diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index 5e975a4..7baeb64 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -42,7 +42,7 @@ jobs:
       - name: Ruff check
         run: poetry run ruff check backend/ tests/
       - name: Pyupgrade
-        run: poetry run pyupgrade backend/ tests/
+        run: poetry run pyupgrade --py311-plus **/*.py
   test:
     runs-on: ubuntu-latest
     strategy:
diff --git a/backend/deps.py b/backend/deps.py
index a57219f..85eca8f 100644
--- a/backend/deps.py
+++ b/backend/deps.py
@@ -20,12 +20,12 @@ def _get_optional_redis(
 ) -> typing.Generator[Redis | None, None, None]:
     if redis_url is None:
         yield None
-
-    redis: Redis = Redis.from_url(redis_url)  # type: ignore
-    try:
-        yield redis
-    finally:
-        redis.close()
+    else:
+        redis: Redis = Redis.from_url(redis_url)  # type: ignore
+        try:
+            yield redis
+        finally:
+            redis.close()
 
 
 def get_optional_redis(redis_url: str | None = cast_optional_str(settings.REDIS_URL)):