fix: "name" and "in" should not be included in openapi headers (#3417)

Exclude the "name" and "in" fields from openapi schema generated for headers.

Add ``BaseSchemaObject._iter_fields()``  method that allows schema types to define the fields that should be included in their openapi schema representation and override that method for ``OpenAPIHeader``.

Closes #3416

litestar/openapi/spec/base.py

@@ -2,7 +2,11 @@
 
 from dataclasses import asdict, dataclass, fields, is_dataclass
 from enum import Enum
-from typing import Any
+from typing import TYPE_CHECKING, Any
+
+if TYPE_CHECKING:
+    from collections.abc import Iterator
+    from dataclasses import Field
 
 __all__ = ("BaseSchemaObject",)
 
@@ -34,13 +38,16 @@ def _normalize_value(value: Any) -> Any:
 class BaseSchemaObject:
     """Base class for schema spec objects"""
 
+    def _iter_fields(self) -> Iterator[Field[Any]]:
+        yield from fields(self)
+
     def to_schema(self) -> dict[str, Any]:
         """Transform the spec dataclass object into a string keyed dictionary. This method traverses all nested values
         recursively.
         """
         result: dict[str, Any] = {}
 
-        for field in fields(self):
+        for field in self._iter_fields():
             value = _normalize_value(getattr(self, field.name, None))
 
             if value is not None:

litestar/openapi/spec/header.py

@@ -1,7 +1,9 @@
 from __future__ import annotations
 
-from dataclasses import dataclass
-from typing import TYPE_CHECKING, Any, Literal
+from dataclasses import Field, dataclass
+from typing import TYPE_CHECKING, Any, Iterator, Literal
+
+from typing_extensions import override
 
 from litestar.openapi.spec.base import BaseSchemaObject
 
@@ -119,3 +121,7 @@ class OpenAPIHeader(BaseSchemaObject):
 
     The key is the media type and the value describes it. The map MUST only contain one entry.
     """
+
+    @override
+    def _iter_fields(self) -> Iterator[Field[Any]]:
+        yield from (f for f in super()._iter_fields() if f.name not in {"name", "param_in"})

tests/e2e/test_openapi/test_spec_headers.py

@@ -0,0 +1,29 @@
+from litestar import Litestar, Request, get
+from litestar.datastructures import ResponseHeader
+
+
+@get("/")
+async def hello_world1(request: Request) -> None:
+    request.logger.info("inside request")
+    return
+
+
+app1 = Litestar(
+    route_handlers=[hello_world1],
+    response_headers=[ResponseHeader(name="X-Version", value="ABCD", description="Test")],
+)
+
+
+def test_included_header_fields() -> None:
+    # https://github.com/litestar-org/litestar/issues/3416
+
+    assert app1.openapi_schema.to_schema()["paths"]["/"]["get"]["responses"]["200"]["headers"] == {
+        "X-Version": {
+            "allowEmptyValue": False,
+            "allowReserved": False,
+            "deprecated": False,
+            "description": "Test",
+            "required": False,
+            "schema": {"type": "string"},
+        }
+    }

tests/unit/test_openapi/test_config.py

@@ -28,16 +28,12 @@ def test_merged_components_correct() -> None:
         "examples": {"example-one": {"summary": "an example"}},
         "headers": {
             "one": {
-                "name": "",
-                "in": "header",
                 "required": False,
                 "deprecated": False,
                 "allowEmptyValue": False,
                 "allowReserved": False,
             },
             "two": {
-                "name": "",
-                "in": "header",
                 "required": False,
                 "deprecated": False,
                 "allowEmptyValue": False,