feat(treesitter): automatically install and use mason's tree-sitter-cli if not installed on system

lua/lazyvim/plugins/treesitter.lua

@@ -13,7 +13,9 @@ return {
         LazyVim.error("Please restart Neovim and run `:TSUpdate` to use the `nvim-treesitter` **main** branch.")
         return
       end
-      TS.update(nil, { summary = true })
+      LazyVim.treesitter.ensure_treesitter_cli(function()
+        TS.update(nil, { summary = true })
+      end)
     end,
     lazy = vim.fn.argc(-1) == 0, -- load treesitter early when opening a file from the cmdline
     event = { "LazyFile", "VeryLazy" },
@@ -59,18 +61,12 @@ return {
       -- some quick sanity checks
       if not TS.get_installed then
         return LazyVim.error("Please use `:Lazy` and update `nvim-treesitter`")
-      elseif vim.fn.executable("tree-sitter") == 0 then
-        return LazyVim.error({
-          "**treesitter-main** requires the `tree-sitter` CLI executable to be installed.",
-          "Run `:checkhealth nvim-treesitter` for more information.",
-        })
       elseif type(opts.ensure_installed) ~= "table" then
         return LazyVim.error("`nvim-treesitter` opts.ensure_installed must be a table")
       end
 
       -- setup treesitter
       TS.setup(opts)
-
       LazyVim.treesitter.get_installed(true) -- initialize the installed langs
 
       -- install missing parsers
@@ -78,8 +74,10 @@ return {
         return not LazyVim.treesitter.have(lang)
       end, opts.ensure_installed or {})
       if #install > 0 then
-        TS.install(install, { summary = true }):await(function()
-          LazyVim.treesitter.get_installed(true) -- refresh the installed langs
+        LazyVim.treesitter.ensure_treesitter_cli(function()
+          TS.install(install, { summary = true }):await(function()
+            LazyVim.treesitter.get_installed(true) -- refresh the installed langs
+          end)
         end)
       end
 

lua/lazyvim/util/treesitter.lua

@@ -33,4 +33,51 @@ function M.indentexpr()
   return M.have() and require("nvim-treesitter").indentexpr() or -1
 end
 
+---@param cb fun()
+function M.ensure_treesitter_cli(cb)
+  if vim.fn.executable("tree-sitter") == 1 then
+    return cb()
+  end
+
+  ---@param msg? string
+  local function fail(msg)
+    return LazyVim.error({
+      "**treesitter-nvim** `main` requires the `tree-sitter` CLI executable to be installed.",
+      "Please install it manually from https://github.com/tree-sitter/tree-sitter/tree/master/crates/cli or",
+      "use your system package manager.",
+      "Run `:checkhealth nvim-treesitter` for more information.",
+      msg,
+    })
+  end
+
+  -- try installing with mason
+  if not pcall(require, "mason") then
+    return fail("`mason.nvim` is disabled in your config, so we cannot install it automatically.")
+  end
+
+  -- check again since we might have installed it already
+  if vim.fn.executable("tree-sitter") == 1 then
+    return cb()
+  end
+
+  local mr = require("mason-registry")
+  mr.refresh(function()
+    local p = mr.get_package("tree-sitter-cli")
+    if not p:is_installed() then
+      LazyVim.info("Installing `tree-sitter-cli` with `mason.nvim`...")
+      p:install(
+        nil,
+        vim.schedule_wrap(function(success)
+          if success then
+            LazyVim.info("Installed `tree-sitter-cli` with `mason.nvim`.")
+            cb()
+          else
+            fail("Failed to install `tree-sitter-cli` with `mason.nvim`.")
+          end
+        end)
+      )
+    end
+  end)
+end
+
 return M