Fix CI failures: Python 3.8 compatibility and Pydantic v1 tests

- Fix Python 3.8 compatibility by importing Annotated from typing_extensions
  when running on Python < 3.9
- Simplify get_typed_signature to not use get_type_hints which was causing
  issues with Pydantic v1 parameter detection (Header, Cookie, Query, etc.)
- Instead, expand globalns with module namespace to help resolve forward
  references while keeping the original annotation resolution logic intact

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

fastapi/dependencies/utils.py

@@ -18,7 +18,6 @@ from typing import (
     Type,
     Union,
     cast,
-    get_type_hints,
 )
 
 import anyio
@@ -228,30 +227,19 @@ def get_typed_signature(call: Callable[..., Any]) -> inspect.Signature:
     unwrapped = inspect.unwrap(call)
     globalns = getattr(unwrapped, "__globals__", {})
 
-    # Try to use get_type_hints first for better forward reference resolution
+    # Get updated globalns from the module (in case classes were defined after the function)
-    # This properly handles Annotated types with forward references when using
+    # This is needed for forward references when using `from __future__ import annotations`
-    # `from __future__ import annotations` (PEP 563)
-    type_hints: Dict[str, Any] = {}
-    try:
-        # include_extras=True preserves Annotated metadata (like Depends)
-        type_hints = get_type_hints(unwrapped, globalns=globalns, include_extras=True)
-    except NameError:
-        # If get_type_hints fails due to unresolved names, try to get updated
-        # globalns from the module (in case classes were defined after the function)
     module_name = getattr(unwrapped, "__module__", None)
     if module_name:
         import importlib
 
         try:
             module = importlib.import_module(module_name)
-                updated_globalns = vars(module)
+            # Merge module namespace with function's globalns
-                type_hints = get_type_hints(
+            # Function's globalns takes precedence for imports made in the function's scope
-                    unwrapped, globalns=updated_globalns, include_extras=True
+            updated_globalns = {**vars(module), **globalns}
-                )
+            globalns = updated_globalns
-            except Exception:
-                pass
         except Exception:
-        # Fall back to manual resolution if get_type_hints fails for other reasons
             pass
 
     typed_params = [
@@ -259,9 +247,7 @@ def get_typed_signature(call: Callable[..., Any]) -> inspect.Signature:
             name=param.name,
             kind=param.kind,
             default=param.default,
-            annotation=type_hints.get(param.name)
+            annotation=get_typed_annotation(param.annotation, globalns),
-            if param.name in type_hints
-            else get_typed_annotation(param.annotation, globalns),
         )
         for param in signature.parameters.values()
     ]

tests/test_annotated_forward_ref.py

@@ -2,8 +2,15 @@
 
 from __future__ import annotations
 
+import sys
 from dataclasses import dataclass
+
+# Annotated is available in typing from Python 3.9+
+# For Python 3.8, we need to import from typing_extensions
+if sys.version_info >= (3, 9):
     from typing import Annotated
+else:
+    from typing_extensions import Annotated
 
 from fastapi import Depends, FastAPI
 from fastapi.testclient import TestClient