Bug: hmts_inject_handler crashes when find_filename_in_parent_node returns nil

[charliie-dev]

Description

When opening a .nix file containing home.file.*.text bindings where the filename cannot be extracted (e.g., find_filename_in_parent_node returns nil), vim.filetype.match({ filename = nil }) is called, which crashes with:

Error executing vim.schedule lua callback:
  .../languagetree.lua:208: vim/filetype.lua:0: At least one of "buf", "filename", or "contents" must be given

Reproduction

Neovim 0.11.6 with nvim-treesitter-context installed.

Open a .nix file with home-manager config like:

home.file = {
  ".config/parallel/will-cite" = {
    text = "";
  };
};

The error triggers because find_filename_in_parent_node can return nil, and that nil is passed directly to vim.filetype.match() without a guard:

hmts.nvim/plugin/hmts.lua

Lines 154 to 161 in a32cd41

	local function hmts_inject_handler(match, _, bufnr, predicate, metadata)
	local path_node = match[predicate[2]]
	local filename = find_filename_in_parent_node(path_node, bufnr)
	local alias = vim.filetype.match({ filename = filename })
	if alias == nil then
	return
	end

local function hmts_inject_handler(match, _, bufnr, predicate, metadata)
    local path_node = match[predicate[2]]
    local filename = find_filename_in_parent_node(path_node, bufnr)
    local alias = vim.filetype.match({ filename = filename })  -- filename can be nil here!

Fix

Add a nil check before calling vim.filetype.match:

if filename == nil then
    return
end

Environment

• Neovim: 0.11.6
• hmts.nvim: a32cd41
• OS: macOS (Darwin 25.4.0)

[charliie-dev]

Duplicate of the fix in PR #35. The same nil guard is needed before vim.filetype.match().