ruby script using Rugged to count the number of trailer keys in use

trailers.rb

#!/usr/bin/env ruby

require 'rugged'
require 'optparse'

# Parse command line options
options = {
  repo_path: '.',
  branch: 'main'
}

OptionParser.new do |opts|
  opts.banner = "Usage: trailer_counter.rb [options]"

  opts.on("-r", "--repo PATH", "Path to git repository") do |repo_path|
    options[:repo_path] = repo_path
  end

  opts.on("-b", "--branch BRANCH", "Branch to analyze (default: main)") do |branch|
    options[:branch] = branch
  end

  opts.on("-h", "--help", "Show this help message") do
    puts opts
    exit
  end
end.parse!

begin
  # Open the repository
  repo = Rugged::Repository.new(options[:repo_path])

  # Set up the counter for trailer keys
  trailer_counts = Hash.new(0)
  commit_count = 0

  # Set up a walker to go through all commits in the branch
  walker = Rugged::Walker.new(repo)

  # Get the branch reference
  branch_ref = repo.references["refs/heads/#{options[:branch]}"]
  if branch_ref.nil?
    puts "Error: Branch '#{options[:branch]}' not found"
    exit 1
  end

  # Push the branch head to the walker
  walker.push(branch_ref.target_id)

  # Walk through all commits
  walker.each do |commit|
    commit_count += 1

    # Extract trailers from the commit message
    trailers = commit.trailers

    # Count each trailer key
    trailers.each do |key, value|
      trailer_counts[key.downcase] += 1
    end
  end

  # Print results
  puts "Analyzed #{commit_count} commits in branch '#{options[:branch]}'"
  puts "\nTrailer Key Counts:"
  puts "-" * 30

  if trailer_counts.empty?
    puts "No trailers found in commit messages"
  else
    # Sort by count (descending)
    trailer_counts.sort_by { |_, count| -count }.each do |key, count|
      puts "#{key}: #{count}"
    end
  end

rescue Rugged::RepositoryError => e
  puts "Error: #{e.message}"
  exit 1
end