From 540362a06c2c14e14472ccd9dad8c31863c5baed Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Wed, 3 Jun 2020 09:00:18 -0700
Subject: [PATCH 1/8] Prepare url_launcher for the Link widget

---
 .../CHANGELOG.md                              |  4 +
 .../lib/link.dart                             | 99 +++++++++++++++++++
 .../pubspec.yaml                              |  2 +-
 3 files changed, 104 insertions(+), 1 deletion(-)
 create mode 100644 packages/url_launcher/url_launcher_platform_interface/lib/link.dart

diff --git a/packages/url_launcher/url_launcher_platform_interface/CHANGELOG.md b/packages/url_launcher/url_launcher_platform_interface/CHANGELOG.md
index 768042be4cef..10057e147adf 100644
--- a/packages/url_launcher/url_launcher_platform_interface/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher_platform_interface/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.9
+
+* Laid the groundwork for introducing a Link widget.
+
 ## 1.0.8
 
 * Added webOnlyWindowName parameter
diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
new file mode 100644
index 000000000000..6df0e2c90a36
--- /dev/null
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
@@ -0,0 +1,99 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:ui';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+/// Signature for a function provided by the [Link] widget that instructs it to
+/// follow the link.
+typedef FollowLink = Future<void> Function();
+
+/// Signature for a builder function passed to the [Link] widget to construct
+/// the widget tree under it.
+typedef LinkWidgetBuilder = Widget Function(
+  BuildContext context,
+  FollowLink followLink,
+);
+
+/// Signature for a delegate function to build the [Link] widget.
+typedef LinkDelegate = Widget Function(LinkInfo linkWidget);
+
+final MethodCodec _codec = const JSONMethodCodec();
+
+/// Defines where a Link URL should be open.
+///
+/// This is a class instead of an enum to allow future customizability e.g.
+/// opening a link in a specific iframe.
+class LinkTarget {
+  /// Const private constructor with a [debugLabel] to allow the creation of
+  /// multiple distinct const instances.
+  const LinkTarget._({this.debugLabel});
+
+  /// Used to distinguish multiple const instances of [LinkTarget].
+  final String debugLabel;
+
+  /// Use the default target for each platform.
+  ///
+  /// On Android, the default is [blank]. On the web, the default is [self].
+  ///
+  /// iOS, on the other hand, defaults to [self] for web URLs, and [blank] for
+  /// non-web URLs.
+  static const defaultTarget = LinkTarget._(debugLabel: 'defaultTarget');
+
+  /// On the web, this opens the link in the same tab where the flutter app is
+  /// running.
+  ///
+  /// On Android and iOS, this opens the link in a webview within the app.
+  static const self = LinkTarget._(debugLabel: 'self');
+
+  /// On the web, this opens the link in a new tab or window (depending on the
+  /// browser and user configuration).
+  ///
+  /// On Android and iOS, this opens the link in the browser or the relevant
+  /// app.
+  static const blank = LinkTarget._(debugLabel: 'blank');
+}
+
+/// Used to override the delegate that builds the link.
+LinkDelegate linkDelegate;
+
+/// Encapsulates all the information necessary to build a Link widget.
+abstract class LinkInfo {
+  /// Called at build time to construct the widget tree under the link.
+  LinkWidgetBuilder get builder;
+
+  /// The destination that this link leads to.
+  Uri get uri;
+
+  /// The target indicating where to open the link.
+  LinkTarget get target;
+
+  /// Whether the link is disabled or not.
+  bool get isDisabled;
+}
+
+/// Pushes the [routeName] into Flutter's navigation system via a platform
+/// message.
+Future<ByteData> pushRouteNameToFramework(
+  String routeName, {
+  @required bool isUsingRouter,
+}) {
+  final MethodCall call = isUsingRouter
+      ? MethodCall('pushRouteInformation', <dynamic, dynamic>{
+          'location': routeName,
+          'state': null,
+        })
+      : MethodCall('pushRoute', routeName);
+  final Completer<ByteData> completer = Completer<ByteData>();
+  window.onPlatformMessage(
+    'flutter/navigation',
+    _codec.encodeMethodCall(call),
+    completer.complete,
+  );
+  return completer.future;
+}
diff --git a/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml b/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
index 0c4096278bcb..e10844a72bd1 100644
--- a/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
@@ -3,7 +3,7 @@ description: A common platform interface for the url_launcher plugin.
 homepage: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher_platform_interface
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 1.0.8
+version: 1.0.9
 
 dependencies:
   flutter:

