Error installing, running Fastlane for Flutter on mac

Question

Following the link Flutter Fastlane docs

Running command:

brew cask install fastlane

Returns:

Gems updated: slack-notifier atomos claide nanaimo xcodeproj rouge xcpretty terminal-notifier tty-screen tty-cursor tty-spinner commander-fastlane faraday faraday_middleware gh_inspector mini_magick rubyzip naturally simctl jwt memoist signet
Gems already up-to-date: fastlane
**ERROR:  Error installing fastlane:
    signet requires Ruby version >= 2.4.0.**
Cleaning up installed gems...
Attempting to uninstall xcpretty-0.2.6
Successfully uninstalled xcpretty-0.2.6
Attempting to uninstall xcodeproj-1.4.4
Successfully uninstalled xcodeproj-1.4.4
Attempting to uninstall rubyzip-1.2.1
Successfully uninstalled rubyzip-1.2.1
Attempting to uninstall nanaimo-0.2.3
Successfully uninstalled nanaimo-0.2.3
Attempting to uninstall memoist-0.15.0
Successfully uninstalled memoist-0.15.0
Attempting to uninstall gh_inspector-1.0.3
Successfully uninstalled gh_inspector-1.0.3
Attempting to uninstall faraday_middleware-0.11.0.1
Successfully uninstalled faraday_middleware-0.11.0.1
Attempting to uninstall faraday-0.12.1
Successfully uninstalled faraday-0.12.1
Attempting to uninstall commander-fastlane-4.4.4
Successfully uninstalled commander-fastlane-4.4.4
Attempting to uninstall claide-1.0.1
Successfully uninstalled claide-1.0.1
Attempting to uninstall rouge-1.11.1
Successfully uninstalled rouge-1.11.1
Clean Up Complete
Detected shell config file at path '~/.bash_profile'
Please add the following line to your bash profile:
export PATH="$HOME/.fastlane/bin:$PATH"
**After doing so close the terminal session and restart it to start using fastlane 🚀
🍺  fastlane was successfully installed!**

which gave this output. But when I run ruby -v

ruby 2.6.5p114 (2019-10-01 revision 67812) [x86_64-darwin16]

I get this output. I added all the paths in .bash_profile and then I run fastlane env or fastlane init inside the android/ folder or anywhere it is giving me this error

/.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday/error.rb:95:in  <.module:Faraday>: superclass mismatch for class ConnectionFailed (TypeError)
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday/error.rb:6:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday.rb:80:in  'block in require_libs'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday.rb:79:in  'each'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday.rb:79:in  'require_libs'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday.rb:242:in  '<.module:Faraday>'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/faraday-0.17.1/lib/faraday.rb:16:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/spaceship/lib/spaceship/client.rb:1:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/spaceship/lib/spaceship.rb:3:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/fastlane/lib/fastlane/setup/setup_ios.rb:1:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/fastlane/lib/fastlane/setup/setup.rb:57:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/fastlane/lib/fastlane.rb:10:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:55:in  'require'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/fastlane/lib/fastlane/cli_tools_distributor.rb:18:in  'take_off'
        from  /.fastlane/bin/bundle/lib/ruby/gems/2.2.0/gems/fastlane-2.28.3/bin/fastlane:20:in  '<.top (required)>'
        from  /.fastlane/bin/bundle/bin/fastlane:22:in  'load'
        from  /.fastlane/bin/bundle/bin/fastlane:22:in  '<.main>'

After trying sudo gem install fastlane it says

Successfully installed fastlane-2.137.0
Parsing documentation for fastlane-2.137.0
Done installing documentation for fastlane after 6 seconds
1 gem installed

But when I again write fastlane env or fastlane init it gives me same above error

Solution

Based on this thread (thanks for @lwj Answer):

https://github.com/fastlane/fastlane/issues/15740

1- It might need to uninstall cask fastlane first:

brew cask uninstall fastlane

2- Then Install it using RubyGems:

sudo gem install fastlane -NV

Also because Apple has changed the default shell to zsh, referring to @fdg13gustav answer: https://stackoverflow.com/a/58310864/1995358

3- Create .zprofile file in your home directory

And regarding this thread: https://github.com/fastlane/fastlane/issues/12609

4- Add these lines to your ~/.zprofile file:

export PATH="$HOME/.fastlane/bin:$PATH"
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8