[url_launcher] Return false on Windows when there is no handler (flutter#5359)

Special-cases the handling of the error for "no registered handler" to return false, rather than throw, which better matches the behavior on other platforms.

Also updates Pigeon to 13 while I'm modifying the Pigeon definition.

Fixes flutter#138142

Author: stuartmorgan-g

packages/url_launcher/url_launcher_windows/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 3.1.1
 
+* Updates `launchUrl` to return false instead of throwing when there is no handler.
 * Updates minimum supported SDK version to Flutter 3.10/Dart 3.0.
 
 ## 3.1.0

packages/url_launcher/url_launcher_windows/lib/src/messages.g.dart

@@ -1,7 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-// Autogenerated from Pigeon (v10.1.2), do not edit directly.
+// Autogenerated from Pigeon (v13.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 
@@ -11,6 +11,17 @@ import 'dart:typed_data' show Float64List, Int32List, Int64List, Uint8List;
 import 'package:flutter/foundation.dart' show ReadBuffer, WriteBuffer;
 import 'package:flutter/services.dart';
 
+List<Object?> wrapResponse(
+    {Object? result, PlatformException? error, bool empty = false}) {
+  if (empty) {
+    return <Object?>[];
+  }
+  if (error == null) {
+    return <Object?>[result];
+  }
+  return <Object?>[error.code, error.message, error.details];
+}
+
 class UrlLauncherApi {
   /// Constructor for [UrlLauncherApi].  The [binaryMessenger] named argument is
   /// available for dependency injection.  If it is left null, the default
@@ -23,7 +34,8 @@ class UrlLauncherApi {
 
   Future<bool> canLaunchUrl(String arg_url) async {
     final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
-        'dev.flutter.pigeon.UrlLauncherApi.canLaunchUrl', codec,
+        'dev.flutter.pigeon.url_launcher_windows.UrlLauncherApi.canLaunchUrl',
+        codec,
         binaryMessenger: _binaryMessenger);
     final List<Object?>? replyList =
         await channel.send(<Object?>[arg_url]) as List<Object?>?;
@@ -48,9 +60,10 @@ class UrlLauncherApi {
     }
   }
 
-  Future<void> launchUrl(String arg_url) async {
+  Future<bool> launchUrl(String arg_url) async {
     final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
-        'dev.flutter.pigeon.UrlLauncherApi.launchUrl', codec,
+        'dev.flutter.pigeon.url_launcher_windows.UrlLauncherApi.launchUrl',
+        codec,
         binaryMessenger: _binaryMessenger);
     final List<Object?>? replyList =
         await channel.send(<Object?>[arg_url]) as List<Object?>?;
@@ -65,8 +78,13 @@ class UrlLauncherApi {
         message: replyList[1] as String?,
         details: replyList[2],
       );
+    } else if (replyList[0] == null) {
+      throw PlatformException(
+        code: 'null-error',
+        message: 'Host platform returned null value for non-null return value.',
+      );
     } else {
-      return;
+      return (replyList[0] as bool?)!;
     }
   }
 }

packages/url_launcher/url_launcher_windows/lib/url_launcher_windows.dart

@@ -41,9 +41,7 @@ class UrlLauncherWindows extends UrlLauncherPlatform {
     required Map<String, String> headers,
     String? webOnlyWindowName,
   }) async {
-    await _hostApi.launchUrl(url);
-    // Failure is handled via a PlatformException from `launchUrl`.
-    return true;
+    return _hostApi.launchUrl(url);
   }
 
   @override

packages/url_launcher/url_launcher_windows/pigeons/messages.dart

@@ -14,5 +14,5 @@ import 'package:pigeon/pigeon.dart';
 @HostApi(dartHostTestHandler: 'TestUrlLauncherApi')
 abstract class UrlLauncherApi {
   bool canLaunchUrl(String url);
-  void launchUrl(String url);
+  bool launchUrl(String url);
 }

packages/url_launcher/url_launcher_windows/pubspec.yaml

@@ -2,7 +2,7 @@ name: url_launcher_windows
 description: Windows implementation of the url_launcher plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/url_launcher/url_launcher_windows
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+url_launcher%22
-version: 3.1.0
+version: 3.1.1
 
 environment:
   sdk: ">=3.0.0 <4.0.0"
@@ -24,7 +24,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  pigeon: ^10.1.2
+  pigeon: ^13.0.0
   test: ^1.16.3
 
 topics:

packages/url_launcher/url_launcher_windows/test/url_launcher_windows_test.dart

@@ -47,7 +47,7 @@ void main() {
       api.canLaunch = true;
 
       expect(
-          plugin.launch(
+          await plugin.launch(
             'http://example.com/',
             useSafariVC: true,
             useWebView: false,
@@ -56,13 +56,30 @@ void main() {
             universalLinksOnly: false,
             headers: const <String, String>{},
           ),
-          completes);
+          true);
       expect(api.argument, 'http://example.com/');
     });
 
     test('handles failure', () async {
       api.canLaunch = false;
 
