feat(util): util method to check if ts lang is available on any Neovim version. See #1422

lua/snacks/health.lua

@@ -128,7 +128,7 @@ function M.has_lang(langs)
   local ret = {} ---@type table<string, boolean>
   local available, missing = {}, {} ---@type string[], string[]
   for _, lang in ipairs(langs) do
-    local has_lang = pcall(vim.treesitter.get_string_parser, "", lang)
+    local has_lang = Snacks.util.get_lang(lang) ~= nil
     ret[lang] = has_lang
     lang = ("`%s`"):format(lang)
     if has_lang then

lua/snacks/picker/core/preview.lua

@@ -277,7 +277,7 @@ function M:highlight(opts)
     })
   end
   self:check_big()
-  local lang = Snacks.picker.highlight.get_lang({ lang = opts.lang, ft = ft })
+  local lang = Snacks.util.get_lang(opts.lang or ft)
   if not (lang and pcall(vim.treesitter.start, self.win.buf, lang)) and ft then
     vim.bo[self.win.buf].syntax = ft
   end

lua/snacks/picker/util/highlight.lua

@@ -3,19 +3,6 @@ local M = {}
 
 M.langs = {} ---@type table<string, boolean>
 
----@param opts? {lang?:string, ft?:string}
-function M.get_lang(opts)
-  opts = opts or {}
-  local lang = opts.lang or (opts.ft and vim.treesitter.language.get_lang(opts.ft)) or nil
-  if not lang then
-    return
-  end
-  if M.langs[lang] == nil then
-    M.langs[lang] = pcall(vim.treesitter.language.add, lang)
-  end
-  return M.langs[lang] and lang or nil
-end
-
 ---@param opts? {buf?:number, code?:string, ft?:string, lang?:string, file?:string, extmarks?:boolean}
 function M.get_highlights(opts)
   opts = opts or {}
@@ -28,7 +15,7 @@ function M.get_highlights(opts)
     or (opts.buf and vim.bo[opts.buf].filetype)
     or (opts.file and vim.filetype.match({ filename = opts.file, buf = 0 }))
     or vim.bo.filetype
-  local lang = M.get_lang({ lang = opts.lang, ft = ft })
+  local lang = Snacks.util.get_lang(opts.lang or ft)
   local parser ---@type vim.treesitter.LanguageTree?
   if lang then
     lang = lang:lower()

lua/snacks/scope.lua

@@ -315,18 +315,6 @@ end
 local TSScope = setmetatable({}, Scope)
 TSScope.__index = TSScope
 
-function TSScope.has_ts(buf)
-  if vim.b[buf].snacks_ts == nil then
-    if vim.b[buf].ts_highlight then
-      vim.b[buf].snacks_ts = true
-    else
-      local ok, parser = pcall(vim.treesitter.get_parser, buf)
-      vim.b[buf].snacks_ts = ok and parser ~= nil
-    end
-  end
-  return vim.b[buf].snacks_ts
-end
-
 -- Expand the scope to fill the range of the node
 function TSScope:fill()
   local n = self.node
@@ -513,7 +501,7 @@ function M.get(cb, opts)
   end
 
   ---@type snacks.scope.Scope
-  local Class = (opts.treesitter.enabled and TSScope.has_ts(opts.buf)) and TSScope or IndentScope
+  local Class = (opts.treesitter.enabled and Snacks.util.get_lang(opts.buf)) and TSScope or IndentScope
   if rawequal(Class, TSScope) and opts.parse ~= false then
     TSScope:init(function()
       opts.parse = false

lua/snacks/util/init.lua

@@ -9,6 +9,7 @@ M.is_win = jit.os:find("Windows")
 
 local uv = vim.uv or vim.loop
 local key_cache = {} ---@type table<string, string>
+local langs = {} ---@type table<string, boolean>
 
 ---@alias snacks.util.hl table<string, string|vim.api.keyset.highlight>
 
@@ -22,6 +23,20 @@ vim.api.nvim_create_autocmd("ColorScheme", {
   end,
 })
 
+---@param lang string|number|nil
+---@overload fun(buf:number):string?
+---@overload fun(ft:string):string?
+---@return string?
+function M.get_lang(lang)
+  lang = type(lang) == "number" and vim.bo[lang].filetype or lang --[[@as string?]]
+  lang = lang and vim.treesitter.language.get_lang(lang) or lang
+  if lang and lang ~= "" and langs[lang] == nil then
+    local ok, ret = pcall(vim.treesitter.language.add, lang)
+    langs[lang] = (ok and ret) or (ok and vim.fn.has("nvim-0.11") == 0)
+  end
+  return langs[lang] and lang or nil
+end
+
 --- Ensures the hl groups are always set, even after a colorscheme change.
 ---@param groups snacks.util.hl
 ---@param opts? { prefix?:string, default?:boolean, managed?:boolean }