Fix 'out of range in dynamic array' error in Task::toJson (facebookin…

…cubator#8735)

Summary:
Task::toJson used to create folly::dynamic::array for drivers and access non-existing
elements via [index]. That resulted in 'out of range in dynamic array' errors.

Fix is to use folly::dynamic::object.

Fixes prestodb/presto#21917

Pull Request resolved: facebookincubator#8735

Reviewed By: spershin

Differential Revision: D53727317

Pulled By: mbasmanova

fbshipit-source-id: afcfd490fd44d67b78c0b70b3f557a179fddd123

velox/exec/Task.cpp

@@ -2154,14 +2154,13 @@ folly::dynamic Task::toJson() const {
     obj["plan"] = planFragment_.planNode->toString(true, true);
   }
 
-  folly::dynamic driverObj = folly::dynamic::array;
-  int index = 0;
-  for (auto& driver : drivers_) {
-    if (driver) {
-      driverObj[index++] = driver->toJson();
+  folly::dynamic drivers = folly::dynamic::object;
+  for (auto i = 0; i < drivers_.size(); ++i) {
+    if (drivers_[i] != nullptr) {
+      drivers[i] = drivers_[i]->toJson();
     }
   }
-  obj["drivers"] = driverObj;
+  obj["drivers"] = drivers;
 
   if (auto buffers = bufferManager_.lock()) {
     if (auto buffer = buffers->getBufferIfExists(taskId_)) {

velox/exec/tests/TaskTest.cpp

@@ -502,14 +502,7 @@ class TaskTest : public HiveConnectorTestBase {
   }
 };
 
-TEST_F(TaskTest, wrongPlanNodeForSplit) {
-  auto connectorSplit = std::make_shared<connector::hive::HiveConnectorSplit>(
-      "test",
-      "file:/tmp/abc",
-      facebook::velox::dwio::common::FileFormat::DWRF,
-      0,
-      100);
-
+TEST_F(TaskTest, toJson) {
   auto plan = PlanBuilder()
                   .tableScan(ROW({"a", "b"}, {INTEGER(), DOUBLE()}))
                   .project({"a * a", "b + b"})
@@ -525,11 +518,42 @@ TEST_F(TaskTest, wrongPlanNodeForSplit) {
       task->toString(), "{Task task-1 (task-1)Plan: -- Project\n\n drivers:\n");
   ASSERT_EQ(
       folly::toPrettyJson(task->toJson()),
-      "{\n  \"concurrentSplitGroups\": 1,\n  \"drivers\": [],\n  \"exchangeClientByPlanNode\": {},\n  \"groupedPartitionedOutput\": false,\n  \"id\": \"task-1\",\n  \"noMoreOutputBuffers\": false,\n  \"numDriversPerSplitGroup\": 0,\n  \"numDriversUngrouped\": 0,\n  \"numFinishedDrivers\": 0,\n  \"numRunningDrivers\": 0,\n  \"numRunningSplitGroups\": 0,\n  \"numThreads\": 0,\n  \"numTotalDrivers\": 0,\n  \"onThreadSince\": \"0\",\n  \"partitionedOutputConsumed\": false,\n  \"pauseRequested\": false,\n  \"plan\": \"-- Project[expressions: (p0:INTEGER, multiply(ROW[\\\"a\\\"],ROW[\\\"a\\\"])), (p1:DOUBLE, plus(ROW[\\\"b\\\"],ROW[\\\"b\\\"]))] -> p0:INTEGER, p1:DOUBLE\\n  -- TableScan[table: hive_table] -> a:INTEGER, b:DOUBLE\\n\",\n  \"shortId\": \"task-1\",\n  \"state\": \"Running\",\n  \"terminateRequested\": false\n}");
+      "{\n  \"concurrentSplitGroups\": 1,\n  \"drivers\": {},\n  \"exchangeClientByPlanNode\": {},\n  \"groupedPartitionedOutput\": false,\n  \"id\": \"task-1\",\n  \"noMoreOutputBuffers\": false,\n  \"numDriversPerSplitGroup\": 0,\n  \"numDriversUngrouped\": 0,\n  \"numFinishedDrivers\": 0,\n  \"numRunningDrivers\": 0,\n  \"numRunningSplitGroups\": 0,\n  \"numThreads\": 0,\n  \"numTotalDrivers\": 0,\n  \"onThreadSince\": \"0\",\n  \"partitionedOutputConsumed\": false,\n  \"pauseRequested\": false,\n  \"plan\": \"-- Project[expressions: (p0:INTEGER, multiply(ROW[\\\"a\\\"],ROW[\\\"a\\\"])), (p1:DOUBLE, plus(ROW[\\\"b\\\"],ROW[\\\"b\\\"]))] -> p0:INTEGER, p1:DOUBLE\\n  -- TableScan[table: hive_table] -> a:INTEGER, b:DOUBLE\\n\",\n  \"shortId\": \"task-1\",\n  \"state\": \"Running\",\n  \"terminateRequested\": false\n}");
   ASSERT_EQ(
       folly::toPrettyJson(task->toShortJson()),
       "{\n  \"id\": \"task-1\",\n  \"numFinishedDrivers\": 0,\n  \"numRunningDrivers\": 0,\n  \"numThreads\": 0,\n  \"numTotalDrivers\": 0,\n  \"pauseRequested\": false,\n  \"shortId\": \"task-1\",\n  \"state\": \"Running\",\n  \"terminateRequested\": false\n}");
 
+  task->start(2);
+
+  ASSERT_NO_THROW(task->toJson());
+  ASSERT_NO_THROW(task->toShortJson());
+
+  task->noMoreSplits("0");
+  waitForTaskCompletion(task.get());
+
+  ASSERT_NO_THROW(task->toJson());
+  ASSERT_NO_THROW(task->toShortJson());
+}
+
+TEST_F(TaskTest, wrongPlanNodeForSplit) {
+  auto connectorSplit = std::make_shared<connector::hive::HiveConnectorSplit>(
+      "test",
+      "file:/tmp/abc",
+      facebook::velox::dwio::common::FileFormat::DWRF,
+      0,
+      100);
+
+  auto plan = PlanBuilder()
+                  .tableScan(ROW({"a", "b"}, {INTEGER(), DOUBLE()}))
+                  .project({"a * a", "b + b"})
+                  .planFragment();
+
+  auto task = Task::create(
+      "task-1",
+      std::move(plan),
+      0,
+      std::make_shared<core::QueryCtx>(driverExecutor_.get()));
+
   // Add split for the source node.
   task->addSplit("0", exec::Split(folly::copy(connectorSplit)));