[BUG] 6.0.0-dev.2: Assertion false positive: "MapCamera is no longer within the cameraConstraint after an option change"

[jjoelson]

What is the bug?

Hi all! I'm testing out some code on the pre-release 6.0.0-dev.2 version. Whenever I include a camera constraint in my map options, I get an assertion failure from lib/src/map/internal_controller.dart:

    assert(
      newOptions.cameraConstraint.constrain(newCamera) == newCamera,
      'MapCamera is no longer within the cameraConstraint after an option change.',
    );

My constraint is a CameraConstraint.containCenter constraint, and I've confirmed that the map center is indeed within the given constraint.

How can we reproduce it?

Create a map with map options that include a camera constraint, but ensure the map options change after the initial build such that FlutterMaps didUpdateWidget is called with the new set of map options.

Do you have a potential solution?

I may have missed it, but it doesn't seem as though MapCamera implements operator ==, which may explain the issue (i.e. the assertion is essentially doing reference equality, which I think would always fail). If someone else is not already working on this then I could work on a PR to add it.

cc @rorystephenson @JaffaKetchup

Platforms

Android, iOS

Severity

Erroneous: Prevents normal functioning and causes errors in the console

[jjoelson]

Turns out to be a relatively simple fix; I just had to implement operator ==/hashCode: #1614

[DevTello]

@JaffaKetchup The same issue if I'm using CameraConstraint.contain(). No problems, if it's CameraConstraint.containCenter()

[JaffaKetchup]

@DevTello If you're still getting this issue in v6.1.0, please open a new issue!

[priyanshi-pandya]

I was getting the same exception, i had to adjust the initialCenter with respect to the cameraConstraints

Like,
initialZoom: 2.3, cameraConstraint: CameraConstraint.contain( bounds: LatLngBounds( const LatLng(-90, -180), const LatLng(90, 180), ), ),

For this above bounds it works perfectly with initialZoom of 2.3, if I go any less than this, its throws me again MapCamera, is not within cameraConstraint error.

Here is my full code

     FlutterMap(
            options: MapOptions(
              minZoom: 1,
              maxZoom: 19,
              initialCenter: const LatLng(0, 0),
              initialZoom: 2.3,
              cameraConstraint: CameraConstraint.contain(
                bounds: LatLngBounds(
                  const LatLng(-90, -180),
                  const LatLng(90, 180),
                ),
              ),
              onTap: (tapPosition, point)  {
                //Tap logic
              },
              onPointerHover: (event, point) {
                //Hover logic                  },
            ),
            mapController: mapProvider.mapController,
            children: [
              TileLayer(
                urlTemplate:
                    'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
                userAgentPackageName: 'com.example.app',
                tileProvider: CancellableNetworkTileProvider(),
              ),
              //other layers
              
            ]
         ),