[BUG] Not possible to define custom extension for lualine

[Wraul]

Field	Description
Plugin	lualine
Nixpkgs	unstable
Home Manager	unstable

• I have read the FAQ and my bug is not listed there.

Description

While migrating my configuration to NixVim I discovered a limitation that prevents me from completely achieving my desired configuration.

The upstream lualine plugin allows the user to define custom extensions by providing a object in the list of extensions. See lualine documentation for details.

Unless I'm missing something this isn't currently possible.

Minimal, Reproducible Example (MRE)

programs.nixvim = {
    plugins.lualine = {
      enable = true;
      extensions = [
        {
          sections = {
            lualine_a = [ "filename" ];
          };
          inactive_sections = {
            lualine_x = [ "location" ];
          };
          filetypes = [ "markdown" ];
        }
      ];
    };
}

[khaneliman]

I'm in the middle of migrating our lualine module to our new standards that will support this better in #2080.

[Wraul]

Thank you for expediting fixing this. It is very much appreciated ❤️.

Unfortunately the fix isn't 100% complete. This oversight could very much be due to my lackluster example though.
The regular sections has special handling for mapping "name" to the first element in the lua record. This is something that should happen in the extension sections as well.

So a more complete example would be like this

programs.nixvim = {
    plugins.lualine = {
      enable = true;
      extensions = [
        {
          sections = {
            lualine_a = [ {
              name = "branch";
              icon = "<U+F418>";
            }];
            lualine_y = [ "progress" ];
            lualine_z = [ "location" ];
          };
          inactive_sections = {
            lualine_x = [ "location" ];
          };
          filetypes = [ "fugitive" ];
        }
      ];
    };
}

And the extensions section should translate to the following lua

{
  extensions = {
    {
      filetypes = { "fugitive" },
      inactive_sections = { lualine_x = { "location" } },
      sections = {
        lualine_a = { { "branch", icon = "<U+F418>" } },
        lualine_y = { "progress" },
        lualine_z = { "location" },
    },
  },
},

But at the moment it appears to be translated to the following

{
  extensions = {
    {
      filetypes = { "fugitive" },
      inactive_sections = { lualine_x = { "location" } },
      sections = {
        lualine_a = { { icon = "<U+F418>", name = "branch" } },
        lualine_y = { "progress" },
        lualine_z = { "location" },
    },
  },
},

[MattSturgeon]

The regular sections has special handling for mapping "name" to the first element in the lua record. This is something that should happen in the extension sections as well.

This is likely something we would remove when refactoring the plugin, as we try to avoid having any unpredictable transformations applied to freeform options.

Instead, you would have to use our "unkeyed" attrs hack:

This nix attrset:

{
  __unkeyed-1 = "a";
  __unkeyed-2 = "b";
  c = "c";
  d = "d";
}

Produces this lua table:

{
  "a",
  "b",
  c = "c",
  d = "d"
}

[Wraul]

@MattSturgeon I see, makes sense I guess.

Thank you so much for the hint! With that I was able to produce my desired configuration.