✨ Update internal AsyncExitStack to fix context for dependencies with yield

fastapi/applications.py

@@ -11,6 +11,7 @@
 )
 from fastapi.exceptions import RequestValidationError
 from fastapi.logger import logger
+from fastapi.middleware.asyncexitstack import AsyncExitStackMiddleware
 from fastapi.openapi.docs import (
     get_redoc_html,
     get_swagger_ui_html,
@@ -21,8 +22,9 @@
 from fastapi.types import DecoratedCallable
 from starlette.applications import Starlette
 from starlette.datastructures import State
-from starlette.exceptions import HTTPException
+from starlette.exceptions import ExceptionMiddleware, HTTPException
 from starlette.middleware import Middleware
+from starlette.middleware.errors import ServerErrorMiddleware
 from starlette.requests import Request
 from starlette.responses import HTMLResponse, JSONResponse, Response
 from starlette.routing import BaseRoute
@@ -134,6 +136,36 @@ def __init__(
         self.openapi_schema: Optional[Dict[str, Any]] = None
         self.setup()
 
+    def build_middleware_stack(self) -> ASGIApp:
+        # Duplicate/override from Starlette to add AsyncExitStackMiddleware after
+        # inside of ExceptionMiddleware
+        debug = self.debug
+        error_handler = None
+        exception_handlers = {}
+
+        for key, value in self.exception_handlers.items():
+            if key in (500, Exception):
+                error_handler = value
+            else:
+                exception_handlers[key] = value
+
+        middleware = (
+            [Middleware(ServerErrorMiddleware, handler=error_handler, debug=debug)]
+            + self.user_middleware
+            + [
+                Middleware(
+                    ExceptionMiddleware, handlers=exception_handlers, debug=debug
+                ),
+                # Add FastAPI-specific AsyncExitStackMiddleware for dependencies
+                Middleware(AsyncExitStackMiddleware),
+            ]
+        )
+
+        app = self.router
+        for cls, options in reversed(middleware):
+            app = cls(app=app, **options)
+        return app
+
     def openapi(self) -> Dict[str, Any]:
         if not self.openapi_schema:
             self.openapi_schema = get_openapi(
@@ -206,12 +238,7 @@ async def redoc_html(req: Request) -> HTMLResponse:
     async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
         if self.root_path:
             scope["root_path"] = self.root_path
-        if AsyncExitStack:
-            async with AsyncExitStack() as stack:
-                scope["fastapi_astack"] = stack
-                await super().__call__(scope, receive, send)
-        else:
-            await super().__call__(scope, receive, send)  # pragma: no cover
+            await super().__call__(scope, receive, send)
 
     def add_api_route(
         self,