+      expect(
+          await plugin.launch(
+            'http://example.com/',
+            useSafariVC: true,
+            useWebView: false,
+            enableJavaScript: false,
+            enableDomStorage: false,
+            universalLinksOnly: false,
+            headers: const <String, String>{},
+          ),
+          false);
+      expect(api.argument, 'http://example.com/');
+    });
+
+    test('handles errors', () async {
+      api.throwError = true;
+
       await expectLater(
           plugin.launch(
             'http://example.com/',
@@ -122,23 +139,27 @@ class _FakeUrlLauncherApi implements UrlLauncherApi {
   /// The argument that was passed to an API call.
   String? argument;
 
-  /// Controls the behavior of the fake implementations.
+  /// Controls the behavior of the fake canLaunch implementations.
   ///
   /// - [canLaunchUrl] returns this value.
-  /// - [launchUrl] throws if this is false.
+  /// - [launchUrl] returns this value if [throwError] is false.
   bool canLaunch = false;
 
+  /// Whether to throw a platform exception.
+  bool throwError = false;
+
   @override
   Future<bool> canLaunchUrl(String url) async {
     argument = url;
     return canLaunch;
   }
 
   @override
-  Future<void> launchUrl(String url) async {
+  Future<bool> launchUrl(String url) async {
     argument = url;
-    if (!canLaunch) {
+    if (throwError) {
       throw PlatformException(code: 'Failed');
     }
+    return canLaunch;
   }
 }

packages/url_launcher/url_launcher_windows/windows/messages.g.cpp

@@ -1,7 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-// Autogenerated from Pigeon (v10.1.2), do not edit directly.
+// Autogenerated from Pigeon (v13.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 #undef _HAS_EXCEPTIONS
@@ -36,7 +36,8 @@ void UrlLauncherApi::SetUp(flutter::BinaryMessenger* binary_messenger,
                            UrlLauncherApi* api) {
   {
     auto channel = std::make_unique<BasicMessageChannel<>>(
-        binary_messenger, "dev.flutter.pigeon.UrlLauncherApi.canLaunchUrl",
+        binary_messenger,
+        "dev.flutter.pigeon.url_launcher_windows.UrlLauncherApi.canLaunchUrl",
         &GetCodec());
     if (api != nullptr) {
       channel->SetMessageHandler(
@@ -68,7 +69,8 @@ void UrlLauncherApi::SetUp(flutter::BinaryMessenger* binary_messenger,
   }
   {
     auto channel = std::make_unique<BasicMessageChannel<>>(
-        binary_messenger, "dev.flutter.pigeon.UrlLauncherApi.launchUrl",
+        binary_messenger,
+        "dev.flutter.pigeon.url_launcher_windows.UrlLauncherApi.launchUrl",
         &GetCodec());
     if (api != nullptr) {
       channel->SetMessageHandler(
@@ -82,13 +84,13 @@ void UrlLauncherApi::SetUp(flutter::BinaryMessenger* binary_messenger,
                 return;
               }
               const auto& url_arg = std::get<std::string>(encodable_url_arg);
-              std::optional<FlutterError> output = api->LaunchUrl(url_arg);
-              if (output.has_value()) {
-                reply(WrapError(output.value()));
+              ErrorOr<bool> output = api->LaunchUrl(url_arg);
+              if (output.has_error()) {
+                reply(WrapError(output.error()));
                 return;
               }
               EncodableList wrapped;
-              wrapped.push_back(EncodableValue());
+              wrapped.push_back(EncodableValue(std::move(output).TakeValue()));
               reply(EncodableValue(std::move(wrapped)));
             } catch (const std::exception& exception) {
               reply(WrapError(exception.what()));

packages/url_launcher/url_launcher_windows/windows/messages.g.h

@@ -1,7 +1,7 @@
 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-// Autogenerated from Pigeon (v10.1.2), do not edit directly.
+// Autogenerated from Pigeon (v13.0.0), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 
 #ifndef PIGEON_MESSAGES_G_H_
@@ -66,7 +66,7 @@ class UrlLauncherApi {
   UrlLauncherApi& operator=(const UrlLauncherApi&) = delete;
   virtual ~UrlLauncherApi() {}
   virtual ErrorOr<bool> CanLaunchUrl(const std::string& url) = 0;
-  virtual std::optional<FlutterError> LaunchUrl(const std::string& url) = 0;
+  virtual ErrorOr<bool> LaunchUrl(const std::string& url) = 0;
 