From 5875f78d86c4efdff28d863a4bb869657399858a Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Thu, 15 Oct 2020 17:33:25 -0700
Subject: [PATCH 2/8] changes

---
 .../url_launcher_platform_interface/lib/link.dart     | 11 +++++------
 .../lib/method_channel_url_launcher.dart              |  4 ++++
 .../lib/url_launcher_platform_interface.dart          |  4 ++++
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
index 6df0e2c90a36..102d19a4f2c8 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
@@ -59,9 +59,6 @@ class LinkTarget {
   static const blank = LinkTarget._(debugLabel: 'blank');
 }
 
-/// Used to override the delegate that builds the link.
-LinkDelegate linkDelegate;
-
 /// Encapsulates all the information necessary to build a Link widget.
 abstract class LinkInfo {
   /// Called at build time to construct the widget tree under the link.
@@ -80,9 +77,11 @@ abstract class LinkInfo {
 /// Pushes the [routeName] into Flutter's navigation system via a platform
 /// message.
 Future<ByteData> pushRouteNameToFramework(
-  String routeName, {
-  @required bool isUsingRouter,
-}) {
+  BuildContext context,
+  String routeName,
+) {
+  final bool isUsingRouter =
+      context.findAncestorWidgetOfExactType<Router>() != null;
   final MethodCall call = isUsingRouter
       ? MethodCall('pushRouteInformation', <dynamic, dynamic>{
           'location': routeName,
diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/method_channel_url_launcher.dart b/packages/url_launcher/url_launcher_platform_interface/lib/method_channel_url_launcher.dart
index f87630ee3045..ac5bfa230289 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/method_channel_url_launcher.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/method_channel_url_launcher.dart
@@ -7,12 +7,16 @@ import 'dart:async';
 import 'package:flutter/services.dart';
 import 'package:meta/meta.dart' show required;
 
+import 'link.dart';
 import 'url_launcher_platform_interface.dart';
 
 const MethodChannel _channel = MethodChannel('plugins.flutter.io/url_launcher');
 
 /// An implementation of [UrlLauncherPlatform] that uses method channels.
 class MethodChannelUrlLauncher extends UrlLauncherPlatform {
+  @override
+  final LinkDelegate linkDelegate = null;
+
   @override
   Future<bool> canLaunch(String url) {
     return _channel.invokeMethod<bool>(
diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/url_launcher_platform_interface.dart b/packages/url_launcher/url_launcher_platform_interface/lib/url_launcher_platform_interface.dart
index 1de5742c1f6f..75002ff9eb4d 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/url_launcher_platform_interface.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/url_launcher_platform_interface.dart
@@ -6,6 +6,7 @@ import 'dart:async';
 
 import 'package:meta/meta.dart' show required;
 import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+import 'package:url_launcher_platform_interface/link.dart';
 
 import 'method_channel_url_launcher.dart';
 
@@ -38,6 +39,9 @@ abstract class UrlLauncherPlatform extends PlatformInterface {
     _instance = instance;
   }
 
+  /// The delegate used by the Link widget to build itself.
+  LinkDelegate get linkDelegate;
+
   /// Returns `true` if this platform is able to launch [url].
   Future<bool> canLaunch(String url) {
     throw UnimplementedError('canLaunch() has not been implemented.');

From 74ed33d4297f89fd64247926f724ab50d9f40384 Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Fri, 16 Oct 2020 11:26:33 -0700
Subject: [PATCH 3/8] tests

---
 .../test/link_test.dart                       | 74 +++++++++++++++++++
 .../method_channel_url_launcher_test.dart     |  5 +-
 2 files changed, 78 insertions(+), 1 deletion(-)
 create mode 100644 packages/url_launcher/url_launcher_platform_interface/test/link_test.dart

