From 64f8d6b20267ea719bc8c6df2f59d7ec2f7f233c Mon Sep 17 00:00:00 2001
From: Dennis Glot <31706897+gl-ot@users.noreply.github.com>
Date: Wed, 17 Mar 2021 23:50:26 +0300
Subject: [PATCH] GODRIVER-1919 Support decoding ObjectIDs from hex strings in
 BSON (#610)

---
 bson/bsoncodec/default_value_decoders.go      |  4 ++++
 bson/bsoncodec/default_value_decoders_test.go | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/bson/bsoncodec/default_value_decoders.go b/bson/bsoncodec/default_value_decoders.go
index 0402265d93..18919e3c40 100644
--- a/bson/bsoncodec/default_value_decoders.go
+++ b/bson/bsoncodec/default_value_decoders.go
@@ -718,6 +718,7 @@ func (dvd DefaultValueDecoders) UndefinedDecodeValue(dc DecodeContext, vr bsonrw
 	return nil
 }
 
+// Accept both 12-byte string and pretty-printed 24-byte hex string formats.
 func (dvd DefaultValueDecoders) objectIDDecodeType(dc DecodeContext, vr bsonrw.ValueReader, t reflect.Type) (reflect.Value, error) {
 	if t != tOID {
 		return emptyValue, ValueDecoderError{
@@ -740,6 +741,9 @@ func (dvd DefaultValueDecoders) objectIDDecodeType(dc DecodeContext, vr bsonrw.V
 		if err != nil {
 			return emptyValue, err
 		}
+		if oid, err = primitive.ObjectIDFromHex(str); err == nil {
+			break
+		}
 		if len(str) != 12 {
 			return emptyValue, fmt.Errorf("an ObjectID string must be exactly 12 bytes long (got %v)", len(str))
 		}
diff --git a/bson/bsoncodec/default_value_decoders_test.go b/bson/bsoncodec/default_value_decoders_test.go
index b7fc2b5636..c1a0f6e0d9 100644
--- a/bson/bsoncodec/default_value_decoders_test.go
+++ b/bson/bsoncodec/default_value_decoders_test.go
@@ -1118,6 +1118,17 @@ func TestDefaultValueDecoders(t *testing.T) {
 					bsonrwtest.ReadString,
 					nil,
 				},
+				{
+					"success/string-hex",
+					primitive.ObjectID{0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x61, 0x62},
+					nil,
+					&bsonrwtest.ValueReaderWriter{
+						BSONType: bsontype.String,
+						Return:   "303132333435363738396162",
+					},
+					bsonrwtest.ReadString,
+					nil,
+				},
 				{
 					"decode null",
 					primitive.ObjectID{},