Changing 'rails new' --master to be --main

Renaming test containing flag

Updating other test referencing master branch

Add notice that --master is deprecated, but still working the same as --main

Only set @main if it's nil

Making warn wildcard

I think a hidden aliaes would be just as good

Improving description & fixing rubocop error

Forgot comma

Deprecation warning was kind of hard - so just doing alias for now

rubocop -a

railties/lib/rails/generators/app_base.rb

@@ -97,7 +97,7 @@ module Rails
         class_option :edge,                type: :boolean, default: false,
                                            desc: "Set up the #{name} with Gemfile pointing to Rails repository"
 
-        class_option :master,              type: :boolean, default: false,
+        class_option :main,                type: :boolean, default: false, aliases: "--master",
                                            desc: "Set up the #{name} with Gemfile pointing to Rails repository main branch"
 
         class_option :rc,                  type: :string, default: nil,
@@ -279,7 +279,7 @@ module Rails
           [
             GemfileEntry.github("rails", "rails/rails", "main")
           ]
-        elsif options.master?
+        elsif options.main?
           [
             GemfileEntry.github("rails", "rails/rails", "main")
           ]

railties/lib/rails/generators/rails/app/templates/Gemfile.tt

@@ -46,7 +46,7 @@ end
 group :development do
 <%- unless options.api? || options.skip_dev_gems? -%>
   # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
-  <%- if options.dev? || options.edge? || options.master? -%>
+  <%- if options.dev? || options.edge? || options.main? -%>
   gem 'web-console', github: 'rails/web-console'
   <%- else -%>
   gem 'web-console', '>= 4.1.0'

railties/lib/rails/generators/rails/plugin/templates/%name%.gemspec.tt

@@ -20,5 +20,5 @@ Gem::Specification.new do |spec|
 
   spec.files = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
 
-  <%= '# ' if options.dev? || options.edge? || options.master? -%>spec.add_dependency "rails", "<%= Array(rails_version_specifier).join('", "') %>"
+  <%= '# ' if options.dev? || options.edge? || options.main? -%>spec.add_dependency "rails", "<%= Array(rails_version_specifier).join('", "') %>"
 end

railties/lib/rails/generators/rails/plugin/templates/Gemfile.tt

@@ -2,7 +2,7 @@ source 'https://rubygems.org'
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
 <% if options[:skip_gemspec] -%>
-<%= '# ' if options.dev? || options.edge? || options.master? -%>gem 'rails', '<%= Array(rails_version_specifier).join("', '") %>'
+<%= '# ' if options.dev? || options.edge? || options.main? -%>gem 'rails', '<%= Array(rails_version_specifier).join("', '") %>'
 <% else -%>
 # Specify your gem's dependencies in <%= name %>.gemspec.
 gemspec

railties/test/generators/app_generator_test.rb

@@ -809,8 +809,8 @@ class AppGeneratorTest < Rails::Generators::TestCase
     end
   end
 
-  def test_web_console_with_master_option
-    run_generator [destination_root, "--master"]
+  def test_web_console_with_main_option
+    run_generator [destination_root, "--main"]
 
     assert_file "Gemfile" do |content|
       assert_match(/gem 'web-console',\s+github: 'rails\/web-console'/, content)
@@ -868,6 +868,14 @@ class AppGeneratorTest < Rails::Generators::TestCase
     assert_file "Gemfile", %r{^gem\s+["']rails["'],\s+github:\s+["']#{Regexp.escape("rails/rails")}["'],\s+branch:\s+["']main["']$}
   end
 
+  def test_main_option
+    generator([destination_root], main: true, skip_webpack_install: true)
+    run_generator_instance
+
+    assert_equal 1, @bundle_commands.count("install")
+    assert_file "Gemfile", %r{^gem\s+["']rails["'],\s+github:\s+["']#{Regexp.escape("rails/rails")}["'],\s+branch:\s+["']main["']$}
+  end
+
   def test_spring
     jruby_skip "spring doesn't run on JRuby"