nvim-config/lua/custom/utils/telescope.lua

local M = {}

-- builtin telescope modules
local actions = require 'telescope.actions'
local builtin = require 'telescope.builtin'

function M.git_stash_mappings()
  builtin.git_stash {
    attach_mappings = function(_, map)
      -- builtin telescope modules
      local utils = require 'telescope.utils'
      local action_state = require 'telescope.actions.state'

      -- Reference: https://github.com/nvim-telescope/telescope.nvim/blob/master/lua/telescope/actions/init.lua#L587
      local function git_apply_stash(prompt_bufnr)
        local selection = action_state.get_selected_entry()
        if selection == nil then
          utils.__warn_no_selection 'actions.git_apply_stash'
          return
        end
        actions.close(prompt_bufnr)
        -- Remove unwanted '--index' flag from command
        local _, ret, stderr = utils.get_os_command_output { 'git', 'stash', 'apply', selection.value }
        if ret == 0 then
          utils.notify('actions.git_apply_stash', {
            msg = string.format("applied: '%s' ", selection.value),
            level = 'INFO',
          })
        else
          utils.notify('actions.git_apply_stash', {
            ---@diagnostic disable-next-line: param-type-mismatch
            msg = string.format("Error when applying: %s. Git returned: '%s'", selection.value, table.concat(stderr, ' ')),
            level = 'ERROR',
          })
        end
      end
      actions.select_default:replace(git_apply_stash)

      -- custom function to match stash index inside curly brackets
      local function match_bracket(str, arr)
        string.gsub(str, '{(.-)}', function(match)
          -- do not insert existing entry into index list
          if not vim.list_contains(arr, match) then
            table.insert(arr, match)
          end
        end)
      end

      local function git_drop_stash(prompt_bufnr)
        local picker = action_state.get_current_picker(prompt_bufnr)
        local selection = picker:get_multi_selection()

        local stashes = {}
        -- scan all multi_selection entries
        for _, entry in ipairs(selection) do
          local value = entry.value
          match_bracket(value, stashes)
        end

        -- scan single selected entry
        local entry = action_state.get_selected_entry()
        if entry == nil and #stashes == 0 then
          vim.notify(
            ---@diagnostic disable-next-line: param-type-mismatch
            string.format('WARN [%s]: Nothing currently selected', 'git_drop_stash'),
            vim.log.levels.WARN,
            { title = 'telescope.nvim' }
          )
          return
        end
        match_bracket(entry.value, stashes)

        local success = {}
        for idx = #stashes, 1, -1 do
          -- execute git command in os
          -- reference: https://github.com/nvim-telescope/telescope.nvim/blob/master/lua/telescope/actions/init.lua#L594
          local _, ret, stderr = utils.get_os_command_output { 'git', 'stash', 'drop', string.format('stash@{%d}', stashes[idx]) }
          if ret ~= 0 then
            -- extracted from telescope.utils.notify:
            vim.notify(
              ---@diagnostic disable-next-line: param-type-mismatch
              string.format("Error when dropping: stash@{%s}. Git returned: '%s'", stashes[idx], table.concat(stderr, ' ')),
              vim.log.levels.ERROR,
              { title = 'telescope.nvim' }
            )
            return
          end
          table.insert(success, stashes[idx])
        end

        -- extracted from telescope.utils.notify:
        vim.notify(string.format("dropping: 'stash@{%s}' ", table.concat(success, ', ')), vim.log.levels.INFO, { title = 'telescope.nvim' })

        -- refresh picker
        actions.close(prompt_bufnr)
        vim.schedule(git_stash_mappings)
      end
      map({ 'n', 'i' }, '<C-S-d>', git_drop_stash)
      return true
    end,
  }
end

return M