1 - regen_start.rb

#!/usr/bin/env ruby
#
# USAGE: Run from Rails root: `bin/regen_start`
#
# ⚠️ WARNING: Backup your project. Rewrites history and modifies files.
#
# Suite of scripts to perform a thorough update of a Rails project during a Git rebase.
# `regen_start` spawns `regen_actions` which handles gems, JS, and DB migrations.
#
# gem uninstall rails
# gem install --user-install specific_install
# gem git_install --user-install https://github.com/rails/rails.git -d activesupport
# gem git_install --user-install https://github.com/rails/rails.git -d activemodel
# gem git_install --user-install https://github.com/rails/rails.git -d activerecord
# gem git_install --user-install https://github.com/rails/rails.git -d activejob
# gem git_install --user-install https://github.com/rails/rails.git -d actionview
# gem git_install --user-install https://github.com/rails/rails.git -d actionpack
# gem git_install --user-install https://github.com/rails/rails.git -d activestorage
# gem git_install --user-install https://github.com/rails/rails.git -d actiontext
# gem git_install --user-install https://github.com/rails/rails.git -d actioncable
# gem git_install --user-install https://github.com/rails/rails.git -d actionmailbox
# gem git_install --user-install https://github.com/rails/rails.git -d actionmailer
# gem git_install --user-install https://github.com/rails/rails.git -d railties
# gem git_install --user-install https://github.com/rails/rails.git
#
# $ ruby32 -v
# ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-openbsd]
# $ rails32 -v
# Rails 7.1.0.beta1
#

# Safety prompt
puts "This script is potentially harmful. Continue? [y/N]: "
response = gets.chomp
unless response.casecmp("y").zero?
  puts "Aborting."
  exit
end

puts "Copying regeneration script to /tmp..."
File.write("/tmp/regen_actions.rb", File.read("bin/regen_actions.rb"))

puts "Initiating rebase..."
puts "Save and exit the editor to continue."
sleep(2)
system("git rebase -i --root --exec 'ruby /tmp/regen_actions.rb'")

2 - regen_actions.rb

#!/usr/bin/env ruby
#
# USAGE: Run from Rails root: `bin/regen_start`
#

def regenerate_rails_app
  puts "Deleting existing files..."
  system("rm -rf *")
  system("git clean -df")
  puts "Done."

  puts "Regenerating Rails app skeleton..."
  if system("rails32 new . --main --database=postgresql --javascript=esbuild --css=sass --asset-pipeline=propshaft --skip-docker")
    puts "Done."
  else
    puts "Failed to regenerate:"
    system("git status")
    exit(1)
  end

  puts "Adding and committing to Git..."
  system("git add -A")
  system("git commit --amend --no-edit")

  puts "Moving onto next commit."
end

def refresh_commit
  puts "Refreshing gems, JS libs, and database migrations..."

  system("bundle")
  system("yarn")
  system("bin/rails db:migrate")

  puts "Adding and committing to Git..."
  system("git add -A")
  system("git commit --amend --no-edit")

  # Check if there are any more commits left to rebase
  if File.exist?(".git/rebase-merge/git-rebase-todo") || File.exist?(".git/rebase-apply/git-rebase-todo")
    puts "Moving onto next commit."
  else
    puts "Removing script from /tmp..."
    File.unlink("/tmp/regen_actions.rb")

    puts "Congratulations! Your Rails app has been thoroughly updated."
  end
end

current_head = `git rev-parse HEAD`.chomp
initial_commit = `git rev-list --max-parents=0 HEAD`.chomp

if current_head == initial_commit
  puts "Initial commit (#{ initial_commit }). Running app regeneration..."
  regenerate_rails_app
else
  puts "Subsequent commit (#{ current_head }). Running misc refresh..."
  refresh_commit
end