Execute fastlane for multiple schemes based off of ".env.scheme_" dotenv files

Fastfile

# fastlane do_task
# fastlane do_task envs:"scheme_1,scheme_2"

lane :do_task do |options|
  # Execute this lane for all schemes if no
  # 'SCHEME` environment variable
  if ENV['SCHEME'] == nil
    envs = options[:envs].to_s.split(",")
    execute_for_all_scheme_envs(envs) { do_task }
    next
  end

  puts "DO TASK FOR #{ENV['SCHEME']}"
end

# Execute a block of code for all schemes
# Scheme list is generated by file prefixed with ".env.scheme_" 
# Example: .env.scheme_dev, .env.scheme_stg, .env.scheme_prod
#
# Note: Each execution will reset environment variables
# and lane context after execution. Handle specific lane context
# values in your execution block as they will be cleared
# after block execution
def execute_for_all_scheme_envs(envs)
  # Environment and lane context cache for resetting
  env_cache = ENV.to_hash
  context_cache = Actions.lane_context.clone

  schemeList = Dir.glob(".env.scheme*")

  # Select only given envs
  if envs && !envs.empty?
    envs.map! { |e| ".env.#{e}" }
    schemeList.select! { |s| envs.include?(s) }
  end

  schemeList.each do |file|
    # Overloading environment for scheme
    Dotenv.overload(file)
    
    # Execute only if scheme
    if ENV["SCHEME"]
      yield
    else
      UI.important("No 'SCHEME' env for #{file} - Skipping...")
    end

    # Reset environment variables
    ENV.clear
    ENV.update(env_cache)

    # Reset lane context
    Actions.lane_context.clear
    Actions.lane_context.update(context_cache)
  end
end