Merge remote-tracking branch 'upstream/master' into sync-german-docs-2025-11-19

docs/en/docs/release-notes.md

@@ -9,10 +9,16 @@ hide:
 
 ### Features
 
+* ✨ Add support for wrapped functions (e.g. `@functools.wraps()`) used with forward references. PR [#5077](https://github.com/fastapi/fastapi/pull/5077) by [@lucaswiman](https://github.com/lucaswiman).
 * ✨ Handle wrapped dependencies. PR [#9555](https://github.com/fastapi/fastapi/pull/9555) by [@phy1729](https://github.com/phy1729).
 
+### Fixes
+
+* 🐛 Fix optional sequence handling with new union syntax from Python 3.10. PR [#14430](https://github.com/fastapi/fastapi/pull/14430) by [@Viicos](https://github.com/Viicos).
+
 ### Refactors
 
+* 🔥 Remove dangling extra condiitonal no longer needed. PR [#14435](https://github.com/fastapi/fastapi/pull/14435) by [@tiangolo](https://github.com/tiangolo).
 * ♻️ Refactor internals, update `is_coroutine` check to reuse internal supported variants (unwrap, check class). PR [#14434](https://github.com/fastapi/fastapi/pull/14434) by [@tiangolo](https://github.com/tiangolo).
 
 ## 0.123.4

fastapi/_compat/v2.py

@@ -17,7 +17,7 @@ from typing import (
 
 from fastapi._compat import may_v1, shared
 from fastapi.openapi.constants import REF_TEMPLATE
-from fastapi.types import IncEx, ModelNameMap
+from fastapi.types import IncEx, ModelNameMap, UnionType
 from pydantic import BaseModel, TypeAdapter, create_model
 from pydantic import PydanticSchemaGenerationError as PydanticSchemaGenerationError
 from pydantic import PydanticUndefinedAnnotation as PydanticUndefinedAnnotation
@@ -381,7 +381,7 @@ def copy_field_info(*, field_info: FieldInfo, annotation: Any) -> FieldInfo:
 
 def serialize_sequence_value(*, field: ModelField, value: Any) -> Sequence[Any]:
     origin_type = get_origin(field.field_info.annotation) or field.field_info.annotation
-    if origin_type is Union:  # Handle optional sequences
+    if origin_type is Union or origin_type is UnionType:  # Handle optional sequences
         union_args = get_args(field.field_info.annotation)
         for union_arg in union_args:
             if union_arg is type(None):

fastapi/dependencies/utils.py

@@ -192,7 +192,8 @@ def get_flat_params(dependant: Dependant) -> List[ModelField]:
 
 def get_typed_signature(call: Callable[..., Any]) -> inspect.Signature:
     signature = inspect.signature(call)
-    globalns = getattr(call, "__globals__", {})
+    unwrapped = inspect.unwrap(call)
+    globalns = getattr(unwrapped, "__globals__", {})
     typed_params = [
         inspect.Parameter(
             name=param.name,
@@ -217,12 +218,13 @@ def get_typed_annotation(annotation: Any, globalns: Dict[str, Any]) -> Any:
 
 def get_typed_return_annotation(call: Callable[..., Any]) -> Any:
     signature = inspect.signature(call)
+    unwrapped = inspect.unwrap(call)
     annotation = signature.return_annotation
 
     if annotation is inspect.Signature.empty:
         return None
 
-    globalns = getattr(call, "__globals__", {})
+    globalns = getattr(unwrapped, "__globals__", {})
     return get_typed_annotation(annotation, globalns)
 
 

fastapi/routing.py

@@ -3,7 +3,6 @@ import email.message
 import functools
 import inspect
 import json
-import sys
 from contextlib import AsyncExitStack, asynccontextmanager
 from enum import Enum, IntEnum
 from typing import (
@@ -79,11 +78,6 @@ from starlette.types import AppType, ASGIApp, Lifespan, Receive, Scope, Send
 from starlette.websockets import WebSocket
 from typing_extensions import Annotated, deprecated
 
-if sys.version_info >= (3, 13):  # pragma: no cover
-    pass
-else:  # pragma: no cover
-    pass
-
 
 # Copy of starlette.routing.request_response modified to include the
 # dependencies' AsyncExitStack

tests/forward_reference_type.py

@@ -0,0 +1,9 @@
+from pydantic import BaseModel
+
+
+def forwardref_method(input: "ForwardRefModel") -> "ForwardRefModel":
+    return ForwardRefModel(x=input.x + 1)
+
+
+class ForwardRefModel(BaseModel):
+    x: int = 0

tests/test_compat.py

@@ -14,7 +14,7 @@ from fastapi.testclient import TestClient
 from pydantic import BaseModel, ConfigDict
 from pydantic.fields import FieldInfo
 
-from .utils import needs_py_lt_314, needs_pydanticv2
+from .utils import needs_py310, needs_py_lt_314, needs_pydanticv2
 
 
 @needs_pydanticv2
@@ -148,6 +148,19 @@ def test_serialize_sequence_value_with_optional_list():
     assert isinstance(result, list)
 
 
+@needs_pydanticv2
+@needs_py310
+def test_serialize_sequence_value_with_optional_list_pipe_union():
+    """Test that serialize_sequence_value handles optional lists correctly (with new syntax)."""
+    from fastapi._compat import v2
+
+    field_info = FieldInfo(annotation=list[str] | None)
+    field = v2.ModelField(name="items", field_info=field_info)
+    result = v2.serialize_sequence_value(field=field, value=["a", "b", "c"])
+    assert result == ["a", "b", "c"]
+    assert isinstance(result, list)
+
+
 @needs_pydanticv2
 def test_serialize_sequence_value_with_none_first_in_union():
     """Test that serialize_sequence_value handles Union[None, List[...]] correctly."""

tests/test_wrapped_method_forward_reference.py

@@ -0,0 +1,31 @@
+import functools
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from .forward_reference_type import forwardref_method
+
+
+def passthrough(f):
+    @functools.wraps(f)
+    def method(*args, **kwargs):
+        return f(*args, **kwargs)
+
+    return method
+
+
+def test_wrapped_method_type_inference():
+    """
+    Regression test ensuring that when a method imported from another module
+    is decorated with something that sets the __wrapped__ attribute (functools.wraps),
+    then the types are still processed correctly, including dereferencing of forward
+    references.
+    """
+    app = FastAPI()
+    client = TestClient(app)
+    app.post("/endpoint")(passthrough(forwardref_method))
+    app.post("/endpoint2")(passthrough(passthrough(forwardref_method)))
+    with client:
+        response = client.post("/endpoint", json={"input": {"x": 0}})
+        response2 = client.post("/endpoint2", json={"input": {"x": 0}})
+    assert response.json() == response2.json() == {"x": 1}