attempt to fix handle_client error and cleanup

lib/server/connection.ml

@@ -685,7 +685,8 @@ let quit t me ~reason =
 
 let close ?(reason = "Client closed") t =
   Option.iter (quit t ~reason) t.user;
-  Outbox.close t.outbox
+  Outbox.close t.outbox;
+  t.user <- None
 
 let on_msg_quit t reason =
   let reason = match reason with

lib/server/server.ml

@@ -75,17 +75,22 @@ let handle_client
       ~server_info
       ~addr:conn_addr
   in
+  Wheel.add ping_wheel conn;
   let reader = Lwt_stream.iter (Connection.on_msg conn) (reader conn_fd) in
   let writer = writer conn_fd (Outbox.stream (Connection.outbox conn)) in
-  let close () = Connection.close conn in
-  Lwt.on_termination reader close;
-  Lwt.on_termination writer close;
-  Wheel.add ping_wheel conn;
+  let both =
     Lwt.finalize
-    (fun () -> writer)
-    (fun () ->
-       Lwt_unix.close conn_fd >|= fun () ->
-       info (fun m -> m "connection closed %a" pp_sockaddr conn_addr))
+      (fun () -> reader <&> writer)
+      (fun () -> Lwt_unix.close conn_fd)
+  in
+  begin
+    Lwt.on_termination reader (fun () -> Connection.close conn);
+    Lwt.on_termination writer (fun () -> Connection.close conn);
+    Lwt.on_termination both
+      (fun () -> info (fun m -> m "connection closed %a" pp_sockaddr conn_addr));
+    Lwt.on_failure both
+      (fun e -> error (fun m -> m "%a:@ %a" pp_sockaddr conn_addr Fmt.exn e));
+  end
 
 type config = {
   port : int;
@@ -130,13 +135,10 @@ let run (cfg : config) : unit Lwt.t =
   in
 
   let on_con (fd, adr) =
-    Lwt.on_failure
-      (handle_client fd adr
+    handle_client fd adr
       ~server_info
       ~router
-         ~ping_wheel)
-      (fun exn ->
-         error (fun m -> m "%a:@ %a" pp_sockaddr adr Fmt.exn exn))
+      ~ping_wheel
   in
 
   let listener_promise =