diff --git a/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart b/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
new file mode 100644
index 000000000000..0d4b5ee44849
--- /dev/null
+++ b/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
@@ -0,0 +1,74 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:ui';
+
+import 'package:mockito/mockito.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:meta/meta.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+
+import 'package:url_launcher_platform_interface/link.dart';
+import 'package:url_launcher_platform_interface/url_launcher_platform_interface.dart';
+
+final MethodCodec _codec = const JSONMethodCodec();
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  PlatformMessageCallback oldHandler;
+  MethodCall lastCall;
+
+  setUp(() {
+    oldHandler = window.onPlatformMessage;
+    window.onPlatformMessage = (String name, ByteData data, PlatformMessageResponseCallback callback) {
+      lastCall = _codec.decodeMethodCall(data);
+      callback(_codec.encodeSuccessEnvelope(true));
+    };
+  });
+
+  tearDown(() {
+    window.onPlatformMessage = oldHandler;
+  });
+
+  test('pushRouteNameToFramework() calls pushRoute when no Router', () async {
+    final CustomBuildContext context = CustomBuildContext(router: null);
+    await pushRouteNameToFramework(context, '/foo/bar');
+    expect(lastCall, isMethodCall(
+      'pushRoute',
+      arguments: '/foo/bar',
+    ));
+  });
+
+  test('pushRouteNameToFramework() calls pushRouteInformation when Router exists', () async {
+    final CustomBuildContext context = CustomBuildContext(router: CustomRouter());
+    await pushRouteNameToFramework(context, '/foo/bar');
+    expect(lastCall, isMethodCall(
+      'pushRouteInformation',
+      arguments: <dynamic, dynamic>{
+          'location': '/foo/bar',
+          'state': null,
+        },
+    ));
+  });
+}
+
+class CustomBuildContext<T> extends Mock implements BuildContext {
+  CustomBuildContext({@required this.router});
+
+  final Router<T> router;
+
+  @override
+  S findAncestorWidgetOfExactType<S extends Widget>() {
+    expect(S, Router);
+    return router as S;
+  }
+}
+
+class CustomRouter extends Mock implements Router {
+  @override
+  String toString({ DiagnosticLevel minLevel = DiagnosticLevel.info }) => '';
+}
diff --git a/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart b/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart
index 628ab48498ec..550a8faca7f1 100644
--- a/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart
@@ -286,4 +286,7 @@ class UrlLauncherPlatformMock extends Mock
 class ImplementsUrlLauncherPlatform extends Mock
     implements UrlLauncherPlatform {}
 
-class ExtendsUrlLauncherPlatform extends UrlLauncherPlatform {}
+class ExtendsUrlLauncherPlatform extends UrlLauncherPlatform {
+  @override
+  final LinkDelegate linkDelegate = null;
+}

From 5e1cc9863e444c497d68091dceb279aadb0d3bdd Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Fri, 16 Oct 2020 11:47:42 -0700
Subject: [PATCH 4/8] formatting and analysis

---
 .../lib/link.dart                             |  1 -
 .../test/link_test.dart                       | 51 ++++++++++++-------
 .../method_channel_url_launcher_test.dart     |  1 +
 3 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
index 102d19a4f2c8..5808f79b9299 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
@@ -5,7 +5,6 @@
 import 'dart:async';
 import 'dart:ui';
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
diff --git a/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart b/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
index 0d4b5ee44849..0b8a239b01f0 100644
--- a/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
@@ -9,10 +9,8 @@ import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:meta/meta.dart';
-import 'package:plugin_platform_interface/plugin_platform_interface.dart';
 
 import 'package:url_launcher_platform_interface/link.dart';
-import 'package:url_launcher_platform_interface/url_launcher_platform_interface.dart';
 
 final MethodCodec _codec = const JSONMethodCodec();
 
@@ -24,7 +22,11 @@ void main() {
 
   setUp(() {
     oldHandler = window.onPlatformMessage;
-    window.onPlatformMessage = (String name, ByteData data, PlatformMessageResponseCallback callback) {
+    window.onPlatformMessage = (
+      String name,
+      ByteData data,
+      PlatformMessageResponseCallback callback,
+    ) {
       lastCall = _codec.decodeMethodCall(data);
       callback(_codec.encodeSuccessEnvelope(true));
     };
@@ -37,23 +39,33 @@ void main() {
   test('pushRouteNameToFramework() calls pushRoute when no Router', () async {
     final CustomBuildContext context = CustomBuildContext(router: null);
     await pushRouteNameToFramework(context, '/foo/bar');
-    expect(lastCall, isMethodCall(
-      'pushRoute',
-      arguments: '/foo/bar',
-    ));
+    expect(
+      lastCall,
+      isMethodCall(
+        'pushRoute',
+        arguments: '/foo/bar',
+      ),
+    );
   });
 
