From b639a59de3ed200229212b8ea828bba4cf2d0b41 Mon Sep 17 00:00:00 2001
From: Marcelo Vanzin <vanzin@cloudera.com>
Date: Wed, 17 Jan 2018 12:24:00 -0800
Subject: [PATCH] [SPARK-23135][ui] Fix rendering of accumulators in the stage
 page.

This follows the behavior of 2.2: only named accumulators with a
value are rendered.
---
 .../org/apache/spark/ui/jobs/StagePage.scala  | 20 ++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
index 7c6e06cf183b..8144dfc6ccbf 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala
@@ -260,7 +260,11 @@ private[ui] class StagePage(parent: StagesTab, store: AppStatusStore) extends We
 
     val accumulableHeaders: Seq[String] = Seq("Accumulable", "Value")
     def accumulableRow(acc: AccumulableInfo): Seq[Node] = {
-      <tr><td>{acc.name}</td><td>{acc.value}</td></tr>
+      if (acc.name != null && acc.value != null) {
+        <tr><td>{acc.name}</td><td>{acc.value}</td></tr>
+      } else {
+        Nil
+      }
     }
     val accumulableTable = UIUtils.listingTable(
       accumulableHeaders,
@@ -856,7 +860,7 @@ private[ui] class TaskPagedTable(
         {formatBytes(task.taskMetrics.map(_.peakExecutionMemory))}
       </td>
       {if (hasAccumulators(stage)) {
-        accumulatorsInfo(task)
+        <td>{accumulatorsInfo(task)}</td>
       }}
       {if (hasInput(stage)) {
         metricInfo(task) { m =>
@@ -912,8 +916,12 @@ private[ui] class TaskPagedTable(
   }
 
   private def accumulatorsInfo(task: TaskData): Seq[Node] = {
-    task.accumulatorUpdates.map { acc =>
-      Unparsed(StringEscapeUtils.escapeHtml4(s"${acc.name}: ${acc.update}"))
+    task.accumulatorUpdates.flatMap { acc =>
+      if (acc.name != null && acc.update.isDefined) {
+        Unparsed(StringEscapeUtils.escapeHtml4(s"${acc.name}: ${acc.update.get}")) ++ <br />
+      } else {
+        Nil
+      }
     }
   }
 
@@ -977,7 +985,9 @@ private object ApiHelper {
     "Shuffle Spill (Disk)" -> TaskIndexNames.DISK_SPILL,
     "Errors" -> TaskIndexNames.ERROR)
 
-  def hasAccumulators(stageData: StageData): Boolean = stageData.accumulatorUpdates.size > 0
+  def hasAccumulators(stageData: StageData): Boolean = {
+    stageData.accumulatorUpdates.exists { acc => acc.name != null && acc.value != null }
+  }
 
   def hasInput(stageData: StageData): Boolean = stageData.inputBytes > 0