Fix forward references inside Annotated dependencies (fixes #13056)

fastapi/dependencies/utils.py

@@ -5,6 +5,7 @@ from collections.abc import Coroutine, Mapping, Sequence
 from contextlib import AsyncExitStack, contextmanager
 from copy import copy, deepcopy
 from dataclasses import dataclass
+from typing import get_type_hints
 from typing import (
     Annotated,
     Any,
@@ -270,8 +271,19 @@ def get_dependant(
     current_scopes = (parent_oauth_scopes or []) + (own_oauth_scopes or [])
     path_param_names = get_path_param_names(path)
     endpoint_signature = get_typed_signature(call)
+
+    # Resolve forward references inside Annotated (fix for issue #13056)
+    try:
+        type_hints = get_type_hints(call, include_extras=True)
+    except Exception:
+        type_hints = {}
+
     signature_params = endpoint_signature.parameters
+
     for param_name, param in signature_params.items():
+        # Inject fully resolved Annotated types (including forward refs)
+        if param_name in type_hints:
+            param = param.replace(annotation=type_hints[param_name])
         is_path_param = param_name in path_param_names
         param_details = analyze_param(
             param_name=param_name,

tests/test_annotated_forwardref.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Annotated
+
+from fastapi import Depends, FastAPI
+from fastapi.testclient import TestClient
+
+
+def test_annotated_forwardref_dependency():
+    app = FastAPI()
+
+    def get_item() -> Item:
+        return Item(name="apple")
+
+    @app.get("/")
+    def read(item: Annotated[Item, Depends(get_item)]):
+        return {"name": item.name}
+
+    @dataclass
+    class Item:
+        name: str
+
+    client = TestClient(app)
+    response = client.get("/")
+
+    assert response.status_code == 200
+    assert response.json() == {"name": "apple"}