fix(flight-planner): refresh stale home from vehicle (#29)

* fix(flight-planner): refresh home on plan activation

* test(flight-planner): cover vehicle home synchronization

* docs(porting): record planner home sync handoff

Author: obazna

MissionPlannerTests/Avalonia/MissionPlanner.Tests/FlightPlannerHomeSyncTests.cs

@@ -0,0 +1,118 @@
+using Avalonia.Headless.XUnit;
+using MissionPlanner.Utilities;
+using MissionPlanner.ViewModels;
+
+namespace MissionPlanner.Tests;
+
+[CollectionDefinition(Name, DisableParallelization = true)]
+public sealed class FlightPlannerHomeSyncCollection {
+  public const string Name = "Flight Planner home synchronization";
+}
+
+[Collection(FlightPlannerHomeSyncCollection.Name)]
+public class FlightPlannerHomeSyncTests {
+  [Fact]
+  public void Reported_home_replaces_saved_home() {
+    using var scope = new PlannerScope();
+    FlightPlannerViewModel vm = scope.ViewModel;
+    SetSanFranciscoHome(vm);
+
+    vm.RefreshHomeFromVehicle(
+        new PointLatLngAlt(50.344417763, 30.89499303, 132),
+        new PointLatLngAlt(-35.363261, 149.165230, 584));
+
+    Assert.Equal(50.344417763, vm.HomeLat, 8);
+    Assert.Equal(30.89499303, vm.HomeLng, 8);
+    Assert.Equal(132, vm.HomeAlt, 6);
+  }
+
+  [Fact]
+  public void Planner_home_refresh_falls_back_to_planned_home() {
+    using var scope = new PlannerScope();
+    FlightPlannerViewModel vm = scope.ViewModel;
+
+    vm.RefreshHomeFromVehicle(
+        new PointLatLngAlt(),
+        new PointLatLngAlt(50.344417763, 30.89499303, 132));
+
+    Assert.Equal(50.344417763, vm.HomeLat, 8);
+    Assert.Equal(30.89499303, vm.HomeLng, 8);
+    Assert.Equal(132, vm.HomeAlt, 6);
+  }
+
+  [Fact]
+  public void Planner_home_refresh_keeps_saved_home_without_vehicle_coordinates() {
+    using var scope = new PlannerScope();
+    FlightPlannerViewModel vm = scope.ViewModel;
+    SetSanFranciscoHome(vm);
+
+    vm.RefreshHomeFromVehicle(new PointLatLngAlt(), new PointLatLngAlt());
+
+    Assert.Equal(37.619373, vm.HomeLat, 8);
+    Assert.Equal(-122.376637, vm.HomeLng, 8);
+    Assert.Equal(5.28, vm.HomeAlt, 6);
+  }
+
+  [AvaloniaFact]
+  public async Task Navigating_to_plan_refreshes_stale_home_from_vehicle() {
+    CurrentState state = AppState.comPort.MAV.cs;
+    PointLatLngAlt previousReportedHome = state.HomeLocation;
+    PointLatLngAlt previousPlannedHome = state.PlannedHomeLocation;
+    var shell = new MainWindowViewModel();
+    var savedPlannerHome = (
+        shell.FlightPlanner.HomeLat,
+        shell.FlightPlanner.HomeLng,
+        shell.FlightPlanner.HomeAlt);
+    try {
+      SetSanFranciscoHome(shell.FlightPlanner);
+      state.HomeLocation = new PointLatLngAlt(50.344417763, 30.89499303, 132);
+      state.PlannedHomeLocation = new PointLatLngAlt(-35.363261, 149.165230, 584);
+
+      await shell.NavigateCommand.ExecuteAsync("PLAN");
+
+      Assert.IsType<FlightPlannerViewModel>(shell.CurrentScreen);
+      Assert.Equal(50.344417763, shell.FlightPlanner.HomeLat, 8);
+      Assert.Equal(30.89499303, shell.FlightPlanner.HomeLng, 8);
+      Assert.Equal(132, shell.FlightPlanner.HomeAlt, 6);
+
+      state.HomeLocation = new PointLatLngAlt(-35.363261, 149.165230, 584);
+
+      await shell.NavigateCommand.ExecuteAsync("PLAN");
+
+      Assert.Equal(-35.363261, shell.FlightPlanner.HomeLat, 8);
+      Assert.Equal(149.165230, shell.FlightPlanner.HomeLng, 8);
+      Assert.Equal(584, shell.FlightPlanner.HomeAlt, 6);
+    } finally {
+      state.HomeLocation = previousReportedHome;
+      state.PlannedHomeLocation = previousPlannedHome;
+      shell.FlightPlanner.HomeLat = savedPlannerHome.HomeLat;
+      shell.FlightPlanner.HomeLng = savedPlannerHome.HomeLng;
+      shell.FlightPlanner.HomeAlt = savedPlannerHome.HomeAlt;
+      shell.Dispose();
+    }
+  }
+
+  private static void SetSanFranciscoHome(FlightPlannerViewModel vm) {
+    vm.HomeLat = 37.619373;
+    vm.HomeLng = -122.376637;
+    vm.HomeAlt = 5.28;
+  }
+
+  private sealed class PlannerScope : IDisposable {
+    private readonly (double Lat, double Lng, double Alt) _savedHome;
+
+    public PlannerScope() {
+      ViewModel = new FlightPlannerViewModel();
+      _savedHome = (ViewModel.HomeLat, ViewModel.HomeLng, ViewModel.HomeAlt);
+    }
+
+    public FlightPlannerViewModel ViewModel { get; }
+
+    public void Dispose() {
+      ViewModel.HomeLat = _savedHome.Lat;
+      ViewModel.HomeLng = _savedHome.Lng;
+      ViewModel.HomeAlt = _savedHome.Alt;
+      ViewModel.Dispose();
+    }
+  }
+}

Porting/STATUS.md

@@ -2,6 +2,34 @@
 
 Updated: **2026-08-31**.
 
