Merge pull request #45784 from oxij/pull/44720-shell-env-edited

nixos/shells: Avoid overriding the environment for other child shells

nixos/modules/config/shells-environment.nix

@@ -163,8 +163,17 @@ in
         /bin/sh
       '';
 
+    # For resetting environment with `. /etc/set-environment` when needed
+    # and discoverability (see motivation of #30418).
+    environment.etc."set-environment".source = config.system.build.setEnvironment;
+
     system.build.setEnvironment = pkgs.writeText "set-environment"
       ''
+        # 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}

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
+            . ${config.system.build.setEnvironment}
+        fi
 
         ${cfge.shellInit}
       '';

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
+      if [ -z "$__NIXOS_SET_ENVIRONMENT_DONE" ]
           fenv source ${config.system.build.setEnvironment}
+      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
@@ -150,7 +152,6 @@ in
       and begin
         ${fishAliases}
 
-
         set fish_function_path ${pkgs.fish-foreign-env}/share/fish-foreign-env/functions $fish_function_path
         fenv source /etc/fish/foreign-env/interactiveShellInit > /dev/null
         set -e fish_function_path[1]

nixos/modules/programs/zsh/zsh.nix

@@ -116,7 +116,9 @@ 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
+            . ${config.system.build.setEnvironment}
+        fi
 
         ${cfge.shellInit}