   // The codec used by UrlLauncherApi.
   static const flutter::StandardMessageCodec& GetCodec();

packages/url_launcher/url_launcher_windows/windows/test/url_launcher_windows_test.cpp

@@ -94,30 +94,45 @@ TEST(UrlLauncherPlugin, CanLaunchHandlesOpenFailure) {
   EXPECT_FALSE(result.value());
 }
 
-TEST(UrlLauncherPlugin, LaunchSuccess) {
+TEST(UrlLauncherPlugin, LaunchReportsSuccess) {
   std::unique_ptr<MockSystemApis> system = std::make_unique<MockSystemApis>();
 
   // Return a success value (>32) from launching.
   EXPECT_CALL(*system, ShellExecuteW)
       .WillOnce(Return(reinterpret_cast<HINSTANCE>(33)));
 
   UrlLauncherPlugin plugin(std::move(system));
-  std::optional<FlutterError> error = plugin.LaunchUrl("https://some.url.com");
+  ErrorOr<bool> result = plugin.LaunchUrl("https://some.url.com");
 
-  EXPECT_FALSE(error.has_value());
+  ASSERT_FALSE(result.has_error());
+  EXPECT_TRUE(result.value());
 }
 
 TEST(UrlLauncherPlugin, LaunchReportsFailure) {
   std::unique_ptr<MockSystemApis> system = std::make_unique<MockSystemApis>();
 
-  // Return a faile value (<=32) from launching.
+  // Return error 31 from launching, indicating no handler.
+  EXPECT_CALL(*system, ShellExecuteW)
+      .WillOnce(Return(reinterpret_cast<HINSTANCE>(SE_ERR_NOASSOC)));
+
+  UrlLauncherPlugin plugin(std::move(system));
+  ErrorOr<bool> result = plugin.LaunchUrl("https://some.url.com");
+
+  ASSERT_FALSE(result.has_error());
+  EXPECT_FALSE(result.value());
+}
+
+TEST(UrlLauncherPlugin, LaunchReportsError) {
+  std::unique_ptr<MockSystemApis> system = std::make_unique<MockSystemApis>();
+
+  // Return a failure value (<=32) from launching.
   EXPECT_CALL(*system, ShellExecuteW)
       .WillOnce(Return(reinterpret_cast<HINSTANCE>(32)));
 
   UrlLauncherPlugin plugin(std::move(system));
-  std::optional<FlutterError> error = plugin.LaunchUrl("https://some.url.com");
+  ErrorOr<bool> result = plugin.LaunchUrl("https://some.url.com");
 
-  EXPECT_TRUE(error.has_value());
+  EXPECT_TRUE(result.has_error());
 }
 
 }  // namespace test

packages/url_launcher/url_launcher_windows/windows/url_launcher_plugin.cpp

@@ -97,8 +97,7 @@ ErrorOr<bool> UrlLauncherPlugin::CanLaunchUrl(const std::string& url) {
   return has_handler;
 }
 
-std::optional<FlutterError> UrlLauncherPlugin::LaunchUrl(
-    const std::string& url) {
+ErrorOr<bool> UrlLauncherPlugin::LaunchUrl(const std::string& url) {
   std::wstring url_wide = Utf16FromUtf8(url);
 
   int status = static_cast<int>(reinterpret_cast<INT_PTR>(
@@ -107,12 +106,18 @@ std::optional<FlutterError> UrlLauncherPlugin::LaunchUrl(
 
   // Per ::ShellExecuteW documentation, anything >32 indicates success.
   if (status <= 32) {
+    if (status == SE_ERR_NOASSOC) {
+      // NOASSOC just means there's nothing registered to handle launching;
+      // return false rather than an error for better consistency with other
+      // platforms.
+      return false;
+    }
     std::ostringstream error_message;
     error_message << "Failed to open " << url << ": ShellExecute error code "
                   << status;
     return FlutterError("open_error", error_message.str());
   }
-  return std::nullopt;
+  return true;
 }
 
 }  // namespace url_launcher_windows

packages/url_launcher/url_launcher_windows/windows/url_launcher_plugin.h

@@ -34,7 +34,7 @@ class UrlLauncherPlugin : public flutter::Plugin, public UrlLauncherApi {
 
   // UrlLauncherApi:
   ErrorOr<bool> CanLaunchUrl(const std::string& url) override;
-  std::optional<FlutterError> LaunchUrl(const std::string& url) override;
+  ErrorOr<bool> LaunchUrl(const std::string& url) override;
 
  private:
   std::unique_ptr<SystemApis> system_apis_;