fix(share_plus): preserve the subject when sharing a URI on iOS

packages/share_plus/share_plus/example/ios/RunnerTests/RunnerTests.swift

@@ -1,12 +1,85 @@
 import Flutter
 import UIKit
 import XCTest
+import share_plus
 
 class RunnerTests: XCTestCase {
 
-  func testExample() {
-    // If you add code to the Runner application, consider adding tests here.
-    // See https://developer.apple.com/documentation/xctest for more information about using XCTest.
+  @MainActor
+  func testUriSharePreservesSubject() throws {
+    let controller = try shareUri(subject: "Subject for Mail")
+    XCTAssertEqual(controller.value(forKey: "subject") as? String, "Subject for Mail")
   }
 
+  @MainActor
+  func testUriShareUsesTitleBeforeLegacySubject() throws {
+    let controller = try shareUri(subject: "Legacy subject", title: "Share title")
+    XCTAssertEqual(controller.value(forKey: "subject") as? String, "Share title")
+  }
+
+  @MainActor
+  func testUriShareWithoutSubject() throws {
+    let controller = try shareUri()
+    XCTAssertNil(controller.value(forKey: "subject"))
+  }
+
+  @MainActor
+  private func shareUri(subject: String? = nil, title: String? = nil) throws
+    -> UIActivityViewController
+  {
+    let scene = try XCTUnwrap(UIApplication.shared.connectedScenes.first as? UIWindowScene)
+    let window = try XCTUnwrap(scene.windows.first(where: { $0.isKeyWindow }))
+    let previousController = window.rootViewController
+    let presenter = RecordingViewController()
+    window.rootViewController = presenter
+    defer { window.rootViewController = previousController }
+
+    let engine = RecordingEngine(name: "share-plus-subject-test")
+    let registrar = try XCTUnwrap(engine.registrar(forPlugin: "share-plus-subject-test"))
+    FPPSharePlusPlugin.register(with: registrar)
+    let handler = try XCTUnwrap(engine.recorder.handler)
+    var arguments: [String: Any] = [
+      "uri": "https://example.test/link",
+      "originX": 1.0, "originY": 1.0, "originWidth": 20.0, "originHeight": 20.0,
+    ]
+    if let subject { arguments["subject"] = subject }
+    if let title { arguments["title"] = title }
+    let call = FlutterMethodCall(methodName: "share", arguments: arguments)
+    handler(FlutterStandardMethodCodec.sharedInstance().encode(call)) { _ in
+      XCTFail("Sharing should wait for the activity to complete")
+    }
+    return try XCTUnwrap(presenter.activityController)
+  }
+}
+
+private final class RecordingEngine: FlutterEngine {
+  let recorder = RecordingMessenger()
+
+  override var binaryMessenger: FlutterBinaryMessenger { recorder }
+}
+
+private final class RecordingMessenger: NSObject, FlutterBinaryMessenger {
+  var handler: FlutterBinaryMessageHandler?
+
+  func send(onChannel channel: String, message: Data?) {}
+  func send(onChannel channel: String, message: Data?, binaryReply callback: FlutterBinaryReply?) {}
+  func cleanUpConnection(_ connection: FlutterBinaryMessengerConnection) {}
+
+  func setMessageHandlerOnChannel(
+    _ channel: String, binaryMessageHandler handler: FlutterBinaryMessageHandler?
+  ) -> FlutterBinaryMessengerConnection {
+    if channel == "dev.fluttercommunity.plus/share" { self.handler = handler }
+    return 1
+  }
+}
+
+private final class RecordingViewController: UIViewController {
+  var activityController: UIActivityViewController?
+
+  override func present(
+    _ viewControllerToPresent: UIViewController, animated flag: Bool,
+    completion: (() -> Void)? = nil
+  ) {
+    activityController = viewControllerToPresent as? UIActivityViewController
+  }
 }

packages/share_plus/share_plus/ios/share_plus/Sources/share_plus/FPPSharePlusPlugin.m

@@ -363,6 +363,7 @@ + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
 
       if (uri) {
         [self shareUri:uri
+                          subject:shareTitle
             excludedActivityTypes:excludedActivityTypes
                    withController:topViewController
                          atSource:originRect
@@ -458,13 +459,14 @@ + (void)share:(NSArray *)shareItems
 }
 
 + (void)shareUri:(NSString *)uri
+                  subject:(NSString *)subject
     excludedActivityTypes:(NSArray<UIActivityType> *)excludedActivityTypes
            withController:(UIViewController *)controller
                  atSource:(CGRect)origin
                  toResult:(FlutterResult)result {
   NSURL *data = [NSURL URLWithString:uri];
   [self share:@[ data ]
-                withSubject:nil
+                withSubject:subject
       excludedActivityTypes:excludedActivityTypes
              withController:controller
                    atSource:origin