amend! assert previous behaviour

nixos/systemd-user: enable systemd-tmpfiles-clean.timer

Set systemd.user.timers.systemd-tmpfiles-clean.wantedBy when any user tmpfiles
rules are set so NixOS knows to enable the unit.

Author: schnusch

nixos/modules/system/boot/systemd/user.nix

@@ -12,6 +12,9 @@ with lib;
 let
   cfg = config.systemd.user;
 
+  hasTmpfiles =
+    cfg.tmpfiles.rules != [ ] || any (cfg': cfg'.rules != [ ]) (attrValues cfg.tmpfiles.users);
+
   systemd = config.systemd.package;
 
   inherit (systemdUtils.lib)
@@ -209,11 +212,16 @@ in
       // mapAttrs' (n: v: nameValuePair "${n}.target" (targetToUnit v)) cfg.targets
       // mapAttrs' (n: v: nameValuePair "${n}.timer" (timerToUnit v)) cfg.timers;
 
-    # Generate timer units for all services that have a ‘startAt’ value.
-    systemd.user.timers = mapAttrs (name: service: {
-      wantedBy = [ "timers.target" ];
-      timerConfig.OnCalendar = service.startAt;
-    }) (filterAttrs (name: service: service.startAt != [ ]) cfg.services);
+    systemd.user.timers =
+      {
+        # enable systemd user tmpfiles
+        systemd-tmpfiles-clean.wantedBy = optional hasTmpfiles "timers.target";
+      }
+      # Generate timer units for all services that have a ‘startAt’ value.
+      // (mapAttrs (name: service: {
+        wantedBy = [ "timers.target" ];
+        timerConfig.OnCalendar = service.startAt;
+      }) (filterAttrs (name: service: service.startAt != [ ]) cfg.services));
 
     # Provide the systemd-user PAM service, required to run systemd
     # user instances.
@@ -232,9 +240,7 @@ in
     systemd.services.systemd-user-sessions.restartIfChanged = false; # Restart kills all active sessions.
 
     # enable systemd user tmpfiles
-    systemd.user.services.systemd-tmpfiles-setup.wantedBy = optional (
-      cfg.tmpfiles.rules != [ ] || any (cfg': cfg'.rules != [ ]) (attrValues cfg.tmpfiles.users)
-    ) "basic.target";
+    systemd.user.services.systemd-tmpfiles-setup.wantedBy = optional hasTmpfiles "basic.target";
 
     # /run/current-system/sw/etc/xdg is in systemd's $XDG_CONFIG_DIRS so we can
     # write the tmpfiles.d rules for everyone there

nixos/tests/systemd-user-tmpfiles-rules.nix

@@ -7,62 +7,36 @@ import ./make-test-python.nix (
       maintainers = [ schnusch ];
     };
 
-    nodes = {
-      machine =
-        { ... }:
-        {
-          users.users = {
-            alice.isNormalUser = true;
-            bob.isNormalUser = true;
-          };
-
-          systemd.user.tmpfiles = {
-            rules = [
-              "d %h/user_tmpfiles_created"
-            ];
-            users.alice.rules = [
-              "d %h/only_alice"
-            ];
-            users.bob.rules = [
-              "D %h/cleaned_up - - - 0"
-            ];
-          };
-
-          # run every 10 seconds
-          systemd.user.timers.systemd-tmpfiles-clean = {
-            wantedBy = [ "timers.target" ];
-            timerConfig = {
-              OnStartupSec = "10s";
-              OnUnitActiveSec = "10s";
-            };
-          };
+    nodes.machine =
+      { ... }:
+      {
+        users.users = {
+          alice.isNormalUser = true;
+          bob.isNormalUser = true;
         };
 
-      default =
-        { ... }:
-        {
-          users.users = {
-            alice.isNormalUser = true;
-          };
+        systemd.user.tmpfiles = {
+          rules = [
+            "d %h/user_tmpfiles_created"
+          ];
+          users.alice.rules = [
+            "d %h/only_alice"
+          ];
+          users.bob.rules = [
+            "D %h/cleaned_up - - - 0"
+          ];
+        };
 
-          systemd.user.tmpfiles = {
-            rules = [
-              "d %h/user_tmpfiles_created"
-            ];
-          };
+        # run every 10 seconds
+        systemd.user.timers.systemd-tmpfiles-clean.timerConfig = {
+          OnStartupSec = "10s";
+          OnUnitActiveSec = "10s";
         };
-    };
+      };
 
     testScript =
       { ... }:
       ''
-        # Test if `systemd-tmpfiles-clean.timer` is not enabled if we do not change
-        # anything below `systemd.user.timers.systemd-tmpfiles-clean`.
-        default.succeed("loginctl enable-linger alice")
-        default.wait_until_succeeds("systemctl --user --machine=alice@ is-active systemd-tmpfiles-setup.service")
-        default.fail("systemctl --user --machine=alice@ is-active systemd-tmpfiles-clean.timer")
-
-        # test user-tmpfiles.d
         machine.succeed("loginctl enable-linger alice bob")
 
         machine.wait_until_succeeds("systemctl --user --machine=alice@ is-active systemd-tmpfiles-setup.service")
@@ -74,11 +48,6 @@ import ./make-test-python.nix (
         machine.succeed("[ ! -e ~bob/only_alice ]")
 
         machine.succeed("systemctl --user --machine=bob@ is-active systemd-tmpfiles-clean.timer")
-        machine.succeed(
-            # we cannot combine `--machine=bob@` and `cat`
-            # runuser -l does not set $XDG_RUNTIME_DIR
-            'runuser -u bob -- env XDG_RUNTIME_DIR="/run/user/$(id -u bob)" systemctl --user cat systemd-tmpfiles-clean.timer >&2'
-        )
         machine.succeed("runuser -u bob -- touch ~bob/cleaned_up/file")
         machine.wait_until_fails("[ -e ~bob/cleaned_up/file ]")
       '';