delete-stale-branches.rb

#!/usr/bin/env ruby

require 'json'
require 'time'

repo = 'xxxx/yyyy'

run = false
usage = "Usage: #{$0} [--run]"

case ARGV[0]
when nil
  warn 'Running in dry-run mode. Pass --run to actually delete branches.'
when '--run'
  run = true
when '--help', '-h'
  puts usage
  exit 0
else
  warn usage
  exit 1
end

# https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/managing-branches-in-your-repository/viewing-branches-in-your-repository
#
# > Stale branches: The Stale view shows all branches that no one has committed to in the last three months,
# > ordered by the branches with the oldest commits first.
stale = Time.now - 7776000 # 3 months ago

branches = `gh api repos/#{repo}/branches --paginate`
exit 1 if !$?.success?

JSON.parse(branches).map { |b| b['name'] }.each do |name|
  next if name.start_with?('archive/')

  branch = `gh api repos/#{repo}/branches/#{name}`
  exit 1 if !$?.success?

  next if Time.parse(JSON.parse(branch)['commit']['commit']['committer']['date']) > stale

  puts name
  if run
    `gh api repos/#{repo}/git/refs/heads/#{name} -X DELETE`
    exit 1 if !$?.success?
  end
end