fastlane_update_bundle_ids.rb

def replace_project_bundle_identifiers(app_info)
  # Should use this to replace bundle ids but currently causes gym to fail
  # https://github.com/fastlane/fastlane/issues/6289
  # app_info.all_targets.each { |target|
  #   update_app_identifier(
  #     xcodeproj: app_info.xcodeproj,
  #     plist_path: target.plist_path,
  #     app_identifier: target.app_id
  #   )
  # }
  
  # Manually find and replace in pbxproj instead
  default_info = AppInfo::DEV
  proj_path = File.expand_path('<path_to_project>.xcodeproj/project.pbxproj', __FILE__)
  pbxproj = File.read(proj_path)

  default_info.all_targets.zip(app_info.all_targets).each do |default, current|
    # Find and replace all instances of default.app_id with current.app_id in pbxproj
    pbxproj = pbxproj.gsub(default.app_id, current.app_id)
  end

  File.open(proj_path, 'w') { |file| file.puts pbxproj }
end