Example app of rebuilding LayoutBuilder without any setState or state changes.

main.dart

import 'dart:developer';

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

void main() {
  runApp(
    const ProviderScope(child: MyApp()),
  );
}

final countProvider = StateProvider((ref) => 0);

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(),
        body: Column(
          children: [
            Row(
              children: const [
                Expanded(
                  child: Padding(
                    padding: EdgeInsets.all(16),
                    child: _DescriptionArea(),
                  ),
                ),
                SizedBox(width: 16),
                _ExpandableBar(),
              ],
            ),
            const SizedBox(height: 32),
            const _CountUpButton(),
            const SizedBox(height: 32),
            const Expanded(child: _Footer()),
          ],
        ),
      ),
    );
  }
}

class _DescriptionArea extends StatelessWidget {
  const _DescriptionArea();

  @override
  Widget build(BuildContext context) {
    return const Text(
      'This is a very long text that need multiple lines to be shown.',
      style: TextStyle(fontSize: 20),
    );
  }
}

class _ExpandableBar extends ConsumerWidget {
  const _ExpandableBar();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final count = ref.watch(countProvider);
    return Container(
      height: 40,
      width: 10.0 * count,
      color: Colors.teal,
    );
  }
}

class _CountUpButton extends ConsumerWidget {
  const _CountUpButton();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 16),
      width: double.infinity,
      child: ElevatedButton(
        onPressed: () {
          ref.read(countProvider.notifier).state += 1;
        },
        child: const Padding(
          padding: EdgeInsets.symmetric(vertical: 16),
          child: Text('ADD'),
        ),
      ),
    );
  }
}

class _Footer extends StatelessWidget {
  const _Footer();

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(16),
      child: LayoutBuilder(
        builder: (context, constraint) {
          log('DEBUG: LayoutBuilder built $constraint');
          return Text(
            'Constraint: $constraint',
            style: const TextStyle(
              fontSize: 20,
              color: Colors.red,
              fontWeight: FontWeight.w700,
            ),
          );
        },
      ),
    );
  }
}