From aebffc34e7af06336c8d90fc3d650faf7625098f Mon Sep 17 00:00:00 2001
From: Lazar Bulovan <lazar.bulovan@l-tech.biz>
Date: Sat, 18 Jul 2026 18:01:32 +0200
Subject: [PATCH] fix: load compiled parser.so via vim.treesitter.language.add

nvim-treesitter's :TSInstall reloads the parsers module from source
(package.loaded['nvim-treesitter.parsers'] = nil), which wipes runtime
config modifications. The old get_parser_configs() approach no longer
works for registering custom parsers with :TSInstall.

New approach:
- The mason build script now compiles parser.c into parser.so during
  :MasonInstall tia-lsp (requires cc/gcc)
- The plugin's setup_syntax finds parser.so via:
  1. opts.ts_parser_path (explicit override)
  2. Mason package dir (resolved from exepath('tia-lsp'))
  3. ~/dev/tia-lsp/parser.so (local dev fallback)
- Loads it with vim.treesitter.language.add('scl', { path = parser.so })
- Starts highlighting via vim.treesitter.start(bufnr, 'scl') in the
  FileType autocmd
- Falls back to notifying the user if no parser.so is found
- Still registers with nvim-treesitter's parsers table as best-effort
  for :TSInstall support (won't survive reload, but works in-session)
---
 lua/tia_lsp/init.lua | 81 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 76 insertions(+), 5 deletions(-)

diff --git a/lua/tia_lsp/init.lua b/lua/tia_lsp/init.lua
index abe09e8..93a81e0 100644
--- a/lua/tia_lsp/init.lua
+++ b/lua/tia_lsp/init.lua
@@ -53,6 +53,9 @@ function M.setup(opts)
     pattern = "scl",
     callback = function(args)
       start_lsp(args.buf)
+      M.notify_parser_install_if_needed(args.buf)
+      -- Start tree-sitter highlighting if the parser is registered
+      pcall(vim.treesitter.start, args.buf, "scl")
     end,
   })
   
@@ -65,6 +68,8 @@ function M.setup(opts)
   for _, bufnr in ipairs(vim.api.nvim_list_bufs()) do
     if vim.bo[bufnr].filetype == "scl" and vim.api.nvim_buf_is_loaded(bufnr) then
       start_lsp(bufnr)
+      M.notify_parser_install_if_needed(bufnr)
+      pcall(vim.treesitter.start, bufnr, "scl")
     end
   end
 
@@ -78,14 +83,80 @@ function M.setup(opts)
   end
 end
 
+-- Find a compiled tree-sitter parser (.so) for SCL.
+-- Looks in: opts.ts_parser_path, mason package dir, ~/dev/tia-lsp.
+-- Returns the path to parser.so, or nil if not found.
+function M.find_parser_so(opts)
+  -- 1. Explicit path from opts
+  if opts.ts_parser_path and vim.fn.filereadable(opts.ts_parser_path) == 1 then
+    return opts.ts_parser_path
+  end
+  -- 2. Mason install: resolve exepath("tia-lsp") -> real bin -> package dir
+  local tia_bin = vim.fn.exepath("tia-lsp")
+  if tia_bin ~= "" then
+    local real_bin = vim.fn.resolve(vim.fn.fnamemodify(tia_bin, ":p"))
+    local pkg_dir = vim.fn.fnamemodify(real_bin, ":h:h")
+    local so = pkg_dir .. "/parser.so"
+    if vim.fn.filereadable(so) == 1 then
+      return so
+    end
+  end
+  -- 3. Local dev path
+  local dev_so = vim.fn.expand("~/dev/tia-lsp/parser.so")
+  if vim.fn.filereadable(dev_so) == 1 then
+    return dev_so
+  end
+  return nil
+end
+
+-- Notify the user once per session if the tree-sitter parser isn't available.
+local parser_notified = false
+
+function M.notify_parser_install_if_needed(bufnr)
+  if parser_notified then return end
+  if vim.bo[bufnr].filetype ~= "scl" then return end
+  local ok = pcall(vim.treesitter.get_parser, bufnr, "scl")
+  if ok then return end
+  parser_notified = true
+  vim.schedule(function()
+    local msg = "SCL: Tree-sitter parser not found. "
+    if vim.fn.exepath("tia-lsp") ~= "" then
+      msg = msg .. "Run :MasonInstall tia-lsp to install it."
+    else
+      msg = msg .. "Install tia-lsp via mason or compile parser.so manually."
+    end
+    vim.notify(msg, vim.log.levels.INFO)
+  end)
+end
+
 function M.setup_syntax(opts)
-  local has_ts, ts = pcall(require, "nvim-treesitter.parsers")
-  if has_ts and ts.get_parser_configs then
-    local ok, parser_config = pcall(ts.get_parser_configs)
-    if ok and parser_config then
+  -- Load the compiled tree-sitter parser (.so) via Neovim's built-in API.
+  -- This bypasses nvim-treesitter's install system, which reloads its
+  -- parsers module from source on :TSInstall and wipes runtime config.
+  local parser_so = M.find_parser_so(opts)
+  if parser_so then
+    local ok, err = pcall(vim.treesitter.language.add, "scl", { path = parser_so })
+    if not ok then
+      vim.notify(
+        "SCL: Failed to load tree-sitter parser from " .. parser_so .. ": " .. tostring(err),
+        vim.log.levels.WARN
+      )
+    end
+  end
+
+  -- Also register with nvim-treesitter (best-effort, for :TSInstall support
+  -- in sessions where the user wants to install from source).
+  local has_ts, parsers = pcall(require, "nvim-treesitter.parsers")
+  if has_ts and type(parsers) == "table" then
+    local parser_config
+    if type(parsers.get_parser_configs) == "function" then
+      parser_config = parsers.get_parser_configs()
+    else
+      parser_config = parsers
+    end
+    if type(parser_config) == "table" then
       parser_config.scl = {
         install_info = {
-          -- Override via setup({ ts_parser_url = "https://your-gitea/tia-lsp.git" }).
           url = opts.ts_parser_url
             or "https://gitea.l-tech.rs/lazar/tia-lsp.git",
           files = { "src/parser.c" },