Height {
 		return errors.New("rollback block below the height of irreversible block")
 	}
 	voteResults = append(voteResults, voteResult.Fork())
diff --git a/protocol/block_test.go b/protocol/block_test.go
index cde41880..6fbb6dfa 100644
--- a/protocol/block_test.go
+++ b/protocol/block_test.go
@@ -71,12 +71,26 @@ func TestCalcReorganizeChain(t *testing.T) {
 		c.store.SaveBlockHeader(newChainBlockHeader)
 	}
 
+	// normal
 	getAttachBlockHeaders, getDetachBlockHeaders, _ := c.calcReorganizeChain(newChainBlockHeader, mainChainBlockHeader)
 	if !testutil.DeepEqual(wantAttachBlockHeaders, getAttachBlockHeaders) {
-		t.Errorf("attach headers want %v but get %v", wantAttachBlockHeaders, getAttachBlockHeaders)
+		t.Errorf("normal test: attach headers want %v but get %v", wantAttachBlockHeaders, getAttachBlockHeaders)
 	}
 
 	if !testutil.DeepEqual(wantDetachBlockHeaders, getDetachBlockHeaders) {
-		t.Errorf("detach headers want %v but get %v", wantDetachBlockHeaders, getDetachBlockHeaders)
+		t.Errorf("normal test: detach headers want %v but get %v", wantDetachBlockHeaders, getDetachBlockHeaders)
+	}
+
+	// detachBlockHeaders is empty
+	forkChainBlockHeader := wantAttachBlockHeaders[7]
+	wantAttachBlockHeaders = wantAttachBlockHeaders[8:]
+	wantDetachBlockHeaders = []*types.BlockHeader{}
+	getAttachBlockHeaders, getDetachBlockHeaders, _ = c.calcReorganizeChain(newChainBlockHeader, forkChainBlockHeader)
+	if !testutil.DeepEqual(wantAttachBlockHeaders, getAttachBlockHeaders) {
+		t.Errorf("detachBlockHeaders is empty test: attach headers want %v but get %v", wantAttachBlockHeaders, getAttachBlockHeaders)
+	}
+
+	if !testutil.DeepEqual(wantDetachBlockHeaders, getDetachBlockHeaders) {
+		t.Errorf("detachBlockHeaders is empty test: detach headers want %v but get %v", wantDetachBlockHeaders, getDetachBlockHeaders)
 	}
 }
-- 
2.11.0