How to prevent format on save on fugitive:// buffers

[dsirov]

Hi!

Though others may want auto-format on save when editing fugitive buffers (like staged file buffer), i.e.:
fugitive:///home/user/nvim-test/.git//0/test.py,
I'd like to prevent auto-formatting in such cases as I have encountered some cases in which black works while isort doesn't on staged fugitive buffer, leading to discrepancies.

How can I achieve that via config.?

Thanks!

[dsirov]

After more digging, it seems that somehow black is somehow miraculously correctly invoked on fugitive buffer, while isort chokes on such a path (as quite expected).

In any case, here is a LazyVim configuration that prevents it:

return {
  "stevearc/conform.nvim",
  optional = true,
  opts = {
    formatters_by_ft = {
      python = function(bufnr)
        local bufname = vim.api.nvim_buf_get_name(bufnr)
        if bufname:match("^fugitive://") then
          return {}
        else
          return { "black", "isort" }
        end
      end,
    },
  },
}

It may be of interest to add this to documentation.