[BUG] Exception "`MapCamera` is no longer within the `cameraConstraint` after an option change" when using particular camera setups

[dumabg]

Current recommended workaround:
Ensure initialCenter and initialZoom are configured in such a way that, if cameraConstraint & initialCameraFit were undefined, the map view would fit inside the desired camera constraint & fit.

---

What is the bug?

A FlutterMap with a cameraConstraint CameraConstraint.contain(bounds: widget.bounds) gives the assert error "MapCamera is no longer within the cameraConstraint after an option change"

How can we reproduce it?

Put a ValueListenableBuilder and a FlutterMap with a cameraConstraint. Change the ValueListenableBuilder value to trigger a new repaint.

Do you have a potential solution?

I've comment the assert and seems that it works

Platforms

Android

Severity

Erroneous: Prevents normal functioning and causes errors in the console

[JaffaKetchup]

Hi @dumabg,
Can I just double check what version you are running?

[thorito]

It happens the same to me.

pubspect.yaml:

  flutter_map: ^6.1.0
  flutter_map_cancellable_tile_provider: ^2.0.0
  flutter_map_marker_cluster: ^1.3.4

My code:

 MapOptions _buildMapOptions() => MapOptions(
    initialCenter: widget._parametersMap.currentPosition.center,
    initialZoom: widget._parametersMap.initialZoom,
    maxZoom: widget._parametersMap.maxZoom,
    minZoom: widget._parametersMap.minZoom,
    initialRotation: widget._parametersMap.rotation,
    cameraConstraint: widget._parametersMap.cameraConstraint,
    initialCameraFit: markers.isNotEmpty &&
            UserPreferences.getInstance().currentPosition == null
        ? markers.getCameraFit(
            minZoom: widget._parametersMap.minZoom,
            maxZoom: widget._parametersMap.initialZoom,
          )
        : null,
    keepAlive: true,
    onMapReady: () {
      // logger.d('onMapReady !!');
    },
    onPositionChanged: (MapPosition position, bool hasGesture) {
      // logger.d('onPositionChanged hasGesture: $hasGesture,
      // position: $position');

      if (hasGesture) {
        ref.read(mapChangedProvider.notifier).changePosition();
      }
    },
    onTap: (_, __) => widget._popupController.hideAllPopups(),
  );

  @override
  Widget build(BuildContext context) {
    final markersAsync = ref.watch(markersProvider);

    return markersAsync.when(
      data: (values) {
        if (values.isNotEmpty) {
          setState(() {
            markers = List.from(values);
          });
        }

        return PopupScope(
          popupController: widget._popupController,
          child: Stack(
            children: [
              FlutterMap(
                mapController: widget._mapController,
                options: _buildMapOptions(),
                children: [
                     ...
				],
          ),
        );
      },
      loading: () => const CustomProgress(),
      error: (error, stackTrace) {
        context.showSnackbar(
          message: error.toString(),
          type: MessageType.error,
        );

        return const SizedBox.shrink();
      },
    );
  }

Error:

MapCamera is no longer within the cameraConstraint after an option change.
'package:flutter_map/src/map/controller/internal.dart':
Failed assertion: line 276 pos 7: 'newOptions.cameraConstraint.constrain(newCamera) == newCamera'

What is the reason for the error?

[JaffaKetchup]

I can't tell exactly without a more minimal reproducible example, but there's a few things that could be causing issues:

• Building the map options in a function
• Not sure if initialCameraFit changes, but changing it will have no effect and could cause issues
• Not sure what PopupScope is, but maybe that's causing issues?

We need an MRE to investigate this further (standalone, no state from other parts of app, no dependencies, etc.).

[iulian0512]

@JaffaKetchup @josxha here is a complete single file minimum reproducible example

// ignore_for_file: prefer_const_constructors, curly_braces_in_flow_control_structures, prefer_const_literals_to_create_immutables

import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:latlong2/latlong.dart';

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int cnt = 0;

  @override
  void initState() {
    super.initState();
    Future(() async {
      await Future.delayed(Duration(seconds: 1));
      cnt++;
      setState(() {});
    });
  }

  @override
  Widget build(BuildContext context) {
    final camConstraint = cnt > 0
        ? CameraConstraint.contain(
            bounds: LatLngBounds(LatLng(43.6884447292, 20.2201924985),
                LatLng(48.2208812526, 29.62654341)))
        : null;
    return Scaffold(
        appBar: AppBar(
          backgroundColor: Theme.of(context).colorScheme.inversePrimary,
          title: Text(widget.title),
        ),
        body: FlutterMap(
            options: MapOptions(
                interactionOptions: InteractionOptions(
                    flags: InteractiveFlag.pinchZoom |
                        InteractiveFlag.drag |
                        InteractiveFlag.doubleTapZoom |
                        InteractiveFlag.scrollWheelZoom,
                    rotationWinGestures: MultiFingerGesture.none,
                    rotationThreshold: double.infinity,
                    cursorKeyboardRotationOptions:
                        CursorKeyboardRotationOptions.disabled()),
                minZoom: 1,
                maxZoom: 20,
                initialZoom: 5.9,
                initialCenter: LatLng(45.80565, 24.937853),
                cameraConstraint: camConstraint),
            children: []));
  }
}

pubspec.yaml

name: flutter_map_constraint_issue
description: "A new Flutter project."

publish_to: "none"

version: 1.0.0+1

environment:
  sdk: ">=3.2.5 <4.0.0"

dependencies:
  cupertino_icons: ^1.0.2
  flutter:
    sdk: flutter
  flutter_map: ^6.1.0

dev_dependencies:
  flutter_lints: ^2.0.0
  flutter_test:
    sdk: flutter

flutter:
  uses-material-design: true

the example above produces after 1 second the error

════════ Exception caught by widgets library ═══════════════════════════════════
The following assertion was thrown building KeyedSubtree-[GlobalKey#de288]:
MapCamera is no longer within the cameraConstraint after an option change.
'package:flutter_map/src/map/controller/internal.dart':
Failed assertion: line 276 pos 7: 'newOptions.cameraConstraint.constrain(newCamera) == newCamera'

The relevant error-causing widget was:
    Scaffold Scaffold:file:///D:/temp/flutter_map_constraint_issue/lib/main.dart:56:12

let me know if i can assist or provide anything else.

[JaffaKetchup]

Thanks @iulian0512, we'll look into this :)

[palicka]

any update on this ? In my case it's not just error in console, but map is not displayed at all
(I'm using 6.1.0 as well)

EDIT:
using CameraConstraint.containCenter() instead of CameraConstraint.contain() fixed the issue for me (.containerCenter is slightly different than .contain, but in my case it doesn't matter)