feat: Add lua language server to pre-commit

Fixes cursorless-dev#2576. Adds lua-language-server linter to pre-commit. There is no
existing pre-commit hook, and also no Ubuntu package for this linter.
I install it using nix package manager, as nixpkgs is one of the only
places with a package. However, there is also a recent bug that prevents
--check invocation of the cli. I have patched this in the
lua-language-server using a nix overlay, until the PR is merged.

This also moves the linting configuration to a single source of true,
that vscode, pre-commit, CI can all use.

.github/workflows/pre-commit.yml

@@ -13,6 +13,8 @@ jobs:
   pre-commit:
     name: Pre-commit
     runs-on: ubuntu-latest
+    env:
+      CURSORLESS_REPO_ROOT: ${{ github.workspace }}
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
@@ -26,6 +28,11 @@ jobs:
       - run: pnpm --color install
       - uses: leafo/gh-actions-lua@v9
       - uses: leafo/gh-actions-luarocks@v4
+      - uses: cachix/install-nix-action@v27
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+      - run: nix profile install --quiet --accept-flake-config nixpkgs#lua-language-server --override-input nixpkgs path:$PWD/patches/lua-language-server.nix
+        shell: bash
       - uses: pre-commit/[email protected]
       - uses: pre-commit-ci/[email protected]
         if: always()

.luarc.json

@@ -0,0 +1,6 @@
+{
+  "runtime.version": "Lua 5.1",
+  "diagnostics.ignoredFiles": "Disable",
+  "diagnostics.globals": ["vim", "talon", "it", "describe"],
+  "workspace.ignoreDir": ["data/playground/lua/"]
+}

.pre-commit-config.yaml

@@ -91,3 +91,10 @@ repos:
     hooks:
       - id: stylua
         exclude: ^data/playground/lua/.*\.lua$
+  - repo: local
+    hooks:
+      - id: lua-language-server
+        name: lua-language-server
+        files: \.(lua|busted)$
+        entry: scripts/lint-lua.sh
+        language: script

.vscode/settings.json

@@ -26,10 +26,6 @@
   "typescript.enablePromptUseWorkspaceTsdk": true,
   "typescript.tsdk": "node_modules/typescript/lib",
   "eslint.workingDirectories": [{ "pattern": "packages/*/" }],
-  "Lua.runtime.version": "Lua 5.1",
-  "Lua.diagnostics.globals": ["vim", "talon", "it", "describe"],
-  "Lua.diagnostics.ignoredFiles": "Disable",
-  "Lua.workspace.ignoreDir": ["data/playground/lua/"],
   "[lua]": {
     "editor.defaultFormatter": "JohnnyMorganz.stylua"
   },

flake.nix

@@ -22,6 +22,7 @@
             pkgs = import nixpkgs {
               inherit system;
               overlays = [
+                (import ./patches/lua-language-server.nix)
                 # https://github.com/NixOS/nixpkgs/pull/317333
                 (final: prev: {
                   nodePackages = prev.nodePackages // {
@@ -45,7 +46,6 @@
                     };
                   };
                   neovim = prev.neovim.override { withNodeJs = true; };
-
                 })
 
               ];
@@ -69,19 +69,21 @@
               [
                 pkgs.corepack
                 pkgs.vsce
+                pkgs.nodejs
+
                 # https://github.com/NixOS/nixpkgs/pull/251418
                 (pkgs.pre-commit.overrideAttrs (previousAttrs: {
                   makeWrapperArgs = ''
                     --set PYTHONPATH $PYTHONPATH
                   '';
                 }))
                 python
+                pkgs.lua-language-server # language server used by pre-commit hooks
 
                 pkgs.neovim
                 pkgs.luajitPackages.busted # for lua testing
                 pkgs.luarocks # pre-commit doesn't auto-install luarocks
                 pkgs.ps
-                pkgs.nodejs
               ];
             # To prevent weird broken non-interactive bash terminal
             buildInputs = [ pkgs.bashInteractive ];

patches/lua-language-server.nix

@@ -0,0 +1,17 @@
+(final: prev: {
+  # There is a recent bug that prevents cli invocation:
+  # See: https://github.com/LuaLS/lua-language-server/pull/2775
+  lua-language-server = prev.lua-language-server.overrideAttrs {
+    postPatch =
+      let
+        patch = prev.fetchurl {
+          url = "https://github.com/LuaLS/lua-language-server/pull/2775.patch";
+          sha256 = "sha256-5hjuNzBHLp9kiD6O8jTL5YlvaqR8IuJPHchIZE2/p/Q=";
+        };
+      in
+      ''
+        patch -p1 < ${patch}
+      ''
+      + prev.lua-language-server.postPatch;
+  };
+})

scripts/lint-lua.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# lua-language-server should be installed automatically by the flake.nix dev shell
+# or .github/workflows/pre-commit.yml
+if ! type lua-language-server &>/dev/null; then
+  echo "ERROR: lua-ls is not installed. Please run 'nix develop' or install it manually."
+  exit 1
+fi
+
+if [ ! -e "${CURSORLESS_REPO_ROOT-nonexistent}" ]; then
+  CURSORLESS_REPO_ROOT=$(git rev-parse --show-toplevel)
+fi
+
+logpath="$(mktemp -d)"
+rm -rf "$logpath/check.json"
+result=$(lua-language-server --check "${CURSORLESS_REPO_ROOT}" \
+  --checklevel="Warning" \
+  --configpath="${CURSORLESS_REPO_ROOT}/.luarc.json" \
+  --logpath="$logpath")
+if [[ ! "$result" == *"no problems found"* ]]; then
+  cat "$logpath/check.json"
+  exit 1
+fi
+
+exit 0