Gem::Commands::RebuildCommand#compare

# File tmp/rubies/ruby-3.4.1/lib/rubygems/commands/rebuild_command.rb, line 131
def compare(source_date_epoch, old_file, new_file)
  date = Time.at(source_date_epoch.to_i).strftime("%F %T %Z")

  old_hash = sha256(old_file)
  new_hash = sha256(new_file)

  say
  say "Built at: #{date} (#{source_date_epoch})"
  say "Original build saved to:   #{old_file}"
  say "Reproduced build saved to: #{new_file}"
  say "Working directory: #{options[:build_path] || Dir.pwd}"
  say
  say "Hash comparison:"
  say "  #{old_hash}\t#{old_file}"
  say "  #{new_hash}\t#{new_file}"
  say

  if old_hash == new_hash
    say "SUCCESS - original and rebuild hashes matched"
  else
    say "FAILURE - original and rebuild hashes did not match"
    say

    if options[:diff]
      if system("diffoscope", old_file, new_file).nil?
        alert_error "error: could not find `diffoscope` executable"
      end
    else
      say "Pass --diff for more details (requires diffoscope to be installed)."
    end

    terminate_interaction 1
  end
end