Add pylance to coc.nvim

coc-pylance.md

Install the pylance extension in vscode or manually download it from the marketplace

The extension path should be similar to this: ~/.vscode/extensions/ms-python.vscode-pylance-2023.11.10

In init.vim, this will automatically detect the latest pylance version because after an upgrade the old plugin might linger for a while:

call coc#config('languageserver', { "pylance": { "module": expand("~/.vscode/extensions/ms-python.vscode-pylance-*/dist/server.bundle.js", 0, 1)[0] } })

In coc-settings.json, we add these env to trick pylance into thinking we are running vscode:

{
  "languageserver": {
    "pylance": {
      "enable": true,
      "filetypes": [
        "python"
      ],
      "env": {
        "ELECTRON_RUN_AS_NODE": "0",
        "VSCODE_NLS_CONFIG": "{\"locale\": \"en\"}"
      },
      "module": "${userHome}/.vscode/extensions/ms-python.vscode-pylance-2023.11.10/dist/server.bundle.js",
      "initializationOptions": {},
      "settings": {
        "python.analysis.typeCheckingMode": "basic",
        "python.analysis.diagnosticMode": "openFilesOnly",
        "python.analysis.stubPath": "./typings",
        "python.analysis.autoSearchPaths": true,
        "python.analysis.extraPaths": [],
        "python.analysis.diagnosticSeverityOverrides": {},
        "python.analysis.useLibraryCodeForTypes": true
      }
    }
  }
}

Doesn't seem to work anymore, at least with the latest version of Pylance.

Still works on 2023.7.20, remember to add the mentioned code in init.vim

Are you running directly on Windows? It appears not, but just curious.

If I run node ~/.vscode/extensions/ms-python.vscode-pylance-2023.7.20/dist/server.bundle.js --stdio I get a message noting that it can only be used from MS products. Even when doing export ELECTRON_RUN_AS_NODE=1 and export VSCODE_NLS_CONFIG=1 beforehand, the same thing occurs.

Does it work for you directly from an interactive shell @nullchilly? I wonder of coc is doing something special that allows it to work.

The code in server.bundle.js is essentially

if not ELECTRON_RUN_AS_NODE or not VSCODE_NLS_CONFIG or --stdio:
  print "no vscode no pylance"

This is why ELECTRON_RUN_AS_NODE=1 VSCODE_NLS_CONFIG=1 works for coc.nvim because it doesn't need --stdio

Unfortunately for neovim native lsp, you will have to use a different method which I can't share publicly because Microsoft will patch it instantly.

Hi @nullchilly I've played around with this and would like to compare notes. I sent you a discord connection request.

Hi @nullchilly, @smackesey, I tried the gist for coc.nvim, but it doesn't seem to recognize the settings. I saw @smackesey's issue on coc.nvim. It's closed, but I don't see a working solution. Have you guys been successful getting coc.nvim to recognize the settings?

I also tried pylance with native-lsp, all good except for the inlayHint feature. Would like to know if anyone has it?

Hmm, inlayhint works for me on native-lsp

My nvim-lspconfig:

{
  "neovim/nvim-lspconfig",
  opts = {
    inlay_hints = { enabled = true },
    servers = {
      pylance = {
        settings = {
          python = {
            analysis = {
              inlayHints = {
                variableTypes = true,
                functionReturnTypes = true,
                callArgumentNames = true,
              },
            },
          },
        },
      },
    },
  },
},

Thanks for the hint @nullchilly. Turns out my config for root_dir has some issue with inlay hints. Now it shows the function return type and function params, but variable types are still missing. Does it show the variable types on your end? Looks like it's the behavior of pylance, I got the same result in vscode. Thanks again bro. You're crazy good at this 😁

doesn't seem to work anymore with new versions (>2023.10.30)

Updated to work with the newest version (2023.11.10)

@nullchilly hi, I'd like to know how to setup a native pylance, I sent you a discord connection request. my user name is KKChang. Thanks

It seems it doesn't support inlay hints.

It seems it doesn't support inlay hints.

Yup, I investigated this my looking at the LSP logs. No matter what I do I can't get inlay hints to work on latest nvim nightly. I can see in the telemetry LSP notification emitted after pylance starts inlay hints are always disabled no matter my settings. My guess is it's running some kind of off-books capabilities check that nvim doesn't pass and turning it off.

I also can't configure typeCheckingMode via lang server settings, though I can with a pyright config file.

@smackesey I found the problem, and it is necessary to set the value of settings.python.pythonPath.

I used nvim-lspconfig to test it.
You can set any non-empty value to the settings.python.pythonPath field, even if it's an invalid path.

Enjoy the Inlay Hints!!!

@Fau818 Thank you so much! Here is a working config

For anyone who doesn't use virtualenv, the tldr config is just:

pylance = {
  settings = {
    python = {
      pythonPath = "/usr/bin/python3",
      analysis = {
        inlayHints = {
          variableTypes = true,
          functionReturnTypes = true,
          callArgumentNames = true,
          pytestParameters = true,
        }
      }
    }
  }
}

@nullchilly
I just looked at your configuration and found that pythonPath affects the library index.
So we can't set the value of pythonPath arbitrarily.

Thank you for providing the configuration file, which helped me find a bug!

HTTP/1.1 410 Gone
Content-Type: text/plain
Date: Thu, 01 Jan 1970 00:00:00 GMT

@nullchilly Hello I send a discord friend request to you I can't send you mesaages if I'm not your friend😥
@mochaaP what does these mean I can't open it😥

has anyone tried this and basedpyright and could comment on how they compare? thank you

Hey @pearagit, IMO, basedpyright's major drawback is that it's really, really slow. Everything from completion to hover just takes forever when compared to Pylance.

But hey fellas, has anyone noticed some issues with semantic highlighting when using Pylance with neovim's built-in LSP?