+## Flight Planner vehicle-home synchronization
+
+- Dedicated branch `fix/flight-planner-vehicle-home-sync` starts from merged `master`
+  `f02eefd87`. Commit `279db6eab` refreshes Flight Planner home state whenever PLAN is selected or
+  reselected; commit `d7132c4d0` adds the isolated helper and shell-navigation regressions. The
+  comparison source is official `ArduPilot/MissionPlanner` commit `2b5589f40`.
+- The persisted `TXT_homelat`/`TXT_homelng` values could remain at an earlier planning site after a
+  different vehicle connected. Adding enough local waypoints then correctly drew the official
+  `last -> home -> first` route, but against that stale home. PLAN activation now prefers the
+  autopilot-reported `HomeLocation`, falls back to `PlannedHomeLocation`, and retains the saved
+  planner home only when neither vehicle coordinate is valid. Route construction and its solid or
+  dashed styling are unchanged.
+- The focused `FlightPlannerHomeSyncTests` pass **4/4**, `PlannerPortParityTests` pass **59/59**,
+  and `dotnet build MissionPlanner.csproj -c Release -m:1 --no-restore` succeeds with **0 warnings /
+  0 errors**. The complete Avalonia suite ran **1562** cases: **1561 passed** and only the existing
+  environment-sensitive `VideoSourceResolverTests.NormalizesCommonStreamSources` `/dev/video0`
+  case failed; neither the resolver nor its test changes on this branch.
+- Behavior, integration and test reviewers approve the implementation and test tuple `279db6eab`
+  + `d7132c4d0`. The worktree still contains only the user's five pre-existing modifications in
+  `Drivers/inf2cat.bat`, `Drivers/uninstall_drivers.bat`,
+  `ExtLibs/Mavlink/regenerate.bat`, `ExtLibs/Mavlink/updatexmls.bat` and `graphs/updatexmls.bat`;
+  none is staged or included. Claude remains disabled.
+- No code or test blocker remains. The screenshot process loaded the older `7de82f8a`, so manual
+  acceptance requires rebuilding and relaunching this branch: connect a vehicle whose reported
+  home differs from the saved planner home, select and reselect PLAN, confirm the Home Location
+  fields follow the vehicle home, then add local waypoints and confirm the closing route remains
+  local. The separately observed Flight Data bearing-axis zoom behavior remains excluded.
+
 ## Flight Planner waypoint viewport stability
 
 - Dedicated branch `fix/flight-planner-waypoint-viewport-stability` starts from merged `master`

ViewModels/FlightPlannerViewModel.cs

@@ -21,7 +21,7 @@
 
 namespace MissionPlanner.ViewModels;
 
-public partial class FlightPlannerViewModel : ViewModelBase, IDisposable {
+public partial class FlightPlannerViewModel : ViewModelBase, IActivationAware, IDisposable {
   private MAVLinkInterface _comPort => AppState.comPort;
   private bool _recomputing;
   private bool _restoringUndo;
@@ -70,6 +70,29 @@ private void OnConnectionChanged() => Dispatcher.UIThread.Post(() => {
     OnPropertyChanged(nameof(VehicleFirmware));
   });
 
+  public void Activate() => RefreshHomeFromVehicle(
+      _comPort.MAV.cs.HomeLocation, _comPort.MAV.cs.PlannedHomeLocation);
+
+  internal void RefreshHomeFromVehicle(PointLatLngAlt? reportedHome,
+      PointLatLngAlt? plannedHome) {
+    PointLatLngAlt? home = IsValidHome(reportedHome)
+        ? reportedHome
+        : IsValidHome(plannedHome) ? plannedHome : null;
+    if (home == null) {
+      return;
+    }
+
+    HomeLat = home.Lat;
+    HomeLng = home.Lng;
+    HomeAlt = home.Alt;
+  }
+
+  private static bool IsValidHome(PointLatLngAlt? home) => home != null
+      && double.IsFinite(home.Lat) && home.Lat is >= -90 and <= 90
+      && double.IsFinite(home.Lng) && home.Lng is >= -180 and <= 180
+      && double.IsFinite(home.Alt)
+      && (home.Lat != 0 || home.Lng != 0);
+
   private void RefreshDisplayView() {
     var profile = Services.DisplayViewService.Current;
     ShowVerifyHeight = profile.displayCheckHeightBox;

ViewModels/MainWindowViewModel.cs

@@ -212,6 +212,9 @@ private async System.Threading.Tasks.Task Navigate(string target) {
       }
       CurrentScreen = nextScreen;
     }
+    if (nextScreen is IActivationAware activation) {
+      activation.Activate();
+    }
   }
 
   [RelayCommand]