-  test('pushRouteNameToFramework() calls pushRouteInformation when Router exists', () async {
-    final CustomBuildContext context = CustomBuildContext(router: CustomRouter());
-    await pushRouteNameToFramework(context, '/foo/bar');
-    expect(lastCall, isMethodCall(
-      'pushRouteInformation',
-      arguments: <dynamic, dynamic>{
-          'location': '/foo/bar',
-          'state': null,
-        },
-    ));
-  });
+  test(
+    'pushRouteNameToFramework() calls pushRouteInformation when Router exists',
+    () async {
+      final CustomBuildContext context =
+          CustomBuildContext(router: CustomRouter());
+      await pushRouteNameToFramework(context, '/foo/bar');
+      expect(
+        lastCall,
+        isMethodCall(
+          'pushRouteInformation',
+          arguments: <dynamic, dynamic>{
+            'location': '/foo/bar',
+            'state': null,
+          },
+        ),
+      );
+    },
+  );
 }
 
 class CustomBuildContext<T> extends Mock implements BuildContext {
@@ -68,7 +80,8 @@ class CustomBuildContext<T> extends Mock implements BuildContext {
   }
 }
 
+// ignore: must_be_immutable
 class CustomRouter extends Mock implements Router {
   @override
-  String toString({ DiagnosticLevel minLevel = DiagnosticLevel.info }) => '';
+  String toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) => '';
 }
diff --git a/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart b/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart
index 550a8faca7f1..d88f53ad58d0 100644
--- a/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/test/method_channel_url_launcher_test.dart
@@ -7,6 +7,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:plugin_platform_interface/plugin_platform_interface.dart';
 
+import 'package:url_launcher_platform_interface/link.dart';
 import 'package:url_launcher_platform_interface/method_channel_url_launcher.dart';
 import 'package:url_launcher_platform_interface/url_launcher_platform_interface.dart';
 

From ad4c1b1c643d14a3264df554c5f428de91ac6efb Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Sun, 18 Oct 2020 01:57:21 -0700
Subject: [PATCH 5/8] handle Router correctly

---
 .../lib/link.dart                             | 36 +++++++++++--------
 .../test/link_test.dart                       | 30 ++++------------
 2 files changed, 29 insertions(+), 37 deletions(-)

diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
index 5808f79b9299..dacfee0b9efc 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
@@ -77,21 +77,29 @@ abstract class LinkInfo {
 /// message.
 Future<ByteData> pushRouteNameToFramework(
   BuildContext context,
-  String routeName,
-) {
-  final bool isUsingRouter =
-      context.findAncestorWidgetOfExactType<Router>() != null;
-  final MethodCall call = isUsingRouter
-      ? MethodCall('pushRouteInformation', <dynamic, dynamic>{
+  String routeName, {
+  @visibleForTesting
+  bool debugForceRouter = false,
+}) {
+  final Completer<ByteData> completer = Completer<ByteData>();
+  if (debugForceRouter || Router.of(context, nullOk: true) != null) {
+    SystemNavigator.routeInformationUpdated(location: routeName);
+    window.onPlatformMessage(
+      'flutter/navigation',
+      _codec.encodeMethodCall(
+        MethodCall('pushRouteInformation', <dynamic, dynamic>{
           'location': routeName,
           'state': null,
-        })
-      : MethodCall('pushRoute', routeName);
-  final Completer<ByteData> completer = Completer<ByteData>();
-  window.onPlatformMessage(
-    'flutter/navigation',
-    _codec.encodeMethodCall(call),
-    completer.complete,
-  );
+        }),
+      ),
+      completer.complete,
+    );
+  } else {
+    window.onPlatformMessage(
+      'flutter/navigation',
+      _codec.encodeMethodCall(MethodCall('pushRoute', routeName)),
+      completer.complete,
+    );
+  }
   return completer.future;
 }
diff --git a/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart b/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
index 0b8a239b01f0..99a885ccc179 100644
--- a/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/test/link_test.dart
@@ -8,7 +8,6 @@ import 'package:mockito/mockito.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:meta/meta.dart';
 
 import 'package:url_launcher_platform_interface/link.dart';
 
