bug: MUHOME not respected by mu activation

[jdek]

Are you following the right branch?

• My Nixpkgs and Home Manager versions are in sync

Is there an existing issue for this?

• I have searched the existing issues

Issue description

The database path can be set by the user, this is useful for keeping the Maildir and the Mu Xapian cache together without affecting XDG_CACHE_HOME. It can be set in a couple methods:

The default location for that is ~/.cache/mu/xapian, but you can change this using the --muhome option, and remember to pass that to the other commands as well. Alternatively, you can use an environment variable MUHOME.

Here the db location is set to XDG_CACHE_HOME/mu:
https://github.com/nix-community/home-manager/blob/master/modules/programs/mu.nix#L56

Maintainer CC

@Karljo

System information

- system: `"x86_64-linux"`
 - host os: `Linux 6.6.32, NixOS, 24.05 (Uakari), 24.05.20240612.cc54fb4`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.18.2`
 - nixpkgs: `/nix/store/aa0zsahvyqnvzkicsh29jirm9hwv95pg-source`