From ec492eda872a8b3adad5c16b99552d30cea27eab Mon Sep 17 00:00:00 2001
From: Alice Kober-Sotzek <aliceks@google.com>
Date: Thu, 9 Nov 2017 15:15:33 +0100
Subject: [PATCH] Correct RefUpdateUtil to work for an empty BatchRefUpdate

RefUpdateUtil#checkResults should not throw a LockFailureException if
the BatchRefUpdate doesn't contain any commands. Instead, it should
silently do nothing as nothing was executed.

Change-Id: Ie8257f8f9eb487f1242cacf004e05357e3fb6317
---
 java/com/google/gerrit/server/update/RefUpdateUtil.java       | 4 ++++
 .../com/google/gerrit/server/update/RefUpdateUtilTest.java    | 1 +
 2 files changed, 5 insertions(+)

diff --git a/java/com/google/gerrit/server/update/RefUpdateUtil.java b/java/com/google/gerrit/server/update/RefUpdateUtil.java
index 86b4eef7c9..17c7812811 100644
--- a/java/com/google/gerrit/server/update/RefUpdateUtil.java
+++ b/java/com/google/gerrit/server/update/RefUpdateUtil.java
@@ -57,6 +57,10 @@ public class RefUpdateUtil {
    */
   @VisibleForTesting
   static void checkResults(BatchRefUpdate bru) throws IOException {
+    if (bru.getCommands().isEmpty()) {
+      return;
+    }
+
     int lockFailure = 0;
     int aborted = 0;
     int failure = 0;
diff --git a/javatests/com/google/gerrit/server/update/RefUpdateUtilTest.java b/javatests/com/google/gerrit/server/update/RefUpdateUtilTest.java
index 286827a056..fc8696aed4 100644
--- a/javatests/com/google/gerrit/server/update/RefUpdateUtilTest.java
+++ b/javatests/com/google/gerrit/server/update/RefUpdateUtilTest.java
@@ -53,6 +53,7 @@ public class RefUpdateUtilTest {
 
   @Test
   public void checkBatchRefUpdateResults() throws Exception {
+    checkResults();
     checkResults(OK);
     checkResults(OK, OK);