Flutter app on Xcode won't launch after upgrade - xcode

Question

I have an app made in Flutter and since the latest version of Xcode absolutely nothing works as before.
I have been struggling with this problem for nearly a week now and the errors vary depending on the hour.
The main problem is that when distributing the application to Apple for review, they reject it with the following message:
2.1 Performance: App Completeness Guideline
2.1 - Performance - App Completeness
We discovered one or more bugs in your app when reviewed on iPad
running iOS 14.0 on Wi-Fi.
Specifically, we were still unable to login through Sign in with Apple
I find this strange as all my previous uploads got verified without any problems.
So to rectify this issue I'm trying to run the app through the simulator as I don't own an iPad.
And here is where the problems start.
Side note: Running on a physical iPhone works without problems and I'm opening the project runner.xcworkspace, not the runner.xccodeproj.
The main problem is that Xcode won't find any libraries, starting with the first one:
GeneratedPluginRegistrant.m:10:9: Module 'apple_sign_in' not found
I have tried every solution related to this issue but to no avail.
Remove the pod files, pod install,
pod deintegrate, pod init, pod install
flutter build ios --release, flutter run
Ive tried removing my project and cloning it for a fresh start
Sometimes not even a boilerplate app will work
I have checked github posts like https://github.com/flutter/flutter/issues/53573 and https://github.com/flutter/flutter/issues/33423 with no luck.
...checked countless threads.
Flutter doctor and pod-file below:
[✓] Flutter (Channel stable, 1.20.4, on Mac OS X 10.15.6 19G2021,
locale en-ES)
• Flutter version 1.20.4 at /Users/peter/flutter
• Framework revision fba99f6cf9 (11 days ago), 2020-09-14 15:32:52 -0700
• Engine revision d1bc06f032
• Dart version 2.9.2
[✓] Android toolchain - develop for Android devices (Android SDK
version 30.0.1)
• Android SDK at /Users/peter/Library/Android/sdk
• Platform android-30, build-tools 30.0.1
• Java binary at:
/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/bin/java
• Java version Java(TM) SE Runtime Environment (build 1.8.0_51-b16)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 12.0)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 12.0, Build version 12A7209
• CocoaPods version 1.9.3
[!] Android Studio (not installed)
• Android Studio not found; download from
https://developer.android.com/studio/index.html
(or visit https://flutter.dev/docs/get-started/install/macos#android-setup
for detailed instructions).
[!] IntelliJ IDEA Community Edition (version 2017.2.5)
• IntelliJ at /Applications/IntelliJ IDEA CE.app
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
• For information about installing plugins, see
https://flutter.dev/intellij-setup/#installing-the-plugins
[✓] Connected device (1 available)
• iPhone 11 (mobile) • F1B8AE15-9028-4E0D-BD9D-2F2C7CC93ECE • ios •
com.apple.CoreSimulator.SimRuntime.iOS-14-0 (simulator)
! Doctor found issues in 2 categories.
podfile:
# Uncomment this line to define a global platform for your project
platform :ios, '9.0'
# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
ENV['COCOAPODS_DISABLE_STATS'] = 'true'
project 'Runner', {
'Debug' => :debug,
'Profile' => :release,
'Release' => :release,
}
def flutter_root
generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
unless File.exist?(generated_xcode_build_settings_path)
raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
end
File.foreach(generated_xcode_build_settings_path) do |line|
matches = line.match(/FLUTTER_ROOT\=(.*)/)
return matches[1].strip if matches
end
raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
end
require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
flutter_ios_podfile_setup
target 'Runner' do
use_frameworks!
use_modular_headers!
flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
end
post_install do |installer|
installer.pods_project.targets.each do |target|
target.build_configurations.each do |config|
config.build_settings['ENABLE_BITCODE'] = 'YES'
config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '9.0'
end
end
end

Answer 1

There are problems with Flutter 1.20.4 and XCode12/iOS14.
You need to update Flutter to the current beta (1.22.0-12.3.pre) which contains a lot of fixes for the new iOS/XCode versions.
See https://flutter.dev/docs/development/ios-14
Edit 10/01/2020:
Flutter 1.22.0 has been released to stable and should work with XCode 12 and iOS 14 out of the box.

Answer 2

It might be a problem with the iOS Simulator.
Check out this forum.
You might want to reply to them pointing out this issue from the forum, seems to have worked for others.

Answer 3

Try to allow the module in xcode to see if it finds apple_sign_in
Open Xcode select Runner > Signing % Capabilities > +Capabilities > Select Apple_Sign_In
Xcode screenshot