Add support for git init --initial-branch=main argument (#539)

Signed-off-by: Jon Dufresne <jon.dufresne@gmail.com>

lib/git.rb

@@ -212,6 +212,9 @@ def self.global_config(name = nil, value = nil)
   #   `"#{directory}/.git"`, create a bare repository at `"#{directory}"`.
   #   See [what is a bare repository?](https://git-scm.com/docs/gitglossary#Documentation/gitglossary.txt-aiddefbarerepositoryabarerepository).
   #
+  # @option options [String] :initial_branch Use the specified name for the
+  #   initial branch in the newly created repository.
+  #
   # @option options [Pathname] :repository the path to put the newly initialized
   #   Git repository. The default for non-bare repository is `"#{directory}/.git"`.
   #

lib/git/base.rb

@@ -34,7 +34,10 @@ def self.init(directory, options = {})
 
       FileUtils.mkdir_p(options[:working_directory]) if options[:working_directory] && !File.directory?(options[:working_directory])
 
-      init_options = { :bare => options[:bare] }
+      init_options = {
+        :bare => options[:bare],
+        :initial_branch => options[:initial_branch],
+      }
 
       options.delete(:working_directory) if options[:bare]
 

lib/git/lib.rb

@@ -71,10 +71,12 @@ def initialize(base = nil, logger = nil)
     # options:
     #   :bare
     #   :working_directory
+    #   :initial_branch
     #
     def init(opts={})
       arr_opts = []
       arr_opts << '--bare' if opts[:bare]
+      arr_opts << "--initial-branch=#{opts[:initial_branch]}" if opts[:initial_branch]
 
       command('init', arr_opts)
     end

tests/units/test_init.rb

@@ -38,6 +38,7 @@ def test_git_init
       assert(File.directory?(File.join(path, '.git')))
       assert(File.exist?(File.join(path, '.git', 'config')))
       assert_equal('false', repo.config('core.bare'))
+      assert_equal("ref: refs/heads/master\n", File.read("#{path}/.git/HEAD"))
     end
   end
 
@@ -61,6 +62,16 @@ def test_git_init_remote_git
     end
   end
 
+  def test_git_init_initial_branch
+    in_temp_dir do |path|
+      repo = Git.init(path, initial_branch: 'main')
+      assert(File.directory?(File.join(path, '.git')))
+      assert(File.exist?(File.join(path, '.git', 'config')))
+      assert_equal('false', repo.config('core.bare'))
+      assert_equal("ref: refs/heads/main\n", File.read("#{path}/.git/HEAD"))
+    end
+  end
+
   def test_git_clone
     in_temp_dir do |path|
       g = Git.clone(@wbare, 'bare-co')