gdscript language server causes panic

[schme]

Summary

When helix connects to a godot 4 language server for the first time, it crashes. Starting helix again and connecting to the same language server works. Probably misbehaviour on the language server side, but perhaps helix should still be resilient enough here not to crash.

Backtrace

thread 'main' panicked at 'language server not yet initialized!', helix-lsp/src/client.rs:274:9
stack backtrace:
   0: rust_begin_unwind
             at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/std/src/panicking.rs:584:5
   1: core::panicking::panic_fmt
             at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/panicking.rs:142:14
   2: core::panicking::panic_display
             at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/panicking.rs:72:5
   3: core::panicking::panic_str
             at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/panicking.rs:56:5
   4: core::option::expect_failed
             at /rustc/897e37553bba8b42751c67658967889d11ecd120/library/core/src/option.rs:1880:5
   5: helix_lsp::client::Client::offset_encoding
   6: helix_term::application::Application::run::{{closure}}
   7: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
   8: tokio::runtime::park::CachedParkThread::block_on
   9: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
  10: tokio::runtime::runtime::Runtime::block_on
  11: hx::main

.helix/languages.toml

[language-server.gdscript]
command = "nc"
args = ["127.0.0.1", "6008"]

[[language]]
name = "gdscript"
language-servers = ["gdscript"]

Reproduction Steps

I tried this:

1. Configure the language server with above settings
2. Run a godot 4 instance with language server on
3. hx MyScript.gd

I expected this to happen:
File opens

Instead, this happened:
Helix crashes every time godot 4 has been freshly started and the language server connected to the first time.

Helix log

11:07:45 here onwards is from an actual crash, the part before was written after a successfull startup after a crash.

~/.cache/helix/helix.log

2023-06-27T11:06:21.757 helix_term::application [ERROR] received malformed notification from Language Server: Unhandled
2023-06-27T11:06:23.251 helix_lsp::transport [ERROR] gdscript <- MethodNotFound: Method not found: shutdown
2023-06-27T11:06:23.251 helix_lsp::client [WARN] language server failed to terminate gracefully - protocol error: MethodNotFound: Method not found: shutdown
2023-06-27T11:06:23.252 helix_lsp::transport [ERROR] err: <- Other(failed to send a message to server

Caused by:
    channel closed)
2023-06-27T11:06:23.252 helix_lsp::transport [ERROR] gdscript err: <- StreamClosed
2023-06-27T11:07:45.217 helix_view::clipboard [DEBUG] Using xclip to interact with the system and selection (primary) clipboard
2023-06-27T11:07:45.224 helix_view::editor [DEBUG] editor status: Loaded 1 file.
2023-06-27T11:07:45.224 helix_lsp::transport [INFO] gdscript -> {"jsonrpc":"2.0","method":"initialize","params":{"capabilities":{"general":{"positionEncodings":["utf-8","utf-32","utf-16"]},"textDocument":{"codeAction":{"codeActionLiteralSupport":{"codeActionKind":{"valueSet":["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}}},"completion":{"completionItem":{"deprecatedSupport":true,"insertReplaceSupport":true,"resolveSupport":{"properties":["documentation","detail","additionalTextEdits"]},"snippetSupport":true,"tagSupport":{"valueSet":[1]}},"completionItemKind":{}},"hover":{"contentFormat":["markdown"]},"inlayHint":{"dynamicRegistration":false},"publishDiagnostics":{"versionSupport":true},"rename":{"dynamicRegistration":false,"honorsChangeAnnotations":false,"prepareSupport":true},"signatureHelp":{"signatureInformation":{"activeParameterSupport":true,"documentationFormat":["markdown"],"parameterInformation":{"labelOffsetSupport":true}}}},"window":{"workDoneProgress":true},"workspace":{"applyEdit":true,"configuration":true,"didChangeConfiguration":{"dynamicRegistration":false},"executeCommand":{"dynamicRegistration":false},"inlayHint":{"refreshSupport":false},"symbol":{"dynamicRegistration":false},"workspaceEdit":{"documentChanges":true,"failureHandling":"abort","normalizesLineEndings":false,"resourceOperations":["create","rename","delete"]},"workspaceFolders":true}},"clientInfo":{"name":"helix","version":"23.05 (06d63d6a)"},"processId":93932,"rootPath":"MyProjectPath","rootUri":"file:///MyProjectFolder","workspaceFolders":[{"name":"MyProjectName","uri":"file:///MyProjectFolder"}]},"id":0}
2023-06-27T11:07:45.229 helix_tui::backend::crossterm [DEBUG] The keyboard enhancement protocol is not supported in this terminal (checked in 4.241815ms)
2023-06-27T11:07:45.230 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-06-27T11:07:45.296 helix_lsp::transport [INFO] gdscript <- {"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"diagnostics":[],"uri":"file:///ScriptInMyProjectFolder.gd"}}
2023-06-27T11:07:45.296 helix_term::application [DEBUG] received editor event: LanguageServerMessage((0, Notification(Notification { jsonrpc: Some(V2), method: "textDocument/publishDiagnostics", params: Map({"diagnostics": Array [], "uri": String("file:///ScriptInMyProjectFolder.gd")}) })))

