Script to find missing files in Xcode .xcodeproj files (they appear red in Xcode 12)

xcode-missing-files.rb

require 'xcodeproj'
project_path = ARGV[0]

project = Xcodeproj::Project.open(project_path)
xcodebuild = `xcodebuild -project '#{project_path}' -showBuildSettings`
build_settings = xcodebuild.scan(/([A-Z_]*) = (.*?)\n/).to_h

missing_files = []
project.files.to_a.each do |file|
  absolute_path = file.real_path

  build_setting = absolute_path.to_s.match(/\${([A-Z_]*)}/)
  if build_setting
    absolute_path = absolute_path.to_s.gsub(/\${([A-Z_]*)}/, build_settings[build_setting[1]])
  end

  missing_files << absolute_path unless File.exist? absolute_path
end

puts "#{missing_files.length} missing files:"
missing_files.each do |f|
  puts f
end