From 63367915ede5582347214f4f6e6f3f7c423f46c9 Mon Sep 17 00:00:00 2001
From: Peter Volf <do.volfp@gmail.com>
Date: Wed, 23 Jul 2025 09:51:09 +0200
Subject: [PATCH] fix: store special dependand names in sets instead of lists

---
 fastapi/dependencies/models.py | 14 +++++++-------
 fastapi/dependencies/utils.py  | 12 ++++++------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/fastapi/dependencies/models.py b/fastapi/dependencies/models.py
index 62fd4cc89..ae1a370ba 100644
--- a/fastapi/dependencies/models.py
+++ b/fastapi/dependencies/models.py
@@ -1,5 +1,5 @@
 from dataclasses import dataclass, field
-from typing import Any, Callable, List, Optional, Sequence, Tuple
+from typing import Any, Callable, List, Optional, Sequence, Set, Tuple
 
 from fastapi._compat import ModelField
 from fastapi.security.base import SecurityBase
@@ -22,12 +22,12 @@ class Dependant:
     security_requirements: List[SecurityRequirement] = field(default_factory=list)
     name: Optional[str] = None
     call: Optional[Callable[..., Any]] = None
-    request_param_names: List[str] = field(default_factory=list)
-    websocket_param_names: List[str] = field(default_factory=list)
-    http_connection_param_names: List[str] = field(default_factory=list)
-    response_param_names: List[str] = field(default_factory=list)
-    background_tasks_param_names: List[str] = field(default_factory=list)
-    security_scopes_param_names: List[str] = field(default_factory=list)
+    request_param_names: Set[str] = field(default_factory=set)
+    websocket_param_names: Set[str] = field(default_factory=set)
+    http_connection_param_names: Set[str] = field(default_factory=set)
+    response_param_names: Set[str] = field(default_factory=set)
+    background_tasks_param_names: Set[str] = field(default_factory=set)
+    security_scopes_param_names: Set[str] = field(default_factory=set)
     security_scopes: Optional[List[str]] = None
     use_cache: bool = True
     path: Optional[str] = None
diff --git a/fastapi/dependencies/utils.py b/fastapi/dependencies/utils.py
index 3b0650251..ee3e1f3e5 100644
--- a/fastapi/dependencies/utils.py
+++ b/fastapi/dependencies/utils.py
@@ -318,22 +318,22 @@ def add_non_field_param_to_dependency(
     *, param_name: str, type_annotation: Any, dependant: Dependant
 ) -> Optional[bool]:
     if lenient_issubclass(type_annotation, Request):
-        dependant.request_param_names.append(param_name)
+        dependant.request_param_names.add(param_name)
         return True
     elif lenient_issubclass(type_annotation, WebSocket):
-        dependant.websocket_param_names.append(param_name)
+        dependant.websocket_param_names.add(param_name)
         return True
     elif lenient_issubclass(type_annotation, HTTPConnection):
-        dependant.http_connection_param_names.append(param_name)
+        dependant.http_connection_param_names.add(param_name)
         return True
     elif lenient_issubclass(type_annotation, Response):
-        dependant.response_param_names.append(param_name)
+        dependant.response_param_names.add(param_name)
         return True
     elif lenient_issubclass(type_annotation, StarletteBackgroundTasks):
-        dependant.background_tasks_param_names.append(param_name)
+        dependant.background_tasks_param_names.add(param_name)
         return True
     elif lenient_issubclass(type_annotation, SecurityScopes):
-        dependant.security_scopes_param_names.append(param_name)
+        dependant.security_scopes_param_names.add(param_name)
         return True
     return None