Issue 1:
I follow the steps on the official website.

clone the beta version

set the environment variable

run flutter doctor

when i make these steps:

Building flutter tool...
The setter 'readEventsEnabled=' was called on null.
Receiver: null
Tried calling: readEventsEnabled=false
package:pub/src/source/hosted.dart 339 BoundHostedSource._throwFriendlyError
package:pub/src/source/hosted.dart 141 BoundHostedSource.doGetVersions
===== asynchronous gap ===========================
package:pub/src/source.dart 169 BoundSource.getVersions
package:pub/src/solver/version_solver.dart 237 SolverCache.getVersions.<fn>
dart:async runZoned
package:pub/src/http.dart 267 withDependencyType
package:pub/src/solver/version_solver.dart 236 SolverCache.getVersions
===== asynchronous gap ===========================
package:pub/src/solver/unselected_package_queue.dart 121 UnselectedPackageQueue._getNumVersions
===== asynchronous gap ===========================
package:pub/src/solver/unselected_package_queue.dart 50 UnselectedPackageQueue.add
===== asynchronous gap ===========================
package:pub/src/solver/version_selection.dart 88 VersionSelection._addDependencies
===== asynchronous gap ===========================
package:pub/src/solver/version_selection.dart 63 VersionSelection.select
===== asynchronous gap ===========================
package:pub/src/solver/backtracking_solver.dart 174 BacktrackingSolver.solve
===== asynchronous gap ===========================
package:pub/src/solver/version_solver.dart 42 resolveVersions.<fn>
package:pub/src/log.dart 409 progress
package:pub/src/solver/version_solver.dart 40 resolveVersions
package:pub/src/entrypoint.dart 195 Entrypoint.acquireDependencies
===== asynchronous gap ===========================
package:pub/src/command/upgrade.dart 41 UpgradeCommand.run
===== asynchronous gap ===========================
package:args/command_runner.dart 194 CommandRunner.runCommand
===== asynchronous gap ===========================
package:pub/src/command_runner.dart 167 PubCommandRunner.runCommand.<fn>
dart:async new Future.sync
package:pub/src/utils.dart 103 captureErrors.<fn>
dart:async runZoned
package:pub/src/utils.dart 122 captureErrors
package:pub/src/command_runner.dart 167 PubCommandRunner.runCommand
===== asynchronous gap ===========================
package:pub/src/command_runner.dart 116 PubCommandRunner.run
===== asynchronous gap ===========================
/b/build/slave/Linux_Engine/build/src/third_party/dart/third_party/pkg/pub/bin/pub.dart 8 main
This is an unexpected error. Please run

pub --trace upgrade --verbosity=error --no-packages-dir

what's wrong with my operations.

thanks 👍

Issue 2:
I found an issue in image picker library in ios only, the cancel button in the navigation bar is not visible if I access camera first. But its working in Andriod.

When I look into the library implementation if found that the image picker controller object reference is missing when camera usage is done. So I tried re-initializing the object each time when we use image picker and deallocating after use manually. It was working fine.

Here what i have done.

- (void)showCamera {
// Camera is not available on simulators
_imagePickerController = [[UIImagePickerController alloc] init];
_imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
_imagePickerController.delegate = self;
_imagePickerController.mediaTypes = @[ (NSString *)kUTTypeImage ];
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
_imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
[_viewController presentViewController:_imagePickerController animated:YES completion:nil];
} else {
[[[UIAlertView alloc] initWithTitle:@"Error"
message:@"Camera not available."
delegate:nil
cancelButtonTitle:@"OK"
otherButtonTitles:nil] show];
}
}

- (void)showPhotoLibrary {
// No need to check if SourceType is available. It always is.
_imagePickerController = [[UIImagePickerController alloc] init];
_imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
_imagePickerController.delegate = self;
_imagePickerController.mediaTypes = @[ (NSString *)kUTTypeImage ];
_imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[_viewController presentViewController:_imagePickerController animated:YES completion: nil];
}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
[_imagePickerController dismissViewControllerAnimated:YES completion:nil];
_result(nil);

_result = nil;
_arguments = nil;
_imagePickerController = nil;
}

Please fix the issue as soon as possible.