From ebe610ebbd91c147dcbdcb31a258b8da3e0044ff Mon Sep 17 00:00:00 2001
From: Luca Pizzini <lpizzini7@gmail.com>
Date: Sat, 17 Sep 2022 16:20:42 +0200
Subject: [PATCH] Fixed InferSchemaType nullable arrays type inference

fixes #12420
---
 test/types/schema.test.ts  | 29 +++++++++++++++++++++++++++++
 types/inferschematype.d.ts |  2 +-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/test/types/schema.test.ts b/test/types/schema.test.ts
index c65b3bfdd9c..bb0a6970839 100644
--- a/test/types/schema.test.ts
+++ b/test/types/schema.test.ts
@@ -741,3 +741,32 @@ function pluginOptions() {
   schema.plugin<any, SomePluginOptions>(pluginFunction2, { option2: 0 });
   expectError(schema.plugin<any, SomePluginOptions>(pluginFunction2, {})); // should error because "option2" is not optional
 }
+
+function gh12420() {
+  const TestSchema = new Schema(
+    {
+      comments: { type: [String], required: false },
+      reference: {
+        type: [
+          {
+            type: { type: String, required: false },
+            value: { type: String, required: false }
+          }
+        ],
+        required: false
+      }
+    },
+    {
+      collection: 'tests',
+      timestamps: false
+    }
+  );
+
+  expectType<{
+    comments?: string[],
+    reference?: {
+      type?: string,
+      value?: string
+    }[]
+  }>({} as InferSchemaType<typeof TestSchema>);
+}
diff --git a/types/inferschematype.d.ts b/types/inferschematype.d.ts
index 5041f830477..e951012692c 100644
--- a/types/inferschematype.d.ts
+++ b/types/inferschematype.d.ts
@@ -69,7 +69,7 @@ type IsPathRequired<P, TypeKey extends TypeKeyBaseType> =
   P extends { required: true | [true, string | undefined] } | ArrayConstructor | any[]
     ? true
     : P extends (Record<TypeKey, ArrayConstructor | any[]>)
-      ? P extends { default: undefined }
+      ? P extends { default: undefined } | { required: false }
         ? false
         : true
       : P extends (Record<TypeKey, any>)