Language server not working in seperate source directory. (Using neovim)

[yoghurt-x86]

I have a elm.json with two source-directories that looks like:

{
    "type": "application",
    "source-directories": [
        "src",
	"../lib"
    ],
    "elm-version": "0.19.1",
    "dependencies": {
        "direct": {
            "elm/browser": "1.0.2",
            "elm/core": "1.0.5",
            "elm/html": "1.0.0",
            "elm/http": "2.0.0",
            "elm/json": "1.1.3"
        },
        "indirect": {
            "elm/bytes": "1.0.8",
            "elm/file": "1.0.5",
            "elm/time": "1.0.0",
            "elm/url": "1.0.0",
            "elm/virtual-dom": "1.0.2"
        }
    },
    "test-dependencies": {
        "direct": {},
        "indirect": {}
    }
}

Here is a picture of the directory structure.

I am using neovim 0.5.0 with the build-in LSP client and elmls config from neovim/nvim-lspconfig
It works as expected in normal projects, i can see warnings and jump to definitions and such, but if i open a file in a source directory like ../lib there is no lsp functionality

If i open Main.elm there is no issues. I can see warning and jump to definitions and such.
With Main.elm open in the current buffer and i run:
:lua print(vim.inspect(vim.lsp.buf_get_clients()))
I get a bunch of output.

If i jump to ../lib/CustomLib.elm and run the same command i get no output.
So it looks like the LSP client isn't attached?

If i instead move the directory ../lib inside the elm project (next to src) then it will work as expected.
But in my case i want multiple elm projects to share the same lib.

Is it possible to get the LSP client to attach in another source directory outside the elm project?

[razzeee]

I don't think we support this at the moment. It might work okayish, if you use vscode workspaces, but that's kind of a workaround.

[yoghurt-x86]

Alright, I've also tried to work around it using a symbolic link like:

But that doesn't work either it seems. Does symbolic links cause trouble?

[razzeee]

Haven't tried that, might depend on your OS and how you create them

[yoghurt-x86]

Something that helps:
I have simply had to add a elm.json to the lib folder like it's a "package". Here is the folder structure:

The elm.json for ./lib

{
    "type": "package",
	"name": "custom/custom",
	"summary": "For testing",
	"license": "MIT",
	"version": "1.0.0",
    "source-directories": [
        "src"
    ],
    "elm-version": "0.19.0 <= v < 0.20.0",
	"exposed-modules": {
        "Whatever": [
            "CustomLib"
		]
	},
    "dependencies": {
		"elm/core": "1.0.0 <= v < 2.0.0"
	},
    "test-dependencies": {}
}

the elm.json for the main project:

{
    "type": "application",
    "source-directories": [
        "src",
	"../lib/src"
    ],
    "elm-version": "0.19.1",
    "dependencies": {
        "direct": {
            "elm/browser": "1.0.2",
            "elm/core": "1.0.5",
            "elm/html": "1.0.0"
        },
        "indirect": {
            "elm/json": "1.1.3",
            "elm/time": "1.0.0",
            "elm/url": "1.0.0",
            "elm/virtual-dom": "1.0.2"
        }
    },
    "test-dependencies": {
        "direct": {},
        "indirect": {}
    }
}

What's weird is that the original project that i started with works fine in vscode, but this is neeeded to make it sort of work in neovim.

Now this doesn't really solve the problem, as i now i can't use ports in my ../lib project...

I think having a shared local library between projects like this is a general problem with elm? Is there any way to configure the language server to know that ../lib belongs to the project I'm working on?

I've also attempted to configure it using an elm-tooling.json file to specify ./proj/src/Main.elm as an entry point with no results.

[razzeee]

I think the problem is, that your opening the folder where your elm.json is and we only do our completions on files in there. For e.g. if you go to one of your dependencies in elm/core I think you loose functionality too.

Basically means this is kind of a duplicate of https://github.com/elm-tooling/elm-language-server/issues/368
Then again, you seem to need more then just definitions/references.

[yoghurt-x86]

I can kind of cheat it to work by making a dummy elm.json that i place in the root folder next to the proj folder.
Now the lsp client is attached when i open up files in ./lib.

I'm not sure if #368 is related. I can jump to definitions in the Browser module for example, and the lsp client will be attached there, and i can further navigate to other code definitions from there.
This files are writable though on my system.

[razzeee]

Yes, they are writable, I just choose to differentiate between packages you can change and packages you shouldn't change (thirdparty ones from your cache) and named that bool writeable

[razzeee]

I'm not sure if #368 is related. I can jump to definitions in the Browser module for example, and the lsp client will be attached there, and i can further navigate to other code definitions from there.

It turned out to actually be a problem in the vscode client, so your probably fine in neovim :)