Add next_rails --init to replace next --init

CHANGELOG.md

@@ -1,5 +1,6 @@
 # main [(unreleased)](https://github.com/fastruby/next_rails/compare/v1.4.2...main)
 
+- [Add next_rails --init](https://github.com/fastruby/next_rails/pull/139)
 - [Add Ruby 3.4 support](https://github.com/fastruby/next_rails/pull/133)
 
 * Your changes/patches go here.

exe/next.sh

@@ -1,5 +1,6 @@
 #!/bin/bash
 if [[ "${@}" == "--init" ]]; then
+  echo "The next --init command is deprecated. Please use the next_rails --init command instead."
   # Add next? top of Gemfile
   cat <<-STRING > Gemfile.tmp
 def next?

exe/next_rails

@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 require "optparse"
 require "next_rails/version"
+require "next_rails"
 
 options = {}
 option_parser = OptionParser.new do |opts|
@@ -11,6 +12,10 @@ option_parser = OptionParser.new do |opts|
       bin/next_rails --version info # Show the version of the gem installed
   MESSAGE
 
+  opts.on("--init", "Setup the dual-boot configuration") do
+    options[:init] = true
+  end
+
   opts.on("--version", "show version of the gem") do
     options[:version] = true
   end
@@ -23,6 +28,8 @@ end
 
 option_parser.parse!
 
+puts NextRails::Init.call if options.fetch(:init, false)
+
 if options.fetch(:version, false)
   puts NextRails::VERSION
   exit 2

lib/next_rails.rb

@@ -2,6 +2,7 @@
 
 require "next_rails/gem_info"
 require "next_rails/version"
+require "next_rails/init"
 require "next_rails/bundle_report"
 require "next_rails/bundle_report/ruby_version_compatibility"
 require "deprecation_tracker"

lib/next_rails/init.rb

@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require 'fileutils'
+
+module NextRails
+  # This class is responsible for installing the dual-boot files for your.
+  class Init
+    def self.call
+      new.call
+    end
+
+    def call
+      return gemfiles_message unless gemfiles?
+      return next_gemfiles_message if next_gemfiles?
+
+      add_next_conditional
+      create_sym_link
+      copy_gemfile_lock
+      message
+    end
+
+    private
+
+    def gemfiles?
+      %w[Gemfile Gemfile.lock].any? { |file| File.exist?(file) }
+    end
+
+    def gemfiles_message
+      'You must have a Gemfile and Gemfile.lock to run the next_rails --init command.'
+    end
+
+    def next_gemfiles?
+      %w[Gemfile.next Gemfile.next.lock].any? { |file| File.exist?(file) }
+    end
+
+    def next_gemfiles_message
+      'The next_rails --init command has already been run.'
+    end
+
+    def add_next_conditional
+      File.open('Gemfile.tmp', 'w') do |file|
+        file.write <<-STRING
+def next?
+  File.basename(__FILE__) == "Gemfile.next"
+end
+        STRING
+      end
+
+      File.open('Gemfile', 'r') do |original|
+        File.open('Gemfile.tmp', 'a') do |temp|
+          temp.write(original.read)
+        end
+      end
+
+      File.rename('Gemfile.tmp', 'Gemfile')
+    end
+
+    def create_sym_link
+      File.symlink('Gemfile', 'Gemfile.next')
+    end
+
+    def copy_gemfile_lock
+      FileUtils.cp('Gemfile.lock', 'Gemfile.next.lock')
+    end
+
+    def message
+      <<-MESSAGE
+Created Gemfile.next (a symlink to your Gemfile). Your Gemfile has been modified to support dual-booting!
+
+There's just one more step: modify your Gemfile to use a newer version of Rails using the \`next?\` helper method.
+
+For example, here's how to go from 5.2.8.1 to 6.0.6.1:
+
+if next?
+  gem "rails", "6.0.6.1"
+else
+  gem "rails", "5.2.8.1"
+end
+      MESSAGE
+    end
+  end
+end

spec/next_rails/init_spec.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'fileutils'
+
+RSpec.describe NextRails::Init do
+  let(:gemfile_content) { "source 'https://rubygems.org'\ngem 'rails'\n" }
+
+  before(:all) do
+    FileUtils.cp('Gemfile', 'Gemfile.original')
+  end
+
+  after(:all) do
+    FileUtils.cp('Gemfile.original', 'Gemfile')
+    FileUtils.rm_f('Gemfile.original')
+  end
+
+  before do
+    FileUtils.rm_f('Gemfile')
+    FileUtils.rm_f('Gemfile.lock')
+    FileUtils.rm_f('Gemfile.next')
+    FileUtils.rm_f('Gemfile.next.lock')
+  end
+
+  after do
+    FileUtils.rm_f('Gemfile')
+    FileUtils.rm_f('Gemfile.lock')
+    FileUtils.rm_f('Gemfile.next')
+    FileUtils.rm_f('Gemfile.next.lock')
+  end
+
+  describe '.call' do
+    it 'already has next Gemfile files' do
+      File.write('Gemfile', gemfile_content)
+      FileUtils.touch('Gemfile.lock')
+      File.write('Gemfile.next', gemfile_content)
+
+      expect(described_class.call).to eq('The next_rails --init command has already been run.')
+    end
+
+    it 'does not have Gemfile files' do
+      expect(described_class.call).to eq('You must have a Gemfile and Gemfile.lock to run the next_rails --init command.')
+    end
+
+    it 'creates Gemfile.next and Gemfile.next.lock' do
+      File.write('Gemfile', gemfile_content)
+      FileUtils.touch('Gemfile.lock')
+
+      expect do
+        described_class.call
+      end.to change { File.exist?('Gemfile.next') }.from(false).to(true)
+         .and change { File.exist?('Gemfile.next.lock') }.from(false).to(true)
+    end
+
+    it 'returns a success message' do
+      File.write('Gemfile', gemfile_content)
+      FileUtils.touch('Gemfile.lock')
+
+      message = described_class.call
+      expect(message).to include('Created Gemfile.next (a symlink to your Gemfile).')
+      expect(message).to include("For example, here's how to go from 5.2.8.1 to 6.0.6.1:")
+    end
+  end
+end