bug: `programs.nh.flake`

[Malix-Labs]

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

programs.nh.flake doesn't get updated right away after a sudo nixos-rebuild switch (or nh os switch), and requires a logout (relaunching my terminal didn't work)

Maintainer CC

@JohnRTitor @A-jay98

System information

- system: `"x86_64-linux"`
- host os: `Linux 6.19.8-cachyos-lto, NixOS, 25.11 (Xantusia), 25.11.20260313.3e20095`
- multi-user?: `yes`
- sandbox: `yes`
- version: `nix-env (Determinate Nix 3.17.0) 2.33.3`
- channels(root): `""`
- nixpkgs: `/nix/store/pg50hqxkrq16049m20pc53d5zn0zfg0n-source`

[jennydaman]

programs.nh.flake sets environment variables e.g. NH_OS_FLAKE and these effects are not applied unless you logout and log back in because of:

home-manager/modules/home-environment.nix

Lines 653 to 655 in d47357a

	# Only source this once.
	if [ -n "$__HM_SESS_VARS_SOURCED" ]; then return; fi
	export __HM_SESS_VARS_SOURCED=1

This code ends up appearing in $HOME/.nix-profile/etc/profile.d/hm-session-vars.sh. You could work around it by running

unset __HM_SESS_VARS_SOURCED
source "$HOME/.nix-profile/etc/profile.d/hm-session-vars.sh"

[Malix-Labs]

Okay, and thanks for the workaround!
Do I close this issue as not planned?