From 692114ec5461e04880961aee41c00a8dc711fc37 Mon Sep 17 00:00:00 2001
From: Benjamin Rewis <32186188+benjirewis@users.noreply.github.com>
Date: Fri, 16 Apr 2021 11:57:20 -0400
Subject: [PATCH] GODRIVER-852 Add documentation warning against the use of
 duplicate key names (#614)

---
 bson/bson.go | 2 ++
 bson/doc.go  | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/bson/bson.go b/bson/bson.go
index ae1a87faa7..0c739dd0ac 100644
--- a/bson/bson.go
+++ b/bson/bson.go
@@ -25,6 +25,8 @@ type Zeroer interface {
 // D is an ordered representation of a BSON document. This type should be used when the order of the elements matters,
 // such as MongoDB command documents. If the order of the elements does not matter, an M should be used instead.
 //
+// A D should not be constructed with duplicate key names, as that can cause undefined server behavior.
+//
 // Example usage:
 //
 // 		bson.D{{"foo", "bar"}, {"hello", "world"}, {"pi", 3.14159}}
diff --git a/bson/doc.go b/bson/doc.go
index 16341568dc..07ba9d8f84 100644
--- a/bson/doc.go
+++ b/bson/doc.go
@@ -29,6 +29,8 @@
 // slice and M is a map. For more information about the use cases for these types, see the documentation on the type
 // definitions.
 //
+// Note that a D should not be constructed with duplicate key names, as that can cause undefined server behavior.
+//
 // Example:
 // 		bson.D{{"foo", "bar"}, {"hello", "world"}, {"pi", 3.14159}}
 //		bson.M{"foo": "bar", "hello": "world", "pi": 3.14159}