From 159771fa2fd4c014fddead79af4025ffac1eab54 Mon Sep 17 00:00:00 2001
From: Ted Tuckman <ted.tuckman@mongodb.com>
Date: Mon, 23 Mar 2020 15:38:14 -0400
Subject: [PATCH] SERVER-46649 Fix out_drop_temp_collections.js to work with
 two phase index builds

---
 .../noPassthrough/out_drop_temp_collection.js | 37 +++++++------------
 src/mongo/db/pipeline/document_source_out.cpp |  5 ---
 2 files changed, 13 insertions(+), 29 deletions(-)

diff --git a/jstests/noPassthrough/out_drop_temp_collection.js b/jstests/noPassthrough/out_drop_temp_collection.js
index 0160dc137de..644718f5d6d 100644
--- a/jstests/noPassthrough/out_drop_temp_collection.js
+++ b/jstests/noPassthrough/out_drop_temp_collection.js
@@ -1,6 +1,5 @@
 /**
- * Test the behaviour of a dropDatabase command during an aggregation containing $out for single
- * phase index builds.
+ * Test the behavior of a dropDatabase command during an aggregation containing $out.
  *
  * @tags: [
  *   assumes_unsharded_collection,
@@ -36,27 +35,22 @@ function runTest(st, testDb, portNum) {
             mode: "alwaysOn",
         }
     });
+    res.forEach(cmdResult => assert.commandWorked(cmdResult));
 
     const aggDone = startParallelShell(() => {
-        const targetColl = db.getSiblingDB("out_drop_temp").out_target_coll;
-        const pipeline = [{$out: "out_target_coll"}];
-        targetColl.aggregate(pipeline);
+        const targetDB = db.getSiblingDB("out_drop_temp");
+        // There are a number of possible error codes depending on configuration and index build
+        // options.
+        assert.commandFailed(targetDB.runCommand(
+            {aggregate: "out_source_coll", pipeline: [{$out: "out_target_coll"}], cursor: {}}));
+        const collList = assert.commandWorked(targetDB.runCommand({listCollections: 1}));
+        assert.eq(collList.cursor.firstBatch.length, 0);
     }, portNum);
 
     waitForCurOpByFilter(testDb, {"failpointMsg": failpointName});
-    // TODO SERVER-45358 Make it easier to run commands without retrying.
-    // Tests are run with an override function that retries commands that fail because of a
-    // background operation. Parallel shells don't automatically have that override, so drop has to
-    // be run in a parallel shell.
-    const dropColl = startParallelShell(() => {
-        const targetDb = db.getSiblingDB("out_drop_temp");
-        assert.commandFailedWithCode(targetDb.runCommand({dropDatabase: 1}), [
-            ErrorCodes.BackgroundOperationInProgressForDatabase,
-            ErrorCodes.BackgroundOperationInProgressForNamespace
-        ]);
-    }, portNum);
-    dropColl();
-    // The $out should complete once the failpoint is disabled, not fail on index creation.
+
+    assert.commandWorked(testDb.runCommand({dropDatabase: 1}));
+
     FixtureHelpers.runCommandOnEachPrimary({
         db: testDb.getSiblingDB("admin"),
         cmdObj: {
@@ -66,13 +60,8 @@ function runTest(st, testDb, portNum) {
     });
     aggDone();
 }
-const conn = MongoRunner.runMongod({});
-if (IndexBuildTest.supportsTwoPhaseIndexBuild(conn)) {
-    jsTest.log("Not running because two phase index builds are enabled.");
-    MongoRunner.stopMongod(conn);
-    return;
-}
 
+const conn = MongoRunner.runMongod({});
 runTest(null, conn.getDB("out_drop_temp"), conn.port);
 MongoRunner.stopMongod(conn);
 const st = new ShardingTest({shards: 2, mongos: 1, config: 1});
diff --git a/src/mongo/db/pipeline/document_source_out.cpp b/src/mongo/db/pipeline/document_source_out.cpp
index 7ba4fdc48bf..31d896057cc 100644
--- a/src/mongo/db/pipeline/document_source_out.cpp
+++ b/src/mongo/db/pipeline/document_source_out.cpp
@@ -127,11 +127,6 @@ void DocumentSourceOut::initialize() {
             "namespace '{}' is capped so it can't be used for {}"_format(outputNs.ns(), kStageName),
             _originalOutOptions["capped"].eoo());
 
-    // Create temp collection, copying options from the existing output collection if any.
-    // Disallows drops and renames on this namespace. This is required to ensure
-    // 'createIndexesOnEmptyCollection' is called on a namespace that both exists and is empty as
-    // the function expects.
-    BackgroundOperation backgroundOp(_tempNs.ns());
     {
         BSONObjBuilder cmd;
         cmd << "create" << _tempNs.coll();