From 03b7031045aa46e1e974b1bee1ce4747aabbb6ca Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Fri, 26 Apr 2024 17:25:17 -0400
Subject: [PATCH 1/2] types(document): make document _id type default to
 unknown instead of any

Fix #14520
---
 types/document.d.ts | 2 +-
 types/types.d.ts    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/types/document.d.ts b/types/document.d.ts
index 2bb82e3c677..c0723e883bf 100644
--- a/types/document.d.ts
+++ b/types/document.d.ts
@@ -16,7 +16,7 @@ declare module 'mongoose' {
    * *  TQueryHelpers - Object with any helpers that should be mixed into the Query type
    * *  DocType - the type of the actual Document created
    */
-  class Document<T = any, TQueryHelpers = any, DocType = any> {
+  class Document<T = unknown, TQueryHelpers = any, DocType = any> {
     constructor(doc?: any);
 
     /** This documents _id. */
diff --git a/types/types.d.ts b/types/types.d.ts
index f63b1934907..08f90c6184c 100644
--- a/types/types.d.ts
+++ b/types/types.d.ts
@@ -83,7 +83,7 @@ declare module 'mongoose' {
     class ObjectId extends mongodb.ObjectId {
     }
 
-    class Subdocument<IdType = any, TQueryHelpers = any, DocType = any> extends Document<IdType, TQueryHelpers, DocType> {
+    class Subdocument<IdType = unknown, TQueryHelpers = any, DocType = any> extends Document<IdType, TQueryHelpers, DocType> {
       $isSingleNested: true;
 
       /** Returns the top level document of this sub-document. */

From 23869fb10cd3e81c1bb2b51878a206ea30bb935e Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Sat, 27 Apr 2024 11:20:42 -0400
Subject: [PATCH 2/2] fix(model): make `recompileSchema()` overwrite existing
 document array discriminators

Fix #14520
---
 lib/schema/documentArray.js |  2 +-
 test/model.test.js          | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/schema/documentArray.js b/lib/schema/documentArray.js
index 2af276500ff..d35c5dfbf10 100644
--- a/lib/schema/documentArray.js
+++ b/lib/schema/documentArray.js
@@ -195,7 +195,7 @@ SchemaDocumentArray.prototype.discriminator = function(name, schema, options) {
     schema = schema.clone();
   }
 
-  schema = discriminator(this.casterConstructor, name, schema, tiedValue);
+  schema = discriminator(this.casterConstructor, name, schema, tiedValue, null, null, options?.overwriteExisting);
 
   const EmbeddedDocument = _createConstructor(schema, null, this.casterConstructor);
   EmbeddedDocument.baseCasterConstructor = this.casterConstructor;
diff --git a/test/model.test.js b/test/model.test.js
index 840b098a86a..9d35f207000 100644
--- a/test/model.test.js
+++ b/test/model.test.js
@@ -7463,6 +7463,23 @@ describe('Model', function() {
     assert.equal(instance.item.whoAmI(), 'I am Test2');
   });
 
+  it('overwrites existing discriminators when calling recompileSchema (gh-14527) (gh-14444)', async function() {
+    const shopItemSchema = new mongoose.Schema({}, { discriminatorKey: 'type' });
+    const shopSchema = new mongoose.Schema({
+      items: { type: [shopItemSchema], required: true }
+    });
+
+    const shopItemSubType = new mongoose.Schema({ prop: Number });
+    shopItemSchema.discriminator(2, shopItemSubType);
+    const shopModel = db.model('shop', shopSchema);
+
+    shopModel.recompileSchema();
+    const doc = new shopModel({
+      items: [{ type: 2, prop: 42 }]
+    });
+    assert.equal(doc.items[0].prop, 42);
+  });
+
   it('inserts versionKey even if schema has `toObject.versionKey` set to false (gh-14344)', async function() {
     const schema = new mongoose.Schema(
       { name: String },