fix: preserve task response header bytes

src/_bentoml_impl/tasks/serde.py

@@ -121,6 +121,7 @@ async def deserialize_response(self, data: bytes) -> Response:
             status_code=response_dict["status"],
         )
         response.raw_headers = [
-            tuple(map(str.encode, h)) for h in response_dict["headers"]
+            (key.encode(self.HEADERS_ENCODING), value.encode(self.HEADERS_ENCODING))
+            for key, value in response_dict["headers"]
         ]
         return response

tests/unit/bentoml_io/test_tasks_serde.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+import pytest
+from starlette.responses import Response
+
+from _bentoml_impl.tasks.serde import JSONSerde
+
+
+@pytest.mark.asyncio
+async def test_response_headers_roundtrip_preserves_latin1_bytes():
+    serde = JSONSerde()
+    response = Response(content=b"ok", status_code=200)
+    response.raw_headers.append((b"x-raw-name", b"caf\xe9"))
+
+    data = await serde.serialize_response(response)
+    restored = await serde.deserialize_response(data)
+
+    restored_headers = dict(restored.raw_headers)
+    assert restored_headers[b"x-raw-name"] == b"caf\xe9"