Eio.Flow.read hangs on closed flow #214
Description
Not sure if I'm doing something wrong, but I've run into the following issue (on the Luv backend).
A fiber waiting on a Eio.Flow.read before another fiber closes it will hang forever, at least for a client type Eio.Net.connect flow.
I've managed to trim it down to the following case:
reproduce.ml
open Eio.Std
let main env =
let run_client ~net ~addr =
traceln "client on";
Switch.run (fun sw ->
let flow = Eio.Net.connect ~sw net addr in
traceln "client <-> server";
let read_loop () =
let b = Cstruct.create 4 in
traceln "client will be stuck after this";
while true do
Eio.Flow.read flow b |> ignore;
traceln "unreachable"
done
in
let d = "Hello from client" in
traceln "client -> %S" d;
Eio.Flow.copy_string d flow;
Fiber.fork ~sw read_loop;
Eio.Flow.close flow);
traceln "client off"
in
let run_server socket =
traceln "server on";
Switch.run (fun sw ->
Eio.Net.accept_sub socket ~sw
(fun ~sw:_ flow _addr ->
traceln "server <-> client";
let b = Buffer.create 100 in
Eio.Flow.copy flow (Eio.Flow.buffer_sink b);
traceln "server <[EOF]- %S" (Buffer.contents b))
~on_error:(traceln "Error handling connection: %a" Fmt.exn));
traceln "server off"
in
let net = Eio.Stdenv.net env in
let addr = `Tcp (Eio.Net.Ipaddr.V4.loopback, 9999) in
Switch.run @@ fun sw ->
let server = Eio.Net.listen net ~sw ~reuse_addr:true ~backlog:5 addr in
Fiber.both (fun () -> run_server server) (fun () -> run_client ~net ~addr)Where the expected output would be:
+server on
+client on
+client <-> server
+client -> "Hello from client"
+server <-> client
+client will be stuck after this
+server <[EOF]- "Hello from client"
+server off
*hangs forever*