Quitting Helix when ocamllsp was active causes delay and exits with an error.

[theteachr]

When quitting the editor from an OCaml source file with ocamllsp active, there is a noticeable delay before exiting with the following error:

Error: Timed out waiting for language servers to shutdown

[kirawi]

Next time, please use the bug format to help diagnose the issue. This may be a duplicate of #2059

[theteachr]

Apologies. I'll update the necessary fields in my next comments. #2059 happens on :wq and not on a plain quit with :q. Seems like that was fixed, but this happens on :q also.

Reproduction Steps

• Open an OCaml source file
• Make sure the LSP for OCaml is up and running for the buffer
• Quit the editor with :q
• Takes a few seconds and exits with an error message

helix.log

helix.log

Platform

macOS 13.1 (Ventura)

Helix Version

helix 22.12 (e2a1a975)

---

This could be a problem at the LSP Implementation. We can close this here if that's the case.

[the-mikedavis]

This part of the log is relevant:

2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "/-----------------------------------------------------------------------\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Internal error: Uncaught exception.\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Jsonrpc: json conversion failed: invalid structured value\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Raised at Jsonrpc__Import.Json.error in file \"jsonrpc/src/import.ml\", line 31, characters 23-50\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Called from Jsonrpc__Import.Option.map in file \"jsonrpc/src/import.ml\", line 7, characters 21-26\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Called from Jsonrpc.Packet.t_of_fields in file \"jsonrpc/src/jsonrpc.ml\", line 271, characters 21-77\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Called from Lsp__Io.Make.read in file \"lsp/src/io.ml\", line 108, characters 24-57\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Called from Fiber__Scheduler.exec in file \"src/fiber/scheduler.ml\", line 73, characters 8-11\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Re-raised at Stdune__Exn.raise_with_backtrace in file \"otherlibs/stdune/exn.ml\" (inlined), line 36, characters 27-56\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Called from Stdune__Exn_with_backtrace.reraise in file \"otherlibs/stdune/exn_with_backtrace.ml\", line 18, characters 33-71\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "| Called from Fiber__Scheduler.exec in file \"src/fiber/scheduler.ml\", line 73, characters 8-11\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "\\-----------------------------------------------------------------------\n"
2023-01-05T23:13:31.638 helix_lsp::transport [ERROR] err <- "\n"

That is stderr output from the language server. It looks like it can't parse the shutdown message. It will take some investigation into the ocamllsp codebase but this looks like an upstream bug to me.

[ulugbekna]

It looks like it can't parse the shutdown message. It will take some investigation into the ocamllsp codebase but this looks like an upstream bug to me.

Hi! ocaml-lsp contributor here.

If I understand correctly, helix is violating the spec by sending params field for shutdown request as null because according to JSONRPC spec params must either be a structured value or be omitted. From the spec:

params
A Structured value that holds the parameter values to be used during the invocation of the method. This member MAY be omitted.

What do you think?

cc @rgrinberg

[the-mikedavis]

Ah good catch, the jsonrpc spec is pretty unambiguous about this:

If present, parameters for the rpc call MUST be provided as a Structured value

https://www.jsonrpc.org/specification#parameter_structures

It should be a small fix to correct this on our end. I'll post a PR.