fix: stop leaking fd's

CHANGES.md

@@ -1,3 +1,7 @@
+# 1.11.6
+
+- Stop leaking file descriptors like a sieve (#701)
+
 # 1.11.5
 
 - Fix process termination. Once the lsp server is stepped, the process will

ocaml-lsp-server/src/dune.ml

@@ -366,19 +366,20 @@ end = struct
       | `Unix s -> Unix.ADDR_UNIX s
       | `Ip (`Host h, `Port p) -> Unix.ADDR_INET (Unix.inet_addr_of_string h, p)
     in
+    let sock =
+      let domain = Unix.domain_of_sockaddr sockaddr in
+      let socket = Unix.socket ~cloexec:true domain Unix.SOCK_STREAM 0 in
+      Lev_fiber.Fd.create socket (`Non_blocking false)
+    in
     let* session =
-      let sock =
-        let domain = Unix.domain_of_sockaddr sockaddr in
-        let socket = Unix.socket ~cloexec:true domain Unix.SOCK_STREAM 0 in
-        Lev_fiber.Fd.create socket (`Non_blocking false)
-      in
       Fiber.map_reduce_errors
         (module Monoid.List (Exn_with_backtrace))
         ~on_error:(fun exn -> Fiber.return [ exn ])
         (fun () -> Csexp_rpc.connect sock sockaddr)
     in
     match session with
     | Error exns ->
+      Lev_fiber.Fd.close sock;
       let message =
         let exn = List.hd exns in
         Format.asprintf "unable to connect to dune %s@.%a"