Checks if entries can be removed from CODEOWNERS file

check_stale_codeowners_entries.rb

#!/usr/bin/env ruby

# This script assumes CODEOWNERS files can be found in "../.github/
lines = File.readlines(File.join(__dir__, "..", ".github", "CODEOWNERS"))

stale_entries = []

lines.each_with_index do |line, index|
  original_line = line

  # Normalize the beginning of each entries
  line = line.gsub(/[[:space:]]+/, " ").strip.delete_prefix(".").delete_prefix("/")

  # Skip if blank line or comment line
  next if line.empty? || line.start_with?("#")

  # Skip if entry has a wildcard character
  next if line.include?("*")

  # Extract the path from the entry
  path = line.match(/^(\S+)\s+.*$/).captures.first rescue line

  # Skip if it's a file
  next if FileTest.file?(path)

  # Skip if it's a non empty directory
  next if (FileTest.directory?(path) && !Dir.empty?(path))

  padding = lines.size.to_s.size
  stale_entries << "#{(index+1).to_s.rjust(padding, " ")}: #{original_line}"
end

puts "Following lines can be removed from CODEOWNERS:"
puts stale_entries