diff --git a/nixos/modules/config/shells-environment.nix b/nixos/modules/config/shells-environment.nix
index 9dc4749b08d1e..7cd9724464ce3 100644
--- a/nixos/modules/config/shells-environment.nix
+++ b/nixos/modules/config/shells-environment.nix
@@ -162,8 +162,13 @@ in
         /bin/sh
       '';
 
-    system.build.setEnvironment = pkgs.writeText "set-environment"
+    environment.etc."set-environment".text =
        ''
+         # DO NOT EDIT -- this file has been generated automatically.
+
+         # Prevent this file from being sourced by child shells.
+         export __NIXOS_SET_ENVIRONMENT_DONE=1
+
          ${exportedEnvVars}
 
          ${cfg.extraInit}
diff --git a/nixos/modules/programs/bash/bash.nix b/nixos/modules/programs/bash/bash.nix
index 69a1a482d0747..7e825dcd87053 100644
--- a/nixos/modules/programs/bash/bash.nix
+++ b/nixos/modules/programs/bash/bash.nix
@@ -126,7 +126,9 @@ in
     programs.bash = {
 
       shellInit = ''
-        ${config.system.build.setEnvironment.text}
+        if [ -z "$__NIXOS_SET_ENVIRONMENT_DONE" ]; then
+          . /etc/set-environment
+        fi
 
         ${cfge.shellInit}
       '';
diff --git a/nixos/modules/programs/fish.nix b/nixos/modules/programs/fish.nix
index c8d94a47be28c..b119d96a93b26 100644
--- a/nixos/modules/programs/fish.nix
+++ b/nixos/modules/programs/fish.nix
@@ -109,7 +109,9 @@ in
       set fish_function_path ${pkgs.fish-foreign-env}/share/fish-foreign-env/functions $__fish_datadir/functions
       
       # source the NixOS environment config
-      fenv source ${config.system.build.setEnvironment}
+      if [ -z "$__NIXOS_SET_ENVIRONMENT_DONE" ]
+        fenv source /etc/set-environment
+      end
 
       # clear fish_function_path so that it will be correctly set when we return to $__fish_datadir/config.fish
       set -e fish_function_path
diff --git a/nixos/modules/programs/zsh/zsh.nix b/nixos/modules/programs/zsh/zsh.nix
index 42d4e1d4ada01..6eceb85dd2777 100644
--- a/nixos/modules/programs/zsh/zsh.nix
+++ b/nixos/modules/programs/zsh/zsh.nix
@@ -103,7 +103,9 @@ in
         if [ -n "$__ETC_ZSHENV_SOURCED" ]; then return; fi
         export __ETC_ZSHENV_SOURCED=1
 
-        ${config.system.build.setEnvironment.text}
+        if [ -z "$__NIXOS_SET_ENVIRONMENT_DONE" ]; then
+          . /etc/set-environment
+        fi
 
         ${cfge.shellInit}
 
diff --git a/nixos/modules/services/editors/emacs.nix b/nixos/modules/services/editors/emacs.nix
index ba7ec967919e7..68f9e8e22fdd5 100644
--- a/nixos/modules/services/editors/emacs.nix
+++ b/nixos/modules/services/editors/emacs.nix
@@ -87,7 +87,7 @@ in {
 
       serviceConfig = {
         Type      = "forking";
-        ExecStart = "${pkgs.bash}/bin/bash -c 'source ${config.system.build.setEnvironment}; exec ${cfg.package}/bin/emacs --daemon'";
+        ExecStart = "${pkgs.bash}/bin/bash -c 'source /etc/set-environment; exec ${cfg.package}/bin/emacs --daemon'";
         ExecStop  = "${cfg.package}/bin/emacsclient --eval (kill-emacs)";
         Restart   = "always";
       };