BEFORE YOU PROCEED

check out easypick.nvim the changed files functionality is included in its default config

telescope-changed-files

Telescope picker to browse files that changed between your branch and develop.

Underneath the picker just runs this git command:

git diff --name-only $(git merge-base HEAD base_branch) 

The base_branch defaults to "develop" but you can change it to be any branch you want (see #use section).

install

Add this to your init.lua:

require('packer').startup(function(use)
	use { "axkirillov/telescope-changed-files" }
end)

require('telescope').load_extension('changed_files')

use

Now you should have the changed_files picker available in telescope. You can then map it to whatever key you like.

map <leader>cf :Telescope changed_files <cr>

To change the base_branch run :Telescope changed_files choose_base_branch. This will open a builtin git branches picker. The branch you pick will then be saved for the duration of your vim session.

Alternatively you can just set it using this global var:

vim.g.telescope_changed_files_base_branch = your_branch

Put it somewhere in your project specific config.