`ImplicitBackButton` misbehaves when Dialogs are shown

[btrautmann]

I'm making use of ImplicitBackButton in perhaps an unexpected way in that in my "flows" (flows are defined as parts of the Widget tree that contain their own ImplicitNavigator that manages 1...N screens), I have a Scaffold whose body consists of a Column that contains a Row which acts an as AppBar (without being an AppBar):

Row(
  children: [
    const ImplicitNavigatorBackButton(),
    Text(
      'Fix details',
      style: Theme.of(context).textTheme.headlineSmall,
    ),
  ],
)

The other item in the Column is an Expanded containing the ImplicitNavigator. This allows me to use the header row across all screens in the flow.

However, I noticed that when showing Dialogs in a flow like this one, ImplicitNavigatorBackButton disappears when the Dialog is shown (see video):

Simulator.Screen.Recording.-.iPhone.14.Pro.Max.-.2023-05-30.at.18.14.10.mp4

I've looked at that code before and I know it does some introspection on the Widget tree, so I suspect the displaying of the dialog is just throwing that introspection logic off.

Directly before the Dialog is shown, the tree looks like this (reminder: FixDetailsFlow uses the structure outlined above):

Once shown, it looks like:

As shown in the video above, the back behavior, even once the button is shown again, takes a few tappy taps to start working again 🙃

Library version:

  implicit_navigator:
    dependency: "direct main"
    description:
      name: implicit_navigator
      sha256: "661e359bd119a6ac1d69f7079096a7b0298b7140b441f256f8fa69cd01a1faad"
      url: "https://pub.dev"
    source: hosted
    version: "1.4.0"

Flutter version:

Flutter 3.10.0-12.0.pre.26 • channel master • https://github.com/flutter/flutter.git
Framework • revision d2646cf87d (6 weeks ago) • 2023-04-21 23:06:17 -0400
Engine • revision b6749106a4
Tools • Dart 3.1.0 (build 3.1.0-30.0.dev) • DevTools 2.23.1

[btrautmann]

Update: Doesn't look like this happens in situations where we don't have nested ImplicitNavigators. In a screen on the root ImplicitNavigator, the button behaves just fine when dialogs are shown.