From 4313a0ff6dc419431998017a20c035439fb083af Mon Sep 17 00:00:00 2001
From: Maddie Zechar <mez2113@columbia.edu>
Date: Tue, 4 Jan 2022 19:05:28 +0000
Subject: SERVER-62019: Remove flag guard from linearFill

---
 jstests/aggregation/sources/setWindowFields/locf.js   |  5 +++++
 src/mongo/db/pipeline/accumulator_locf.cpp            |  4 ++--
 src/mongo/db/pipeline/document_source_fill.cpp        |  4 ++--
 .../window_function/window_function_expression.cpp    |  8 +++++---
 src/mongo/db/query/query_feature_flags.idl            | 19 ++++++++++++-------
 5 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/jstests/aggregation/sources/setWindowFields/locf.js b/jstests/aggregation/sources/setWindowFields/locf.js
index b6a7d7960b6..8038c2cbc1b 100644
--- a/jstests/aggregation/sources/setWindowFields/locf.js
+++ b/jstests/aggregation/sources/setWindowFields/locf.js
@@ -12,6 +12,11 @@ load("jstests/aggregation/extras/window_function_helpers.js");
 load("jstests/aggregation/extras/utils.js");  // For arrayEq.
 load("jstests/libs/feature_flag_util.js");    // For isEnabled.
 
+if (!FeatureFlagUtil.isEnabled(db, "Locf")) {
+    jsTestLog("Skipping as featureFlagLocf is not enabled");
+    return;
+}
+
 const coll = db[jsTestName()];
 coll.drop();
 
diff --git a/src/mongo/db/pipeline/accumulator_locf.cpp b/src/mongo/db/pipeline/accumulator_locf.cpp
index 9d7749e6a5a..01ac81bf029 100644
--- a/src/mongo/db/pipeline/accumulator_locf.cpp
+++ b/src/mongo/db/pipeline/accumulator_locf.cpp
@@ -41,8 +41,8 @@ namespace mongo {
 REGISTER_WINDOW_FUNCTION_CONDITIONALLY(
     locf,
     mongo::window_function::ExpressionFromLeftUnboundedWindowFunction<AccumulatorLocf>::parse,
-    multiversion::FeatureCompatibilityVersion::kVersion_5_2,
-    true);
+    feature_flags::gFeatureFlagLocf.getVersion(),
+    feature_flags::gFeatureFlagLocf.isEnabledAndIgnoreFCV());
 
 AccumulatorLocf::AccumulatorLocf(ExpressionContext* const expCtx)
     : AccumulatorForWindowFunctions(expCtx) {
diff --git a/src/mongo/db/pipeline/document_source_fill.cpp b/src/mongo/db/pipeline/document_source_fill.cpp
index 282ca7586f2..beb335bf31f 100644
--- a/src/mongo/db/pipeline/document_source_fill.cpp
+++ b/src/mongo/db/pipeline/document_source_fill.cpp
@@ -44,8 +44,8 @@ REGISTER_DOCUMENT_SOURCE_CONDITIONALLY(fill,
                                        document_source_fill::createFromBson,
                                        AllowedWithApiStrict::kNeverInVersion1,
                                        AllowedWithClientType::kAny,
-                                       multiversion::FeatureCompatibilityVersion::kVersion_5_2,
-                                       feature_flags::gFlagFill.isEnabledAndIgnoreFCV());
+                                       feature_flags::gFeatureFlagFill.getVersion(),
+                                       feature_flags::gFeatureFlagFill.isEnabledAndIgnoreFCV());
 namespace document_source_fill {
 
 std::list<boost::intrusive_ptr<DocumentSource>> createFromBson(
diff --git a/src/mongo/db/pipeline/window_function/window_function_expression.cpp b/src/mongo/db/pipeline/window_function/window_function_expression.cpp
index 10229d9eedb..cd5d3ad6da8 100644
--- a/src/mongo/db/pipeline/window_function/window_function_expression.cpp
+++ b/src/mongo/db/pipeline/window_function/window_function_expression.cpp
@@ -58,9 +58,11 @@ REGISTER_WINDOW_FUNCTION(derivative, ExpressionDerivative::parse);
 REGISTER_WINDOW_FUNCTION(first, ExpressionFirst::parse);
 REGISTER_WINDOW_FUNCTION(last, ExpressionLast::parse);
 REGISTER_WINDOW_FUNCTION_CONDITIONALLY(linearFill,
-                                       ExpressionLinearFill::parse,
-                                       multiversion::FeatureCompatibilityVersion::kVersion_5_2,
-                                       feature_flags::gFlagFill.isEnabledAndIgnoreFCV());
+                                       (ExpressionLinearFill::parse),
+                                       feature_flags::gFeatureFlagFill.getVersion(),
+                                       feature_flags::gFeatureFlagFill.isEnabledAndIgnoreFCV());
+// TODO SERVER-52247 Replace boost::none with 'gFeatureFlagExactTopNAccumulator.getVersion()' below
+// once 'gFeatureFlagExactTopNAccumulator' is set to true by default and is configured with an FCV.
 REGISTER_WINDOW_FUNCTION_CONDITIONALLY(
     minN,
     (ExpressionN<WindowFunctionMinN, AccumulatorMinN>::parse),
diff --git a/src/mongo/db/query/query_feature_flags.idl b/src/mongo/db/query/query_feature_flags.idl
index 5607f3069f7..17a33beb4be 100644
--- a/src/mongo/db/query/query_feature_flags.idl
+++ b/src/mongo/db/query/query_feature_flags.idl
@@ -82,13 +82,6 @@ feature_flags:
       cpp_varname: gFeatureFlagSbePlanCache
       default: false
 
-    featureFlagFill:
-        description: >
-          When disabled, this flag does not allow $fill, $locf or the linear interpolation window function
-          to parse. It will be removed when PM-1935 is complete
-        cpp_varname: gFlagFill
-        default: false
-
     featureFlagSortArray:
         description: "Feature flag for allowing use of the $sortArray aggregation expression"
         cpp_varname: gFeatureFlagSortArray
@@ -100,6 +93,18 @@ feature_flags:
       cpp_varname: gFeatureFlagChangeStreamsVisibility
       default: false
 
+    featureFlagLocf:
+        description: "Feature flag for allowing $locf window function"
+        cpp_varname: gFeatureFlagLocf
+        default: true
+        version: 5.2
+
+    featureFlagFill:
+        description: "Feature flag for allowing $fill and $linearFill window functions"
+        cpp_varname: gFeatureFlagFill
+        default: true
+        version: 5.3
+
     featureFlagPerShardCursor:
       description: "Feature flag for enabling a per-shard cursor via mongos"
       cpp_varname: gFeatureFlagPerShardCursor
-- 
cgit v1.2.1