How to get the filename where the line of vimscript/lua is in?

Question

As title. Say I have a line to create an augroup located in file git.lua. What I want to achieve is that that line will always create an augroup named git.lua without hard-coding it by the string "git.lua", so I can renamed the file and no code needs to change. I did try calling nvim API like vim.fn.bufname(and removing the prefix to get git.lua) in git.lua, but this resulted in an augroup of name plugins.lua, since this is where git.lua got imported/required. So what's the correct way to achieve this?

In short: I want to have a line of code to create an augroup, such that I can renamed that file and that line will always create an augroup as per the new name.

Answer 1

Courtesy of the comments:

vim.fn.expand('<sfile>:p')

Answer 2

It seems that hard-coding the filename for each file is the simplest way to achieve what you want to do. So the code is:

vim.api.nvim_create_augroup('LSP.lua', { clear = true })

vim.api.nvim_create_autocmd('CursorHold', {
  group = 'LSP.lua',
  pattern = '*',
...

That is: you cannot replace xxx.lua with vim.fn.expand('%:t').

Here is an example of some state-of-the-art nvim-v0.9 plugin using the same method: https://github.com/akinsho/bufferline.nvim/blob/e70be6232f632d16d2412b1faf85554285036278/lua/bufferline.lua#L34