From c540a205558830d6a2ec7147a004516f741b6e23 Mon Sep 17 00:00:00 2001
From: Charlie Swanson <charlie.swanson@mongodb.com>
Date: Tue, 5 Oct 2021 01:49:50 +0000
Subject: SERVER-60520 Allow $searchMeta by default

Default the 'enableSearchMeta' parameter to true
---
 jstests/aggregation/documents.js                     | 3 ---
 jstests/aggregation/variables/search_meta.js         | 3 ---
 src/mongo/db/pipeline/document_source_union_with.cpp | 4 +++-
 src/mongo/db/query/query_knobs.idl                   | 2 +-
 4 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/jstests/aggregation/documents.js b/jstests/aggregation/documents.js
index 5996b5dd4ff..deffe8fcf15 100644
--- a/jstests/aggregation/documents.js
+++ b/jstests/aggregation/documents.js
@@ -15,15 +15,12 @@
 
 (function() {
 "use strict";
-load('jstests/libs/fixture_helpers.js');  // for runCommandOnEachPrimary.
 
 const writeConcernOptions = {
     writeConcern: {w: "majority"}
 };
 
 const currDB = db;
-FixtureHelpers.runCommandOnEachPrimary(
-    {db: db.getSiblingDB("admin"), cmdObj: {setParameter: 1, enableSearchMeta: true}});
 const coll = currDB.documents;
 coll.drop(writeConcernOptions);
 coll.insert({a: 1}, writeConcernOptions);
diff --git a/jstests/aggregation/variables/search_meta.js b/jstests/aggregation/variables/search_meta.js
index 5a29598b6bc..b1e5ee71a1f 100644
--- a/jstests/aggregation/variables/search_meta.js
+++ b/jstests/aggregation/variables/search_meta.js
@@ -10,9 +10,6 @@
  */
 (function() {
 "use strict";
-load('jstests/libs/fixture_helpers.js');  // for runCommandOnEachPrimary.
-FixtureHelpers.runCommandOnEachPrimary(
-    {db: db.getSiblingDB("admin"), cmdObj: {setParameter: 1, enableSearchMeta: true}});
 
 const coll = db.searchCollector;
 coll.drop();
diff --git a/src/mongo/db/pipeline/document_source_union_with.cpp b/src/mongo/db/pipeline/document_source_union_with.cpp
index 05f388ff87a..d54e95b8425 100644
--- a/src/mongo/db/pipeline/document_source_union_with.cpp
+++ b/src/mongo/db/pipeline/document_source_union_with.cpp
@@ -211,7 +211,9 @@ DocumentSource::GetNextResult DocumentSourceUnionWith::doGetNext() {
         logStartingSubPipeline(serializedPipe);
         // $$SEARCH_META can be set during runtime earlier in the pipeline, and therefore must be
         // copied to the subpipeline manually.
-        if (enableSearchMeta.load()) {
+        if (serverGlobalParams.featureCompatibility.getVersion() >=
+                ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44 &&
+            enableSearchMeta.load()) {
             auto metaVal = pExpCtx->variables.getValue(Variables::kSearchMetaId, Document());
             if (!metaVal.missing()) {
                 _pipeline->getContext()->variables.setReservedValue(
diff --git a/src/mongo/db/query/query_knobs.idl b/src/mongo/db/query/query_knobs.idl
index d68433340a0..7eaba46f916 100644
--- a/src/mongo/db/query/query_knobs.idl
+++ b/src/mongo/db/query/query_knobs.idl
@@ -421,7 +421,7 @@ server_parameters:
     set_at: [ startup, runtime ]
     cpp_varname: "enableSearchMeta"
     cpp_vartype: AtomicWord<bool>
-    default: false
+    default: true
 
   enableTimeoutOfInactiveSessionCursors:
     description: "If true, cursors opened within sessions are eligible for inactive cursor timeout."
-- 
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