codecompanion doesn't let me merge context.providers

[auipga]

This issue is about the key

• programs.nixvim.plugins.codecompanion.settings.context.providers

context is not explicitely defined in codecompanion/default.nix

The result I want is:

{
  programs.nixvim.plugins.codecompanion.settings.context.providers = [
    { name = "git_diff"; opts = { max_lines = 400; }; }
    { name = "lsp";      opts = { diagnostics = true; definition = true; }; }
    { name = "vectorcode"; opts = { top_k = 15; }; }
  ];
}

But I need/want to merge across multiple files which won't work the ways I tried.
I don't know whether this is a bug, just not implemented or my own misconfiguration.

• File 1:

# codecompanion.nix
{
  programs.nixvim.plugins.codecompanion.settings = {
  
    # Try 1: just define
    context.providers = [
      { name = "git_diff"; opts = { max_lines = 400; }; }
      { name = "lsp";      opts = { diagnostics = true; definition = true; }; }
    ];
    
    # Try 2: use mkMerge
    context.providers = lib.mkMerge [
      [
        { name = "git_diff"; opts = { max_lines = 400; }; }
        { name = "lsp";      opts = { diagnostics = true; definition = true; }; }
      ]
    ];
    
    # Try 3: use ++ and mkDefault
    context.providers = [
      { name = "git_diff"; opts = { max_lines = 400; }; }
      { name = "lsp";      opts = { diagnostics = true; definition = true; }; }
    ] ++ lib.mkDefault [];
    
    # Try 4: use mkBefore here and mkAfter in the other file
    context.providers = lib.mkBefore [
      { name = "git_diff"; opts = { max_lines = 400; }; }
      { name = "lsp";      opts = { diagnostics = true; definition = true; }; }
    ];
  
  };
}

• File 2:

# codecompanion-vectorcode.nix
{
  programs.nixvim.plugins.codecompanion.settings = {
  
    # Try 1: just define
    context.providers = [
      { name = "vectorcode"; opts = { top_k = 15; }; }
    ];
    
    # Try 2: use mkMerge
    context.providers = lib.mkMerge [
      [
        { name = "vectorcode"; opts = { top_k = 15; }; }
      ]
    ];
    
    # Try 3: use ++ and mkDefault
    context.providers = [
      { name = "vectorcode"; opts = { top_k = 15; }; }
    ] ++ lib.mkDefault [];
    
    # Try 4: use mkAfter here and mkBefore in the other file
    context.providers = lib.mkAfter [
      { name = "vectorcode"; opts = { top_k = 15; }; }
    ];
  
  };
}

(I omitted non-relevant lines)

[MattSturgeon]

Firstly, you can inspect the generated lua using nixvim's nixvim-print-init tool.

Secondly, you seem to misunderstand how wrappers like mkMerge, mkAfter, mkDefault, etc work. They wrap option definitions in a custom attrset understood by the module system. You cannot use // or ++ on the result of a wrapped definition.

The way list merging works uses ++ under the hood. You cannot merge definitions for the same list element from multiple definitions. Defining the list multiple times will always add additional elements to the list.

This is unlike attrsets, which when defined multiple times will attempt to merge the keys recursively.