From b5a4458b68cdda5f24c2721beec2fe7a0a05c477 Mon Sep 17 00:00:00 2001
From: Brian Gough <bjg@network-theory.co.uk>
Date: Wed, 15 Feb 2017 14:12:36 +0000
Subject: [PATCH] check sha1 hash value only if present

---
 services/document-updater/app/coffee/RedisManager.coffee | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/services/document-updater/app/coffee/RedisManager.coffee b/services/document-updater/app/coffee/RedisManager.coffee
index d9f210f1d6..ab95d1129f 100644
--- a/services/document-updater/app/coffee/RedisManager.coffee
+++ b/services/document-updater/app/coffee/RedisManager.coffee
@@ -67,7 +67,9 @@ module.exports = RedisManager =
 		multi.exec (error, [docLines, version, storedHash, doc_project_id, ranges])->
 			timer.done()
 			return callback(error) if error?
-			if docLines?
+
+			# check sha1 hash value if present
+			if docLines? and storedHash?
 				computedHash = RedisManager._computeHash(docLines)
 				if computedHash isnt storedHash
 					logger.error project_id: project_id, doc_id: doc_id, doc_project_id: doc_project_id, computedHash: computedHash, storedHash: storedHash, "hash mismatch on retrieved document"