eclipse-theia/theia

Crash of the LanguageServer in the Julia VS code extension

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#8,472 opened on Sep 4, 2020

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Description

Bug Description:

The Julia VS Code extension installs correctly within Theia. However, when using it, the LanguageServer frequently crashes, due to requests looking like:

[Trace - 10:56:22 AM] Sending request 'julia/getModuleAt - (37)'.
Params: {
    "textDocument": {
        "uri": "file:///home/project/theia-jl/test.jl"
    },
    "version": 30,
    "position": {
        "_line": 11,
        "_character": 0
    }
}

instead of the expected

[Trace - 10:56:22 AM] Sending request 'julia/getModuleAt - (37)'.
Params: {
    "textDocument": {
        "uri": "file:///home/project/theia-jl/test.jl"
    },
    "version": 30,
    "position": {
        "line": 11,
        "character": 0
    }
}

Steps to Reproduce:

  1. Run Theia from the theia-full docker image
  2. install Julia inside the docker container
    • see comment below for a Dockerfile automating this step
  3. install the Julia VS code extension (from the open VSX registry)
  4. open any Julia file and start typing some code, hovering over keywords...
    • see comment below for an example Julia source file
  5. the LanguageServer should crash pretty quickly

Additional Information

  • Operating System: Ubuntu
  • Theia Version: Theia Multi-Language Example @theia/callhierarchy 1.5.0 @theia/console 1.5.0 @theia/core 1.5.0 @theia/cpp-debug 1.0.0 @theia/debug 1.5.0 @theia/editor 1.5.0 @theia/editor-preview 1.5.0 @theia/file-search 1.5.0 @theia/filesystem 1.5.0 @theia/getting-started 1.5.0 @theia/git 1.5.0 @theia/keymaps 1.5.0 @theia/markers 1.5.0 @theia/messages 1.5.0 @theia/metrics 1.5.0 @theia/mini-browser 1.5.0 @theia/monaco 1.5.0 @theia/navigator 1.5.0 @theia/outline-view 1.5.0 @theia/output 1.5.0 @theia/plugin-ext 1.5.0 @theia/plugin-ext-vscode 1.5.0 @theia/preferences 1.5.0 @theia/preview 1.5.0 @theia/process 1.5.0 @theia/scm 1.5.0 @theia/scm-extra 1.5.0 @theia/search-in-workspace 1.5.0 @theia/task 1.5.0 @theia/terminal 1.5.0 @theia/typehierarchy 1.5.0 @theia/userstorage 1.5.0 @theia/variable-resolver 1.5.0 @theia/vsx-registry 1.5.0 @theia/workspace 1.5.0

Contributor guide

Tech stack
typescript
Domain
developer experiencebackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Understanding of Language Server ProtocolFamiliarity with Theia plugin systemTypeScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
The issue is that the Julia LanguageServer receives position objects with keys ' line' and ' character' instead of 'line' and 'character'. This indicates a serialization issue in Theia's LSP implementation. To fix, investigate how the Theia plugin host serializes the Position interface, likely in files under 'packages/plugin ext/src/plugin ext lsp/'. Compare with the VS Code implementation to ensure compliance with the LSP specification. The fix would involve removing the underscore prefix in the serialization of Position's line and character properties.