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Author: Andrew Or

core/src/main/scala/org/apache/spark/Accumulator.scala

@@ -85,7 +85,7 @@ private[spark] object Accumulators extends Logging {
    * This global map holds the original accumulator objects that are created on the driver.
    * It keeps weak references to these objects so that accumulators can be garbage-collected
    * once the RDDs and user-code that reference them are cleaned up.
-   * TODO: Don't use a global map; these should be tied to a SparkContext at the very least.
+   * TODO: Don't use a global map; these should be tied to a SparkContext (SPARK-13051).
    */
   @GuardedBy("Accumulators")
   val originals = mutable.Map[Long, WeakReference[Accumulable[_, _]]]()

core/src/main/scala/org/apache/spark/scheduler/SparkListener.scala

@@ -61,6 +61,7 @@ case class SparkListenerTaskEnd(
     taskType: String,
     reason: TaskEndReason,
     taskInfo: TaskInfo,
+    // may be null if the task has failed
     @Nullable taskMetrics: TaskMetrics)
   extends SparkListenerEvent
 

core/src/test/scala/org/apache/spark/InternalAccumulatorSuite.scala

@@ -220,7 +220,7 @@ class InternalAccumulatorSuite extends SparkFunSuite with LocalSparkContext {
     rdd.count()
   }
 
-  // TODO: these two tests are incorrect; they don't actually trigger stage retries.
+  // TODO: these two tests are incorrect; they don't actually trigger stage retries (SPARK-13053).
   ignore("internal accumulators in fully resubmitted stages") {
     testInternalAccumulatorsWithFailedTasks((i: Int) => true) // fail all tasks
   }
@@ -259,7 +259,7 @@ class InternalAccumulatorSuite extends SparkFunSuite with LocalSparkContext {
 
   /**
    * Test whether internal accumulators are merged properly if some tasks fail.
-   * TODO: make this actually retry the stage.
+   * TODO: make this actually retry the stage (SPARK-13053).
    */
   private def testInternalAccumulatorsWithFailedTasks(failCondition: (Int => Boolean)): Unit = {
     val listener = new SaveInfoListener