Flutter: find non-nearest ancestor of given type

main.dart

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Material(
        child: Center(
          child: MyWidget(
            identity: 'a',
            child: MyWidget(
              identity: 'b',
              child: MyWidget(
                identity: 'c',
                child: MyFind(),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class MyWidget extends StatefulWidget {
  final String identity;
  final Widget child;

  const MyWidget({
    Key? key,
    required this.identity,
    required this.child,
  }) : super(key: key);

  static MyWidgetState findNearest(BuildContext context) {
    return context.findAncestorStateOfType<MyWidgetState>()!;
  }

  static MyWidgetState findRoot(BuildContext context) {
    return context.findRootAncestorStateOfType<MyWidgetState>()!;
  }

  static MyWidgetState findWith(
    BuildContext context, {
    required String identity,
  }) {
    return context
        .findAncestorStatesOfType<MyWidgetState>()
        .firstWhere((state) => state.widget.identity == identity);
  }

  @override
  State<MyWidget> createState() => MyWidgetState();
}

class MyWidgetState extends State<MyWidget> {
  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        Text(widget.identity),
        Container(
          padding: const EdgeInsets.all(8),
          margin: const EdgeInsets.all(8),
          decoration: BoxDecoration(border: Border.all()),
          child: widget.child,
        ),
      ],
    );
  }
}

class MyFind extends StatelessWidget {
  const MyFind({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final nearest = MyWidget.findNearest(context);
    final root = MyWidget.findRoot(context);
    final mid = MyWidget.findWith(context, identity: 'b');
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: [
        Text('nearest: ${nearest.widget.identity}'),
        Text('root: ${root.widget.identity}'),
        Text('mid: ${mid.widget.identity}'),
      ],
    );
  }
}

extension BuildContextX on BuildContext {
  Iterable<T> findAncestorStatesOfType<T extends State>() sync* {
    final ancestor = findAncestorStateOfType<T>();
    if (ancestor != null) {
      yield ancestor;
      yield* ancestor.context.findAncestorStatesOfType<T>();
    }
  }
}