Rate limiter: clear up remaining todos

reddit_api_async/rate_limiter.ml

@@ -230,8 +230,6 @@ module By_headers = struct
               return (`Repeat ()))))
   ;;
 
-  (* TODO: Allow retries once per minute? *)
-
   let update_server_side_info t ~new_server_side_info =
     (match t.state with
     | State.Created | State.Consuming_rate_limit _ -> ()
@@ -253,7 +251,10 @@ module By_headers = struct
   let permit_request t =
     let%bind () = wait_until_ready t in
     match t.state with
-    | Waiting_on_first_request _ -> (* TODO is this impossible? *) assert false
+    | Waiting_on_first_request _ ->
+      raise_s
+        [%message
+          "Unexpectedly in [Waiting_on_first_request] state after [wait_until_ready]."]
     | Created ->
       let received_response = Ivar.create () in
       t.state <- Waiting_on_first_request { received_response };
@@ -275,7 +276,6 @@ module By_headers = struct
       (* We assume that, in the absence of ratelimit headers, we must have hit
          some authentication failure. As a heuristic to avoid getting stuck, we
          immediately reset [t.ready]. *)
-      (* TODO: What to do here? *)
       t.state <- Created
     | Some response_server_side_info ->
       let new_server_side_info =

test/test_rate_limiter.ml

@@ -117,9 +117,11 @@ let%expect_test _ =
   Rate_limiter.notify_response
     rate_limiter
     (build_header ~server_time:(00 ^: 10) ~limit_remaining:10);
+  let%bind () = Log.Global.flushed () in
   print ();
   [%expect
     {|
+    ("Rate limit is resetting"(old_remaining_api_calls 0))
     ((time (1970-01-01 00:00:00.000000000Z))
      (is_ready true)
      (rate_limiter (
@@ -138,10 +140,8 @@ let%expect_test _ =
           return (`Repeat (n - 1)))
   in
   print ();
-  (* TODO It's not actually resetting: It's just exhausted. *)
   [%expect
     {|
-    ("Rate limit is resetting"(old_remaining_api_calls 0))
     ((time (1970-01-01 00:00:00.000000000Z))
      (is_ready false)
      (rate_limiter (