From 342dca1efe952834101277f501ad8bd47b234d38 Mon Sep 17 00:00:00 2001
From: Eugene Kim <ek@harmony.one>
Date: Wed, 4 Sep 2019 12:23:02 -0700
Subject: [PATCH] Keep nil epoch check just in case

---
 core/rawdb/accessors_chain.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/core/rawdb/accessors_chain.go b/core/rawdb/accessors_chain.go
index 7e2f98607..a07c438ae 100644
--- a/core/rawdb/accessors_chain.go
+++ b/core/rawdb/accessors_chain.go
@@ -350,6 +350,10 @@ func WriteBlock(db DatabaseWriter, block *types.Block) {
 	WriteHeader(db, block.Header())
 	// TODO ek – maybe roll the below into WriteHeader()
 	epoch := block.Header().Epoch()
+	if epoch == nil {
+		// backward compatibility
+		return
+	}
 	epochBlockNum := block.Number()
 	writeOne := func() {
 		if err := WriteEpochBlockNumber(db, epoch, epochBlockNum); err != nil {