Fixed broken test and improved logging

Author: kayousterhout

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

@@ -954,8 +954,8 @@ class DAGScheduler(
         // Do nothing here; the TaskScheduler handles these failures and resubmits the task.
 
       case other =>
-        // Unrecognized failure - abort all jobs depending on this stage
-        abortStage(stageIdToStage(task.stageId), task + " failed: " + other)
+        // Unrecognized failure - also do nothing. If the task fails repeatedly, the TaskScheduler
+        // will abort the job.
     }
   }
 

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

@@ -21,6 +21,12 @@ import scala.collection._
 
 import org.apache.spark.executor.TaskMetrics
 
+/**
+ * Stores information about a stage to pass from the scheduler to SparkListeners.
+ *
+ * taskInfos stores the metrics for all tasks that have completed, including redundant, speculated
+ * tasks.
+ */
 class StageInfo(
     stage: Stage,
     val taskInfos: mutable.Buffer[(TaskInfo, TaskMetrics)] = mutable.Buffer[(TaskInfo, TaskMetrics)]()