Invalid Podfile file: undefined method `exists?’ for File:Class.

Not possible to run “pod install” for Flutter iOS app any more starting from today. Is it due to Cocoapods or Flutter?

[!] Invalid `Podfile` file: undefined method `exists?' for File:Class.


 #  from /Users/tt/flutterApp/ios/Podfile:34
 #  -------------------------------------------
 #  
 >    flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
 #  end
 #  -------------------------------------------

Solution this fix problem :

gem cleanup
brew uninstall cocoapods
sudo gem uninstall cocoapods
sudo gem install cocoapods -v 1.10.0 -n /usr/local/bin
sudo gem install cocoapods-user-defined-build-types
pod install --repo-update