Declare Swift 6 language mode and document minimum requirements

README.md

@@ -21,7 +21,14 @@ Add to `ios/Runner/Info.plist` (on macOS, `macos/Runner/Info.plist` plus the Loc
 <string>Used to show your current location on the map.</string>
 ```
 
-Minimum: iOS 17, macOS 14, Dart 3.10, Flutter 3.41.
+### Minimum requirements
+
+| | |
+|---|---|
+| iOS | 17.0 |
+| macOS | 14.0 |
+| Flutter / Dart | 3.41 / 3.10 |
+| Xcode | 16+ (the native code is Swift 6 language mode — data-race safety is compiler-enforced) |
 
 ## Quick start
 

darwin/mapkit_flutter.podspec

@@ -21,11 +21,14 @@ and modern MapKit configurations.
 
   s.ios.deployment_target = '17.0'
   s.osx.deployment_target = '14.0'
-  s.swift_version = '5.0'
+  # Swift 6 language mode: data-race safety enforced by the compiler, not a
+  # flag stack (subsumes the old -strict-concurrency=complete). Needs
+  # Xcode 16+, already below Flutter's own minimum.
+  s.swift_version = '6.0'
 
   s.pod_target_xcconfig = {
     'DEFINES_MODULE' => 'YES',
-    'SWIFT_VERSION' => '5.0',
-    'OTHER_SWIFT_FLAGS' => '-warnings-as-errors -strict-concurrency=complete'
+    'SWIFT_VERSION' => '6.0',
+    'OTHER_SWIFT_FLAGS' => '-warnings-as-errors'
   }
 end

darwin/mapkit_flutter/Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.9
+// swift-tools-version: 6.0
 import PackageDescription
 
 let package = Package(
@@ -12,6 +12,8 @@ let package = Package(
     .library(name: "mapkit-flutter", targets: ["mapkit_flutter"])
   ],
   targets: [
+    // swiftLanguageMode defaults to v6 under tools 6.0 — data-race safety is
+    // compiler-enforced, matching the podspec's swift_version = '6.0'.
     .target(name: "mapkit_flutter")
   ]
 )

darwin/mapkit_flutter/Sources/mapkit_flutter/MapView/MapKitViewHost.swift

@@ -164,9 +164,8 @@ public class MapKitViewHost: NSObject, @preconcurrency MapKitHostApi {
         #if os(iOS)
         let coord = coordinate.clCoordinate
         Task { @MainActor in
-            let request = MKLookAroundSceneRequest(coordinate: coord)
             do {
-                guard let scene = try await request.scene else {
+                guard let scene = try await Self.requestLookAroundScene(at: coord) else {
                     completion(.success(false))
                     return
                 }
@@ -193,6 +192,18 @@ public class MapKitViewHost: NSObject, @preconcurrency MapKitHostApi {
         #endif
     }
 
+    #if os(iOS)
+    /// Runs the scene request off the main actor and hands the result back
+    /// with `sending`: older SDKs don't mark `MKLookAroundScene` Sendable, so
+    /// awaiting `request.scene` directly from `@MainActor` fails to compile
+    /// there. Region isolation proves the fresh scene is safe to move.
+    private nonisolated static func requestLookAroundScene(
+        at coordinate: CLLocationCoordinate2D
+    ) async throws -> sending MKLookAroundScene? {
+        try await MKLookAroundSceneRequest(coordinate: coordinate).scene
+    }
+    #endif
+
     func addTileOverlay(overlay overlayData: PlatformTileOverlay) throws {
         let overlay = FlutterTileOverlay(fromPlatform: overlayData)
         if !overlay.id.isEmpty, tileOverlays[overlay.id] != nil {
@@ -293,22 +304,25 @@ extension MapKitViewHost: MKMapViewDelegate {
 
 extension MapKitViewHost {
     private func takeSnapshot(options: PlatformSnapshotOptions) async throws -> FlutterStandardTypedData? {
+        // Caller-side options exist only for `size`/`mapRect` in the
+        // compositing pass below; the snapshotter gets its own copy off-actor.
         let snapshotOptions = MKMapSnapshotter.Options()
         snapshotOptions.region = self.mapView.region
         snapshotOptions.size = self.mapView.frame.size
+
         #if os(iOS)
-        // Unspecified traits report displayScale == 0; leaving `scale` unset
-        // falls back to MapKit's main-screen default.
+        // Unspecified traits report displayScale == 0; 0 leaves `scale` unset
+        // so MapKit falls back to its main-screen default.
         let displayScale = self.mapView.traitCollection.displayScale
-        if displayScale > 0 {
-            snapshotOptions.scale = displayScale
-        }
+        #else
+        let displayScale: CGFloat = 0
         #endif
-        snapshotOptions.showsBuildings = options.showsBuildings
-        snapshotOptions.pointOfInterestFilter = options.showsPointsOfInterest ? .includingAll : .excludingAll
-
-        let snapshotter = MKMapSnapshotter(options: snapshotOptions)
-        let snapshot = try await snapshotter.start()
+        let snapshot = try await Self.takeSnapshot(
+            region: snapshotOptions.region,
+            size: snapshotOptions.size,
+            scale: displayScale,
+            showsBuildings: options.showsBuildings,
+            showsPointsOfInterest: options.showsPointsOfInterest)
 
         #if os(iOS)
         let image = UIGraphicsImageRenderer(size: snapshotOptions.size).image { context in
@@ -340,6 +354,32 @@ extension MapKitViewHost {
         return FlutterStandardTypedData(bytes: imageData)
     }
 
+    /// Runs the snapshotter off the main actor and hands the result back with
+    /// `sending`: older SDKs don't mark `MKMapSnapshotter.Snapshot` Sendable,
+    /// so awaiting `start()` directly from `@MainActor` fails to compile
+    /// there. Only Sendable value types cross in; the options and snapshotter
+    /// live entirely in this disconnected region, so the fresh snapshot is
+    /// provably safe to move out.
+    private nonisolated static func takeSnapshot(
+        region: MKCoordinateRegion,
+        size: CGSize,
+        scale: CGFloat,
+        showsBuildings: Bool,
+        showsPointsOfInterest: Bool
+    ) async throws -> sending MKMapSnapshotter.Snapshot {
+        let options = MKMapSnapshotter.Options()
+        options.region = region
+        options.size = size
+        #if os(iOS)
+        if scale > 0 {
+            options.scale = scale
+        }
+        #endif
+        options.showsBuildings = showsBuildings
+        options.pointOfInterestFilter = showsPointsOfInterest ? .includingAll : .excludingAll
+        return try await MKMapSnapshotter(options: options).start()
+    }
+
     #if os(iOS)
     private func drawAnnotations(annotation: FlutterAnnotation, point: CGPoint) {
         let annotationView = self.getAnnotationView(annotation: annotation)