从原生页面跳转到Flutter页面A，再到Flutter页面B，B返回到A，A再返回时依然报错

[tianyingzhong]

[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: 'package:flutter/src/widgets/routes.dart': Failed assertion: line 1261 pos 12: 'scope != null': is not true.
#0 _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:42:39)
#1 _AssertionError._throwNew (dart:core-patch/errors_patch.dart:38:5)
#2 ModalRoute.willPop (package:flutter/src/widgets/routes.dart:1261:12)
#3 BoostContainerState.maybePop (package:flutter_boost/container/boost_container.dart:185:57)
#4 BoostContainerState.initState. (package:flutter_boost/container/boost_container.dart:163:32)
#5 BoostContainerState.performBackPressed (package:flutter_boost/container/boost_container.dart:175:25)
#6 ContainerCoordinator._onChannelEvent (package:flutter_boost/container/container_coordinator.dart:118:17)
#7 new ContainerCoordinator. (package:flutter_boost/container/container_coordinator.dart:44:13)
#8 new BoostChannel. (package:flutter_boost/channel/boost_channel.dart:46:14)
#9 MethodChannel._handleAsMethodCall (package:flutter/src/services/platform_channel.dart:409:55)
#10 MethodChannel.setMethodCallHandler. (package:flutter/src/services/platform_channel.dart:377:54)
#11 _DefaultBinaryMessenger.handlePlatformMessage (package:flutter/src/services/binding.dart:199:33)
#12 _invoke3. (dart:ui/hooks.dart:290:15)
#13 _rootRun (dart:async/zone.dart:1184:13)
#14 _CustomZone.run (dart:async/zone.dart:1077:19)
#15 _CustomZone.runGuarded (dart:async/zone.dart:979:7)
#16 _invoke3 (dart:ui/hooks.dart:289:10)
#17 _dispatchPlatformMessage (dart:ui/hooks.dart:164:5)

场景是：
从原生页面跳转到Flutter页面A，A进入页面B，B返回A，A页面按返回键报以上错误
说明一下，A页面在调用网络接口的时候使用了加载框，接口结束后有关闭加载框。

[tianyingzhong]

我试了把 assert(scope != null); 注释了，就可以正常返回了，加这个是为了干什么呢？

@OverRide
Future willPop() async {
final _ModalScopeState scope = _scopeKey.currentState;
// assert(scope != null);
for (final WillPopCallback callback in List.from(_willPopCallbacks)) {
if (!await callback())
return RoutePopDisposition.doNotPop;
}
return await super.willPop();
}

[bailiangjin]

同样遇到了该问题

[nightfallsad]

[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: 'package:flutter/src/widgets/routes.dart': Failed assertion: line 1261 pos 12: 'scope != null': is not true.
#0 _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:42:39)
#1 _AssertionError._throwNew (dart:core-patch/errors_patch.dart:38:5)
#2 ModalRoute.willPop (package:flutter/src/widgets/routes.dart:1261:12)
#3 BoostContainerState.maybePop (package:flutter_boost/container/boost_container.dart:185:57)
#4 BoostContainerState.initState. (package:flutter_boost/container/boost_container.dart:163:32)
#5 BoostContainerState.performBackPressed (package:flutter_boost/container/boost_container.dart:175:25)
#6 ContainerCoordinator._onChannelEvent (package:flutter_boost/container/container_coordinator.dart:118:17)
#7 new ContainerCoordinator. (package:flutter_boost/container/container_coordinator.dart:44:13)
#8 new BoostChannel. (package:flutter_boost/channel/boost_channel.dart:46:14)
#9 MethodChannel._handleAsMethodCall (package:flutter/src/services/platform_channel.dart:409:55)
#10 MethodChannel.setMethodCallHandler. (package:flutter/src/services/platform_channel.dart:377:54)
#11 _DefaultBinaryMessenger.handlePlatformMessage (package:flutter/src/services/binding.dart:199:33)
#12 _invoke3. (dart:ui/hooks.dart:290:15)
#13 _rootRun (dart:async/zone.dart:1184:13)
#14 _CustomZone.run (dart:async/zone.dart:1077:19)
#15 _CustomZone.runGuarded (dart:async/zone.dart:979:7)
#16 _invoke3 (dart:ui/hooks.dart:289:10)
#17 _dispatchPlatformMessage (dart:ui/hooks.dart:164:5)

场景是：
从原生页面跳转到Flutter页面A，A进入页面B，B返回A，A页面按返回键报以上错误
说明一下，A页面在调用网络接口的时候使用了加载框，接口结束后有关闭加载框。

发下flutter和boost版本

[nightfallsad]

[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: 'package:flutter/src/widgets/routes.dart': Failed assertion: line 1261 pos 12: 'scope != null': is not true.
#0 _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:42:39)
#1 _AssertionError._throwNew (dart:core-patch/errors_patch.dart:38:5)
#2 ModalRoute.willPop (package:flutter/src/widgets/routes.dart:1261:12)
#3 BoostContainerState.maybePop (package:flutter_boost/container/boost_container.dart:185:57)
#4 BoostContainerState.initState. (package:flutter_boost/container/boost_container.dart:163:32)
#5 BoostContainerState.performBackPressed (package:flutter_boost/container/boost_container.dart:175:25)
#6 ContainerCoordinator._onChannelEvent (package:flutter_boost/container/container_coordinator.dart:118:17)
#7 new ContainerCoordinator. (package:flutter_boost/container/container_coordinator.dart:44:13)
#8 new BoostChannel. (package:flutter_boost/channel/boost_channel.dart:46:14)
#9 MethodChannel._handleAsMethodCall (package:flutter/src/services/platform_channel.dart:409:55)
#10 MethodChannel.setMethodCallHandler. (package:flutter/src/services/platform_channel.dart:377:54)
#11 _DefaultBinaryMessenger.handlePlatformMessage (package:flutter/src/services/binding.dart:199:33)
#12 _invoke3. (dart:ui/hooks.dart:290:15)
#13 _rootRun (dart:async/zone.dart:1184:13)
#14 _CustomZone.run (dart:async/zone.dart:1077:19)
#15 _CustomZone.runGuarded (dart:async/zone.dart:979:7)
#16 _invoke3 (dart:ui/hooks.dart:289:10)
#17 _dispatchPlatformMessage (dart:ui/hooks.dart:164:5)

场景是：
从原生页面跳转到Flutter页面A，A进入页面B，B返回A，A页面按返回键报以上错误
说明一下，A页面在调用网络接口的时候使用了加载框，接口结束后有关闭加载框。

1.17.1-hotfixes分支已经提交了commit，稍后merge到1.22.4-hotfix分支