Automatically select Xcode based on files

.github_actions_selectXcode_action.yml

name: "Select Xcode"
description: "Selects the version of xcode specified in this action"
runs:
  using: "composite"
  steps:
    - name: set DEVELOPER_DIR to select Xcode
      shell: bash
      env:
        ACTIONS_ALLOW_UNSECURE_COMMANDS: true
      run: echo ::set-env name=DEVELOPER_DIR::$(/usr/bin/ruby Resources/selectXcode.rb PRINT .xcode-build)

.github_workflows_swift.local.yml

(...)

      - id: selectXcode
        uses: ./.github/actions/selectXcode

(...)

.xcode-build

# Write one or many buildnumbers here
15A5209g

AnyScript.sh

# Call this in Any Script that needs the correct DEVELOPER_DIR set

eval $(/usr/bin/ruby Resources/selectXcode.rb SOURCE .xcode-build)

echo $DEVELOPER_DIR

fastlane_Fastfile

(...)

before_all do |lane|
  Dir.chdir("..") do
    UI.message %x(ruby Resources/selectXcode.rb LIST .xcode-build)
    ENV["DEVELOPER_DIR"] = %x(ruby Resources/selectXcode.rb PRINT .xcode-build)
    UI.message "DEVELOPER_DIR set to #{ENV["DEVELOPER_DIR"]}"
  end

  ensure_xcode_version()
end

(...)

Resources_selectXcode.rb

#!/usr/bin/env ruby

require 'open3'

def show_help
  puts <<-EOF
Usage: ./script.rb [SET|PRINT|LIST|SOURCE|--help] [path/to/.xcode-build]

This script sets the DEVELOPER_DIR environment variable to the path of a specific Xcode version.
The Xcode build versions are specified in a file provided as an argument.

Options:
    SET     Set the DEVELOPER_DIR environment variable
    PRINT   Only print the Xcode path without setting the environment variable
    LIST    Lists the available Xcodes with their build versions
    SOURCE  Prints an export statement to set the DEVELOPER_DIR environment variable in the parent shell
    --help  Show this help message
  EOF
  exit(0)
end

def get_xcode_build_version(path)
  `defaults read "#{path}/Contents/version.plist" ProductBuildVersion 2>/dev/null`.strip
end

def has_xcode_build_string(path, xcode_version)
  xcode_build = get_xcode_build_version(path)
  xcode_build == xcode_version
end

def find_xcodes
  stdout, _stderr, _status = Open3.capture3('mdfind', 'kMDItemCFBundleIdentifier = "com.apple.dt.Xcode"')
  stdout.split("\n")
end

def filter_xcodes(xcodes, xcode_version)
  xcodes.select { |xcode| has_xcode_build_string(xcode, xcode_version) }
end

if ARGV.length < 1 || ARGV.include?('--help')
  show_help
end

operation = ARGV[0]

if operation == 'LIST'
  xcodes = find_xcodes
  xcodes.each do |xcode|
    puts "#{xcode}: #{get_xcode_build_version(xcode)}"
  end
  exit(0)
end

if ARGV.length != 2
  show_help
end

xcode_build_version_path = ARGV[1]

unless File.file?(xcode_build_version_path)
  puts "The .xcode-build file does not exist at the given path."
  exit(1)
end

xcodes = find_xcodes

File.open(xcode_build_version_path).each_line do |line|
  next if line.start_with?('#')

  specified_xcode_build = line.strip
  matching_xcodes = filter_xcodes(xcodes, specified_xcode_build)

  next if matching_xcodes.empty?

  developer_dir = "#{matching_xcodes.first}/Contents/Developer"

  case operation
  when 'SET'
    puts "Looking for an Xcode with build #{specified_xcode_build} (specified in #{xcode_build_version_path})"
    ENV['DEVELOPER_DIR'] = developer_dir
    puts "DEVELOPER_DIR set to #{developer_dir}"
  when 'PRINT'
    print developer_dir
  when 'SOURCE'
    puts "export DEVELOPER_DIR=#{developer_dir}"
  else
    puts "Invalid option: #{operation}"
    puts "Use --help for usage information."
    exit(1)
  end

  exit(0)
end

puts "No Xcode with the specified build versions was found."
exit(1)