@@ -37,8 +36,7 @@ void main() {
   });
 
   test('pushRouteNameToFramework() calls pushRoute when no Router', () async {
-    final CustomBuildContext context = CustomBuildContext(router: null);
-    await pushRouteNameToFramework(context, '/foo/bar');
+    await pushRouteNameToFramework(CustomBuildContext(), '/foo/bar');
     expect(
       lastCall,
       isMethodCall(
@@ -51,9 +49,11 @@ void main() {
   test(
     'pushRouteNameToFramework() calls pushRouteInformation when Router exists',
     () async {
-      final CustomBuildContext context =
-          CustomBuildContext(router: CustomRouter());
-      await pushRouteNameToFramework(context, '/foo/bar');
+      await pushRouteNameToFramework(
+        CustomBuildContext(),
+        '/foo/bar',
+        debugForceRouter: true,
+      );
       expect(
         lastCall,
         isMethodCall(
@@ -68,20 +68,4 @@ void main() {
   );
 }
 
-class CustomBuildContext<T> extends Mock implements BuildContext {
-  CustomBuildContext({@required this.router});
-
-  final Router<T> router;
-
-  @override
-  S findAncestorWidgetOfExactType<S extends Widget>() {
-    expect(S, Router);
-    return router as S;
-  }
-}
-
-// ignore: must_be_immutable
-class CustomRouter extends Mock implements Router {
-  @override
-  String toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) => '';
-}
+class CustomBuildContext<T> extends Mock implements BuildContext {}

From b26f8e65afeb38ea21a2b44963ffc1ebbb0762e2 Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Sun, 18 Oct 2020 02:29:31 -0700
Subject: [PATCH 6/8] bump min version of flutter sdk

---
 .../url_launcher/url_launcher_platform_interface/pubspec.yaml   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml b/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
index e10844a72bd1..d628699f97dc 100644
--- a/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
@@ -19,4 +19,4 @@ dev_dependencies:
 
 environment:
   sdk: ">=2.1.0 <3.0.0"
-  flutter: ">=1.9.1+hotfix.4 <2.0.0"
+  flutter: ">=1.23.0-18.0.pre <2.0.0"

From 7cea39f4483ef1372ca8dad552521c667f2bb7ff Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Sun, 18 Oct 2020 02:30:14 -0700
Subject: [PATCH 7/8] formatting

---
 .../url_launcher/url_launcher_platform_interface/lib/link.dart | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
index dacfee0b9efc..17a527802cd1 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
@@ -78,8 +78,7 @@ abstract class LinkInfo {
 Future<ByteData> pushRouteNameToFramework(
   BuildContext context,
   String routeName, {
-  @visibleForTesting
-  bool debugForceRouter = false,
+  @visibleForTesting bool debugForceRouter = false,
 }) {
   final Completer<ByteData> completer = Completer<ByteData>();
   if (debugForceRouter || Router.of(context, nullOk: true) != null) {

From 247991c90ddd72cdeace0c8bbf0582fba3389acb Mon Sep 17 00:00:00 2001
From: Mouad Debbar <mdebbar@google.com>
Date: Mon, 19 Oct 2020 10:34:13 -0700
Subject: [PATCH 8/8] version

---
 .../url_launcher_platform_interface/lib/link.dart     | 11 ++++++++++-
 .../url_launcher_platform_interface/pubspec.yaml      |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
index 17a527802cd1..425dc886d29f 100644
--- a/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
+++ b/packages/url_launcher/url_launcher_platform_interface/lib/link.dart
@@ -81,7 +81,7 @@ Future<ByteData> pushRouteNameToFramework(
   @visibleForTesting bool debugForceRouter = false,
 }) {
   final Completer<ByteData> completer = Completer<ByteData>();
-  if (debugForceRouter || Router.of(context, nullOk: true) != null) {
+  if (debugForceRouter || _hasRouter(context)) {
     SystemNavigator.routeInformationUpdated(location: routeName);
     window.onPlatformMessage(
       'flutter/navigation',
@@ -102,3 +102,12 @@ Future<ByteData> pushRouteNameToFramework(
   }
   return completer.future;
 }
+
+bool _hasRouter(BuildContext context) {
+  try {
+    return Router.of(context) != null;
+  } on AssertionError {
+    // When a `Router` can't be found, an assertion error is thrown.
+    return false;
+  }
+}
diff --git a/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml b/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
index d628699f97dc..ce0fdd936c9a 100644
--- a/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_platform_interface/pubspec.yaml
@@ -19,4 +19,4 @@ dev_dependencies:
 
 environment:
   sdk: ">=2.1.0 <3.0.0"
-  flutter: ">=1.23.0-18.0.pre <2.0.0"
+  flutter: ">=1.22.0 <2.0.0"