[serve] Don't overwrite self.handle in StarletteEndpoint (#14111)

python/ray/serve/http_proxy.py

@@ -37,6 +37,9 @@ class ServeStarletteEndpoint:
     def __init__(self, client, endpoint_tag: EndpointTag):
         self.client = client
         self.endpoint_tag = endpoint_tag
+        # This will be lazily populated when the first request comes in.
+        # TODO(edoakes): we should be able to construct the handle here, but
+        # that currently breaks pytest. This seems like a bug.
         self.handle = None
 
     async def __call__(self, scope, receive, send):
@@ -45,14 +48,15 @@ class ServeStarletteEndpoint:
         headers = {k.decode(): v.decode() for k, v in scope["headers"]}
         if self.handle is None:
             self.handle = self.client.get_handle(self.endpoint_tag, sync=False)
-        self.handle = self.handle.options(
+
+        object_ref = await self.handle.options(
             method_name=headers.get("X-SERVE-CALL-METHOD".lower(),
                                     DEFAULT.VALUE),
             shard_key=headers.get("X-SERVE-SHARD-KEY".lower(), DEFAULT.VALUE),
             http_method=scope["method"].upper(),
-            http_headers=headers)
-        request = build_starlette_request(scope, http_body_bytes)
-        object_ref = await self.handle.remote(request)
+            http_headers=headers).remote(
+                build_starlette_request(scope, http_body_bytes))
+
         result = await object_ref
 
         if isinstance(result, RayTaskError):