Platform

Linux

Terminal Emulator

gnome-terminal

Helix Version

23.05-171-g6c6923c3

[the-mikedavis]

The gdscript language server is breaking the spec around initialization: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#initialize

... the server is not allowed to send any requests or notifications to the client until it has responded with an InitializeResult ...

We send the initialize request and before the server responds by sending the InitializeResult, it sends a textDocument/publishDiagnostics notification. We need the InitializeResult before publicDiagnostic because we need to know its position encoding to be able to translate the positions in the publicDiagnostic notification.

The relevant lines of the logfile:

2023-06-27T11:07:45.224 helix_lsp::transport [INFO] gdscript -> {"jsonrpc":"2.0","method":"initialize","params":{"capabilities":{"general":{"positionEncodings":["utf-8","utf-32","utf-16"]},"textDocument":{"codeAction":{"codeActionLiteralSupport":{"codeActionKind":{"valueSet":["","quickfix","refactor","refactor.extract","refactor.inline","refactor.rewrite","source","source.organizeImports"]}}},"completion":{"completionItem":{"deprecatedSupport":true,"insertReplaceSupport":true,"resolveSupport":{"properties":["documentation","detail","additionalTextEdits"]},"snippetSupport":true,"tagSupport":{"valueSet":[1]}},"completionItemKind":{}},"hover":{"contentFormat":["markdown"]},"inlayHint":{"dynamicRegistration":false},"publishDiagnostics":{"versionSupport":true},"rename":{"dynamicRegistration":false,"honorsChangeAnnotations":false,"prepareSupport":true},"signatureHelp":{"signatureInformation":{"activeParameterSupport":true,"documentationFormat":["markdown"],"parameterInformation":{"labelOffsetSupport":true}}}},"window":{"workDoneProgress":true},"workspace":{"applyEdit":true,"configuration":true,"didChangeConfiguration":{"dynamicRegistration":false},"executeCommand":{"dynamicRegistration":false},"inlayHint":{"refreshSupport":false},"symbol":{"dynamicRegistration":false},"workspaceEdit":{"documentChanges":true,"failureHandling":"abort","normalizesLineEndings":false,"resourceOperations":["create","rename","delete"]},"workspaceFolders":true}},"clientInfo":{"name":"helix","version":"23.05 (06d63d6a)"},"processId":93932,"rootPath":"MyProjectPath","rootUri":"file:///MyProjectFolder","workspaceFolders":[{"name":"MyProjectName","uri":"file:///MyProjectFolder"}]},"id":0}
2023-06-27T11:07:45.296 helix_lsp::transport [INFO] gdscript <- {"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"diagnostics":[],"uri":"file:///ScriptInMyProjectFolder.gd"}}

So this should be reported and fixed upstream. We can also handle this a little better on the client side by discarding the notification, I'll open a PR for that (edit: #7467).

[schme]

Thanks for the clear and concise answer! I'll work on reporting the bug as well.