Preserve explicit -> None return annotations in @depends-wrapped endpoint signatures

fastapi_decorators/decorators.py

@@ -82,7 +82,7 @@ def decorator(func: F) -> F:
 
         new_signature = original_signature.replace(
             parameters=tuple(all_params.values()),
-            return_annotation=hints.get("return", original_signature.return_annotation),
+            return_annotation=original_signature.return_annotation,
         )
 
         wrapper = _create_wrapper(func, all_params)

tests/test_app.py

@@ -1,7 +1,9 @@
 from time import sleep, time
+from fastapi import FastAPI, status
 from fastapi.testclient import TestClient
 import pytest
 from tests.app import app, fake_db, rate_limit_store, cache_storage, error_log
+from fastapi_decorators import depends
 
 client = TestClient(app)
 
@@ -168,3 +170,22 @@ def test_expects_header() -> None:
     response = client.get("/headers", headers=headers)
     assert response.status_code == 200
     assert response.json() == headers
+
+
+def test_depends_keeps_none_return_annotation_for_204() -> None:
+    test_app = FastAPI()
+
+    @depends
+    def with_test() -> None:
+        pass
+
+    @test_app.get("/test", status_code=status.HTTP_204_NO_CONTENT)
+    @with_test
+    async def endpoint() -> None:
+        pass
+
+    assert endpoint is not None
+    test_client = TestClient(test_app)
+    response = test_client.get("/test")
+    assert response.status_code == status.HTTP_204_NO_CONTENT
+    assert response.content == b""