TIL: git conditional config with and without home-manager

Today I learnt how to use git conditional config to use multiple identities easily.
I use git for my private project and the projects I need to work at my day job.
To keep these two projects apart, I have a ~/projects folder in my home directory with the two subfolder ~/projects/work and ~/projects/personal. Now we can tell git to always use the one identity for all projects under ~/projects/personal and another for ~/projects/work. We just add two includeIfs in our git config. With includeIf we can specify other files to source if the condition is met. The prepended “gitdir:” just means every git repository under this directory. ^[1]

[includeIf "gitdir:~/projects/personal/"]
	path = "./personal"

[includeIf "gitdir:~/projects/work/"]
	path = "./work"

In the personal config, we specify our personal identity

[user]
	email = "alex@confusedalex.dev"
	name = "confusedalex"
	signingKey = "05AF71643F6E2ED3"

and do the same for the work config.

Integrating with home-manager

Because I use home-manager I want to specify these conditionals with nix. We just need to add a list we attributes sets for every include.

Everything under contents must follow the structure as in git-config.

{
  programs.git = {
    enable = true;
    # ...
    includes = [
      {
        condition = "gitdir:~/projects/personal/";
        contents = {
          user = {
            name = "confusedalex";
            email = "alex@confusedalex.dev";
            signingKey = "05AF71643F6E2ED3";
          };
          gpg.format = "openpgp";
        };
      }
      {
        condition = "gitdir:~/projects/work/";
        contents = {
            #...
        };
      }
    ];
  };
}

1. https://git-scm.com/docs/git-config#_includes ↩