ci: add luals workflow

Optional for now; can be run locally with `make luacheck`.

Author: clason

.github/workflows/lint.yml

@@ -23,10 +23,10 @@ jobs:
           sudo luarocks install luacheck
 
       - name: Lint
-        run: sudo make lint
+        run: make lint
 
   stylua:
-    name: stylua
+    name: Stylua
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
@@ -35,4 +35,12 @@ jobs:
           token: ${{ secrets.GITHUB_TOKEN }}
           version: latest
           # CLI arguments
-          args: --color always --check lua/
+          args: --color always --check .
+
+  luals:
+    name: Luals
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - run: make checklua
+

.luarc.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "https://raw.githubusercontent.com/LuaLS/vscode-lua/master/setting/schema.json",
+  "runtime": {
+    "version": "LuaJIT"
+  },
+  "workspace": {
+    "library": [
+      "$VIMRUNTIME",
+      "${3rd}/busted/library"
+    ],
+    "ignoreDir": [
+      ".test-deps",
+      "lua/tests"
+    ],
+    "checkThirdParty": "Disable"
+  },
+  "diagnostics": {
+    "groupFileStatus": {
+      "strict": "Opened",
+      "strong": "Opened"
+    },
+    "groupSeverity": {
+      "strong": "Warning",
+      "strict": "Warning"
+    },
+    "unusedLocalExclude": [ "_*" ]
+  }
+}

Makefile

@@ -1,10 +1,63 @@
-.PHONY: test lint docgen
+LUALS_VERSION := 3.15.0
 
+DEPDIR ?= .test-deps
+CURL ?= curl -sL --create-dirs
+
+ifeq ($(shell uname -s),Darwin)
+    LUALS_ARCH ?= darwin-arm64
+    STYLUA_ARCH ?= macos-aarch64
+else
+    LUALS_ARCH ?= linux-x64
+    STYLUA_ARCH ?= linux-x86_64
+endif
+
+LUALS := $(DEPDIR)/lua-language-server-$(LUALS_VERSION)-$(LUALS_ARCH)
+LUALS_TARBALL := $(LUALS).tar.gz
+LUALS_URL := https://github.com/LuaLS/lua-language-server/releases/download/$(LUALS_VERSION)/$(notdir $(LUALS_TARBALL))
+
+.PHONY: luals
+luals: $(LUALS)
+
+$(LUALS):
+	$(CURL) $(LUALS_URL) -o $(LUALS_TARBALL)
+	mkdir $@
+	tar -xf $(LUALS_TARBALL) -C $@
+	rm -rf $(LUALS_TARBALL)
+
+STYLUA := $(DEPDIR)/stylua-$(STYLUA_ARCH)
+STYLUA_TARBALL := $(STYLUA).zip
+STYLUA_URL := https://github.com/JohnnyMorganz/StyLua/releases/latest/download/$(notdir $(STYLUA_TARBALL))
+
+.PHONY: stylua
+stylua: $(STYLUA)
+
+$(STYLUA):
+	$(CURL) $(STYLUA_URL) -o $(STYLUA_TARBALL)
+	unzip $(STYLUA_TARBALL) -d $(STYLUA)
+	rm -rf $(STYLUA_TARBALL)
+
+.PHONY: formatlua
+formatlua: $(STYLUA)
+	$(STYLUA)/stylua .
+
+.PHONY: checklua
+checklua: $(LUALS) $(NVIM)
+	VIMRUNTIME=$(NVIM_RUNTIME) $(LUALS)/bin/lua-language-server \
+		--configpath=../.luarc.json \
+		--check=./
+
+.PHONY: test
 test:
 	nvim --headless --noplugin -u scripts/minimal_init.vim -c "PlenaryBustedDirectory lua/tests/automated/ { minimal_init = './scripts/minimal_init.vim' }"
 
-lint:
+.PHONY: lint
+luacheck:
 	luacheck lua/telescope
 
+.PHONY: docgen
 docgen:
 	nvim --headless --noplugin -u scripts/minimal_init.vim -c "luafile ./scripts/gendocs.lua" -c 'qa'
+
+.PHONY: clean
+clean:
+	rm -rf $(DEPDIR)