1 files changed, 38 insertions, 12 deletions
diff --git a/src/mongo/db/update/unset_node_test.cpp b/src/mongo/db/update/unset_node_test.cpp
index d45b2472a90..4595183ef0d 100644
--- a/src/mongo/db/update/unset_node_test.cpp
+++ b/src/mongo/db/update/unset_node_test.cpp
@@ -36,6 +36,7 @@
 #include "mongo/db/json.h"
 #include "mongo/db/pipeline/expression_context_for_test.h"
 #include "mongo/db/update/update_node_test_fixture.h"
+#include "mongo/idl/server_parameter_test_util.h"
 #include "mongo/unittest/death_test.h"
 #include "mongo/unittest/unittest.h"
 
@@ -369,18 +370,43 @@ TEST_F(UnsetNodeTest, ApplyFieldWithDot) {
 }
 
 TEST_F(UnsetNodeTest, ApplyCannotRemoveRequiredPartOfDBRef) {
-    auto update = fromjson("{$unset: {'a.$id': true}}");
-    boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());
-    UnsetNode node;
-    ASSERT_OK(node.init(update["$unset"]["a.$id"], expCtx));
-
-    mutablebson::Document doc(fromjson("{a: {$ref: 'c', $id: 0}}"));
-    setPathTaken(makeRuntimeUpdatePathForTest("a.$id"));
-    ASSERT_THROWS_CODE_AND_WHAT(
-        node.apply(getApplyParams(doc.root()["a"]["$id"]), getUpdateNodeApplyParams()),
-        AssertionException,
-        ErrorCodes::InvalidDBRef,
-        "The DBRef $ref field must be followed by a $id field");
+    {
+        RAIIServerParameterControllerForTest controller("featureFlagDotsAndDollars", false);
+        auto update = fromjson("{$unset: {'a.$id': true}}");
+        boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());
+        UnsetNode node;
+        ASSERT_OK(node.init(update["$unset"]["a.$id"], expCtx));
+
+        mutablebson::Document doc(fromjson("{a: {$ref: 'c', $id: 0}}"));
+        setPathTaken(makeRuntimeUpdatePathForTest("a.$id"));
+        ASSERT_THROWS_CODE_AND_WHAT(
+            node.apply(getApplyParams(doc.root()["a"]["$id"]), getUpdateNodeApplyParams()),
+            AssertionException,
+            ErrorCodes::InvalidDBRef,
+            "The DBRef $ref field must be followed by a $id field");
+    }
+    {
+        RAIIServerParameterControllerForTest controller("featureFlagDotsAndDollars", true);
+        auto update = fromjson("{$unset: {'a.$id': true}}");
+        boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());
+        UnsetNode node;
+        ASSERT_OK(node.init(update["$unset"]["a.$id"], expCtx));
+
+        mutablebson::Document doc(fromjson("{a: {$ref: 'c', $id: 0}}"));
+        setPathTaken(makeRuntimeUpdatePathForTest("a.$id"));
+        auto result =
+            node.apply(getApplyParams(doc.root()["a"]["$id"]), getUpdateNodeApplyParams());
+        ASSERT_FALSE(result.noop);
+        ASSERT_FALSE(result.indexesAffected);
+        auto updated = BSON("a" << BSON("$ref"
+                                        << "c"));
+        ASSERT_EQUALS(updated, doc);
+        ASSERT_FALSE(doc.isInPlaceModeEnabled());
+
+        assertOplogEntry(fromjson("{$unset: {'a.$id': true}}"),
+                         fromjson("{$v: 2, diff: {sa: {d: {$id: false}}}}"));
+        ASSERT_EQUALS(getModifiedPaths(), "{a.$id}");
+    }
 }
 
 TEST_F(UnsetNodeTest, ApplyCanRemoveRequiredPartOfDBRefIfValidateForStorageIsFalse) {