From 3bdae61fc79a55ddbe966622c2313614e0503f2a Mon Sep 17 00:00:00 2001
From: hasezoey <hasezoey@gmail.com>
Date: Fri, 16 Jun 2023 12:41:07 +0200
Subject: [PATCH] types: augment bson.ObjectId instead of adding on own type

fixes #12537
---
 test/types/mongo.test.ts | 13 +++++++++++++
 types/augmentations.d.ts |  9 +++++++++
 types/index.d.ts         |  1 +
 types/types.d.ts         |  1 -
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 types/augmentations.d.ts

diff --git a/test/types/mongo.test.ts b/test/types/mongo.test.ts
index 320ae24501b..42fda3587d7 100644
--- a/test/types/mongo.test.ts
+++ b/test/types/mongo.test.ts
@@ -1,4 +1,17 @@
 import * as mongoose from 'mongoose';
 import { expectType } from 'tsd';
+import * as bson from 'bson';
 
 import GridFSBucket = mongoose.mongo.GridFSBucket;
+
+function gh12537() {
+  const schema = new mongoose.Schema({ test: String });
+  const model = mongoose.model('Test', schema);
+
+  const doc = new model({});
+
+  const v = new bson.ObjectId('somehex');
+  expectType<string>(v._id.toHexString());
+
+  doc._id = new bson.ObjectId('somehex');
+}
diff --git a/types/augmentations.d.ts b/types/augmentations.d.ts
new file mode 100644
index 00000000000..6ed3e6f2c93
--- /dev/null
+++ b/types/augmentations.d.ts
@@ -0,0 +1,9 @@
+// the import below is said to be unused, but actually required so that types get merged and not overwritten
+import * as bson from 'bson';
+
+declare module 'bson' {
+  interface ObjectId {
+    /** Mongoose automatically adds a conveniency "_id" getter on the base ObjectId class */
+    _id: this;
+  }
+}
diff --git a/types/index.d.ts b/types/index.d.ts
index cfed86c51c3..ec716fa29d3 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -22,6 +22,7 @@
 /// <reference path="./validation.d.ts" />
 /// <reference path="./inferschematype.d.ts" />
 /// <reference path="./virtuals.d.ts" />
+/// <reference path="./augmentations.d.ts" />
 
 declare class NativeDate extends global.Date { }
 
diff --git a/types/types.d.ts b/types/types.d.ts
index 29652243403..55b48138ad3 100644
--- a/types/types.d.ts
+++ b/types/types.d.ts
@@ -80,7 +80,6 @@ declare module 'mongoose' {
     }
 
     class ObjectId extends mongodb.ObjectId {
-      _id: this;
     }
 
     class Subdocument<IdType = any> extends Document<IdType> {