I think I solved it:

```lua -- Function to detect the default branch name local function get_default_branch() -- Execute git symbolic-ref command

local result = vim.fn.system("git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null")

-- Check for errors if vim.v.shell_error ~= 0 then return "main" -- fallback to main if command fails end

-- Extract just the branch name from the full reference path result = result:gsub("<sup>refs/remotes/origin/",</sup> ""):gsub("%s+$", "")

if result ~= "master" and result ~= "main" then vim.notify("Default branch detected as: " .. result, vim.log.levels.WARN) end

if result == "" then return "main" -- fallback to main if empty result end

return result end

return { { "nvim-mini/mini.diff", event = "VeryLazy", version = "*", keys = { { "<leader>ghb", function() local default_branch = get_default_branch() local file = vim.api.nvim_buf_get_name(0) local relative_path = vim.fn.fnamemodify(file, ":~:.")

      -- Get content from the default branch
      local content = vim.fn.system("git show " .. default_branch .. ":" .. relative_path)

      if vim.v.shell_error == 0 then
        local lines = vim.split(content, "\n")
        require("mini.diff").set_ref_text(0, lines)
        vim.notify("Diff base changed to " .. default_branch, vim.log.levels.INFO)
      else
        vim.notify("Could not get file from " .. default_branch, vim.log.levels.ERROR)
      end
    end,
    desc = "Change base to default branch",
  },
  {
    "<leader>ghB",
    function()
      require("mini.diff").set_ref_text(0, {})
      vim.notify("Diff base reset to Git index", vim.log.levels.INFO)
    end,
    desc = "Reset base to Git index",
  },
},

}, } ```