From 3520755823f44da74b08202be77c3e3f56dbabe3 Mon Sep 17 00:00:00 2001
From: Yurii Motov <yurii.motov.monte@gmail.com>
Date: Fri, 4 Jul 2025 17:07:28 +0200
Subject: [PATCH] Restore smart_union=True config for Pydantic V1

---
 fastapi/openapi/models.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fastapi/openapi/models.py b/fastapi/openapi/models.py
index ad21ceb8c..207ffb643 100644
--- a/fastapi/openapi/models.py
+++ b/fastapi/openapi/models.py
@@ -63,6 +63,7 @@ class BaseModelWithConfig(BaseModel):
 
         class Config:
             extra = "allow"
+            smart_union = True
 
 
 class Contact(BaseModelWithConfig):