Bug: Preview show "[Process exited 0]" when delta is used

[Zeioth]

On linux

EDIT: I see previewers.new_termopen_previewer is a Telescope method, so I should probably report it there.

[debugloop]

Your EDIT is entirely correct, nothing I can do about this message from my end 🙃

[medwatt]

I came across this issue. Is there a solution for it?

[Ajaymamtora]

Is there any fix for this?

[debugloop]

Hi, there is no "fix" for this. Feel free to read up on it at the issue created by OP, which concerns the API I am using.

As far as I can tell that issue only contains hacky fixes which involve stripping the last line or similar. I am not willing to implement those just for aesthetics, others might consider the line useful: It is proof that delta ran successfully and no lingering terminal is running in the background. Further, this message actually comes from the underlying :term command used by the Telescope API which I in turn use here. You can try it out yourself by running :term echo for instance.

Feel free to create an issue with Telescope, as anything I could do would basically patch their API response anyhow. If they respond similarly, you could decide to take it up in a Neovim issue. However, I hardly think they'll consider it: This would be a breaking change for plugins and scripts which might depend on that line being there.

[Ajaymamtora]

Thanks I read that but how would I use the workaround for just undo-telescope?

[debugloop]

I haven't tried it myself, but you would do the same as the commenters there: Set the previewer in the opts and Telescope should pick it up correctly. You can copy the previewer used by telescope-undo as a base and implement their changes on top or go for theirs entirely at first 👍🏻

[Ajaymamtora]

I haven't tried it myself, but you would do the same as the commenters there: Set the previewer in the opts and Telescope should pick it up correctly. You can copy the previewer used by telescope-undo as a base and implement their changes on top or go for theirs entirely at first 👍🏻

Thanks I used yours as a base then merged it in, this seems to work:

    local function open_undo_ts()
      local previewers = require("telescope.previewers")

      local function get_previewer(opts)
        if opts.use_custom_command ~= nil then
          return previewers.new_termopen_previewer({
            get_command = function(entry)
              local difftext = entry.value.diff:gsub("'", [['"'"']])
              return vim.tbl_map(function(part)
                return part:gsub("$DIFF", difftext)
              end, opts.use_custom_command)
            end,
          })
        end

        local has_powershell = vim.fn.executable("powershell") == 1
        local has_bash = vim.fn.executable("bash") == 1

        if
          opts.use_delta
          and not _G.__os.is_wsl
          and (has_powershell or has_bash)
          and vim.fn.executable("delta") == 1
        then
          return previewers.new_termopen_previewer({
            get_command = function(entry)
              local append = opts.side_by_side and " -s" or ""
              if has_powershell then
                return {
                  "powershell",
                  "-Command",
                  "echo '" .. entry.value.diff:gsub([[']], [['']]) .. "' | delta" .. append,
                }
              elseif has_bash then
                return {
                  "bash",
                  "-c",
                  "echo '" .. entry.value.diff:gsub("'", [['"'"']]) .. "' | delta" .. append,
                }
              end
            end,
          })
        else
          -- Original undo previewer
          -- return previewers.new_buffer_previewer({
          --   define_preview = function(self, entry)
          --     vim.api.nvim_buf_set_lines(self.state.bufnr, 0, -1, true, vim.split(entry.value.diff, "\n"))
          --     require("telescope.previewers.utils").highlighter(
          --       self.state.bufnr,
          --       "diff",
          --       { preview = { treesitter = { enable = {} } } }
          --     )
          --   end,
          -- })
          return previewers.new_buffer_previewer({
            define_preview = function(self, entry, status)
              local dir_name = vim.fn.substitute(vim.fn.getcwd(), "^.*/", "", "")
              local t = {}
              if entry.value == dir_name then
                local s = vim.fn.system("git status -s")
                for chunk in string.gmatch(s, "[^\n]+") do
                  t[#t + 1] = chunk
                end
              else
                local s = vim.fn.system("git -C " .. entry.value .. " status -s")
                for chunk in string.gmatch(s, "[^\n]+") do
                  t[#t + 1] = chunk
                end
              end
              vim.api.nvim_buf_set_lines(self.state.bufnr, 0, -1, true, t)
            end,
          })
        end
      end

      require("telescope").extensions.undo.undo({
        get_previewer = get_previewer,
      })
    end

    vim.api.nvim_create_user_command("TelescopeUndo", open_undo_ts, {})