systemd: start enabled service on restart when idle

Port 2.0

(cherry picked from commit 5a20a8f162)

core/cmd/dms/systemd_restart.go

@@ -20,9 +20,16 @@ var runSystemctl = func(args ...string) error {
 	return err
 }
 
+// Assigned in init: shellApp's config refers back to trySystemdRestart.
+var shellRunning func() bool
+
+func init() {
+	shellRunning = func() bool { return len(shellApp.PIDs()) > 0 }
+}
+
 func trySystemdRestart() (bool, error) {
 	if err := runSystemctl("--user", "is-active", "--quiet", dmsSystemdUnit); err != nil {
-		return false, nil
+		return trySystemdStart()
 	}
 
 	if err := runSystemctl("--user", "restart", dmsSystemdUnit); err != nil {
@@ -30,3 +37,23 @@ func trySystemdRestart() (bool, error) {
 	}
 	return true, nil
 }
+
+// With nothing running, restart would spawn an unmanaged daemon that blocks
+// the unit once the session target starts it. A running hand-started
+// instance is left to the plain restart path.
+func trySystemdStart() (bool, error) {
+	if shellRunning() {
+		return false, nil
+	}
+	if err := runSystemctl("--user", "is-enabled", "--quiet", dmsSystemdUnit); err != nil {
+		return false, nil
+	}
+	if err := runSystemctl("--user", "is-active", "--quiet", "graphical-session.target"); err != nil {
+		return false, nil
+	}
+
+	if err := runSystemctl("--user", "start", dmsSystemdUnit); err != nil {
+		return true, fmt.Errorf("starting %s: %w", dmsSystemdUnit, err)
+	}
+	return true, nil
+}

core/cmd/dms/systemd_restart_test.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"errors"
+	"slices"
+	"strings"
+	"testing"
+)
+
+func TestTrySystemdRestart(t *testing.T) {
+	tests := []struct {
+		name        string
+		running     bool
+		ok          []string
+		wantHandled bool
+		wantCall    string
+	}{
+		{"active unit restarts", false, []string{"is-active dms.service", "restart"}, true, "restart dms.service"},
+		{"enabled inactive unit starts", false, []string{"is-enabled", "is-active graphical-session.target", "start"}, true, "start dms.service"},
+		{"hand-started instance keeps plain restart", true, []string{"is-enabled", "is-active graphical-session.target", "start"}, false, ""},
+		{"session target not up", false, []string{"is-enabled"}, false, ""},
+		{"unit disabled", false, []string{"is-active graphical-session.target"}, false, ""},
+		{"no systemd", false, nil, false, ""},
+	}
+
+	origSystemctl, origRunning := runSystemctl, shellRunning
+	t.Cleanup(func() { runSystemctl, shellRunning = origSystemctl, origRunning })
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			shellRunning = func() bool { return tt.running }
+			var calls []string
+			runSystemctl = func(args ...string) error {
+				call := strings.Join(slices.DeleteFunc(slices.Clone(args), func(a string) bool {
+					return strings.HasPrefix(a, "--")
+				}), " ")
+				calls = append(calls, call)
+				for _, prefix := range tt.ok {
+					if strings.HasPrefix(call, prefix) {
+						return nil
+					}
+				}
+				return errors.New("exit status 3")
+			}
+
+			handled, err := trySystemdRestart()
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if handled != tt.wantHandled {
+				t.Fatalf("handled = %v, want %v (calls %q)", handled, tt.wantHandled, calls)
+			}
+			if tt.wantCall != "" && !slices.Contains(calls, tt.wantCall) {
+				t.Fatalf("missing %q in calls %q", tt.wantCall, calls)
+			}
+			if !tt.wantHandled && slices.ContainsFunc(calls, func(c string) bool { return strings.HasPrefix(c, "start") }) {
+				t.Fatalf("unexpected start in calls %q", calls)
+			}
+		})
+	}
+}

core/go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/charmbracelet/bubbletea v1.3.10
 	github.com/charmbracelet/lipgloss v1.1.0
 	github.com/dlclark/regexp2/v2 v2.9.1
-	github.com/duxlabs-dev/dux-go v1.6.3-0.20261020163124-e2ca52bdf500
+	github.com/duxlabs-dev/dux-go v1.6.3-0.20261023041949-220eb5ff21dc
 	github.com/duxlabs-dev/dux-gop v1.6.3-0.20261020163819-0e4888f1fcea
 	github.com/fsnotify/fsnotify v1.10.1
 	github.com/go-git/go-git/v6 v6.0.0-beta.1

core/go.sum

@@ -97,8 +97,8 @@ github.com/digitalocean/go-smbios v0.0.0-20180907143718-390a4f403a8e h1:vUmf0yez
 github.com/digitalocean/go-smbios v0.0.0-20180907143718-390a4f403a8e/go.mod h1:YTIHhz/QFSYnu/EhlF2SpU2Uk+32abacUYA5ZPljz1A=
 github.com/dlclark/regexp2/v2 v2.9.1 h1:q6bZW/NN9VodqMjYXpuic2lZxdHPfFTzGS+MJxIJmKQ=
 github.com/dlclark/regexp2/v2 v2.9.1/go.mod h1:avUrQvPaLz2DrFNHJF0taWAFFX2C1GMSSoeiqFjcBmU=
-github.com/duxlabs-dev/dux-go v1.6.3-0.20261020163124-e2ca52bdf500 h1:y02m7QgoX4rwauY9HePIPGCRDJ/fMirBmgj78IkeUsc=
-github.com/duxlabs-dev/dux-go v1.6.3-0.20261020163124-e2ca52bdf500/go.mod h1:b+hBqIgOVAmlFKJ+33SY2pH4kJjXpifNeioPMxwC4Nk=
+github.com/duxlabs-dev/dux-go v1.6.3-0.20261023041949-220eb5ff21dc h1:oZhWdM7mlEevEm1zaeOeDfIMQkvtZSW8UNqrAZldbAY=
+github.com/duxlabs-dev/dux-go v1.6.3-0.20261023041949-220eb5ff21dc/go.mod h1:b+hBqIgOVAmlFKJ+33SY2pH4kJjXpifNeioPMxwC4Nk=
 github.com/duxlabs-dev/dux-gop v1.6.3-0.20261020163819-0e4888f1fcea h1:+z9uPtBmpXXBPupB6++/8avPA0weOkzAz7jBoE+yIok=
 github.com/duxlabs-dev/dux-gop v1.6.3-0.20261020163819-0e4888f1fcea/go.mod h1:IYu4GO7zR61w3+tDmjg71dQDInXe5TcP3lHQqJpZYR0=
 github.com/ebitengine/purego v0.11.2 h1:WWiTx8rD8zYdOwSj8O/NiNbsOvSAgJMTlyV1XlbUSeU=

flake.nix

@@ -111,7 +111,7 @@
               inherit version;
               pname = "dms-shell";
               src = ./core;
-              vendorHash = "sha256-fN7v7DuWaqhtD28cTr0FZUIyW7nUqhQoVuatsL2fuo4=";
+              vendorHash = "sha256-sKkafJm4PkV/gCdcwdmHVMTnlv8EO9hDk5YDxHwt9/E=";
 
               subPackages = [ "cmd/dms" ];