ElmLS does not send textDocument/publishDiagnostics when entrypoint module is depended by tests and elm-test is installed locally.

[IzumiSy]

This only happens with vim-lsp environment. I cannot reproduce this issue on VSCode.
I confirmed the same behavior on VSCode as well. See repro steps.

Expected Behavior

ElmLS sends textDocument/publishDiagnostics to show an error

Current Behavior

No diagnostic appears.

Possible Solution

Possible reason of this issue is that elm-test cannot discover elm binary when it is installed locally, as vim-lsp logging says.

Mon Jul 18 02:21:21 2022:["<---",1,"elm-language-server",{"response":{"method":"window/logMessage","jsonrpc":"2.0","params":{"message":"{\"shortMessage\":\"Command failed with exit code 1: ./node_modules/.bin/elm-test make tests/Tests/Main.elm --report json\",\"command\":\"./node_modules/.bin/elm-test make tests/Tests/Main.elm --report json\",\"escapedCommand\":\"\\\"./node_modules/.bin/elm-test\\\" make \\\"tests/Tests/Main.elm\\\" --report json\",\"exitCode\":1,\"stdout\":\"\",\"stderr\":\"Cannot find elm executable, make sure it is installed.\\n(If elm is not on your path or is called something different the --compiler flag might help.)\\n\",\"failed\":true,\"timedOut\":false,\"isCanceled\":false,\"killed\":false}","type":2}}}]
Mon Jul 18 02:21:21 2022:["<---",1,"elm-language-server",{"response":{"method":"window/logMessage","jsonrpc":"2.0","params":{"message":"Received an invalid json, skipping error.","type":2}}}]
Mon Jul 18 02:21:21 2022:["<---",1,"elm-language-server",{"response":{"method":"window/logMessage","jsonrpc":"2.0","params":{"message":"Received an invalid json, skipping error.","type":2}}}]
Mon Jul 18 02:21:21 2022:["<---",1,"elm-language-server",{"response":{"method":"window/logMessage","jsonrpc":"2.0","params":{"message":"Received an invalid json, skipping error.","type":2}}}]

I have confirmed that using --compiler option when calling elm-test internally for the environment that has installed elm toolchains locally will fix this problem.

My opened PR is #729

Steps to Reproduce (for bugs)

0. Install elm, elm-test locally.

$ npm install -D elm elm-format elm-test

Then, update vim-lsp preference to use them.

let g:lsp_settings = {
\   'elm-language-server': {
\     'initialization_options': {
\       'elmPath': './node_modules/.bin/elm',
\       'elmTestPath': './node_modules/.bin/elm-test'
\     }
\   }
\ }

For VSCode, use the following setting.

1. Create modules.

src/App.elm

module App exposing (main)

import Bar
import Browser
import Html exposing (Html, button, div, text)
import Html.Events exposing (onClick)


type alias Model =
    { count : Int }


initialModel : Model
initialModel =
    { count = 0 }


type Msg
    = Increment
    | Decrement


update : Msg -> Model -> Model
update msg model =
    case msg of
        Increment ->
            { model | count = model.count + 1 }

        Decrement ->
            { model | count = model.count - 1 }


view : Model -> Html Msg
view model =
    div []
        [ button [ onClick Increment ] [ text "+1" ]
        , div [] [ text <| String.fromInt model.count ]
        , button [ onClick Decrement ] [ text "-1" ]
        , div [] [ text Bar.aaa ]
        ]


main : Program () Model Msg
main =
    Browser.sandbox
        { init = initialModel
        , view = view
        , update = update
        }

src/Bar.elm

module Bar exposing (aaa)


aaa : String
aaa =
    "aaa"

tests/Test/Main.elm

module Tests.Main exposing (suite)

import App
import Test


suite : Test.Test
suite =
    let
        _ =
            App.main
    in
    Test.todo "main test"

2. Update Bar.elm to raise a compile error

src/Bar.elm

+ module Nothing.Bar exposing (aaa)
- module Bar exposing (aaa)


aaa : String
aaa =
    "aaa"

Then, no error occurs, even though it must be.

Context

n/a

Your Environment

• Version used: 2.4.1
• Editor used: vim + vim-lsp
• Environment name and version (e.g. node.js 5.4): Node.js v16.15.0
• Operating System and version: Ubuntu WSL

[IzumiSy]

Closing by #729