Fix systemd service restart

tests/runtime_restart.rs

@@ -124,6 +124,29 @@ fn public_restart_preview_and_cancel_preserve_draft_and_saved_files() {
     assert_eq!(app.states().applied(), &RuntimeObservation::Unknown);
 }
 
+#[test]
+fn public_restart_preview_accepts_metadata_free_ipv4_and_broader_legacy_routes() {
+    let fixture = fixture("wg-quick@wg0.service", 30);
+    let server_path = fixture._root.path().join("server.conf");
+    let mut server = fs::read(&server_path).expect("synthetic server config reads");
+    server.extend_from_slice(
+        b"\n[Peer]\nPublicKey = AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=\nAllowedIPs = 10.20.0.19/32\n\n[Peer]\nPublicKey = AQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQE=\nAllowedIPs = 192.0.2.0/24, 2001:db8::/48\n",
+    );
+    fs::write(&server_path, &server).expect("install synthetic legacy peers");
+    let app = Application::open_from_saved_store(fixture.store.clone())
+        .expect("open metadata-free legacy peers");
+
+    let preview = app.preview_restart().expect("valid routes are restartable");
+
+    assert_eq!(preview.interface(), "wg0");
+    assert_eq!(preview.systemd_unit(), "wg-quick@wg0.service");
+    assert_eq!(
+        fs::read(server_path).expect("server config remains readable"),
+        server
+    );
+    assert!(app.list_backups().expect("preview is read-only").is_empty());
+}
+
 #[test]
 fn restore_changes_the_settings_used_by_the_next_restart_preview() {
     let fixture = fixture("wg-quick@wg0.service", 30);